Physiology

The process of melanin synthesis and distribution is called melanogenesis, a process that is based on melanocytes present among the basal cells of the epidermis. Pigments formed in melanocyte melanosomes are then stored in the basal layer of epidermal cells, as well as in dermal macro-phages, which become melanophores. From the embryological point of view, melanocytes derive from the melanoblasts of the neural crest, from where they migrate during the first months of life into the skin, eye, cochlea, bone, peripheral nervous system, heart and adipose tissue. The melanic pigments, eumelanin and pheomelanin, are the final product of complex biochemical reactions starting from the amino acid L-tyrosine. Melanin has a major role in skin homeostasis through the photoprotection it offers from the harmful effect of ultraviolet radiation. Melanin absorbs and/or reflects ultraviolet radiation but is also involved in the neutralizing process of free radicals and reactive oxygen species. Pigmentogenesis is a dependent oxygen process and is controlled by intrinsic factors (genetic and hormonal) as well as extrinsic factors (ultraviolet radiation). Melanogenesis is stimulated by stimulant melanocytic hormone, adrenocorticotropin hormone, estrogens and proges-terone. The present review aimed to provide a summary of recent data about melanogenesis physiology.

Our senses of touch and hearing are dependent on the conversion of external mechanical forces into electrical impulses by the opening of mechanosensitive channels in sensory cells. This remarkable feat involves the conversion of a macroscopic mechanical displacement into a subnanoscopic conformational change within the ion channel. The mechanosensitive channel NOMPC, responsible for hearing and touch in flies, is a homotetramer composed of four pore-forming transmembrane domains and four helical chains of 29 ankyrin repeats that extend 150 Å into the cytoplasm. Previous work has shown that the ankyrin chains behave as biological springs under extension and that tethering them to microtubules could be involved in the transmission of external forces to the NOMPC gate. Here we combine normal mode analysis (NMA), full-atom molecular dynamics simulations, and continuum mechanics to characterize the material properties of the chains under extreme compression and extension. NMA reveals tha...

Exercise has the potential to decrease negative side effects, lower societal medical costs, and increase quality of life. Exposure to physical exercise increased participation and led the way for a variety of pilot testing movement-based interventions with a diverse, rural, clinical mental health patient population in treatment for numerous clinical diagnoses. The original research (Reuille-Dupont, 2015) is briefly outlined before a discussion of theory used to determine and perform movement-based interventions for psychological and physical health goal treatments. Throughout the paper, psychological and exercise science theory and research are overlaid to explain the physical implications and psychological shifts of movement-based treatment. It is important to understand common terminology to engage clients and other health care practitioners in movement-based treatment for psychological and physical health. In addition, as specialists in understanding the body’s role in experience, it is the somatic psychologist’s responsibility to promote and advocate for “exercise as medicine” when possible. Included are visuals to help outline and overlap the disciplines for better understanding, increased awareness, and expanding the language somatic psychologists need to engage in multidisciplinary healthcare teams.

Keywords: physical movement treatment, movement for mental health, exercise science, somatic psychology

The effect of 5-aminoimidazole-4-carboxamide-ribonucleoside (AICAR) activation of the AMP-activated protein kinase (AMPK) on the transport of the model radiolabeled dipeptide [3H]-D-Phe-L-Gln was investigated in the human epithelial colon cancer cell line Caco-2. Uptake and transepithelial fluxes of [3H]-D-Phe-L-Gln were carried out in differentiated Caco-2 cell monolayers, and hPepT1 and glucose transporter 2 (GLUT2) protein levels were quantified by immunogold electron microscopy. AICAR treatment of Caco-2 cells significantly inhibited apical [3H]-D-Phe-L-Gln uptake, matched by a decrease in brush-border membrane hPepT1 protein but with a concomitant increase in the facilitated glucose transporter GLUT2. A restructuring of the apical brush-border membrane was seen by electron microscopy. The hPepT1-mediated transepithelial (A-to-B) peptide flux across the Caco-2 monolayers showed no significant alteration in AICAR-treated cells. The electrical resistance in the AICAR-treated monol...

Perforated whole-cell patch-clamp recordings obtained with nystatin are frequently used to preserve intracellular integrity. However, the perforated-patch configuration may sometimes undergo a spontaneous change into the conventional whole-cell configuration, especially when lymphocytes are investigated. The electrophysiological criteria-- previously described--for establishing the existence of the perforated whole-cell configuration have been shown to be insufficient. Thus, the dye eosin, applied to the pipette solution, was tested as a tool for discriminating between the perforated and the conventional whole-cell configurations on rat T-lymphocytes. The dye never entered the cell from the pipette during the entire measurement in the perforated whole-cell configuration. In contrast, all cells in the conventional whole-cell configuration became red immediately after membrane rupture. Eosin barely changed the currents studied. The results suggest that eosin is a dye of choice for verifying a true perforated-patch configuration.

Soccer is an intermittent team-sport, where performance is determined by a myriad of psychological, technical, tactical, and physical factors. Among the physical factors, endurance appears to play a key role into counteracting the fatigue-related reduction in running performance observed during soccer matches. One physiological determinant of endurance is movement economy, which represents the aerobic energy cost to exercise at a given submaximal velocity. While the role of movement economy has been extensively examined in endurance athletes, it has received little attention in soccer players, but may be an important factor, given the prolonged demands of match play. For this reason, the current review discusses the nature, impact, and trainability of movement economy specific to soccer players. A summary of current knowledge and limitations of movement economy in soccer is provided, with an insight into future research directions, to make this important parameter more valuable when assessing and training soccer players' running performance.

Özet
Bu çalışmada; Hekimbaşı Mustafa Behçet Efendi tarafından İtalyanca aslından Türkçeye “Tercüme-i Fisiologica”
ismiyle tercüme edilen ve Esin Kâhya’nın günümüz Türkçesine aktarımı olan “Mustafa Behçet Efendi ve Türkçe İlk
Fizyoloji Kitabı” isimli eser ele alınarak, uyku ve uyanıklık bölümü günümüz bilgileri ile karşılaştırılmıştır. Mustafa
Behçet Efendi (1774-1834), Hekimbaşı olarak görev yapmış ve ilk Türkçe fizyoloji kitabını (Tercüme-i Fisiologica)
İtalyan bilim adamı Caldani (1725–1813)’nin Fisiologica adlı eserinden tercüme etmiştir. Mustafa Behçet Efendi Tercüme-
i Fisiologica’da uyanıklığı beş duyu ve görünmeyen hislerin faal halde olması durumu olarak tarif etmektedir.
Uykusuzluk halinde yorgunluk baş gösterir ve sağlıklı kişi 16-18 saat uykusuz kalabilmektedir. Bu durumda nabzın
hareketi daha gergin olur ve solunum hızı da artar. Uykusuzluk daha uzun sürerse, vücutta gevşeme, kavrama kabiliyetinde
düşüş, solunumda yavaşlama ve göz kapaklarının kapandığı gözlemlenir. Uykunun normal vakti yakın
olduğunda vücut hisseder, genel olarak uyuşukluk his olunur ve özellikle uzun kaslarda çok daha fazla hissedilip
kavrama kabiliyeti kaybolur. Uykuyu getiren şeyler arasında; kan kaybı, serinletici ilaçlar, afyon, baş ve ayağa su
uygulanması, çok yemek yemek, sıcak ilaçlar, sindirimi güç besinler, doğrudan veya dolaylı olarak kuvvetsizlik veren
her şey tabii olmayan bir uykuya sebep olur. Uykuda, istemli kaslar istirahate çekilir. Uykuda solunum hafifler,
nabız yavaşlar, sindirimde besinlerin emilimi hızlanır, sinir sisteminde hissizlik oluşur. Uyku vakti geçip, uyanıklık
yaklaştıkça insan ya isteyerek uyanır yahut duyuların bazısının hareketleri vasıtasıyla uyanma olur. Uyanıklığın
uzun sürmesinden dolayı kuvvetten düşmeyle ilgili olarak hastalıklar ortaya çıkar. Rüya tam olan uykuda görülmeyip,
muhtemelen iyi uyuyamayıp, uykusuzluğa yakın bir halde, yan tarafa yatmış ve sırt üstü yatanlarda görülür. Uyku
ve uykusuzluğun fazlası daima kötü belirtilerdendir. Uzun uykusuzluk; hezeyan, delilik ve spazm meydana getirir ve
şiddetli hastalıklardan yorgunluk ve takatsizliğe sebep olan uyku tehlikelidir. Rahat ve huzur veren iyi uykudur ve sıhhat
verir ve hezeyan ve deliliğin şiddetini yatıştıran uyku iyi belirtilerdendir. Mustafa Behçet Efendi’nin geleneksel tıp
bilgilerini de aktararak yazdığı fizyoloji kitabında çoğu bilimsel önermenin doğruluğunun zamanla ispatlanmış olması
dikkate değerdir. Özellikle uykudan uyanmada duyuların rolünü, uykuya meyilde inhibitör alanların hâkimiyetini,
istemli kasların REM uykusundaki atoni halini ve uyku-uykusuzluğun etkilerini çok güzel açıklamıştır. Dönemindeki
bilgi birikimi ve teknolojik imkânlarla yazılan bu kitapta uyku fizyolojisine ayrıca yer verilmesi de bir başka önemli
noktadır.

Population of loggerhead turtles nesting in the Mediterranean Sea has probably evolved from the North Atlantic (NA) population, but is geographically and genetically distinct. We aggregated previously published and new unpublished data, and took two approaches to comparing these populations: an empirical one based on statistical analyses of morphological data, and a physiological one based on a Dynamic Energy Budget (DEB) model. We then analyzed causes of faster growth and maturation, but smaller size at puberty and ultimate size of the Mediterranean (MED) loggerhead turtles relative to their NA conspecifics. The empirical analysis showed that young juvenile, sexually mature, and fully grown MED individuals were consistently smaller in terms of length and mass. The physiological approach suggested physiological adaptations of the MED population to higher salinity and scarcer food availability. In particular, these adaptations included an increase in somatic maintenance needs, and a decrease in energy investment to reach and maintain sexual maturity. Our study therefore offers a mechanistic underpinning of previously observed but unexplained life-history traits, and showcases an application of DEB theory as a tool for comparative analysis of two distinct populations of the same species.

Idiopathic pulmonary fibrosis (IPF) is thought to involve inflammatory infiltration of leukocytes, lung injury induced by reactive oxygen species (ROS), in particular superoxide anion, and fibrosis (collagen deposition). No treatment has been shown to improve definitively the prognosis for IPF patients. Superoxide dismutase (SOD) catalyzes the dismutation of superoxide anion to hydrogen peroxide, which is subsequently detoxified by catalase. Lecithinized SOD (PC-SOD) has overcome clinical limitations of SOD, including low tissue affinity and low stability in plasma. In this study, we examined the effect of PC-SOD on bleomycin-induced pulmonary fibrosis. Severity of the bleomycin-induced fibrosis in mice was assessed by various methods, including determination of hydroxyproline levels in lung tissue. Intravenous administration of PC-SOD suppressed the bleomycin-induced increase in the number of leukocytes in bronchoalveolar lavage fluid. Bleomycin-induced collagen deposition and incr...

Unusual regions of densely packed membranous tubules known as tubular aggregates (TAs) have been observed in skeletal muscle fibres of mammals under numerous pathological conditions but also in health. Their causality is unclear. It is neither known whether TAs are destructive and should be treated or whether they have a compensating function in an endangered muscle. In spite of many similarities, the histochemical, immunocytochemical and ultrastructural characteristics of tubular aggregates do vary. Histochemistry provided an overall characteristic of TAs as membranous inclusions with a variety of enzymatic activities. Immunocytochemical evidence revealed that tubular aggregates contain miscellaneous proteins and that derive from membranes of sarcoplasmic reticulum and mitochondria. No evidence for the presence of contractile and cytoskeletal proteins in TAs was found. Ultrastructurally, TAs are characterized as more or less densely packed aggregates of vesicular or tubular membran...

Background: Aerobic and intense exercises with an increase in free radicals cause damages at the cellular level, heart disease, cancer, and the development of aging processes, which one of its symptoms is increased serum concentrations of liver enzymes. Objective: The purpose of this study was to investigate the concurrent effect of four weeks of aerobic training and propolis supplementation on the activity of liver enzymes, including ALT, AST, and SOD in endurance athletes. Methods: Thirty-two male athletes (age: 21±1.4 years) in track and field were randomly divided into three groups: exercise group, exercise with placebo group, and exercise with supplement group. Propolis supplementation was taken as two tablets (500 mg) twice a day and aerobic exercise was performed for 4 weeks and in 24 sessions with an intensity of 60 to 65% of heart rate. The statistical method was done using one-way ANOVA and Tukey post hoc test by SPSS v. 18 software. Findings: The results showed that there was a statistically significant difference between groups in serum levels of SOD, AST, and ALT (P<0.05). There was not a statistically significant difference between the exercise group and placebo+exercise group in serum levels of SOD, AST, and ALT (P>0.05). Conclusion: The results showed that aerobic exercise alone can increase SOD levels and propolis supplementation with aerobic exercise can reduce AST and ALT serum levels and lead to improved liver cell function.

Parathyroid hormone-related protein (PTHrP) is the major mediator of the humoral hypercalcemia of malignancy and of malignant osteolysis associated with skeletal metastases of common epithelial cancers. PTHrP secretion is regulated by the extracellular calcium concentration ([Ca(2+)](o)) in several types of normal and malignant cells. Because the [Ca(2+)](o)-sensing receptor (CaR) is a key mediator of [Ca(2+)](o)-regulated hormone secretion [e.g., of parathyroid hormone (PTH) by parathyroid chief cells], we investigated the expression of the CaR and PTHrP in normal and neoplastic glial cells and studied the effects of [Ca(2+)](o) on PTHrP secretion. Our results show that primary embryonic human astrocytes (HPA) express CaR mRNA and protein as detected by RT-PCR and Western analysis, respectively. Furthermore, astrocytomas and meningiomas also express the CaR at similar levels as assessed by RT-PCR and Northern and Western blot analyses. HPA and astrocytomas express transcripts encod...

The Association of American Medical Colleges has encouraged educators to investigate proper linkage of simulation experiences with medical curricula. The authors aimed to determine if student knowledge and satisfaction differ between participation in web-based and manikin simulations for learning shock physiology and treatment and to determine if a specific training sequencing had a differential effect on learning. All 40 second-year medical students participated in a randomized, counterbalanced study with two interventions: group 1 ( n = 20) participated in a web-based simulation followed by a manikin simulation and group 2 ( n = 20) participated in reverse order. Knowledge and attitudes were documented. Mixed-model ANOVA indicated a significant main effect of time ( F1,38 = 18.6, P &lt; 0.001, ηp2 = 0.33). Group 1 scored significantly higher on quiz 2 (81.5%) than on quiz 1 (74.3%, t19 = 3.9, P = 0.001), for an observed difference of 7.2% (95% confidence interval: 3.3, 11.0). Mean...

We investigated whether spiders fed lipid-rich rather than protein-rich prey elevate metabolism to avoid carrying excessive lipid deposits, or whether they store ingested lipids as a buffer against possible future starvation. We fed wolf spiders (Pardosa prativaga) prey of different lipid:protein compositions and measured the metabolic rate of spiders using closed respirometry during feeding and fasting. After a 16-day feeding period, spider lipid:protein composition was significantly affected by the lipid:protein composition of their prey. Feeding caused a large and fast increase in metabolism. The cost of feeding and digestion was estimated to average 21% of the ingested energy irrespective of diet. We found no
difference in basal metabolic rate between dietary treatments. During starvation ˙VO2 and ˙VCO2 decreased gradually, and the larger lipid stores in spiders fed lipid-rich prey appeared to extend survival of these spiders under starvation compared to spiders fed protein-rich prey. The results show that these spiders do not adjust metabolism in order to maintain a constant body composition when prey nutrient composition varies. Instead, lipids are stored efficiently and help to prepare the spiders for the long periods of food deprivation that may occur as a consequence of their opportunistic feeding strategy.