An interspecies computational study on limb lengthening

Distraction osteogenesis is a surgical technique that produces large volumes of new bone by gradually separating two osteotomized bone segments. A previously proposed mechanical-based model that includes the effect of pre-traction stresses (stress level in the gap tissue before each distraction step) during limb lengthening is used here. In the present work, the spatial and temporal patterns of tissue distribution during distraction osteogenesis in different species (sheep, rabbit) and in the human are compared numerically to predict experimental results. Interspecies differential characteristics such as size, distraction protocol, and rate of distraction, among others, are chosen according to experiments. Tissue distributions and reaction forces are then analysed as indicators of the healing pattern. The results obtained are in agreement with experimental findings regarding both tissue distribution and reaction forces. The ability of the model to qualitatively predict the two animal models and the human healing pattern in distraction osteogenesis indicates its potential in understanding the influence of mechanics in this complex process.

Usefulness of Video-EEG monitoring in patients with drug-resistant epilepsy

OBJECTIVE

To evaluate the characteristics of patients on whom long-term Video-EEG monitoring is performed in a specialist centre and to assess its suitability to study refractory epilepsy patients.

METHODS

A prospective analysis and study of Video-EEG monitoring was performed in a series of 100 refractory epilepsy patients from a single centre. The analysis included demographic data, the time until the first seizure, the methods used to provoke seizures, and the outcome (usefulness, change in the management, pharmacological and surgical improvement). A subgroup analysis based on diagnosis was performed.

RESULTS

The study was performed mainly on young people (mean 34.4 years) and the first seizure appeared in a mean of 30hours, requiring most of the patients to withdraw the medication. Nevertheless, there were no cases of status epilepticus. The usefulness of the test was high in all the groups. The management was changed in 65% of the patients with pharmacological and surgical improvement.

CONCLUSION

Long-term Video-EEG monitoring is a suitable test to study refractory epilepsy patients. The main problem in our country is accesibility.

Evaluating the non-tuberculous mycobacteria effect in the tuberculosis infection diagnosis

The aim of the present study was to determine the role of previous non-tuberculous mycobacteria sensitisation in children as a factor of discordant results between tuberculin skin test (TST) and an in vitro T-cell based assay (T-SPOT.TB; Oxford Immunotec, Oxford, UK). We enrolled 21 non-bacille Calmette-Guérin-vaccinated paediatric patients for suspicious of latent tuberculosis infection (LTBI). These patients yielded a positive TST and a negative T-SPOT.TB. Cells were stimulated with Mycobacterium avium sensitin (having cross-reaction with Mycobacterium intracellulare and Mycobacterium scrofulaceum) and the presence of reactive T-cells was determined by an ex vivo ELISPOT. From the 21 patients, in 10 cases (47.6%), we obtained a positive ELISPOT result after stimulation with M. avium sensitin, in six (28.6%) cases, the result was negative and in the remaining five (23.8%) cases, the result was indeterminate. In conclusion, previous non-tuberculous mycobacteria sensitisation induces false-positive results in the TST for diagnosing LTBI and the use of gamma-interferon tests could avoid unnecessary chemoprophylaxis treatment among a child population.

Exploratory Factor Analysis and Psychometric Properties of the General Health Questionnaire in Spanish Adolescents

The aim of this study was to assess the homogeneity of items, reliability as a metric indicator of global quality (internal consistency and temporal stability), and the exploratory factor structure of the General Health Questionnaire-28 (GHQ-28) in a sample of 2,010 Spanish adolescents. Mean age was 15.9 yr. (range 14-19, SD = 2.1). The test was administered twice with 20 days between responses. Answers were scored on a Likert-type scale. The internal consistency and test-retest reliabilities obtained were .93 and .94. In exploratory factor analysis, four factors explained 52.7% of the variance. These results indicated that the GHQ-28 is a psychometrically sound mental health measure in Spanish adolescents.

A new combination of extraction and derivatization methods that reduces the complexity and preparation time in determining phospholipid fatty acids in solid environmental samples

Combinations of three extraction methods (modified Folch method, modified Bligh and Dyer and microwave-assisted extraction (MAE)) and two derivatization methods (alkaline methanolysis and derivatization with trimethylsulfonium hydroxide (TMSH)) are compared for determining phospholipid fatty acids (PLFAs) in soil and solid organic samples (animal manures, compost and vermicompost). The modified Folch method rendered the greatest total amount of PLFAs and the highest yields of individual PLFA biomarkers; the effect was most apparent in the vermicompost samples. MAE rendered similar extraction yields as the modified Bligh and Dyer method (the most commonly used extraction method), although MAE is much simpler and faster. The highest conversion yields of PLFAs into fatty acid methyl esters were achieved with TMSH as the derivatization agent. The modified Folch method together with derivatization with TMSH was the least complex and time consuming method of determining microbial community structure in solid environmental samples.

[Role of decompressive craniectomy in brain injury patient]

Second level therapeutic maneuvres for controlling intracranial hypertension (ICH) proposed by the European Brain Injury Consortium and the American Association of Neurological Surgeons include barbiturates, moderate hypothermia and decompressive craniectomy (DC). However, neither barbiturates nor hypothermia have been demonstrated to improve its outcome. DC could be a therapeutic option in the management of ICH without intracerebral masses. Therefore, our goal has been to review and analyze the clinical usefulness of DC in patients with brain injury in an attempt to deal with some concerns of the critical care physicians. Can DC improve patient outcome? Currently, there are no randomized and controlled clinical trials supporting or rejecting the practice of DC in adults. Most published reports provide level II of evidence. However, most of those studies have shown that the outcome is better in patients with DC. When should DC be performed? It should be performed early to prevent ICH from occurring more than 12 hours. What are the effects of DC on intracranial pressure and brain oxygenation? In most patients, ICP can be maintained below 25 mmHg after a DC. However, to improve brain oxygenation (PtiO(2)), the probe must be placed in the healthy area of the most severely damaged cerebral hemisphere. What is the suggested surgical procedure? Frontal-subtemporal-parietal-occipital craniectomies, including enlargement of the dura by duroplasty. And finally, what are the current contraindications of DC? Glasgow Coma Scale score 3 points post-resuscitation states with dilated and arreactive pupils, age > 65 years old, ICH > 12 hours, persistent (a-yv)DO(2) < 3.2% or PtiO(2) < 10 mmHg maintained from the moment of admission.

Renal vein extension using gonadal vein: a useful strategy for right kidney living donor harvested using laparoscopy

INTRODUCTION

Vascular management of the right renal vein during laparoscopic living donor nephrectomy is still an unsolved problem. This short vessel has limited the use of right kidneys. However, the right kidney should be harvested in some instances. Based on experience in open donor nephrectomy, our unit has used the donor gonadal vein to obtain a longer renal vein in this setting.

METHODS

Four consecutive living related donors with the indication for laparoscopic right nephrectomy underwent this procedure. Three donors were females and the overall average age was 48.5 years. The renal vein was controlled with a 30-mm stapler and we included 5-6 cm of the ipsilateral gonadal vein during the harvest. The donor kidney was perfused and renal vessels prepared under cold conditions. The gonadal vein was opened longitudinally and sutured to the donor right renal vein as a wide tube in 3 cases and as a spiral tube in 1 case with 6-0 monofilament suture.

RESULTS

This procedure extended the bench work between 25 to 40 minutes permitting an 2.5- to 3.5-cm extension of the donor vein. The transplantations were performed in the usual mode and the vein enlargement enormously facilitated the implantation surgery. All recipients displayed immediate graft function; no complications were observed with this strategy.

CONCLUSIONS

Vein extension with the gonadal vein was a simple, safe method to enlarge the renal vein among right living donor kidneys procured using laparoscopy.

Duration of delayed graft function is an important predictor of 1-year serum creatinine

OBJECTIVE

The purpose of this study was to evaluate the importance of various factors on 1-year serum creatinine (SCr) as a surrogate endpoint for allograft survival among a series of kidney transplantations performed at 2 centers.

PATIENTS AND METHODS

Two hundred sixty consecutive renal transplantations were included with overall mean age of 40 +/- 13 years, including 55% men and 19% living donor grafts. Factors considered for analysis were donor and recipient ages, and sexes, number of transplantations, panel-reactive antibodies, total number of HLA mismatches, cold ischemia time (CIT), acute rejection (AR) rate, and presence/duration of delayed graft function (DGF). Multiple regression analyses were performed for 1-year SCr, AR rate, and DGF duration.

RESULTS

One-year SCr was 1.46 +/- 0.5 mg/dL, 6-month AR rate was 22%, and DGF rate was 29% of mean duration 3 +/- 8 days. Multiple regression analysis for lower 1-year SCr value identified as significant female recipient sex, lower donor age, absence of AR within 6 months, and decreased DGF duration (P < .05). The only significant factor affecting AR rate was DGF duration. Finally, prolonged CIT was associated with a longer DGF duration.

CONCLUSIONS

We confirmed that 1-year SCr was primarily affected by well-known factors, such as AR incidence, donor age, and female recipient sex. However, we identified DGF duration as a significant factor affecting 1-year SCr. AR rate was also associated with DGF duration, which in turn depended upon longer CIT.

Porcine myelomonocytic markers and cell populations

This review focuses in what is currently known about swine myeloid markers, the expression and function of these receptors in the biology of porcine myelomonocytic cells, the regulation of their expression along the different developmental stages of these cells and their utility to investigate the heterogeneity of monocyte and macrophage populations. Although the number of monoclonal antibodies recognizing surface antigens expressed on either swine granulocytes or monocytes is low compared with those available for human or mouse, they have contributed significantly to study the members of myeloid lineages in this species, allowing to discriminate different maturation stages of these cells in bone marrow and to reveal the heterogeneity of blood monocytes and tissue macrophages. Porcine myeloid cells share many similarities with humans, highlighting the relevance of the pig as a biomedical model.

[Spontaneous Subarachnoid Haemorrhage multicenter database from the Group for the Study of Vascular Pathology of the Spanish Society for Neurosurgery: presentation, inclusion criteria and development of an internet-based registry]

INTRODUCTION

Subarachnoid haemorrhage is one of the most severe neurosurgical diseases. Its study is crucial for improving the care of these patients in our environment. With this goal the Group for the Study of Neurovascular Pathology of the Spanish Society for Neurosurgery (SENEC) decided to create a multicenter registry for the study of this disease.

MATERIALS AND METHODS

In this database we have prospectively included all cases with spontaneous subarachnoid haemorrhage admitted to the participant hospitals from November 2004 to November 2007. The fields to be included in the database were selected by consensus, including age, past medical history, clinical characteristics at admission, radiological characteristics including presence or absence of an aneurysm and its size and location, type and complications of the aneurysm treatment, outcome assessed by the Glasgow Outcome Scale (GOS) at discharge and six months after the bleeding as well as the angiographic result of the aneurysm treatment. All fields were collected by means of an electronic form posted in secure web page.

RESULTS

During the three years of study a total of 1149 patients have been included by 14 Hospitals. The time needed to fill in a patient in the registry is approximately 3.4 minutes. This series of patients with spontaneous SAH is similar to other non-selected in-hospital series of SAH. The mean age of the patients is 55 years and there is a 4:3 female to male ratio. In relation to the severity of the bleeding 32% of the patients were in poor clinical grade at admission (WFNS 4 or 5). 5% of the patients died before angiography could be performed. An aneurysm was confirmed as the origin of the bleeding in 76% of the patients (aSAH), while in 19% of the patients no lesion was found in the angiographic studies and were thus classified as idiopathic subarachnoid hemorrhage (ISAH). Of those patients with aSAH, 47% were treated endovascularly, 39% surgically, 3% received a combined treatment and 11% did not receive any treatment for their aneurysm because of early death. Regarding outcome, there is a 22% mortality in the series. Only 40% of the patients with aSAH reached a good outcome at discharge (GOS = 5).

CONCLUSIONS

Spontaneous SAH continues to be a disease with high morbidity and mortality. This database can be an ideal instrument for improving the knowledge about this disease in our environment and to achieve better results. It would be desirable that this database could in the future be the origin of a national registry of spontaneous SAH.

The glucose-lowering agent sodium tungstate increases the levels and translocation of GLUT4 in L6 myotubes through a mechanism associated with ERK1/2 and MEF2D

AIMS/HYPOTHESIS

The aim of this study was to investigate the action of the glucose-lowering compound sodium tungstate on glucose transport in muscle myotubes and to unravel the molecular events underlying the effects observed.

METHODS

We studied the effects of tungstate on 2-deoxy-D: -glucose uptake, levels and translocation of the glucose transporters GLUT4 and GLUT1, and Glut4 (also known as Slc2a4) promoter activity. We also measured the modifications of individual components of the signalling pathways involved in the effects observed.

RESULTS

Tungstate increased 2-deoxy-D: -glucose uptake in differentiated L6 myotubes through an increase in the total amount and translocation of GLUT4 transporter. The effects on glucose uptake were additive to those of insulin. Tungstate activated transcription of the Glut4 promoter, as shown by an increase in Glut4 mRNA, and by a promoter reporter assay. The assay of deletions of the Glut4 promoter indicated that the effect of tungstate is mediated by the myocyte enhancer factor 2 (MEF2)-binding domain. Accordingly, MEF2 levels and DNA binding activities were increased in response to the treatment. Tungstate-induced glucose uptake and GLUT4 transcriptional activation were dependent on the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), while no changes were observed in the phosphorylation state of the beta subunit of the insulin receptor, in the phosphatidylinositol 3-kinase pathway or in the activation of 5'AMP-activated protein kinase.

CONCLUSIONS/INTERPRETATION

Tungstate activates glucose uptake in myotubes through a novel ERK1/2-dependent mechanism. This effect is exerted by an increase in the content and translocation of the GLUT4 transporter. This is the first report of a glucose-lowering compound activating Glut4 transcription through an ERK1/2-dependent increase in MEF2 levels.

On the role of bone damage in calcium homeostasis

Bone serves as the reservoir of some minerals including calcium. If calcium is needed anywhere in the body, it can be removed from the bone matrix by resorption and put back into the blood flow. During bone remodelling the resorbed tissue is replaced by osteoid which gets mineralized very slowly. Then, calcium homeostasis is controlled by bone remodelling, among other processes: the more intense is the remodelling activity, the lower is the mineral content of bone matrix. Bone remodelling is initiated by the presence of microstructural damage. Some experimental evidences show that the fatigue properties of bone are degraded and more microdamage is accumulated due to the external load as the mineral content increases. That damage initiates bone remodelling and the mineral content is so reduced. Therefore, this process prevents the mineral content of bone matrix to reach very high (non-physiological) values. A bone remodelling model has been used to simulate this regulatory process. In this model, damage is an initiation factor for bone remodelling and is estimated through a fatigue algorithm, depending on the macroscopic strain level. Mineral content depends on bone remodelling and mineralization rate. Finally, the bone fatigue properties are defined as dependent on the mineral content, closing the interconnection between damage and mineral content. The remodelling model was applied to a simplified example consisting of a bar under tension with an initially heterogeneous mineral distribution. Considering the fatigue properties as dependent on the mineral content, the mineral distribution tends to be homogeneous with an ash fraction within the physiological range. If such dependance is not considered and fatigue properties are assumed constant, the homogenization is not always achieved and the mineral content may rise up to high non-physiological values. Thus, the interconnection between mineral content and fatigue properties is essential for the maintenance of bone's structural integrity as well as for the calcium homeostasis.

Evaluation of a Legionella urinary antigen enzyme immunoassay for rapid detection of Legionella pneumophila in water samples

Despite advances in medium formulations and pretreatment techniques, recovery of Legionella from water samples can still be quite low, difficult and time consuming. The aim of this study was to evaluate the utility of a Legionella urinary antigen enzyme immunoassay (Bartels ELISA, Trinity Biotech, Ireland) for the detection of Legionella in water samples. Reference ATCC Legionella strains were used to spike water samples to a final concentration of 10(4)-10(5)cfu/ml. The lower detection limit of the test for all Legionella pneumophila serogroups was assessed by serial dilutions of spiked water samples. Legionella antigen was detected in all filtered samples except for those spiked with L. bozemanii and L. longbeachae. The lower detection limit for soluble L. pneumophila serogroup 1 antigen was 780cfu/ml. Bartels ELISA could be a useful method for antigen detection in water samples when a high recovery of L. pneumophila is suspected. The test could be used as a rapid screening method for the detection of Legionella in a large number of samples. However, the low sensitivity of the test requires to keep on performing conventional culture for isolation and for further studies on isolated bacteria.