A new mathematical model to evaluate simazine removal in three different immobilized-biomass reactors.

A new mathematical model based on the cinetical Langmuir equation is developed to interpret and predict the effectiveness of simazine (SZ) removal in immobilized-biomass reactor (IBR), to consider herbicide-support affinity (Cx), and herbicide-cell affinity (Cy). Three solid supports: sepiolite monolith, granular sepiolite, and alginate were used in pilot-scale reactors that were inoculated with Klebsiella planticola DSZ. The abiotic process was analysed by measuring the SZ sorption capacity of the reactor supports. Sepiolite monolith showed the maximum value for herbicide-support affinity (28.02+/-0.9%). The effectiveness of the biotic process was estimated considering the formation of biomass and SZ biodegradation. Granular sepiolite showed either higher affinity with SZ and viability rate (0.90) throughout the process, and SZ removal rate was 3.39+/-0.06 mg/h. The mathematical model presented in this paper provides useful insights into the interpretation of experimental data as well as prediction for the implementation of biological reactors.

[Tumours in the pineal region in the paediatric age. Reports of 23 cases and a review of the literature]. / Tumores de la region pineal en la edad pediatrica. Presentacion de 23 casos y revision de la bibliografia.

INTRODUCTION: Tumours in the pineal region are located at a meeting point of several neurovascular structures that are difficult to reach surgically and for which the possibility of resection is limited; as a result the management of these lesions usually requires associated adjunctive treatment with radiotherapy and/or chemotherapy. PATIENTS AND METHODS: This study is a retrospective analysis of the epidemiological, clinical, neuroimaging and pathological characteristics of 23 patients with tumours in the pineal region who were treated between the years 1997 and 2010 in the Hospital Infantil Niño Jesús. The factors involved in the prognosis of this cohort following surgical or adjunctive treatment are also discussed. RESULTS: Subjects included in the study were 6 girls and 17 boys with ages ranging from 4 months to 18 years. It was found that the initial symptoms in 95% of the patients were signs of acute or subacute hydrocephalus, which required the placement of a ventriculoperitoneal shunt (82%). A histological sample of the tumour tissue was collected in all cases. Biopsy samples were taken in the case of five patients and 18 underwent surgery involving a craniotomy. Germinoma (eight cases) and mature teratoma (one case) were the tumours with the longest survival times; non-germinomatous tumours (three cases), those of the pineal parenchyma (four cases) and gliomas (five cases) presented the highest rates of recurrence and a poorer prognosis. CONCLUSIONS: The study of tumour markers can be used to guide the diagnosis of certain tumours of the pineal region. At present, the recommended procedure involves taking a histological sample of the tumour in order to establish an accurate diagnosis and a specific oncological treatment.

Assessment of soft tissue injury in open tibial shaft fractures by transcutaneous oximetry.

Transcutaneous oximetry was performed on 32 patients with 33 open tibial shaft fractures in an attempt to identify those patients at risk for the subsequent development of serious complications. Oxygen electrodes were placed on areas of intact skin, over viable compartments at the fracture site (wound) as well as on the anterior chest wall (control). Simultaneous wound and chest wall measurements were obtained after equilibration (30 minutes) on both room air and 100% oxygen. Values obtained were expressed as absolute values and as percentages of the wound measurement divided by the chest measurement. The study group consisted of 27 male and five female patients with an average age of 37 years (range, 17-63 years). There were 8 Grade I, 12 Grade II, and 13 Grade III fractures as described by Gustilo et al. Complications requiring medical or surgical intervention occurred in six patients: four deep infections, one deep vein thrombosis, and one superficial infection with severe bone and soft tissue loss requiring multiple procedures. Transcutaneous oximetry with patients breathing 100% oxygen was found to correlate with the development of complications in this study group. Five (42%) of 12 patients with transcutaneous oximetry values < or = 85 mm Hg and a wound-to-chest ratio < or = 25% developed a complication, whereas only one of 19 patients with either a fracture site value greater than 85 mm Hg or a wound to chest ratio greater than 25% developed a complication (p = 0.007).

Chondromalacia of the trochlear notch in athletes who throw.

Six athletes who throw and one shot-putter who underwent elbow arthroscopy were found to have an area of chondromalacia involving the posterolateral aspect of the olecranon. Preoperative symptoms were pain and tenderness to palpation over the lateral edge of the olecranon. On physical examination, range of motion was full or only slightly decreased (< 5 degrees) in five patients; coexistent loose bodies were also noted in two patients having a 20 degrees loss of extension. None of the patients exhibited ligamentous laxity to valgus stress testing of the elbow. During arthroscopy, the involved area was distinct from the bare area of the olecranon. This area was found as an isolated lesion in only one of seven patients; localized synovitis was noted in five patients, olecranon osteophytes in three, and loose bodies in two. A reciprocal lesion on the articular surface of the humerus was not identified in any patient. During arthroscopy, the lesion was debrided to a stable margin, and all associated pathologic conditions were addressed. Six of the seven athletes were able to return to their sport at premorbidity levels with this approach. This area of trochlear chondromalacia has not been previously described and, in our study, occurred in individuals whose elbows were subjected to repetitive valgus stress with lateral compression.