Highlighting the structure-function relationship of the brain with the Ising model and graph theory

With the advent of neuroimaging techniques, it becomes feasible to explore the structure-function relationships in the brain. When the brain is not involved in any cognitive task or stimulated by any external output, it preserves important activities which follow well-defined spatial distribution patterns. Understanding the self-organization of the brain from its anatomical structure, it has been recently suggested to model the observed functional pattern from the structure of white matter fiber bundles. Different models which study synchronization (e.g., the Kuramoto model) or global dynamics (e.g., the Ising model) have shown success in capturing fundamental properties of the brain. In particular, these models can explain the competition between modularity and specialization and the need for integration in the brain. Graphing the functional and structural brain organization supports the model and can also highlight the strategy used to process and organize large amount of information traveling between the different modules. How the flow of information can be prevented or partially destroyed in pathological states, like in severe brain injured patients with disorders of consciousness or by pharmacological induction like in anaesthesia, will also help us to better understand how global or integrated behavior can emerge from local and modular interactions.

Open and closed chest extrathoracic cannulation for cardiopulmonary bypass and extracorporeal life support: methods, indications, and outcomes

Extrathoracic cannulation to establish cardiopulmonary bypass has been widely applied in recent years and includes: (a) repeat surgery, (b) minimally invasive surgery, and (c) cases with diseased vessels such as porcelain, aneurysmal, and dissecting aorta. In addition, the success and relative ease of peripheral cannulation, among other technological advances, has permitted the development of closed chest extracorporeal life support, in the form of cardiopulmonary support and extracorporeal membrane oxygenation. With this development have come applications for cardiopulmonary bypass based support outside the traditional cardiac theatre setting, including emergency circulatory support for patients in cardiogenic shock and respiratory support for patients with severely impaired gas exchange. This review summarises the approach to extrathoracic cannulation for the generalist.

Leptospirosis: a case report of a patient with pulmonary haemorrhage successfully managed with extra corporeal membrane oxygenation

Leptospirosis is a zoonosis of worldwide significance. Pulmonary involvement is common but often mild and of little clinical significance. However, over the last two decades an increasing number of cases have been reported with pulmonary haemorrhage as a prominent feature [Carvalho CR, Bethlem EP. Pulmonary complications of leptospirosis. Clin Chest Med, 2002;23(2):469-78]. These cases are particularly challenging to treat as they often have resistant hypoxaemia despite maximal invasive mechanical ventilation. Consequently, there is a high mortality rate. Here, we present a case of severe leptospirosis complicated by massive pulmonary haemorrhage which was successfully managed by extra corporeal membrane oxygenation (ECMO).

Role of ECMO in the treatment of respiratory syncytial virus bronchiolitis: a collaborative report

AIM

To report the collaborative experience of extracorporeal membrane oxygenation (ECMO) in the treatment of respiratory syncytial virus (RSV) bronchiolitis between April 1989 and January 1995.

METHODS

The medical records of patients with confirmed RSV bronchiolitis referred to three centres (Leicester, Glasgow, and Great Ormond Street) were reviewed.

RESULTS

Twenty four infants were identified. Seventeen had been born prematurely (gestational range 23-40 weeks, median 30 weeks). Thirteen infants had been mechanically ventilated after birth and seven of these had evidence of bronchopulmonary dysplasia (BPD). The age of onset of RSV infection varied from three to 64 weeks (mean 17.4 weeks, median 12 weeks). Ventilation before ECMO ranged from one to 16 days and oxygenation indices at the time of referral ranged from 21-73 (mean 39). Ribavirin was used in eight of the 24 patients. Sixteen patients received venoarterial and eight veno-venous ECMO. ECMO hours ranged from 32-647 (median 196 hours). One infant died (survival rate 96%). Cranial ultrasound abnormalities were detected in three patients. However, at follow up only one of the 23 survivors had evidence of developmental delay.

CONCLUSION

A group of paediatric patients in whom ECMO can be of benefit has been identified. The use of ECMO should be considered when other means of support prove unsuccessful.

Extracorporeal life support in paediatrics

Extracorporeal membrane oxygenation (ECMO) is a life support technique based on modifications of heart-lung bypass technology. It is used to support severe but potentially reversible pulmonary or cardiopulmonary failure. There is increasing use of the technique for neonates and a return of interest in its use for adults. The number of non-neonatal paediatric patients receiving pulmonary support with ECMO worldwide is, however, small, and survival rates average less than 50%. Initial experience in 15 patients aged 3 months to 5 years with a high survival and low morbidity is reported.

Salvage of postoperative pulmonary hypertensive crisis using ECMO via cervical cannulation in a case of truncus arteriosus

The survival of patients with truncus arteriosus beyond one year of age is rare without surgical treatment [3 . Early surgery may be associated with a mortality but is still preferable, as the risks of established pulmonary hypertensive disease complicate delayed surgery [2]. We report the successful salvage of a pulmonary hypertensive crisis 24 h after corrective surgery in a late presenting patient using extracorporeal membrane oxygenation (ECMO) via cervical cannulation. Post-operative pulmonary hypertensive crises may present a difficult management problem. Extracorporeal membrane oxygenation is therapeutic in these circumstances in addition to providing life support. Cervical cannulation remains the method of choice in the postoperative cardiac patient.

Neonatal extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation is an effective life support technique that has had most success in the treatment of neonatal cardiopulmonary failure. We review the technique and its potential indications and present the latest UK and worldwide survival data.

Radiation inactivation of rabbit muscle aldolase

Pulse radiolysis and steady-state X-radiolysis have been used to investigate the radiation inactivation of aldolase from rabbit muscle. Both eaq-and OH readily react with aldolase, and contribute to inactivation. The radical anions (CNS)2-and (Br)2-react with aldolase at neutral pH. The progressive addition of alkali results in an increase in the second-order rate constants, with an apparent pK approximately 10 +/- 0-3, and with the formation of an unstable intermediate, lambdamax approximately 400 nm resembling a phenoxyl radical. Steady-state radiolysis in the presence of (CNS)2-and (Br)2- at alkaline pH results in increased aldolase inactivation, with a pK of enzyme inactivation similar to that observed for reaction of the radical anions. We propose that a reaction of the radical anoins with tyrosine residues accounts for the resultant inactivation.