The effect of 12-month participation in osteogenic and non-osteogenic sports on bone development in adolescent male athletes. The PRO-BONE study

Objectives

Research investigating the longitudinal effects of the most popular sports on bone development in adolescent males is scarce. The aim is to investigate the effect of 12-month participation in osteogenic and non-osteogenic sports on bone development.

Horloge interne,sommeil et médias électroniques : le comportement à risque des adolescents

The internal clock located in the suprachiasmatic nuclei of the hypothalamus is controlled by genetic factors (clock genes) and environmental factors (light-dark and sleep-wake alternations). Light is the major component of the clock control. Clock desynchronization occurs when the internal clock is no longer in phase with the environment resulting in a phase shift (phase advance or phase delay depending of the time of exposure to light). An increasing number of children and adolescents are experiencing chronic exposure to light at night due to misuse, including late at night, of electronic media. This results in a clock desynchronization, i.e. a shift of the clock circadian phase (which is delayed with exposure to light at night) with concomitant health issues: disturbances of sleep which is both shortened and delayed, mood alterations, fatigue etc. This risky behavior of children and adolescents is becoming a public health issue.     

Factors related to memory absence and delusional memories in patients in intensive care units managed with light sedation

ObjectivesCurrently, light sedation is typically given to patients in intensive care units and studies have not extensively examined the factors related to absences or abnormalities of their memories. We, therefore, analysed the factors related to the absence/abnormalities of patients’ memories in intensive care units.Research MethodologyA secondary analysis of previously collected survey data examining patients’ experiences in an intensive care unit was undertaken (n = 405; women = 38%; median age = 70 years). To observe absent or distorted memories, patients were interviewed after leaving the intensive care unit. We analysed key factors through content analysis of the interviews and field notes.SettingThe intensive care unit of a university hospital. Main outcome measure: Patients’ absent or distorted memories after leaving the intensive care unit.ResultsHalf the patients reported an absence of memories. This was associated with old age and with longer duration of mechanical ventilation. Absent or fragmentary memories were not distressing. Fragmentary and fearful intensive care unit memories were associated with being older. Delusional memories, some of which reflected actual events, were present in 3% of patients.ConclusionAbsence of memories were not distressing, delusional memories occurred less and these memories could comprise of an event in ICU that is difficult for patients to understand.     

Innate antibody catalysis

Catalysis by antibodies is often assumed to require immunization with artificial haptens, which are proposed to stimulate adaptive immune processes and enable the development of catalytic sites with the ability to bind the transition state. Contrary to this assumption, we describe here a serine protease-like catalytic triad in an antibody light chain raised by immunization with vasoactive intestinal peptide (VIP), the structure and function of which is inherited via a germline V_L gene. The serine protease mechanism was evident from loss of the catalytic activity by site directed mutagenesis at a framework region residue Asp1 (present study) and at two complementarity determining region residues Ser27a and His 93 (Gao, Q-S., Sun, M., Rees, A., Paul, S., 1995. Site-directed mutagenesis of proteolytic antibody light chain. J. Mol. Biol. 253, 658–664). All three catalytic residues (Ser27a, His93, Asp1) are also present in the germline counterpart of the mature V_L gene, but the mature and germline sequences differ by four amino acids remote from the catalytic site. Reversion mutations were introduced at these amino acids in the mature light chain (His27 d:Asp, Thr28e:Ser, Ile34:Asn, Gln96:Trp; Kabat numbering, germline encoded residues shown second), generating the germline configuration of the protein. The germline light chain expressed peptidase activity, determined by assaying the cleavage of VIP and a synthetic protease substrate, Pro–Phe–Arg–Methylcoumarinamide. Differences between the kinetic constants for the mature and germline light chains were marginal. Diisopropylfluorophosphate, a serine protease inhibitor, blocked the peptidase activity of the germline light chain, suggesting the presence of the catalytic triad in a functional state. Like the mature light chain, the germline protein preferentially cleaves peptide bonds on the C-terminal side of basic residues. We conclude that the catalytic activity of certain antibodies is an innate function, originating over the course of phylogenetic evolution of the V_L genes, as opposed to somatic processes.     

Zur histogenese und cytogenese des tapetum lucidum cellulosum der katze

Zusammenfassung Die postnatale Entwicklung des Tapetum lucidum cellulosum der Katze wird mit licht- und elektronenmikroskopischen Methoden untersucht. Bereits am ersten postnatalen Tag sind im Bereich des prospektiven Tapetum zwei Zellarten voneinander zu unterscheiden: 1. mesenchymale Bindegewebszellen und 2. prospektive Tapetumzellen, die durch elektronendichte Tapetumstäbchen gekennzeichnet sind. Die Mesenchymzellen unterteilen als parallel zur Retinaoberfläche ausgebreitete Zellplatten in der Choriodea am hinteren Augenpol den weiten extracellulären Raum in 20–25 etwa 5 m hohe Schichten. Die Tapetumzellen liegen zwischen den Mesenchymzellplatten und wachsen im Verlaufe der ersten vier postnatalen Wochen innerhalb der Schichten in die Breite, bis sie den extracellulären Raum vollständig ausfüllen und als polygonale Zellen direkt aneinander grenzen. Im weiteren Verlauf der Entwicklung werden die Mesenchymzellplatten rückgebildet, so daß bei der adulten Katze die Tapetumzellschichten direkt übereinander liegen und nur von Netzen elastischer und kollagener Fasern getrennt sind.Die von einer Elementarmembran umgebenen Tapetumstäbchen enthalten einen elektronendichten, in den ersten postnatalen Wochen mit einer Periode von 100 Å quergestreiften Kern. Zunächst nehmen sie an Zahl und Länge zu und füllen am Ende der vierten postnatalen Woche, zu Bündeln von parallel verlaufenden Stäbchen geordnet, das Cytoplasma der Tapetumzellen. Dann nehmen die Tapetumstäbchen an Dicke zu, und ihre Querstreifung wird von einem elektronendichten Material überlagert. Die Entwicklung der Tapetumstäbchen hat eine starke Ähnlichkeit mit der in der Literatur beschriebenen Entwicklung von Melanosomen in Melanocyten. Das Tapetum lucidum cellulosum wird als ein dichter Verband hochdifferenzierter extrakutaner Melanocyten angesehen.

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Summary The postnatal development of the tapetum lucidum cellulosum of the cat was studied by light and electron microscopy. Already by the first postnatal day two cell types can be distinguished in the prospective tapeta area: 1. mesenchymal cells and 2. prospective tapetal cells, characterized by electron dense, membrane bound, rod-like inclusions. The flattened mesenchymal elements form 20–25 separate layers of cells, which are arranged parallel to the surface of the retina, subdividing the extracellular space of the chorioidea at the posterior pole of the eye into 5 m high compartments. These compartments contain the tapetal cells which enlarge (in their longitudinal axis) during the first four weeks post partum until they occupy the extracellular space almost completely. At this stage, the tapetal cells are polygonal in shape and closely attached to each other. During the subsequent period of development there is a gradual involution of the mesenchymal cell plates. Thus, in adult cats the individual layers of tapetal cells are only separated from each other by networks of collagen and elastic fibers.The tapetal rods are bound by unit membranes and contain an electron dense core which, during the early postnatal weeks, exhibits a periodic cross-striation (100 Å). The tapetal rods increase in number and length during the first four weeks post partum; by the end of the fourth week, they occupy the whole cytoplasm of the tapetal cells. Parallelly arranged rods are grouped into individual bundles coursing inside the cytoplasm in different directions. Thereafter, the tapetal rods increase in thickness and their cross-striation becomes obscured by an electron dense material. This development of the tapetal rods closely resembles that of melanosomes.Thus the tapetum lucidum cellulosum can be regarded as a compact tissue made up of modified extracutaneous melanocytes.

Auszugsweise vorgetragen auf der 69. Versammlung der Anatomischen Gesellschaft in Kiel, Juni 1974.     

Chronic cocaine treatment induces dysregulation in the circadian pattern of rats' feeding behavior

The effects of protracted cocaine administration (15 mg/kg i.p., twice a day for 9 days) on the circadian pattern of feeding behavior was studied in individually housed male Sprague-Dawley rats, maintained under a 12:12 light:dark cycle. Water and food were available ad libitum and food intake was measured twice a day before, during and after withdrawal of cocaine (or saline) treatment. Neither total 24-h food intake, nor body mass at the end of the experiment, was significantly different between cocaine-treated and control animals. However, cocaine administration affected the temporal distribution of food consumption. During the dark (activity) phase, rats receiving cocaine injections consumed significantly less food than control animals, and this effect persisted for up to 3 days of cocaine withdrawal. During the light (rest) phase, cocaine administration promoted food consumption and a significantly higher food intake was also observed during the first five cocaine withdrawal days. Continuous monitoring of locomotor activity did not reveal significant changes in the circadian pattern of activity between the two experimental groups during different treatment periods, except for an acute increase in locomotion within an hour after daytime cocaine injection. The results of this study demonstrate that sub-chronic cocaine administration alters the circadian pattern of rats' feeding behavior.     

Electrophoretic analysis of multiple forms of rat cardiac myosin: Effects of hypophysectomy and thyroxine replacement

Electrophoretic analysis in pyrophosphate gels of intact myosin of adult rat myocardium revealed the presence of five distinct components, two in atrial myosin (A₁, A₂) and three in ventricular myosin (V₁, V₂, V₃). Analysis of Ca²⁺-activated myosin ATPase activity in the gels revealed that A₁, A₂ and V₁ had about the same specific activity; V₃ had the lowest activity, while that of V₂ was intermediate. At 3 weeks of age, ventricular myosin was exclusively V₁, there being a slow age-dependent shift in myosin distribution toward the adult pattern. Hypophysectomy of juvenile rats caused a shift towards V₃, which by 45 days after operation accounted for 90% of total myosin. This shift was prevented by daily administration of 5 μg of thyroxine. When chronically hypophysectomized rats were similarly treated, there was a rapid shift of myosin components towards V₁. These changes in distribution of myosin components were associated with appropriate changes in Ca²⁺-activated ATPase activity of electrophoretically purified ventricular myosin as measured in the gel. Sodium dodecyl sulphate gel analysis of purified myosin showed little or no contaminants. For both V₁ and V₃ rich myosins, the ratio of the two ventricular light chains (V-LC₁, V-LC₂) and the ratio of light chains to heavy chains are consistent with the model that each intact molecule contains two each of V-LC₁ and V-LC₂. Sodium dodecyl sulphate electrophoresis of purified atrial myosin revealed two types of light chains: A-LC₁ (mol. wt 27 000, not resolved from V-LC₁) and A-LC₂ (mol. wt 22 000), the latter being distinct from V-LC₂.     

Acute effects of light and darkness on sleep in the pigeon (Columba livia)

In addition to entraining circadian rhythms, light has acute effects on sleep and wakefulness in mammals. To determine whether light and darkness have similar effects in birds, the only non-mammalian group that displays sleep patterns comparable to mammals, we examined the effects of lighting changes on sleep and wakefulness in the pigeon. We quantified sleep behavior (i.e., bilateral or unilateral eye closure) in pigeons maintained under a 12:12 LD cycle, and immediately following a change from a 12:12 to a 3:3 LD cycle. During both LD cycles, sleep was most prevalent during dark periods. During the 3:3 LD cycle, darkness had the greatest sleep promoting effect during the hours corresponding to the subjective night of the preceding 12:12 LD cycle, whereas light suppressed sleep across circadian phases. As previously suggested, the light-induced decrease in sleep in the subjective night might be partly mediated by the suppression of melatonin by light. Although the sleep promoting effect of darkness was modulated by the circadian rhythm, sleep in darkness occurred during all circadian phases, suggesting that darkness per se may play a direct role in inducing sleep. In addition to the effects of lighting on behavioral state, we observed an overall bias toward more right eye closure under all lighting conditions, possibly reflecting a response to the novel testing environment.     

The effect of salbutamol on performance in endurance cyclists

The effect of salbutamol (S) on cycling performance was examined in 15 highly trained non-asthmatic male cyclists. A double-blind, randomized cross-over design was used with S or placebo (P) administered using a metered-dose inhaler and a spacer device 20 min before each testing session. The S dose was 400 μg (four puffs), which is twice the normal therapeutic level. Subjects were habituated to all the laboratory procedures in the week prior to actual data collection. The subjects performed four tests under S and P conditions on separate days over 2 weeks. These included measurement of maximal O₂ uptake (cycle ergometry) with assessment of pulmonary function before and after, a submaximal (90% of ventilatory threshold) square-wave work transition from a base of unloaded cycling, a 60-s modified Wingate test, and a simulated 20 km time trial. No significant differences were observed in any of the dependent variables related to aerobic endurance or cycling performance between the S and P conditions. These results support other findings that an acute dose (400 μg) of S has no performance-enhancing properties.     

从兔外周血直接克隆B细胞κ轻链的可变区

目的 从兔外周血总RNA中直接扩增出B细胞κ轻链的可变区序列.方法 首先从IMGT/GENE-DB数据库中获取大耳白兔Ig胚系基因Vκ(IGKV)、Jκ(IGKJ)和Cκ(IGKC)的cDNA序列、设计引物,然后以非免疫兔外周血总RNA为模板进行RT-PCR扩增,回收产物并克隆到T载体,随机挑选单克隆测序,最终将序列提交到IMGT/V-QUEST,分析出每个克隆的Vκ-Jκ组合,并利用BioEdit的本地Blast程序比较出Cκ的基因型.结果 共设计出4对引物,其中引物对RK.C1[4-5-9]无产物,引物对RK.C1[1-2-7]、RK.C1[3-6-8]和RK.C2[1-2-3-4]有产物,分别回收、克隆到T载体后各挑取20个克隆,共获得51个克隆的插入子序列.没有任何2个克隆的插入子序列完全相同,每个克隆均包含完整的兔Vκ、Jκ及Cκ的5'端序列,其中Vκ-Jκ-IGKC1组合的克隆33个,Vκ-Jκ-IGKC2组合的克隆18个;68个Vκ胚系基因中有22个出现,其中频率最高的是IGKV1S10*01(12次),其次是IGKV1S36*01、IGKV1S37*01和IGKV1S4*01(各5次),其余均为3次以下;8个Jκ胚系基因中只有1个出现,为IGKJ1-2*01;2个Cκ基因的等位基因分别为IGKC1*01和IGKC2*03.33个Vκ-[IGKJ1-2*01]-[IGKC1*01]克隆中有17种不同的组合方式,其中频率最高的为[IGKV1S10*01]-[IGKJ1-2*01]-[IGKC1*01](7次).18个Vκ-[IGKJ1-2*01]-[IGKC2*03]克隆中有11种不同的组合方式,频率最高的为[IGKV1S10*01]-[IGKJ1-2*01]-[IGKC2*03](5次).Vκ-Jκ-Cκ组合方式相同的克隆,序列仍具有明显的差异.结论 利用自行设计的兼并引物,成功并特异地从兔外周血总RNA中直接扩增出了κ轻链的可变区,且产物具有良好的多样性,但所有Vκ-Jκ-Cκ组合中只出现了1种Jκ基因.