Baroreflex and chemoreflex dysfunction in streptozotocin-diabetic rats

Several investigators have demonstrated that streptozotocin (STZ) diabetes induces changes in the autonomic control of the cardiovascular system. Changes in cardiovascular function may be related to peripheral neuropathy. The aim of the present study was to analyze changes in heart rate (HR) and arterial pressure (AP) as well as baroreflex and chemoreflex sensitivity in STZ-induced diabetic male Wistar rats (STZ, 50 mg/kg, iv, 15 days). Intra-arterial blood pressure signals were obtained for control and diabetic rats (N = 9, each group). Data were processed in a data acquisition system (CODAS, 1 kHz). Baroreflex sensitivity was evaluated by measuring heart rate changes induced by arterial pressure variation produced by phenylephrine and sodium nitroprusside injection. Increasing doses of potassium cyanide (KCN) were used to evaluate bradycardic and pressor responses evoked by chemoreflex activation. STZ induced hyperglycemia (447 ± 49 vs 126 ± 3 mg/dl), and a reduction in AP (99 ± 3 vs 118 ± 2 mmHg), resting HR (296 ± 11 vs 355 ± 16 bpm) and plasma insulin levels (16 ± 1 vs 57 ± 11 µU/ml). We also observed that the reflex bradycardia (-1.68 ± 0.1 vs -1.25 ± 0.1 bpm/mmHg, in the diabetic group) and tachycardia (-3.68 ± 0.5 vs -1.75 ± 0.3 bpm/mmHg, in the diabetic group) produced by vasopressor and depressor agents were impaired in the diabetic group. Bradycardia evoked by chemoreflex activation was attenuated in diabetic rats (control: -17 ± 1, -86 ± 19, -185 ± 18, -208 ± 17 vs diabetic: -7 ± 1, -23 ± 5, -95 ± 13, -140 ± 13 bpm), as also was the pressor response (control: 6 ± 1, 30 ± 7, 54 ± 4, 59 ± 5 vs diabetic: 6 ± 1, 8 ± 2, 33 ± 4, 42 ± 5 mmHg). In conclusion, the cardiovascular responses evoked by baroreflex and chemoreflex activation are impaired in diabetic rats. The alterations of cardiovascular responses may be secondary to the autonomic dysfunction of cardiovascular control

Nitric oxide release from the S-nitrosothiol zinc phthalocyanine complex by flash photolysis

The photogeneration of nitric oxide (NO) using laser flash photolysis was investigated for S-nitroso-glutathione (GSNO) and S-nitroso-N-acetylcysteine (NacySNO) at pH 6.4 (PBS/HCl) and 7.4 (PBS). Irradiation of S-nitrosothiol with light (lambda = 355 nm followed by absorption spectroscopy) resulted in the homolytic decomposition of NacySNO and GSNO to generate radicals (GS· and NacyS·) and NO. The release of NO from donor compounds measured with an ISO-Nometer apparatus was larger at pH 7.4 than pH 6.4. NacySNO was also incorporated into dipalmitoyl-phosphatidylcholine liposomes in the presence and absence of zinc phthalocyanine (ZnPC), a well-known photosensitizer useful for photodynamic therapy. Liposomes are usually used as carriers for hydrophobic compounds such as ZnPC. Inclusion of ZnPC resulted in a decrease in NO liberation in liposomal medium. However, there was a synergistic action of both photosensitizers and S-nitrosothiols resulting in the formation of other reactive species such as peroxynitrite, which is a potent oxidizing agent. These data show that NO release depends on pH and the medium, as well as on the laser energy applied to the system. Changes in the absorption spectrum were monitored as a function of light exposure.

Swimming training increases cardiac vagal activity and induces cardiac hypertrophy in rats

The effect of swimming training (ST) on vagal and sympathetic cardiac effects was investigated in sedentary (S, N = 12) and trained (T, N = 12) male Wistar rats (200-220 g). ST consisted of 60-min swimming sessions 5 days/week for 8 weeks, with a 5% body weight load attached to the tail. The effect of the autonomic nervous system in generating training-induced resting bradycardia (RB) was examined indirectly after cardiac muscarinic and adrenergic receptor blockade. Cardiac hypertrophy was evaluated by cardiac weight and myocyte morphometry. Plasma catecholamine concentrations and citrate synthase activity in soleus muscle were also determined in both groups. Resting heart rate was significantly reduced in T rats (355 ± 16 vs 330 ± 20 bpm). RB was associated with a significantly increased cardiac vagal effect in T rats (103 ± 25 vs 158 ± 40 bpm), since the sympathetic cardiac effect and intrinsic heart rate were similar for the two groups. Likewise, no significant difference was observed for plasma catecholamine concentrations between S and T rats. In T rats, left ventricle weight (13%) and myocyte dimension (21%) were significantly increased, suggesting cardiac hypertrophy. Skeletal muscle citrate synthase activity was significantly increased by 52% in T rats, indicating endurance conditioning. These data suggest that RB induced by ST is mainly mediated parasympathetically and differs from other training modes, like running, that seems to mainly decrease intrinsic heart rate in rats. The increased cardiac vagal activity associated with ST is of clinical relevance, since both are related to increased life expectancy and prevention of cardiac events.

Selvitys Helsingin seudun pääväylien liikenteen toimivuudesta ja ruuhkautumisesta

Tämän selvityksen tavoitteena oli laatia käytettävissä olevaa mittaustietoa ja maastokäyntejä hyödyntäen asiantuntija-arviona kokonaisnäkemys Helsingin seudun pääväylien ruuhkautuvuudesta. Analyysiin haettiin LAM-tietokannasta pääväylien pisteistä vuosien 2003 ja 2010 jokaisen tunnin liikennemäärä ja keskinopeus ajosuunnittain. Lisäksi LAM-aineistoa yhdisteltiin Liikenneviraston keli- ja häiriötietoihin. LAM -pisteiden mittaustietojen perusteella on ruuhkattomien päivien määrä vähentynyt selvästi vuoden 2003 jälkeen. Ruuhkattomat päivät ovat vähentyneet noin puolessa mittauspisteistä sekä aamu- että iltaruuhkassa. Ruuhkat ovat muuttuneet vakavammiksi. Lähes kaikissa mittauspisteissä, joissa ruuhkattomat päivät vähenivät, kasvoi myös vakavampien ruuhkien määrä. Aamuliikenteessä ruuhkautuminen on lisääntynyt varsinkin Kehä I:llä sekä säteittäisväylillä Kehä III:n sisäpuolella. Iltapäiväliikenteessä ruuhkautuminen on yleisempää kehäteillä kuin säteittäisväylillä. Vakavat ruuhkat keskittyvät säteittäisväylillä yksittäisten liittymien yhteydessä sijaitseviin pullonkauloihin ja väylien päätepisteisiin katuverkolle saavuttaessa. Kehä III:n ulkopuolella suuret nopeushajonnat alkavat aiheuttaa ruuhkia myös linjaosuuksille väylillä, joiden liikennemäärä on lähellä kapasiteettia. Ruuhkautuminen on yleisintä marras-, joulu- ja tammikuussa, jolloin olosuhteet näyttävät lisäävän erityisesti lieviä ruuhkia. Huonolla talvikelillä ruuhkautuvien tuntien osuus kasvaa hieman ja erittäin huonolla talvikelillä ruuhkautuminen on kaksi kertaa todennäköisempää kuin normaalilla kelillä. Huonon kelin vaikutus näkyy voimakkaasti varsinkin pisteissä, joiden liikennemäärä on lähellä tien kapasiteettia. Ruuhkautumisen riskiä huonoilla keleillä lisää se, että huonon ja erittäin huonon ajokelin aikana häiriöriski on suurempi kuin normaalin talvikelin aikana. Toimenpidesuosituksena esitettiin säteittäisväylien lisäkaistoja pahimmin ruuhkautuneilla liittymäväleillä Kehä I:n ja Kehä III:n välillä. Toimenpiteiden suunnittelussa tulee huomioida, että käynnissä olevien Kehä I:n ja Kehä III:n työmaiden valmistuminen voi muuttaa ruuhkautumistilannetta huomattavasti. Kehä III:n ulkopuolella säteittäisten pääväylien linjaosuuksien ruuhkautumista voidaan vähentää toteuttamalla vaihtuvia nopeusrajoituksia. Nopeusrajoitusten laskemisen lisäksi raskaan liikenteen ohituskiellot ruuhka-aikoina vähentäisivät nopeushajontaa ja voisivat siten vähentää ruuhkia sekä säteittäisväylillä että kehäteillä.

Comparison of serum hormone levels of captive and free-living maned wolves Chrysocyon brachyurus

Serum hormone levels were compared between captive and free-living maned wolves and seasonal variations of sex hormones were studied. Blood samples were collected from 16 male and 26 female adult animals from Brazilian zoos, and from 30 male and 24 female free-living adults to determine serum progesterone and testosterone by radioimmunoassay. Serum testosterone concentrations varied (P < 0.05) across seasons for 16 captive males, being higher in autumn (2184.7 ± 355.1 pg/mL) than in summer (1080.7 ± 205.4 pg/mL), winter (1270.1 ± 276.6 pg/mL) and spring (963.9 ± 248.1 pg/mL), although they did not differ between summer, winter and spring. Testosterone concentration of 30 free-living males differed (P < 0.05) between autumn (824.1 ± 512.2 pg/mL), winter (14.4 ± 8.0 pg/mL) and spring (151.9 ± 90.5 pg/mL). Comparison between captive and free-living animals showed no difference in autumn (P > 0.05). Sixteen captive males showed higher testosterone concentration during winter and spring compared with 30 free-living animals (P < 0.05). Progesterone concentration varied among seasons in 26 captive females (P < 0.05), being higher in autumn (15.3 ± 3.1 ng/mL) than in summer (6.6 ± 1.5 ng/mL), winter (5.3 ± 3.1 ng/mL) and spring (4.3 ± 0.7 ng/mL). Progesterone concentration of 24 free-living females varied between autumn (17.1 ± 6.0 ng/mL) and winter (1.7 ± 0.3 ng/mL) (P < 0.05), but we could not obtain data for spring or summer. No difference in progesterone levels was observed between captive and free-living females in autumn and winter.

Effects of acute administration of selective serotonin reuptake inhibitors on sympathetic nerve activity

Serotonergic mechanisms have an important function in the central control of circulation. Here, the acute effects of three selective serotonin (5-HT) reuptake inhibitors (SSRIs) on autonomic and cardiorespiratory variables were measured in rats. Although SSRIs require 2-3 weeks to achieve their full antidepressant effects, it has been shown that they cause an immediate inhibition of 5-HT reuptake. Seventy male Wistar rats were anesthetized with urethane and instrumented to record blood pressure, heart rate, renal sympathetic nerve activity (RSNA), and respiratory frequency. At lower doses, the acute cardiovascular effects of fluoxetine, paroxetine and sertraline administered intravenously were insignificant and variable. At middle and higher doses, a general pattern was observed, with significant reductions in sympathetic nerve activity. At 10 min, fluoxetine (3 and 10 mg/kg) reduced RSNA by -33±4.7 and -31±5.4%, respectively, without changes in blood pressure; 3 and 10 mg/kg paroxetine reduced RSNA by -35±5.4 and -31±5.5%, respectively, with an increase in blood pressure +26.3±2.5; 3 mg/kg sertraline reduced RSNA by -59.4±8.6%, without changes in blood pressure. Sympathoinhibition began 5 min after injection and lasted approximately 30 min. For fluoxetine and sertraline, but not paroxetine, there was a reduction in heart rate that was nearly parallel to the sympathoinhibition. The effect of these drugs on the other variables was insignificant. In conclusion, acute peripheral administration of SSRIs caused early autonomic cardiovascular effects, particularly sympathoinhibition, as measured by RSNA. Although a peripheral action cannot be ruled out, such effects are presumably mostly central.

Murhenäytelmä laidunmaalla, merellä ja ilmassa

Kirjallisuusarvostelu

Malnourished patients on hemodialysis improve after receiving a nutritional intervention

INTRODUCTION: Malnutrition is multifactorial and may be modified by nutritional intervention. We aimed to assess the impact of an intervention on the nutritional status of malnourished hemodialysis patients and their acceptance of a non-industrialized nutritional supplement. METHODS: 18 patients were studied, they were selected from a previous nutritional assessment where nutritional risk was defined as: subjective global assessment > 15 plus one criterion for malnutrition. The following variables were assessed: anthropometric parameters, subjective global assessment, dietary intake, six-minute walking test, quality of life (SF-36), and biochemical tests. Patients were randomized to either Control or Intervention Groups. The Intervention Group received a dietetic supplement during dialysis containing 355 kcal, prepared from simple ingredients. After three months, subjects from the Control Group and other patients also considered at nutritional risk underwent the same intervention. The study groups were compared after three months, and all patients were analyzed before and after the intervention. RESULTS: Fifteen men and three women, aged 56.4 ± 15.6 years-old, nine in each group, were studied. The Intervention Group showed an improvement in the subjective global assessment (p = 0.04). There were differences in role physical and bodily pain domains of SF-36, with improvement in the Intervention Group and worsening in the Control Group (p = 0.034 and p = 0.021). Comparisons before and after intervention for all patients showed improvement in the subjective global assessment (16.18 ± 4.27 versus 14.37 ± 4.20, p = 0.04), and in the six-minute walking test (496.60 ± 132.59 versus 547.80 ± 132.48 m; p = 0.036). The nutritional supplement was well tolerated by all patients, and it did not cause side effects. CONCLUSIONS: The nutritional intervention improved the subjective global assessment and quality of life of hemodialysis patients at short-term. A global intervention by a dietitian produced specific and nonspecific positive effects in the whole group. Nutritional supplementation was feasible, palatable, and had low cost. Its clinical impact and effectiveness need to be further assessed in a larger group of patients at long-term.

Plan för hantering av översvämningsriskerna i Kyro älvs vattendragsområde för år 2016-2021

En plan för hantering av översvämningsriskerna i Kyro älv för åren 2016-2021har utarbetats. I planen presenteras en preliminär bedömning av översvämningsriskerna, kartor över översvämningshotade områden och över översvämningsrisk, bedömning av översvämningsska-dorna, målen för hanteringen av översvämningsriskerna och åtgärder för att förhindra och minska översvämningsriskerna. I riskhanterings-planen presenteras även de berörda parternas och medborgarnas deltagande och hörande under planeringen. Planen för hantering av översvämningsriskerna har beretts i samarbete med översvämningsgruppen för Kyro älvs avrinningsområde, NTM-centralen i Södra Öster-botten och Finlands miljöcentral. Skador orsakade av översvämningar i Kyro älv kan förebyggas och minskas på många olika sätt. Spektret av åtgärder sträcker sig från planering av markanvändning till att på egen hand skydda sin fastighet och från uppgörande av översvämningsprognoser till operativ be-kämpning av översvämningar. Åtgärderna som presenteras i planen omfattar åtgärder för förebyggande av översvämningar, översväm-ningsskyddsåtgärder, verksamhet vid översvämning, beredskapsåtgärder samt åtgärder efter en översvämning. Tyngdpunkten ligger på förebyggande av skador och beredskap. I planen presenteras effektiverad informationsspridning, så att privata och offentliga aktörer bättre kan bereda sig inför översvämningar också på egen hand. Åtgärder för att kvarhålla översvämningsvatten på avrinningsområdet, framförs bl.a. i skogsområden och torvproduktionsområden som tas ur bruk. Dessutom presenteras en planering av utveckling av användningen av invallningsområdena längs Kyro älv så att områdena kunde användas så effektivt som möjligt också vid ovanliga översvämningar. Kommu-ner, invånare och invallningsföretag i Kyro älvdalen samt NTM-centralen har en central roll vid genomförandet av åtgärder för hantering av översvämningsrisker. Planen baserar sig på lagen om översvämningsrisker och vid utarbetandet har man utnyttjat den preliminära bedömningen av översväm-ningsrisker i vattendragsområdet, översvämningskartor och befintliga dokument om hantering av översvämningsrisker. Förslaget till plan har varit på remiss och alla har haft möjlighet att presentera sina åtgärder om planen. Jord- och skogsbruksministeriet har godkänt planen i december 2015. Planen granskas enligt behov senast år 2021.

Tuhtia evästä EU-keskustelijalle

Kirjallisuusarvostelu