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1.
BJOG ; 130(8): 881-890, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36808862

RESUMO

OBJECTIVE: Deceleration area (DA) and capacity (DC) of the fetal heart rate can help predict risk of intrapartum fetal compromise. However, their predictive value in higher risk pregnancies is unclear. We investigated whether they can predict the onset of hypotension during brief hypoxaemia repeated at a rate consistent with early labour in fetal sheep with pre-existing hypoxaemia. DESIGN: Prospective, controlled study. SETTING: Laboratory. SAMPLE: Chronically instrumented, unanaesthetised near-term fetal sheep. METHODS: One-minute complete umbilical cord occlusions (UCOs) were performed every 5 minutes in fetal sheep with baseline pa O2 <17 mmHg (hypoxaemic, n = 8) and >17 mmHg (normoxic, n = 11) for 4 hours or until arterial pressure fell <20 mmHg. MAIN OUTCOME MEASURES: DA, DC and arterial pressure. RESULTS: Normoxic fetuses showed effective cardiovascular adaptation without hypotension and mild acidaemia (lowest arterial pressure 40.7 ± 2.8 mmHg, pH 7.35 ± 0.03). Hypoxaemic fetuses developed hypotension (lowest arterial pressure 20.8 ± 1.9 mmHg, P < 0.001) and acidaemia (final pH 7.07 ± 0.05). In hypoxaemic fetuses, decelerations showed faster falls in FHR over the first 40 seconds of UCOs but the final deceleration depth was not different to normoxic fetuses. DC was modestly higher in hypoxaemic fetuses during the penultimate (P = 0.04) and final (P = 0.012) 20 minutes of UCOs. DA was not different between groups. CONCLUSION: Chronically hypoxaemic fetuses had early onset of cardiovascular compromise during labour-like brief repeated UCOs. DA was unable to identify developing hypotension in this setting, while DC only showed modest differences between groups. These findings highlight that DA and DC thresholds need to be adjusted for antenatal risk factors, potentially limiting their clinical utility.


Assuntos
Acidose , Hipotensão , Animais , Feminino , Gravidez , Acidose/etiologia , Feto , Frequência Cardíaca Fetal/fisiologia , Hipotensão/complicações , Hipóxia/complicações , Estudos Prospectivos , Ovinos , Cordão Umbilical/irrigação sanguínea
2.
BJOG ; 128(9): 1433-1442, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33369871

RESUMO

OBJECTIVE: Cardiotocography is widely used to assess fetal well-being during labour. The positive predictive value of current clinical algorithms to identify hypoxia-ischaemia is poor. In experimental studies, fetal hypotension is the strongest predictor of hypoxic-ischaemic injury. Cohort studies suggest that deceleration area and deceleration capacity of the fetal heart rate trace correlate with fetal acidaemia, but it is not known whether they are indices of fetal arterial hypotension. DESIGN: Prospective, controlled study. SETTING: Laboratory. SAMPLE: Near-term fetal sheep. METHODS: One minute of complete umbilical cord occlusions (UCOs) every 5 minutes (1:5 min, n = 6) or every 2.5 minutes (1:2.5 min, n = 12) for 4 hours or until fetal mean arterial blood pressure fell <20 mmHg. MAIN OUTCOME MEASURES: Deceleration area and capacity during the UCO series were related to evolving hypotension. RESULTS: The 1:5 min group developed only mild metabolic acidaemia, without hypotension. By contrast, 10/12 fetuses in the 1:2.5-min group progressively developed severe metabolic acidaemia and hypotension, reaching 16.8 ± 0.9 mmHg after 71.2 ± 6.7 UCOs. Deceleration area and capacity remained unchanged throughout the UCO series in the 1:5-min group, but progressively increased in the 1:2.5-min group. The severity of hypotension was closely correlated with both deceleration area (P < 0.001, R2  = 0.66, n = 18) and capacity (P < 0.001, R2  = 0.67, n = 18). Deceleration area and capacity predicted development of hypotension at a median of 103 and 123 minutes before the final occlusion, respectively. CONCLUSIONS: Both deceleration area and capacity were strongly associated with developing fetal hypotension, supporting their potential to improve identification of fetuses at risk of hypotension leading to hypoxic-ischaemic injury during labour. TWEETABLE ABSTRACT: Deceleration area and capacity of fetal heart rate identify developing hypotension during labour-like hypoxia.


Assuntos
Cardiotocografia/métodos , Frequência Cardíaca Fetal/fisiologia , Cordão Umbilical/irrigação sanguínea , Animais , Feminino , Humanos , Hipóxia-Isquemia Encefálica/prevenção & controle , Trabalho de Parto , Gravidez , Estudos Prospectivos , Ovinos
3.
Nutr Metab Cardiovasc Dis ; 24(11): 1174-80, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24984825

RESUMO

BACKGROUND AND AIMS: Risk of type 2 diabetes mellitus (T2DM) differs according to ethnicity. Levels of apolipoprotein M (ApoM) have been shown to be decreased in T2DM. However, its role in different ethnicities is not known. We examined the differences in plasma ApoM levels in Swedish residents born in Iraq (Iraqis) and Sweden (Swedes) in relation to T2DM and insulin resistance (IR). METHODS AND RESULTS: Iraqis and Swedes, aged 45-65 years residing in Rosengård area of Malmö were randomly selected from census records and underwent an oral glucose tolerance test. Plasma levels of ApoM were quantified in 162 participants (Iraqis, n = 91; Swedes, n = 71) by a sandwich ELISA method. Age-, sex-, and body mass index (BMI) adjusted plasma ApoM levels differed by country of birth, with Swedes having 18% higher levels compared to Iraqis (p = 0.001). ApoM levels (mean ± SD) were significantly decreased in Swedes with T2DM (0.73 ± 0.18) compared to those with normal glucose tolerance (NGT) (0.89 ± 0.24; p = 0.03). By contrast, no significant difference in ApoM levels was found between Iraqis with T2DM (0.70 ± 0.17) and those with NGT (0.73 ± 0.13; p = 0.41). In multivariate linear regression analysis with an interaction term between IR and country of birth, low ApoM levels remained significantly associated with IR in Swedes (p = 0.008), independently of age, sex, BMI, family history of diabetes, HDL, LDL, and triglycerides, but not in Iraqis (p = 0.35). CONCLUSION: Our results show that ApoM levels differ according to country of birth and are associated with IR and T2DM only in Swedes.


Assuntos
Apolipoproteínas/sangue , Resistência à Insulina/etnologia , Lipocalinas/sangue , Idoso , Apolipoproteínas/genética , Apolipoproteínas M , Índice de Massa Corporal , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Estudos Transversais , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/etnologia , Feminino , Teste de Tolerância a Glucose , Humanos , Insulina/sangue , Iraque/etnologia , Lipocalinas/genética , Masculino , Pessoa de Meia-Idade , Suécia/epidemiologia , Triglicerídeos/sangue , População Branca
4.
Diabetologia ; 56(2): 252-8, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23096095

RESUMO

AIMS/HYPOTHESIS: Our aim was to study whether glycaemic control differs between individuals with latent autoimmune diabetes in adults (LADA) and patients with type 2 diabetes, and whether it is influenced by time on insulin therapy. METHODS: We performed a retrospective study of 372 patients with LADA (205 men and 167 women; median age 54 years, range 35-80 years) from Swedish cohorts from Skåne (n = 272) and Västerbotten (n = 100). Age- and sex-matched patients with type 2 diabetes were included as controls. Data on the use of oral hypoglycaemic agents (OHAs), insulin and insulin-OHA combination therapy was retrieved from the medical records. Poor glycaemic control was defined as HbA(1c) ≥7.0% (≥53 mmol/mol) at follow-up. RESULTS: The individuals with LADA and with type 2 diabetes were followed for an average of 107 months. LADA patients were leaner than type 2 diabetes patients at diagnosis (BMI 27.7 vs 31.0 kg/m(2); p < 0.001) and follow-up (BMI 27.9 vs 30.2 kg/m(2); p < 0.001). Patients with LADA had been treated with insulin for longer than those with type 2 diabetes (53.3 vs 28.8 months; p < 0.001). There was no significant difference between the patient groups with regard to poor glycaemic control at diagnosis, but more patients with LADA (67.8%) than type 2 diabetes patients (53.0%; p < 0.001) had poor glycaemic control at follow-up. Patients with LADA had worse glycaemic control at follow-up compared with participants with type 2 diabetes (OR = 1.8, 95% CI 1.2, 2.7), adjusted for age at diagnosis, HbA(1c), BMI at diagnosis, follow-up time and duration of insulin treatment. CONCLUSIONS/INTERPRETATION: Individuals with LADA have worse glycaemic control than patients with type 2 diabetes despite a longer time on insulin therapy.


Assuntos
Doenças Autoimunes/tratamento farmacológico , Glicemia/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Diabetes Mellitus Tipo 2/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
6.
Trials ; 23(1): 607, 2022 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35897022

RESUMO

BACKGROUND: Short-term trials conducted in adults with type 2 diabetes mellitus (T2DM) showed that reducing sedentary behaviour by performing regular short bouts of light-intensity physical activity enhances health. Moreover, support for reducing sedentary behaviour may be provided at a low cost via mobile health technology (mHealth). There are a wide range of mHealth solutions available including SMS text message reminders and activity trackers that monitor the physical activity level and notify the user of prolonged sitting periods. The aim of this study is to evaluate the effects of a mHealth intervention on sedentary behaviour and physical activity and the associated changes in health in adults with T2DM. METHODS: A dual-arm, 12-month, randomized controlled trial (RCT) will be conducted within a nationwide Swedish collaboration for diabetes research in primary health care. Individuals with T2DM (n = 142) and mainly sedentary work will be recruited across primary health care centres in five regions in Sweden. Participants will be randomized (1:1) into two groups. A mHealth intervention group who will receive an activity tracker wristband (Garmin Vivofit4), regular SMS text message reminders, and counselling with a diabetes specialist nurse, or a comparator group who will receive counselling with a diabetes specialist nurse only. The primary outcomes are device-measured total sitting time and total number of steps (activPAL3). The secondary outcomes are fatigue, health-related quality of life and musculoskeletal problems (self-reported questionnaires), number of sick leave days (diaries), diabetes medications (clinical record review) and cardiometabolic biomarkers including waist circumference, mean blood pressure, HbA1c, HDL-cholesterol and triglycerides. DISCUSSION: Successful interventions to increase physical activity among those with T2DM have been costly and long-term effectiveness remains uncertain. The use of mHealth technologies such as activity trackers and SMS text reminders may increase awareness of prolonged sedentary behaviour and encourage increase in regular physical activity. mHealth may, therefore, provide a valuable and novel tool to improve health outcomes and clinical management in those with T2DM. This 12-month RCT will evaluate longer-term effects of a mHealth intervention suitable for real-world primary health care settings. TRIAL REGISTRATION: ClinicalTrials.gov NCT04219800 . Registered on 7 January 2020.


Assuntos
Diabetes Mellitus Tipo 2 , Telemedicina , Adulto , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/terapia , Exercício Físico/fisiologia , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Comportamento Sedentário , Postura Sentada
8.
Dev Neurosci ; 33(3-4): 280-7, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21822007

RESUMO

Moderate cerebral hypothermia significantly improves survival without disability from perinatal hypoxia-ischemia. However, protection is partial. Insulin-like growth factor 1 (IGF-1) plays a key role in oligodendrocyte survival and myelination. The purpose of this study was to test the hypothesis that the combination of IGF-1 plus hypothermia could reduce postischemic white matter damage compared with hypothermia alone. Unanesthetized near-term fetal sheep received 30 min of cerebral ischemia, followed by either an infusion of 3 µg of IGF-1 intracerebroventricularly from 4.5 to 5.5 h plus cooling from 5.5 to 72 h (IGF-1 + hypothermia; n = 8), vehicle infusion plus cooling from 5.5 to 72 h (vehicle + hypothermia; n = 12), sham cooling plus sham infusion (ischemia control; n = 12) or sham ischemia (n = 5). The fetal extradural temperature was reduced from 39.4 ± 0.1°C to between 30 and 33°C. White matter was assessed after 5 days. Ischemia was associated with severe loss of CNPase-positive oligodendrocytes in white matter compared with sham ischemia (380 ± 138 vs. 1,180 ± 152 cells/field; mean ± SD; p < 0.001). Delayed hypothermia reduced cell loss (847 ± 297 cells/field, p < 0.01, vs. ischemia control), but there was no significant difference between vehicle + hypothermia and IGF-1 + hypothermia (1,015 ± 211 cells/field; NS). Ischemia was associated with increased caspase 3 expression in white matter (216 ± 41 vs. 19 ± 18 cells/field; p < 0.001). Hypothermia reduced numbers of activated caspase 3-positive cells (116 ± 81 cells/field; p < 0.05), with no significant difference between vehicle + hypothermia and IGF-1 + hypothermia (91 ± 27 cells/field; NS). In conclusion, delayed cotreatment with IGF-1 plus hypothermia after ischemia was associated with an improvement in white matter damage similar to that achieved by hypothermia alone.


Assuntos
Isquemia Encefálica/patologia , Isquemia Encefálica/fisiopatologia , Feto , Hipotermia Induzida , Fator de Crescimento Insulin-Like I/farmacologia , Fibras Nervosas Mielinizadas/efeitos dos fármacos , Ovinos , Animais , Temperatura Corporal , Encéfalo/citologia , Encéfalo/metabolismo , Encéfalo/patologia , Feto/efeitos dos fármacos , Feto/patologia , Feto/fisiopatologia , Humanos , Fibras Nervosas Mielinizadas/patologia
9.
Am J Physiol Regul Integr Comp Physiol ; 299(2): R664-72, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20484698

RESUMO

Fetal exposure to inflammatory mediators is associated with a greater risk of brain injury and may cause endothelial dysfunction; however, nearly all the evidence is derived from gram-negative bacteria. Intrapleural injections of OK-432, a killed Su-strain of Streptococcus pyogenes, has been used to treat fetal chylothorax. In this study, we evaluated the neural and cardiovascular effects of OK-432 in preterm fetal sheep (104 +/- 1 days, term 147 days). OK-432 (0.1 mg, n = 6) or saline vehicle (n = 7) was infused in the fetal pleura, and fetuses were monitored for 7 days. Blood samples were taken routinely for plasma nitrite measurement. Fetal brains were taken for histological assessment at the end of the experiment. Between 3 and 7 h postinjection, OK-432 administration was associated with transient suppression of fetal body and breathing movements and electtroencephalogram activity (P < 0.05), increased carotid and femoral vascular resistance (P < 0.05), but no change in blood pressure. Brain activity and behavior then returned to normal except in one fetus that developed seizures. OK-432 fetuses showed progressive, sustained vasodilatation (P < 0.05), with lower blood pressure after 4 days (P < 0.05), but normal heart rate. There were no changes in plasma nitrite levels. Histological studies showed bilateral infarction in the dorsal limb of the hippocampus of the fetus that developed seizures, but no injury in other fetuses. We conclude that a single low-dose injection of OK-432 can be associated with risk of focal cerebral injury in the preterm fetus and chronic central and peripheral vasodilatation that does not appear to be mediated by nitric oxide.


Assuntos
Encéfalo/efeitos dos fármacos , Sistema Cardiovascular/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , Picibanil/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Encéfalo/embriologia , Encéfalo/patologia , Sistema Cardiovascular/embriologia , Infarto Cerebral/induzido quimicamente , Eletroencefalografia , Feminino , Sangue Fetal/metabolismo , Movimento Fetal/efeitos dos fármacos , Idade Gestacional , Frequência Cardíaca/efeitos dos fármacos , Infusões Parenterais , Nitritos/sangue , Picibanil/administração & dosagem , Picibanil/toxicidade , Pleura , Gravidez , Mecânica Respiratória/efeitos dos fármacos , Convulsões/induzido quimicamente , Ovinos , Fatores de Tempo , Resistência Vascular/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos
10.
Am J Physiol Regul Integr Comp Physiol ; 298(3): R700-6, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20071614

RESUMO

Activation of the hypothalamic-pituitary-adrenal (HPA) axis is a critical response to perinatal hypoxia. Recent data show that adenosine appears to inhibit baseline levels of fetal cortisol and to restrict the increase in ACTH and cortisol during moderate hypoxia. Because adenosine increases substantially during profound asphyxia, it is possible, but untested, that counterintuitively it might restrict the HPA response to more severe insults. It is unclear which receptors mediate the effects of adenosine on the HPA axis; however, adenosine A(1) receptor activation is important for adaptation to hypoxia. We therefore investigated whether adenosine A(1) receptor blockade modulates ACTH and cortisol levels in fetal sheep at 118 to 126 days gestation, randomly allocated to receive an intravenous infusion of either vehicle (vehicle-occlusion, n = 7) or 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, an A(1) receptor antagonist, DPCPX-occlusion, n = 7) infused 60 min before and during 10 min of umbilical cord occlusion, or infusion of DPCPX for 70 min without occlusion (DPCPX-sham, n = 6). Experiments were terminated after 72 h. Fetal ACTH levels increased significantly (P < 0.01) during occlusion, but not sham occlusion, and returned to baseline values by 60 min after occlusion. In the vehicle-occlusion group, fetal cortisol and cortisone plasma levels increased significantly (P < 0.05) 60 min after the occlusion and returned to baseline values by 24 h. In contrast, there was a marked increase in both fetal cortisol and cortisone during DPCPX infusion before occlusion to a level greater even than the maximum rise seen after occlusion alone. This increase was sustained after occlusion, with increased cortisol levels compared with occlusion alone up to 72 h. In conclusion, fetal cortisol concentrations are suppressed by adenosine A(1) receptor activity, largely though a direct adrenal mechanism. This suppression can be partially overcome by supraphysiological stimuli such as asphyxia.


Assuntos
Asfixia/fisiopatologia , Sistema Hipotálamo-Hipofisário/fisiologia , Sistema Hipófise-Suprarrenal/fisiologia , Receptor A1 de Adenosina/metabolismo , Antagonistas do Receptor A1 de Adenosina , Hormônio Adrenocorticotrópico/sangue , Animais , Dióxido de Carbono/sangue , Feminino , Idade Gestacional , Hidrocortisona/sangue , Oxigênio/sangue , Gravidez , Ovinos , Cordão Umbilical , Xantinas/farmacologia
11.
Sci Rep ; 9(1): 13640, 2019 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-31541150

RESUMO

The prevalence of type 2 diabetes (T2D) has increased dramatically in Middle Eastern populations that represent the largest non-European immigrant group in Sweden today. As proneurotensin predicts T2D, the aim of this study was to investigate differences in proneurotensin levels across populations of Middle Eastern and Caucasian origin and to study its associations with indices of glucose regulation. Participants in the age 30 to 75 years, living in Malmö, Sweden, and born in Iraq or Sweden, were recruited from the census register. Anthropometrics and fasting samples were collected and oral glucose tolerance tests conducted assessing insulin secretion (DIo) as well as insulin sensitivity (ISI). A total of 2155 individuals participated in the study, 1398 were Iraqi-born and 757 were Swedish-born participants. Higher fasting proneurotensin levels were observed in Iraqi- compared to Swedish-born participants (137.5 vs. 119.8 pmol/L; p < 0.001) data adjusted for age, sex and body mass index. In Iraqi participants only, plasma proneurotensin was associated with impaired glucose regulation assessed as ISI, DIo and HbA1c, and significant interactions between country of birth and proneurotensin were observed (Pinteraction ISI = 0.048; Pinteraction DIo = 0.014; PinteractionHbA1c = 0.029). We report higher levels of proneurotensin in the general Middle Eastern population. The finding that Middle Eastern origin modifies the relationship of proneurotensin with indices of glucose regulation suggests that proneurotensin may be a stronger determinant of T2D in Middle Eastern as compared to Caucasian populations. These findings may explain part of the excess T2D risk in the Middle Eastern population but needs to be explored further.


Assuntos
Diabetes Mellitus Tipo 2/diagnóstico , Glucose/metabolismo , Neurotensina/sangue , Precursores de Proteínas/sangue , Adulto , Idoso , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/etnologia , Emigrantes e Imigrantes/estatística & dados numéricos , Feminino , Teste de Tolerância a Glucose , Humanos , Iraque/etnologia , Masculino , Pessoa de Meia-Idade , Suécia/etnologia , Migrantes
12.
Sci Rep ; 9(1): 10142, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31300687

RESUMO

It is widely believed that rewarming slowly after therapeutic hypothermia for hypoxic-ischemic (HI) encephalopathy can improve outcomes, but its impact on white matter injury after HI is unclear. Fetal sheep (0.85 gestation) received 30 min ischemia-normothermia (n = 8), or hypothermia from 3-48 h with rapid spontaneous rewarming over 1 h (ischemia-48 h hypothermia, n = 8), or 48 h with slow rewarming over 24 h (ischemia-slow rewarming, n = 7) or 72 h with rapid rewarming (ischemia-72 h hypothermia, n = 8). Ischemia was associated with loss of total and mature oligodendrocytes and reduced area fraction of myelin basic protein (MBP) and 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase; immature/mature oligodendrocytes) and increased microglia and astrocytes. Total numbers of oligodendrocytes were increased by all hypothermia protocols but only ischemia-72 h hypothermia attenuated loss of mature oligodendrocytes. All hypothermia protocols similarly increased the area fraction of MBP, whereas there was only an intermediate effect on the area fraction of CNPase. Microglia were suppressed by all hypothermia protocols, with the greatest reduction after ischemia-72 h hypothermia, and an intermediate effect after ischemia-slow rewarming. By contrast, induction of astrocytes was significantly reduced only after ischemia-slow rewarming. In conclusion, slow rewarming after hypothermia did not improve oligodendrocyte survival or myelination or suppression of microgliosis compared to fast rewarming, but modestly reduced astrocytosis.


Assuntos
Isquemia Encefálica/terapia , Encéfalo/embriologia , Hipotermia Induzida , Reaquecimento/métodos , Substância Branca/fisiologia , Animais , Gasometria , Isquemia Encefálica/fisiopatologia , Feminino , Hipóxia-Isquemia Encefálica/fisiopatologia , Hipóxia-Isquemia Encefálica/terapia , Masculino , Gravidez , Ovinos , Substância Branca/citologia
13.
Cell Mol Neurobiol ; 28(8): 1027-31, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18807174

RESUMO

Amyloid beta (Abeta) was shown to bind the 75 kD neurotrophin receptor (p75(NTR)) to induce neuronal death. We synthesized a p75(NTR) antagonistic peptide (CATDIKGAEC) that contains the KGA motif that is present in the toxic part of Abeta and closely resembles the binding site of NGF for p75(NTR). In vivo injections of Abeta into the cerebral cortex of B57BL/6 mice together with the peptide produced significantly less inflammation than simultaneous injections of Abeta and a control (CKETIADGAC, scrambled) peptide injected into the contralateral cortex. These data suggest that blocking the binding of Abeta to p75(NTR) may reduce neuronal loss in Alzheimer's disease.


Assuntos
Peptídeos beta-Amiloides/toxicidade , Encefalite/patologia , Peptídeos Cíclicos/farmacologia , Receptores de Fator de Crescimento Neural/antagonistas & inibidores , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL
14.
Bioelectrochemistry ; 121: 135-141, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29413863

RESUMO

Decreasing the time gap between two identical electric pulses is expected to render bioeffects similar to those of a single pulse of equivalent total duration. In this study, we show that it is not necessarily true, and that the effects vary for different permeabilization markers. We exposed individual CHO or NG108 cells to one 300-ns pulse (3.7-11.6 kV/cm), or a pair of such pulses (0.4-1000 µs interval), or to a single 600-ns pulse of the same amplitude. Electropermeabilization was evaluated (a) by the uptake of YO-PRO-1 (YP) dye; (b) by the amplitude of elicited Ca2+ transients, and (c) by the entry of Tl+ ions. For YP uptake, applying a 600-ns pulse or a pair of 300-ns pulses doubled the effect of a single 300-ns pulse; this additive effect did not depend on the time interval between pulses or the electric field, indicating that already permeabilized cells are as susceptible to electropermeabilization as naïve cells. In contrast, Ca2+ transients and Tl+ uptake increased in a supra-additive fashion when two pulses were delivered instead of one. Paired pulses at 3.7 kV/cm with minimal separation (0.4 and 1 µs) elicited 50-100% larger Ca2+ transients than either a single 600-ns pulse or paired pulses with longer separation (10-1000 µs). This paradoxically high efficiency of the closest spaced pulses was emphasized when Ca2+ transients were elicited in a Ca2+-free solution (when the endoplasmic reticulum (ER) was the sole significant source of Ca2+), but was eliminated by Ca2+ depletion from the ER and was not observed for Tl+ entry through the electropermeabilized membrane. We conclude that closely spaced paired pulses specifically target ER, by either permeabilizing it to a greater extent than a single double-duration pulse thus causing more Ca2+ leak, or by amplifying Ca2+-induced Ca2+ release by an unknown mechanism.


Assuntos
Permeabilidade da Membrana Celular , Sistemas de Liberação de Medicamentos/métodos , Eletroporação/métodos , Corantes Fluorescentes/farmacocinética , Compostos de Quinolínio/farmacocinética , Tálio/farmacocinética , Animais , Benzoxazóis/administração & dosagem , Benzoxazóis/farmacocinética , Células CHO , Cálcio/metabolismo , Linhagem Celular Tumoral , Cricetulus , Corantes Fluorescentes/administração & dosagem , Compostos de Quinolínio/administração & dosagem , Ratos , Tálio/administração & dosagem
16.
Neuroscience ; 142(3): 615-28, 2006 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-16952424

RESUMO

Central alpha-adrenergic receptor activity is important for fetal adaptation to hypoxia before birth. It is unclear whether it is also important during recovery. We therefore tested the hypothesis that an infusion of the specific alpha(2)-adrenergic receptor antagonist idazoxan (1 mg/kg/h i.v.) from 15 min to 4 h after profound hypoxia induced by 25 min umbilical cord occlusion in fetal sheep at 70% of gestation (equivalent to the 28-32 weeks in humans) would increase neural injury. After 3 days' recovery, idazoxan infusion was associated with a significant increase in neuronal loss in the hippocampus (P<0.05), expression of cleaved caspase-3 (P<0.05), and numbers of activated microglia (P<0.05). There was no significant effect on other neuronal regions or on loss of O4-positive premyelinating oligodendrocytes in the subcortical white matter. Idazoxan was associated with an increase in evolving epileptiform electroencephalographic (EEG) transient activity after occlusion (difference at peak 2.5+/-1.0 vs. 11.7+/-4.7 counts/min, P<0.05) and significantly reduced average spectral edge frequency, but not EEG intensity, from 54 until 72 h after occlusion (P<0.05). Hippocampal neuronal loss was correlated with total numbers of epileptiform transients during idazoxan infusion (P<0.01; r(2)=0.7). In conclusion, endogenous inhibitory alpha(2)-adrenergic receptor activation after severe hypoxia appears to significantly limit evolving hippocampal damage in the immature brain.


Assuntos
Hipóxia/patologia , Efeitos Tardios da Exposição Pré-Natal/patologia , Receptores Adrenérgicos alfa 2/metabolismo , Antagonistas Adrenérgicos alfa/administração & dosagem , Análise de Variância , Animais , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Artérias Carótidas/efeitos dos fármacos , Artérias Carótidas/fisiopatologia , Caspase 3/metabolismo , Morte Celular/fisiologia , Eletroencefalografia/métodos , Embrião de Mamíferos , Feminino , Frequência Cardíaca Fetal/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Hipóxia/fisiopatologia , Idazoxano/administração & dosagem , Imuno-Histoquímica/métodos , Microglia/patologia , Neurônios/efeitos dos fármacos , Neurônios/patologia , Antígenos O/metabolismo , Fosfopiruvato Hidratase/metabolismo , Gravidez , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Fluxo Sanguíneo Regional/efeitos dos fármacos , Ovinos , Fatores de Tempo
17.
Prog Neurobiol ; 70(6): 443-62, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-14568359

RESUMO

Insulin-like growth factor-1 (IGF-1) is a naturally occurring neurotrophic factor that plays an important role in promoting cell proliferation and differentiation during normal brain development and maturation. The present review examines recent evidence that endogenous IGF-1 also plays a significant role in recovery from insults such as hypoxia-ischemia and that giving additional exogenous IGF-1 can actively ameliorate damage. It is now well established that neurons and other cell types die many hours or even days after initial injury due to activation of programmed cell death pathways. IGF-1 and its binding proteins and receptors are intensely induced within damaged brain regions following brain injury, suggesting a possible a role for IGF-1 in brain recovery. Exogenous administration of IGF-1 within a few hours after brain injury is now known to be protective in both gray and white matter and leads to improved somatic function. In contrast, pre-treatment is ineffective, likely reflecting limited intracerebral penetration of IGF-1 into the uninjured brain. The neuroprotective effects of IGF-1 are mediated by IGF-1 receptors and its binding proteins and are specific to particular cellular phenotypes and brain regions. The window of opportunity for treatment with IGF-1 is limited to a few hours after normothermic brain injury, reflecting its specific actions on early, intracellular events in the apoptotic cascade. However, injury-associated mild post-hypoxic hypothermia, which delays the development of cell death, can shift and dramatically extend the window of opportunity for delayed treatment with IGF-1. Such a combined approach is likely to be essential for any clinical treatment.


Assuntos
Hipóxia-Isquemia Encefálica/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Fármacos Neuroprotetores/metabolismo , Animais , Apoptose , Humanos , Hipóxia-Isquemia Encefálica/tratamento farmacológico , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/metabolismo , Fator de Crescimento Insulin-Like I/farmacologia , Fármacos Neuroprotetores/farmacologia , Receptor IGF Tipo 1/metabolismo , Fatores de Tempo
18.
Endocr Dev ; 9: 31-43, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15879686

RESUMO

It is now well established that neurons and other cell types may die many hours or even days after hypoxic-ischemic injury due to activation of programmed cell death (apoptotic) pathways. The potent anti-apoptotic factor IGF-1 and its binding proteins and receptors are intensely induced within damaged brain regions following brain injury suggesting a possible a role for IGF-1 in endogenous brain recovery. Exogenous administration of IGF-1 within a few hours after brain injury has now been shown to be protective in both grey and white matter, and leads to improved long-term neurological function. The limited window of opportunity for treatment with IGF-1 can be extended by spontaneous mild post-hypoxic hypothermia, probably due to delayed evolution of apoptotic processes. The efficacy of IGF-1 is specific to particular cellular phenotypes and brain regions, and its neuroprotective effects are mediated by IGF-1 receptors and binding proteins. Intriguingly its naturally cleaved N-terminal tripeptide (glycine-proline-glutamate, GPE) has been demonstrated to be neuroprotective after both central and peripheral administration. Peripheral administration of GPE also prevents the loss of dopamine neurons and improves long-term functional recovery following 6-OHDA lesion. However, GPE is unlikely to contribute significantly to the direct effects of IGF-1.


Assuntos
Hipóxia-Isquemia Encefálica/tratamento farmacológico , Fator de Crescimento Insulin-Like I/farmacologia , Fármacos Neuroprotetores/farmacologia , Animais , Modelos Animais de Doenças
19.
Diabetes Metab ; 41(1): 45-54, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25284578

RESUMO

AIMS: Immigrant populations from the Middle East develop diabetes earlier than indigenous European populations; however, the underlying etiology is poorly understood. This study looked at the risk factors associated with early diabetes onset and, in non-diabetics, glycaemic control in immigrants from Iraq compared with native Swedes. METHODS: This cross-sectional population-based study comprised 1398 Iraqi immigrants and 757 Swedes (ages 30-75years) residing in the same area of Malmö, Sweden. Outcomes were age at diabetes onset and glycaemic control (HbA1c) as assessed by Cox proportional hazards and linear regression, respectively. RESULTS: In Iraqis vs Swedes, clustering in the family history (in two or more relatives) was more prevalent (23.2% vs 3.6%, P<0.001) and diabetes onset occurred earlier (47.6years vs 53.4years, P=0.001). Having an Iraqi background independently raised the hazard ratio (HR) for diabetes onset. Diabetes risk due to family history was augmented by obesity, with the highest HRs observed in obese participants with clustering in the family history (HR: 5.1, 95% CI: 3.2-8.2) after adjusting for country of birth and gender. In participants without previously diagnosed diabetes (Iraqis: n=1270; Swedes: n=728), HbA1c levels were slightly higher in Iraqis than in Swedes (4.5% vs 4.4%, P=0.038). This difference was explained primarily by clustering in the family history rather than age, obesity, lifestyle or socioeconomic status. CONCLUSION: The study shows that the greater predisposition to diabetes in Middle Eastern immigrants may be explained by a more extensive family history of the disorder; clinical interventions tailored to Middle Eastern immigrants with such a family history are thus warranted.


Assuntos
Diabetes Mellitus Tipo 2/epidemiologia , Emigrantes e Imigrantes/estatística & dados numéricos , Hiperglicemia/epidemiologia , Adulto , Idade de Início , Idoso , Estudos Transversais , Diabetes Mellitus Tipo 2/etnologia , Família , Feminino , Hemoglobinas Glicadas , Humanos , Hiperglicemia/etnologia , Masculino , Pessoa de Meia-Idade , Oriente Médio/etnologia , Suécia/epidemiologia
20.
Int J Dev Neurosci ; 45: 66-74, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25546019

RESUMO

Perinatal ischemic brain injury can occur as a result of a global ischemic insult or focal ischemic stroke in the preterm or full-term neonate. One of the most striking features of HI injury is that, after initial recovery of cellular oxidative metabolism, there is a delayed, 'secondary' mitochondrial failure that spreads over time from the most severely damaged areas outwards, into previously undamaged regions. This secondary failure is accompanied by transient seizure activity and cytotoxic edema. The specific mechanisms of this spread are poorly understood, but it is at least partly associated with spreading waves of depression that can trigger cell death in neighboring uninjured tissues. Both Connexin and Pannexin hemichannels may mediate release of paracrine molecules that in turn propagate cell death messages by releasing intracellular mediators, such as ATP, NAD(+), or glutamate or by abnormally prolonged opening to allow cell edema. This review will discuss the controversy around the relative contribution of both Connexin and Pannexin hemichannels and mechanisms by which they may contribute to the spread of ischemic brain injury.


Assuntos
Lesões Encefálicas/metabolismo , Isquemia Encefálica/metabolismo , Junções Comunicantes/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Animais , Lesões Encefálicas/patologia , Isquemia Encefálica/patologia , Conexinas , Junções Comunicantes/patologia , Humanos , Modelos Neurológicos
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