Analysis of elastin gene expression in the developing chick aorta using cloned elastin cDNA

A segment of chick elastin cDNA cloned in the plasmid pBR322 was sequenced by the method of Maxam and Gilbert ((1977) Proc. Natl. Acad. Sci. U. S. A. 74, 560-564) and the 192-base pair insert was found to be derived from the nontranslated region of the 3' end of the mRNA. The nick-translated cDNA was used to identify and to estimate the relative amounts of elastin mRNA in the developing chick embryo aorta by blot hybridization. A single species of 3.5 kilobases hybridized to the cDNA probe and this species increased greatly between day 7 and day 14 of embryonic development. This increase was paralleled by an increase in translatable aortic elastin mRNA and by the in vivo rate of elastin synthesis, demonstrating that the change in synthesis during development is largely controlled by the elastin mRNA content of the aorta.     

Collagen and elastin synthesis by desmoid tumor in vitro

In order to characterize human desmoid tumors in vitro, the production of collagen and elastin and the expression of collagen types alpha1(I), alpha1(III) and transforming growth factor (TGF)-beta1 mRNA were investigated in six desmoid tumors; five derived from familial adenomatous polyposis patients and one from a sporadic case. The proportion of collagen production to total protein production was determined by 3H-imino acid incorporation, an indicator of collagen synthesis, using high-performance liquid chromatography (HPLC). The proportion of collagen production to total protein production was much higher in all six desmoid tumors compared with human skin fibroblasts (HSF). Quantitatively, the rate of elastin synthesis in desmoid tumor cells monitored by valine-proline peptide was also significantly higher than in HSF. Pro-alpha1(I) collagen mRNA was highly expressed in both desmoid tumors and HSF at approximately the same level, whereas pro-alpha1(III) collagen mRNA was more abundant in some of the desmoid tumors than the normal skin fibroblastic cell lines. Tumor growth factor-beta1 mRNA, which is believed to stimulate collagen synthesis, was expressed in both desmoid tumors and HSF to the same extent. These results demonstrate the increased formation of collagen and elastin in desmoid tumors in vitro and suggest that the increased synthesis of elastin rather than of collagen and TGF-beta1 may be involved in increased fibrogenesis by desmoid tumors.     

Synthesis of elastin. A rapid formation of lysine-derived crosslinks by chick embryo aorta

Aortas of 13-day-old chick embryo were labeled for 0.5 hr with [14C]lysine and subjected to a serial extraction after chase for 1-24 hr with [12C]lysine. Substantial radioactivity was found in insoluble elastin after 3 hr chase. The effect of beta-amino-propionitrile on labeling with [14C]lysine was also examined. Each fraction was hydrolyzed and applied to a short column on an amino acid analyzer. Radioactivity was found in desmosine and isodesmosine of insoluble elastin as early as 1 hr after the beginning of chase. The radioactivity increased rapidly at 2 hr and very slowly thereafter. A large count, which was separated into five peaks on a long column, was observed in other lysine derivatives at 2 hr and increased steadily up to 24 hr, while the lysine count decreased from 1 : 0.5 to 1 : 6 against lysine derivatives and from 1 : 0.04 to 1 : 0.9 against quarter-desmosine after 24 hr. The oxidation of lysine residues incorporated during the 0.5 hr pulse was almost completed during the first 1 hr of chase, and these oxidized residues were incorporated into crosslinks during the following 1 hr. It is suggested that poorly crosslinked elastin accumulated in the soluble fractions. The presence of crosslinking derived from lysine residues was also indicated in the microfibril fraction.     

Insulin synthesis in chick embryo retinas during development

Retinas of chick embryos contain insulin and further, are capable of synthesizing it, as demonstrated by incubating retinas at different ages (7th-18th day) with [3H]leucine. The synthesized radioactive insulin was isolated and assayed by means of a HPLC procedure. The synthesis of insulin was found to be highest in the youngest retinas studied (day 7), afterwards it declined with age except for an increment found at 14-15 day. Explants of chick embryo retinas, cultured in vitro, rapidly degraded insulin. Nevertheless, the content of immunoreactive insulin in retinal explants diminished slowly with the age of culture, so that, after 8 days of incubation, it was about 60% of the content found in the retinas at the beginning of incubation. This was proof that cultured explants are capable of efficiently synthesizing insulin. The synthesized [3H]insulin was released from explants into the medium. This was evident also after 6-8 days in culture.     

Age-dependent improvement in passive avoidance learning of the young chick: Cholinergic mediation?

Studied cholinergic mediation of the age-dependent improvement in response suppression of the young chick by determining the performance of 144 Vantress?×?Arbor Acre 4-day-old chicks, pretreated with scopolamine (SCO), during passive avoidance (PA) and extinction testing. In Exp I, Ss were trained to keypeck for heat reward (prepunishment training), and then tested for PA learning under immediate, 2-sec-delayed, or no shock condition. Half of the Ss in each condition received saline injections before prepunishment training and .5 mg/kg SCO injections after training. The rest received .5 mg/kg SCO injections both before and after training. For Ss in both SCO groups, delaying shock onset resulted in significantly less response suppression than immediate response-contingent shock. In Exp II, 4-day-old Ss injected with saline or SCO were trained to keypeck for heat reward and then tested for resistance to extinction under response-contingent shock or nonshock conditions. Punishment decreased the number of extinction responses for both saline and SCO groups. Results indicte that the age-dependent improvement in response suppression of the young chick cannot be explained solely by a significant increase in central cholinergic functioning. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of the steady-state Na+ channel current in pacemaker depolarizations in young embryonic chick ventricular myocytes

Thresholds to noxious mechanical and thermal stimulation were measured in 6 groups of sheep prior to induction of anaesthesia and subsequently for a period of 2 h in the post-anaesthetic period. Groups 1-4 were anaesthetised using thiopentone and underwent ventral midline laparotomy. Four animals (group 5) underwent anaesthesia but not surgery, and a further 6 sheep (group 6) undergoing surgery were anaesthetised using ketamine. Groups 1-3 were intravenously administered the following drugs intra-operatively: flunixin meglumine, carprofen and buprenorphine, respectively. Groups 4-6 received no additional treatment. Thresholds to the mechanical test were not changed in the post-anaesthetic period for any group. There was a significant reduction in the responses to thermal stimulation after surgery for sheep in group 4 (45 and 60 min), while sheep in group 2 had thresholds to thermal stimulation greater than those recorded in the remaining groups at all time points post-operatively. Responses to thermal stimulation in sheep undergoing anaesthesia but not surgery (group 5) were unaltered during the 2 h recording period after anaesthesia ended. These data indicate that abdominal surgery induces thermal but not mechanical hyperalgesia in sheep, which appears to be centrally mediated. Moreover, the absence of mechanical hyperalgesia raises the possibility that central changes in noxious information processing may not be detected using mechanical stimuli in the same time course as thermal stimuli.     

Defining the rhythmicity of memory-enhancing acoustic stimuli in the young domestic chick (Gallus gallus).

Research has demonstrated that exposure to a rhythmic auditory stimulus can promote retention of a simple memory task in an avian species. In the current study, day-old domestic chicks (Gallus gallus) were trained on a weakly reinforced discriminative avoidance task for which retention is typically lost 30 min posttraining. Exposure to rhythmic stimuli 5 min posttraining prevented memory loss, but only when sequences were highly metrical and contained sufficient repetition. These data provide further support for the claim that rhythmicity is a key feature of memory-enhancing auditory stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Elevated nighttime activity of chick pineal ILOT channels requires protein synthesis

Free-running circadian rhythms in melatonin secretion persist in dissociated chick pineal cells. Calcium and cyclic AMP interact at several levels in the regulation of melatonin biosynthesis and secretion. Extracellular Ca2+ is required for optimal stimulation of melatonin secretion by cAMP analogues and protagonists. Increased Ca2+ influx during the circadian night is thought to play a role in the circadian clock regulation of melatonin secretion. We have recently described a nonselective cationic channel, ILOT, in chick pineal cells that is regulated by the intrinsic circadian oscillator. Active ILOT channels are detected only during the nighttime and may explain the nocturnal increase in Ca2+ influx. The mechanism by which the activity of ILOT is regulated by the circadian oscillator is not known. In the present study, the effect of the translational inhibitor anisomycin (10(-6) M) on the nighttime activity of ILOT channels was examined. The results show that protein synthesis is required for the detection of ILOT channel activity during the nighttime in cells maintained on light-dark cycles or constant dark conditions.     

Pharmacobehavioural evidence for nitric oxide and noradrenaline interactions with ryanodine receptors during memory formation in the young chick.

Impairment of nitric oxide (NO) production, ryanodine receptor (RyR) calcium channel function and adrenoceptor activation have been found to prevent the formation of the long-term memory stage in young chicks trained on a single-trial discrimination avoidance task. The current study investigated whether these three activities were linked, and if so, the sequence of activation. Young chicks were trained using either a strongly or weakly reinforced variant of the single-trial discrimination avoidance task, yielding either a persistent or labile memory trace, respectively. Following strongly reinforced training, retention loss induced by a RyR inhibitor was prevented by a NO donor or noradrenaline (NA). A RyR agonist also prevented retention loss induced by either NO synthase or β1+2-adrenoceptor inhibition. These findings were interpreted to reflect the capacity of NO, RyR-dependent calcium release and NA to modulate memory by preventing retention loss. A second set of studies used weakly reinforced training. Although the administration of a RyR agonist promoted long-term memory formation, this facilitation was compromised in the presence of a β1+2-adrenoceptor antagonist, but not a NO synthase inhibitor. Similarly, the inhibition of RyRs interfered with the facilitation of retention induced by a NO donor, but not NA. These differential findings with weakly reinforced training suggest that NO facilitates memory formation through mechanisms involving RyR-dependent calcium release. The findings also indicate that RyRs may promote memory formation through noradrenergic activation of β2-adrenoceptors. This study demonstrates an intricate role for RyRs underlying memory formation. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Protein synthesis inhibitors delay transneuronal death in the piriform cortex of young adult rats

It has been demonstrated that apoptotic cell death is an active process that is dependent on RNA and protein synthesis. The question remains as to whether neuronal death in adult, mammalian brains can also be demonstrated in vivo to be dependent on protein synthesis. To address this question we have analysed transneuronal death in the piriform (olfactory) cortex. Following unilateral olfactory bulb ablation in young adult rats, layer IIa of the piriform cortex undergoes rapid degeneration, that commences 12 h after ablation and that is almost complete at 48 h. In order to block protein synthesis, three to six subcutaneous injections of the short acting protein synthesis inhibitor anisomycin, were given at 2 h intervals beginning just before the ablation of the olfactory bulb. In other cases a single injection of the long acting protein synthesis inhibitor emetine were made intracerebrally just before or after olfactory bulb ablation. The number of dying cells was then counted in sections through the rostrocaudal extent of the piriform cortex. Both anisomycin and emetine injections markedly reduced the number of pyknotic cells in layer IIa of the piriform cortex after olfactory bulb ablation. The effect of anisomycin was dose-dependent, near lethal doses leading to an almost complete absence of cell death (six injections of 100 mg/kg). As the doses of anisomycin were reduced, more dying cells were observed. Emetine was only effective at near lethal doses (10 mg/kg) and showed a greater capacity to reduce the levels of cell death when injected into structures near the piriform cortex (e.g., accumbens nucleus) than when injected into more distant structures. To further confirm that the cell death observed was due to apoptosis, we analysed sections by tunel staining to demonstrate DNA fragmentation. We found that tunel-positive cells were also always pyknotic, one of the landmarks of apoptosis. The appearance of pyknotic cells labelled by the tunel method demonstrated that the dying cells in the piriform cortex did indeed undergo apoptosis.     

Changes in pyridinoline content of elastin during ontogeny

It has been shown that, contrary to desmosine and isodesmosine, the content of pyridinoline increases in elastin preparations obtained from rat and bovine aortae and from bovine ligmentum nuchae throughout the whole lifespan. The molar proportion of this cross-linking amino acid is within the range of 0.6 - 2.5 leucine equivalents per 100 amino acid residues.     

Biochemical studies of chick brain development and maturation: II. Alterations in the mechanisms of cell-free protein synthesis

The molecular mechanisms responsible for the decreased cell-free protein synthetic activity of chicken brain (cerebrum, cerebellum, and optic lobes) from the late embryonic stage to the adult stage were investigated. The changes in polyribosome content closely paralleled changes in cell-free protein synthetic activity; both increased during late embryonic development, reached a maximum around hatching,and thereafter decreased to the level found in the adult. Both cell sap and microsomal or ribosomal fractions from the adult brain tissue were less active in protein synthesis; however, the microsomal or ribosomal fractions contributed more to the decreased protein synthesis than did the cell sap. The lower activity of adult cell sap in protein synthesis was primarily due to a decreased activity in the aminoacylation of tRNA with no apparent change in the ability of the cell sap to catalyze the elongation of polyphenylalanine synthesis. Ribosomal particles (80 S) from adult and embryonic brain tissue had similar biological activities and fidelity in the translation of polyuridylic acid; however, the cell-free protein synthetic activity of the embryonic post-mitochondrial supernatant preparation was more sensitive to inhibitors of the initiation of protein synthesis (aurintricarboxylic acid and polyinosinic acid) than adult post-mitochondrial supernatant, indicating a decreased initiation capacity in adult brain post-mitochondrial supernatant compared to embryonic brain post-mitochondrial supernatant.     

小儿肾病综合征60例护理体会

目的:探讨肾病综合症患儿护理干预措施.方法:对60例患儿在常规护理基础上予以积极护理干预.结果:症状缓解54例缓解率为85.7%.结论:护理干预可以提高患儿遵医行为、增加患儿缓解率,并能提高生活质量,收到良好的效果.     

Banded figers in high temperature coacervates of elastin peptides

Electron micrographs of negatively stained coacervates of the synthetic polypentapeptide of propoelastin and of alpha-elastin exhibit banded fibers when the coacervates are formed, stained, and dried at temperatures greater than 50 degrees. This apparent increase in order occurs at the same temperature as an increase in order in aqueous solution and as a change in the volume expansion coefficient of fibrous elastin.     

Quantification of alterations in structure and function of elastin in the arterial media

The effect of environmental tobacco smoke (ETS) exposure on adults with asthma has not been well characterized. In a prospective cohort study of 451 nonsmoking adults with asthma, we evaluated the impact of ETS exposure on asthma severity, health status, and health care utilization over 18 mo. There were 129 subjects (29%; 95% CI, 25-33%) who reported regular ETS exposure, falling into three categories: exposure at baseline but none at follow-up (n = 43, 10%), no baseline exposure and new exposure at follow-up (n = 56, 12%), and exposure at both baseline and follow-up (n = 30, 7%). In cross-sectional analyses, subjects with baseline ETS exposure had greater severity-of-asthma scores (score difference, 1.7; 95% CI, 0. 2-3.1), worse asthma-specific quality of life scores (score difference, 3.5; 95% CI, 0.03-7.0), and worse scores on the Medical Outcomes Study SF-36 physical component summary (score difference, 3. 0; 95% CI, 0-6.0) than unexposed subjects. They also had greater odds of emergency department visits (odds ratio [OR] = 2.1; 95% CI, 1.2-3.5), urgent physician visits (OR = 1.9; 95% CI, 1.1-3.3), and hospitalizations (OR = 1.9; 95% CI, 1.02-3.6). In longitudinal follow-up, subjects reporting ETS cessation showed improvement in severity-of-asthma scores (score reduction, -3.2; 95% CI, -4.4 to -2. 0) and physical component summary scores (score increase, 5.3; 95% CI, 2.6-8.1). Environmental tobacco smoke cessation decreased the odds of emergency department visits (OR = 0.4; 95% CI, 0.2-0.97) and hospitalizations (OR = 0.2; 95% CI, 0.04-0.97) after adjustment for covariates. Environmental tobacco smoke initiation was associated with greater asthma severity only in subjects with high-level (>= 3 h/wk) exposure (score increase, 1.4; 95% CI, 0.03-2.7). In conclusion, self-reported ETS exposure is associated with greater asthma severity, worse health status, and increased health care utilization in adults with asthma.     

Arterial disease in antiquity

The study of papyrus writings and of mummified human remains provides an insight into the diseases and the practice of medicine in ancient times. Paleopathology, developed in the latter part of the last century and now incorporating modern technology and diagnostic techniques, has shown that arterial disease was not uncommon and that the arterial lesions of 3000 years ago were no different from those we see today.     

Arterial hypertension in children

It is considered hypertension in children, the persistent increase of the blood pressure values above percentile 95 for age and sex, in no less than three determinations, with adequate register techniques. Blood pressure is maintained mainly by the regulation of metabolism of sodium and water in the intravascular space, through the adequate balance of intake, filtration, reabsorption and renal throughout. It is also regulated by hormonal factors. Weight gain control in teen-agers could be useful to prevent high blood pressure in adults. In children, it is generally secondary to renal, reno-vascular, endocrinological or tumoral diseases. Clinical manifestations and the recommended diagnostic procedures are analysed to detect the most frequent causes of hypertension at different ages. Most cases response with antihypertensive drugs in combination with hyposodic diet. For the hypertensive crisis, asa diuretics and powerful antihypertensive drugs may be employed. Patients with chronic renal insufficiency could also need dialytic treatments. Renovascular diseases require almost always invasive treatments. Better prognosis in children with severe high blood pressure is related with recent diagnostic procedures, surgical techniques and antihypertensive drugs improvements.