Does training or deprivation modulate amygdala activation?

Amygdala involvement in visual emotional processing has been unequivocally established, but the amygdala's participation in auditory emotional processing is less clear. In a previous functional magnetic resonance imaging study (Klinge et al., 2010) we investigated the amygdala's role in auditory emotional processing in blind and sighted humans. We observed stronger amygdala responses to auditory emotional stimuli in the blind who were also better at discriminating emotional stimuli. Importantly, inter-individual differences in this skill correlated with amygdala activation. While these data suggested that the amygdala serves the dominant sensory modality for emotional perception, we could not rule out possible influences of use-dependent training effects. To disambiguate between plastic changes due to deprivation or training we now studied professional actors who have undergone extensive perceptual and expressive auditory emotional trainings but no sensory deprivation. Actors showed emotion discrimination skills comparable to those of blind individuals. However, in contrast to blind volunteers they lacked increased amygdala activations. Surprisingly, actors selectively rated angry stimuli as less intense than control participants, paralleled by a down-regulation of amygdala responses via the anterior cingulate cortex. Taken together, the data from our two studies suggest that enhanced amygdala responses in the blind are mainly due to deprivation-induced plasticity, as highly trained actors who possess the same excellent emotion discrimination skills as the blind did not show these responses. It is also conceivable that the actors' training requires a more professional and controlled dealing with the emotional stimuli, resulting in a down-regulation of affective experience and accompanying amygdala responses.     

Prehospital fluid resuscitation: conventional wisdom or inadequate science?

After 25 years, the medical community remains unconvinced that prehospital fluid resuscitation in traumatised patients improves survival. Despite this lack of conviction, fluid resuscitation has been introduced in almost every Emergency Medical System (EMS) throughout the world and few would be prepared to suggest its removal. Is there a logic behind this dichotomy or is it a case of conventional wisdom having no basis in science? The aim of this paper is to identify and explore the essential questions which underlie the logic of current practice in an attempt to guide future conventions. There are three questions which need to be addressed:

• 1 What is the right focus for scientific evaluation?
• 2 Is current clinical practice appropriate?
• 3 Do the risks and complications outweigh any potential benefit?

Fluid resuscitation is potentially life-saving when performed in the right manner, on the right patient, at the right time. The focus must be changed from technical issues to the knowledge and judgement required to deliver therapy appropriate to the needs of the particular patient.     

Rational or rationalized choices in fluid resuscitation?

The war between colloids and crystalloids wages on. In a large multinational survey of fluid prescribing practices in critically ill patients, we have a new and intriguing snapshot of global fluid resuscitation practices. Colloids are more often used for impaired perfusion or low cardiac output, and the choice of colloid or crystalloid varies enormously between countries. Why are some ICUs prescribing colloids more often than crystalloids when there is little convincing evidence that colloids are superior for fluid resuscitation? Are colloids advantageous in certain diseases, or in specific regional patient populations that have not yet been elucidated? Perhaps we should look inwards: the answer may not be more randomized clinical trials, but better adherence to current guidelines and treatment recommendations.     

Sepsis: an arginine deficiency state?

OBJECTIVE: Sepsis is a major health problem considering its significant morbidity and mortality rate. The amino acid L-arginine has recently received substantial attention in relation to human sepsis. However, knowledge of arginine metabolism during sepsis is limited. Therefore, we reviewed the current knowledge about arginine metabolism in sepsis. DATA SOURCE: This review summarizes the literature on arginine metabolism both in general and in relation to sepsis. Moreover, arginine-related therapies are reviewed and discussed, which includes therapies of both nitric oxide (NO) and arginine administration and therapies directed toward inhibition of NO. DATA: In sepsis, protein breakdown is increased, which is a key process to maintain arginine delivery, because both endogenous de novo production from citrulline and food intake are reduced. Arginine catabolism, on the other hand, is markedly increased by enhanced use of arginine in the arginase and NO pathways. As a result, lowered plasma arginine levels are usually found. Clinical symptoms of sepsis that are related to changes in arginine metabolism are mainly related to hemodynamic alterations and diminished microcirculation. NO administration and arginine supplementation as a monotherapy demonstrated beneficial effects, whereas nonselective NO synthase inhibition seemed not to be beneficial, and selective NO synthase 2 inhibition was not beneficial overall. CONCLUSIONS: Because sepsis has all the characteristics of an arginine-deficiency state, we hypothesise that arginine supplementation is a logical option in the treatment of sepsis. This is supported by substantial experimental and clinical data on NO donors and NO inhibitors. However, further evidence is required to prove our hypothesis.     

Anemia: when is it iron deficiency?

Iron deficiency anemia, the most common of childhood anemias, presents many challenges to the practitioner. Careful history taking that includes nutritional assessment may uncover this frequently subtle condition. In keeping with AAP recommendations, screening will aid in diagnosing this condition in populations at risk. Prompt treatment and conscientious follow-up will afford the most optimal outcome.     

Anemia: when is it not iron deficiency?

Anemia presents a challenge both in determination of cause and appropriate management. Careful history taking and appropriate screening in keeping with AAP recommendations will aid in identifying cases of anemia. Judicious use of laboratory testing will assist in achieving accurate diagnosis. Finally, appropriately timed and monitored treatment strategies will offer the most optimal outcome.     

Peritoneal fluid adipokines: ready for prime time?

Background Visceral adipose tissues secret a variety of adipokines; however, it is not known whether they are present in the peritoneal fluid. It was the aim of this study to investigate peritoneal fluid concentrations of novel (cartonectin, omentin) and classical adipokines (leptin, adiponectin, resistin, visfatin) in patients with ascites. Material and methods Ninety‐six patients (71 men and 25 women) undergoing paracentesis were included. Of these, 76 suffered from liver cirrhosis. Adipokines were measured by enzyme‐linked immunosorbent assay or Western blot. Results Each adipokine was detected in ascites with a broad range. Serum–ascites ratios (SAR) correlated with clinical and laboratory parameters. The main variables influencing peritoneal fluid adipokine concentrations were body mass index (BMI), local inflammation, systemic inflammation and serum adipokine concentrations. Resistin was significantly higher in patients with peritonitis and showed a positive correlation with peripheral leucocytes (white blood cell count). Leptin was correlated with the underlying disease. Visfatin correlated with peripheral white blood cell and C‐reactive protein levels. Omentin expression was correlated with ascitic leucocyte count, ascitic albumin concentration and low albumin SAR. BMI was correlated positively with ascitic leptin levels and cartonectin protein levels. Conclusions Peritoneal fluid adipokine concentrations are characterized by individual SARs, depend on the presence of peritonitis, and correlate with underlying disease, BMI and systemic inflammation. The data open a new field of research on the role of the peritoneum and visceral adipokines in gastrointestinal diseases.     

Nebulized furosemide for the management of dyspnea: does the evidence support its use?

Dyspnea is a common and distressing symptom associated with multiple chronic illnesses and high levels of burden for individuals, their families and health care systems. The subjective nature dyspnea and a poor understanding of pathophysiological mechanisms challenge the clinician in developing management plans. Nebulized furosemide has been identified as a novel approach to dyspnea management. This review summarizes published studies, both clinical and experimental, reporting the use of nebulized furosemide. The search criteria yielded 42 articles published in the period 1988 to 2004. Although nebulized furosemide appeared to have a positive influence on dyspnea and physiological measurements, caution must be taken with the results primarily coming from small-scale clinical trials or observation trials. Despite the limitations of the studies reported, given the range of conditions reporting effectiveness of nebulized furosemide, further investigation of this potential novel treatment of dyspnea is warranted.     

Estimation of fluid status changes in critically ill patients: Fluid balance chart or electronic bed weight?

Purpose

Monitoring of fluid balance (FB) can be achieved by subtracting recorded fluid output from input or by measuring changes in body weight (BW). The latter approach is difficult in the critically ill. Recently, hospital beds have become available with the ability to directly weigh patients in the intensive care unit (ICU) patients directly. We sought to compare FB estimates obtained by these 2 methods in a cohort of critically ill patients.

Materials and Methods

Between November 2010 and May 2011, all patients admitted in our ICU for more than 2 consecutive days and nursed on a Hill-Rom (Batesville, Ind) Total Care bed were weighed daily at midnight hours. Fluids charting was done by electronic spreadsheet with automated 24 hours calculation. Differences in BW and FB between 2 consecutive days were compared using correlation and Bland-Altman analysis. Corrections for unmeasured fluids losses were performed using a predetermined formula based on peak temperature and intubation status.

Results

We obtained complete data in 160 (31%) of 504 admissions exceeding 2 days (153 patients) resulting in 435 data points. The change in BW over 24 hours and FB for the same period was only weakly correlated before (r = 0.34; P < .001; Fig. 1) or after correction for insensible fluid losses (r = 0.34; P < .001). On Bland-Altman plot, the mean bias was small (0.07 kg), but the 95% limits of agreement, very large (−5.8 and 6.0 kg). The lack of agreement increased with the magnitude of the changes.

Conclusion

Obtaining daily weights in ICU patients proved difficult. Compliance was poor. The correlation between changes in BWs and FB was weak. Further studies are required to establish if accurate and reproducible daily weighing of ICU patients is feasible.     

Herbal or complementary medicine: fact or fiction?

Although herbal medications have been used in medical therapy since the dawn of civilization, they have not undergone careful scientific assessment. Some herbal derivations are exceptional and have become standard therapy in cardiovascular disease; eg, digitalis, reserpine, and aspirin. The high prevalence of herbal use around the world and in the United States today may have a negative impact on patient care when herbal preparations are used in combination with medications ordered by healthcare providers who are not advised of the patient's use of herbs. Healthcare providers need to be familiar with all herbal medications in order to prevent potentially serious reactions between conventional and herbal medications. They should be asking patients about herbal use when first obtaining a medical history. Patients who use alternative therapies do not tell their healthcare providers about such use.