[Toward the appropriate use of teleradiology]

Teleradiology involves much more than merely transmitting images and information between two points: teleradiology consists of sharing knowledge and working together in a network. It facilitates rapid access to radiological reports and second opinions, remote consulting among physicians, improved patient care, access to complex tools for postprocessing and computer-aided diagnosis, support for research and training projects, ties between isolated healthcare providers and busier or more experienced providers, 24-hour coverage, and competition among radiology departments. A close relation with the radiologist leads to better care. However, teleradiology should not have negative effects on the efficacy of the clinical radiology service that is closest to the patient. This article focuses on the legal requirements of teleradiology services and on the clinical problems that can arise in teleradiology settings, with the ultimate aim of ensuring the appropriate use of teleradiology to improve healthcare.

Laparoscopic resection with transanal specimen extraction for sigmoid diverticulitis

BACKGROUND

This prospective study evaluated the technical aspects and microbiological consequences of laparoscopic resection with transanal specimen extraction and per ano transcolonic stapler anvil insertion in patients requiring elective operation for previous diverticulitis.

METHODS

Laparoscopic sigmoid colectomy was performed with three ports, and specimen extraction carried out transanally through a complete opening of the rectal stump. A triple-stapled anastomosis restored colonic continuity. Systematic intraoperative bacteriological sampling was performed. Intraoperative data as well as microbiological and postoperative outcomes were evaluated prospectively.

RESULTS

Sixteen consecutive patients were studied over a 6-month period. All procedures were technically satisfactory, with a mean(s.d.) operating time of 120·9(41·9) min. No conversion or additional access was required. Four of the 16 patients developed complications, but none required intervention. Although polybacterial growth was present in all peritoneal culture samples, no infection-related complications were observed. Two patients had an extended course of perioperative antibiotic cover owing to overt peritoneal cavity contamination during surgery, and in two further patients antibiotics were instituted empirically following the development of postoperative fever alone.

CONCLUSION

Transanal specimen extraction in addition to per ano transcolonic stapler anvil insertion allows laparoscopic sigmoid resection to be performed with just three ports. Although intraperitoneal bacterial contamination occurs, this does not appear to translate into infectious morbidity.

Oxidative stress and altered mitochondrial function in neurodegenerative diseases: lessons from mouse models

Oxidative stress has been consistently linked to ageing-related neurodegenerative diseases leading to the generation of lipid peroxides, carbonyl proteins and oxidative DNA damage in tissue samples from affected brains. Studies from mouse models that express disease-specific mutant proteins associated to the major neurodegenerative processes have underscored a critical role of mitochondria in the pathogenesis of these diseases. There is strong evidence that mitochondrial dysfunction is an early event in neurodegeneration. Mitochondria are the main cellular source of reactive oxygen species and key regulators of cell death. Moreover, mitochondria are highly dynamic organelles that divide, fuse and move along axons and dendrites to supply cellular energetic demands; therefore, impairment of any of these processes would directly impact on neuronal viability. Most of the disease-specific pathogenic mutant proteins have been shown to target mitochondria, promoting oxidative stress and the mitochondrial apoptotic pathway. In addition, disease-specific mutant proteins may also impair mitochondrial dynamics and recycling of damaged mitochondria via autophagy. Collectively, these data suggest that ROS-mediated defective mitochondria may accumulate during and contribute to disease progression. Strategies aimed to improve mitochondrial function or ROS scavenging may thus be of potential clinical relevance.

[Carotid revascularisation using angioplasty and stent in 134 consecutive cases in a reference hospital: a risky technique?]

INTRODUCTION

Carotid revascularisation (CR) using angioplasty and stent (ASC) is an effective procedure in the prevention of ischaemic stroke, but with a controversial morbidity and mortality in the different studies conducted in this field.

METHODS

The results of the ASCs performed in the Virgen de la Arrixaca University Hospital (Murcia) between January 2006 and April 2009 were analysed (epidemiology, indication, grade of residual stenosis and procedure complications). All patients subjected to ASC were pre-selected and followed up by neurologists, and they followed a strict medical protocol for performing the procedure. All ASCs were performed by a team consisting of two surgeons, an anaesthetist and a nurse.

RESULTS

A total of 134 ASC were performed. The mean age of our patients was 72.7 years, with the large majority (75%) being male. The most prevalent diseases were, high blood pressure (81%), smoking (66.4%), and diabetes (38.1%). The most common indications for CR were symptomatic carotid stenosis with a level of stenosis of 75-99%, either in the left (33.6%) or right (32.1%), followed by asymptomatic stenosis combined with risk factors (11.2% in the left side and 10.4% in the right side). A level of stenosis less than 30% was achieved in 132 of the 134 ASC (98.5%). performed. Five patients (3.7%) had complications associated with the procedure, of which four were different clinical presentations of a re-perfusion syndrome and one an asymptomatic thrombosis of the stent.

CONCLUSIONS

ASC is a complex technique that must be performed by appropriately trained specialists. The performing a minimum number of procedures per year and an admission protocol controlled by Neurology are essential conditions for a low rate of complications. Under these conditions, the morbidity and mortality of the technique is no higher than that of endarterectomy.

Si-nanocrystal-based LEDs fabricated by ion implantation and plasma-enhanced chemical vapour deposition

An in-depth study of the physical and electrical properties of Si-nanocrystal-based MOSLEDs is presented. The active layers were fabricated with different concentrations of Si by both ion implantation and plasma-enhanced chemical vapour deposition. Devices fabricated by ion implantation exhibit a combination of direct current and field-effect luminescence under a bipolar pulsed excitation. The onset of the emission decreases with the Si excess from 6 to 3 V. The direct current emission is attributed to impact ionization and is associated with the reasonably high current levels observed in current-voltage measurements. This behaviour is in good agreement with transmission electron microscopy images that revealed a continuous and uniform Si nanocrystal distribution. The emission power efficiency is relatively low, approximately 10(-3)%, and the emission intensity exhibits fast degradation rates, as revealed from accelerated ageing experiments. Devices fabricated by chemical deposition only exhibit field-effect luminescence, whose onset decreases with the Si excess from 20 to 6 V. The absence of the continuous emission is explained by the observation of a 5 nm region free of nanocrystals, which strongly reduces the direct current through the gate. The main benefit of having this nanocrystal-free region is that tunnelling current flow assisted by nanocrystals is blocked by the SiO2 stack so that power consumption is strongly reduced, which in return increases the device power efficiency up to 0.1%. In addition, the accelerated ageing studies reveal a 50% degradation rate reduction as compared to implanted structures.

Brain Edema after Carotid Revascularization: Benign Syndrome or Prelude to Hemorrhage?

Brain edema (BE) post carotid revascularization (CR) is considered a benign presentation of the hyperperfusion syndrome. Its physiopathology has been related to production of vasogenic edema that tends to progressive spontaneous resolution. Its relation with post-CR hemorrhage remains unclear. Three cases of BE post-CR are described and compared to controls. Clinical evolution, medical management, and plain-CT and perfusion-CT (PCT) results are analysed. Two cases of BE had a benign course, with a progressive resolution of edema and disappearance of neurologic deficits. Effective blood pressure control was achieved in these patients. The third case suffered massive hemorrhage 24h after initial BE and died. This patient reached peak systolic levels of 220 mmHg before conversion to hemorrhage. Plain-CT and PCT findings were similar in the three patients with BE. CT showed signs of hemispheric brain swelling ipsilateral to CR. PCT showed low MTT and high CBF values on the hemisphere ipsilateral to CR compared to the contralateral hemisphere, with symmetric CBV values. Plain-CT and PCT in controls showed no abnormalities. BE post CR can be reversible but may also herald a hemorrhagic complication. A common physiopathology of post-CR BE and hemorrhage is suggested by PCT findings, related to failure of autoregulation and secondary blood-brain-barrier dysfunction. Spontaneous resolution of BE post-CR should not be routinely expected in clinical practice. Conversion to hemorrhage might be related with deficient blood pressure control and secondary rupture of the already damaged vessel wall.

Fresnel-Gaussian shape invariant for optical ray tracing

We propose a technique for ray tracing, based in the propagation of a Gaussian shape invariant under the Fresnel diffraction integral. The technique uses two driving independent terms to direct the ray and is based on the fact that at any arbitrary distance, the center of the propagated Gaussian beam corresponds to the geometrical projection of the center of the incident beam. We present computer simulations as examples of the use of the technique consisting in the calculation of rays through lenses and optical media where the index of refraction varies as a function of position.

[Trunk control test: early predictor of gait balance and capacity at 6 months of the stroke]

INTRODUCTION

It has been challenging to establish a prognostic tool in the acute period following stroke to predict gait outcomes. The purpose of this study is to determine the relationship between trunk control and other early functional prognostic measures with equilibrium and the capacity to ambulate at six months following acute stroke.

METHODS

Sixty-eight patients with stoke admitted consecutively to the Physical Medicine and Rehabilitation unit were followed prospectively. At one and two weeks following admission, the following data were collected: sex, age, type of stroke, urinary incontinence, National Institutes of Health Stroke Scale (NIHSS) and the Trunk Control Test (TCT). At six months following acute stroke, balance was assessed with the Berg Balance score, baropodometry, and computerized posturography as well as gait capacity (measured as velocity and gait ability and limits)

RESULTS

This study found a significant correlation between age, sex, urinary incontinence, TCT and NIHSS at one and two weeks from onset of stroke and the results of equilibrium and gait capacity at six months (p<0.05). When the TCT is <37 in the second week following acute stroke, the Berg Balance score was found to be lower, and with worse gait characteristics (<0.001). The TCT score in the second week is predictive of the achieving functional gait at the six month endpoint (area beneath the curve 0.920).

CONCLUSIONS

The TCT is a simple and quick test which may be considered as an early prognostic indicator for functional motor endpoints in the patient with stroke.