Gamma-ray bursts (GRBs) have been separated into two classes, originally along the lines of duration and spectral properties, called 'short/hard' and 'long/soft.' The latter have been conclusively ...linked to the explosive deaths of massive stars, while the former are thought to result from the merger or collapse of compact objects. In recent years, indications have been accumulating that the short/hard versus long/soft division does not map directly onto what would be expected from the two classes of progenitors, leading to a new classification scheme called Type I and Type II which is based on multiple observational criteria. We use a large sample of GRB afterglow and prompt-emission data (adding further GRB afterglow observations in this work) to compare the optical afterglows (or the lack thereof) of Type I GRBs with those of Type II GRBs. In comparison to the afterglows of Type II GRBs, we find that those of Type I GRBs have a lower average luminosity and show an intrinsic spread of luminosities at least as wide. From late and deep upper limits on the optical transients, we establish limits on the maximum optical luminosity of any associated supernova (SN), confirming older works and adding new results. We use deep upper limits on Type I GRB optical afterglows to constrain the parameter space of possible mini-SN emission associated with a compact-object merger. Using the prompt-emission data, we search for correlations between the parameters of the prompt emission and the late optical afterglow luminosities. We find tentative correlations between the bolometric isotropic energy release and the optical afterglow luminosity at a fixed time after the trigger (positive), and between the host offset and the luminosity (negative), but no significant correlation between the isotropic energy release and the duration of the GRBs. We also discuss three anomalous GRBs, GRB 060505, GRB 060614, and GRB 060121, in light of their optical afterglow luminosities.
Dietary acid load in health and disease Wieërs, Michiel L. A. J.; Beynon-Cobb, Beverley; Visser, Wesley J. ...
Pflügers Archiv,
04/2024, Letnik:
476, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Maintaining an appropriate acid–base equilibrium is crucial for human health. A primary influencer of this equilibrium is diet, as foods are metabolized into non-volatile acids or bases. Dietary acid ...load (DAL) is a measure of the acid load derived from diet, taking into account both the potential renal acid load (PRAL) from food components like protein, potassium, phosphorus, calcium, and magnesium, and the organic acids from foods, which are metabolized to bicarbonate and thus have an alkalinizing effect. Current Western diets are characterized by a high DAL, due to large amounts of animal protein and processed foods. A chronic low-grade metabolic acidosis can occur following a Western diet and is associated with increased morbidity and mortality. Nutritional advice focusing on DAL, rather than macronutrients, is gaining rapid attention as it provides a more holistic approach to managing health. However, current evidence for the role of DAL is mainly associative, and underlying mechanisms are poorly understood. This review focusses on the role of DAL in multiple conditions such as obesity, cardiovascular health, impaired kidney function, and cancer.
We show that expression of the microtubule depolymerizing kinesin KIF2C is induced by transformation of immortalized human bronchial epithelial cells (HBEC) by expression of K-Ras(G12V) and knockdown ...of p53. Further investigation demonstrates that this is due to the K-Ras/ERK1/2 MAPK pathway, as loss of p53 had little effect on KIF2C expression. In addition to KIF2C, we also found that the related kinesin KIF2A is modestly upregulated in this model system; both proteins are expressed more highly in many lung cancer cell lines compared to normal tissue. As a consequence of their depolymerizing activity, these kinesins increase dynamic instability of microtubules. Depletion of either of these kinesins impairs the ability of cells transformed with mutant K-Ras to migrate and invade matrigel. However, depletion of these kinesins does not reverse the epithelial to mesenchymal transition (EMT) caused by mutant K-Ras. Our studies indicate that increased expression of microtubule destabilizing factors can occur during oncogenesis to support enhanced migration and invasion of tumor cells.
Sudden death from cardiac causes, often due to ventricular fibrillation, claims at least 250,000 persons annually in the United States.
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The American Heart Association guidelines for advanced ...cardiac life support state that antiarrhythmic medications are “acceptable, probably helpful” for the treatment of ventricular fibrillation or pulseless ventricular tachycardia that persists after three or more shocks from an external defibrillator (often called “shock-refractory” ventricular fibrillation or tachycardia).
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This guarded recommendation reflects the limited evidence supporting the use of these agents, none of which have been convincingly demonstrated to improve the success of attempted resuscitation after cardiac arrest.
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We conducted . . .
CONTEXT Use of automated external defibrillators (AEDs) by
first arriving emergency medical technicians (EMTs) is advocated to
improve the outcome for out-of-hospital ventricular fibrillation (VF).
...However, adding AEDs to the emergency medical system in Seattle, Wash,
did not improve survival. Studies in animals have shown improved
outcomes when cardiopulmonary resuscitation (CPR) was administered
prior to an initial shock for VF of several minutes' duration. OBJECTIVE To evaluate the effects of providing 90 seconds of CPR
to persons with out-of-hospital VF prior to delivery of a shock by
first-arriving EMTs. DESIGN Observational, prospectively defined, population-based
study with 42 months of preintervention analysis (July 1, 1990-December
31, 1993) and 36 months of postintervention analysis (January 1,
1994-December 31, 1996). SETTING Seattle fire department–based, 2-tiered emergency medical
system. PARTICIPANTS A total of 639 patients treated for out-of-hospital
VF before the intervention and 478 after the intervention. INTERVENTION Modification of the protocol for use of AEDs,
emphasizing approximately 90 seconds of CPR prior to delivery of a
shock. MAIN OUTCOME MEASURES Survival and neurologic status at hospital
discharge determined by retrospective chart review as a function of
early (<4 minutes) and later (≥4 minutes) response intervals. RESULTS Survival improved from 24% (155/639) to 30% (142/478)
(P=.04). That benefit was predominantly in
patients for whom the initial response interval was 4 minutes or longer
(survival, 17% 56/321 before vs 27% 60/220 after;
P = .01). In a multivariate logistic model, adjusting for
differences in patient and resuscitation factors between the periods,
the protocol intervention was estimated to improve survival
significantly (odds ratio, 1.42; 95% confidence interval, 1.07-1.90;
P = .02). Overall, the proportion of victims who survived
with favorable neurologic recovery increased from 17% (106/634) to
23% (109/474) (P = .01). Among survivors, the proportion
having favorable neurologic function at hospital discharge increased
from 71% (106/150) to 79% (109/138) (P<.11). CONCLUSION The routine provision of approximately 90 seconds of
CPR prior to use of AED was associated with increased survival when
response intervals were 4 minutes or longer.
To evaluate the feasibility, safety, and efficacy of interventions aimed at improving neurologic outcome after cardiac arrest.
The authors conducted a double-blind, placebo-controlled, randomized ...clinical trial with factorial design to see if magnesium, diazepam, or both, when given immediately following resuscitation from out-of-hospital cardiac arrest, would increase the proportion of patients awakening, defined as following commands or having comprehensible speech. If the patient regained a systolic blood pressure of at least 90 mm Hg and had not awakened, paramedics injected IV two syringes stored in a sealed kit. The first always contained either 2 g magnesium sulfate (M) or placebo (P); the second contained either 10 mg diazepam (D) or P. Awakening at any time by 3 months was determined by record review, and independence at 3 months was determined by telephone calls. Over 30 months, 300 patients were randomized in balanced blocks of 4, 75 each to MD, MP, PD, or PP. The study was conducted under waiver of consent.
Despite the design, the four treatment groups differed on baseline variables collected before randomization. Percent awake by 3 months for each group were: MD, 29.3%; MP, 46.7%; PD, 30.7%; PP, 37.3%. Percent independent at 3 months were: MD, 17.3%; MP, 34.7%; PD, 17.3%; PP, 25.3%. Significant interactions were lacking. After adjusting for baseline imbalances, none of these differences was significant, and no adverse effects were identified.
Neither magnesium nor diazepam significantly improved neurologic outcome from cardiac arrest.
The incidence of sudden cardiac death is roughly 3 times greater in men than in women. However, in patients treated for out-of-hospital cardiac arrest, the relationships between sex and survival ...after adjustment for age and cardiac rhythm are unclear.
In this retrospective cohort study, we examined 7069 men and 2582 women who were treated for out-of-hospital cardiac arrest in Seattle and suburban King County between 1990 and 1998. We compared successful prehospital resuscitation (hospital admission) and survival from event to discharge in men and women. Women had markedly reduced rates of ventricular fibrillation (VF), slightly older age, fewer witnessed arrests, and fewer arrests in public locations than men. Although their unadjusted resuscitation rate was lower (29% versus 32%, P<0.0001), women had a greater likelihood of resuscitation than men after adjustment for VF (odds ratio OR 1.13; 95% confidence interval CI, 1.03 to 1.25) and after adjustment for VF plus additional factors (OR, 1.27; 95% CI, 1.14 to 1.41). The difference in resuscitation rates between men and women decreased as they aged (test for trend, P<0.0001). Unadjusted survival rates were also lower in women than in men (11% versus 15%, P<0.0001). Women had similar survival after adjustment for VF (OR, 0.97; 95% CI, 0.85 to 1.11) and after adjustment for VF plus additional factors (OR, 1.09; 95% CI, 0.93 to 1.27).
The lower unadjusted resuscitation and survival rates observed in women were primarily due to women's lower incidence of VF, a relatively favorable cardiac rhythm. After adjustment for VF and other factors, women had higher resuscitation rates than men, but similar rates of survival from event to discharge.
The hypothesis that a family history of myocardial infarction (MI) or primary cardiac arrest (PCA) is an independent risk factor for primary cardiac arrest was examined in a population-based ...case-control study. In addition, we investigated whether recognized risk factors account for the familial aggregation of these cardiovascular events.
PCA cases, 25 to 74 years old, attended by paramedics during the period 1988 to 1994 and population-based control subjects matched for age and sex were identified from the community by random digit dialing. All subjects were free of recognized clinical heart disease and major comorbidity. A detailed history of MI and PCA in first-degree relatives was collected in interviews with the spouses of case and control subjects by trained interviewers using a standardized questionnaire. For each familial relationship, there was a higher rate of MI or primary cardiac arrest (MI/PCA) in relatives of case compared with relatives of control subjects. Overall, the rate of MI/PCA among first-degree relatives of cardiac arrest patients was almost 50% higher than that in first-degree relatives of control subjects (rate ratio RR=1.46; 95% CI=1.23 to 1.72). In a multivariate logistic model, family history of MI/PCA was associated with PCA (RR=1.57; 95% CI=1.27 to 1.95) even after adjustment for other common risk factors.
Family history of MI or PCA is positively associated with the risk of primary cardiac arrest. This association is mostly independent of familial aggregation of other common risk factors.
Cardiac arrest is the leading cause of death among dialysis patients in the United States. We measured the outcome of cardiac arrests attended by Emergency Medical Services (EMS) staff at ...hemodialysis facilities in a 14-year population-based retrospective study to identify cardiac arrest cases at a dialysis unit. Associated factors were determined using unconditional logistic regression. Of the 102 cardiac arrests identified around the time of dialysis, 10 occurred before, 72 during, and 20 after hemodialysis. The initial measured abnormality was ventricular fibrillation or tachycardia in 72 cases. Of those who survived transportation to a hospital, survival to discharge was 24 with 15% survival at 1 year. Compared to arrests that occurred prior to dialysis, the odds of ventricular fibrillation were 5-fold greater in patients on dialysis but 14-fold greater in those arresting after dialysis. One-third of cases occurred after the introduction of automated external defibrillators, and in half of the cases these devices were attached prior to EMS arrival. Once these devices were attached, most were used for defibrillation. We conclude that ventricular arrhythmias are the predominant features among arrested in-center dialysis patients with most occurrences during dialysis. The role of these devices in dialysis units will need a larger study to evaluate their efficacy.
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