Seven photosynthethic microbiomes were collected from field environmental samples to test their potential in polyhydroxybutyrate (PHB) and exopolysaccharides (EPS) production, both alternatives to ...chemical-based polymers. Microscope observations together with microbial sequence analysis revealed the microbiome enrichment in cyanobacteria after culture growth under phosphorus limitation. PHB and EPS production were studied under three culture factors (phototrophy, mixotrophy and heterotrophy) by evaluating and optimizing the effect of three parameters (organic and inorganic carbon and days under light:dark cycles) by Box-Behnken design. Results showed that optimal conditions for both biopolymers synthesis were microbiome-dependent; however, the addition of organic carbon boosted PHB production in all the tested microbiomes, producing up to 14 %dcw PHB with the addition of 1.2 g acetate·L-1 and seven days under light:dark photoperiods. The highest EPS production was 59 mg·L-1 with the addition of 1.2 g acetate·L-1 and four days under light:dark photoperiods. The methodology used is suitable for enriching microbiomes in cyanobacteria, and for testing the best conditions for bioproduct synthesis for further scale up.
Abstract The role of interspinous devices (ISD) after lumbar herniated disc surgery for the prevention of postoperative back pain is controversial. The aim of this comparative prospective study was ...to determine outcomes in a selective cohort with L5–S1 disc herniation and degenerative disc changes after microdiscectomy with or without insertion of an ISD. One hundred and two consecutive patients underwent an L5–S1 microdiscectomy with or without implantation of an ISD. Group 1 consisted of 47 patients, with mild (n = 22), moderate (n = 14) or severe (n = 11) degenerative disc changes who had microdiscectomy alone. Group 2 comprised 45 patients with similar types of disc changes who underwent microdiscectomy with an ISD implant. The Visual Analogue Scale (VAS) was used to grade low-back pain and postoperative clinical status was rated according to the modified MacNab criteria. Mean VAS score for low-back pain improved significantly at 1 year follow-up from 7.3 at baseline to 2.75 ( p < 0.001) in Group 1 and from 6.7 to 1.5 ( p = 0.001) in Group 2. VAS score at 1 year showed significant improvements in 21 Group 1 patients versus 30 Group 2 patients ( p = 0.001). Forty four percent of Group 1 patients and 80% of Group 2 patients showed improvement using the modified MacNab criteria. Patients in both groups reported significant improvement in sciatic pain and disability after microdiscectomy with or without an ISD implant. Patients with mild degenerative disc changes were more likely to achieve improvement of their low-back pain when treated with both microdiscectomy and ISD insertion.
The objective of this study was to analyze the association of cerebellar tonsillar descent and syringomyelia in patients with posterior fossa arachnoid cysts. We reviewed the medical records of ten ...patients (mean, age 33; range, 24–49 years) diagnosed with posterior fossa arachnoid cyst and tonsillar descent. Symptoms evolved over a mean of 12 months (range, 6 months to 3 years). Syringomyelia was present in six cases. Six patients underwent a suboccipital craniectomy, three cases underwent an additional C1 laminectomy, and a further case had a limited craniectomy and tonsillar reduction. Three patients were also treated for hydrocephalus: one with a ventriculoperitoneal shunt and two with endoscopic third ventriculostomy. Two patients had conservative treatment. The posterior fossa arachnoid cysts were located at the vermis-cisterna magna (
n
= 4), the cerebellar hemispheres (
n
= 2), the cerebellopontine angle (
n
= 3), and the quadrigeminal cistern (
n
= 1). A patient with achondroplasia showed features of platybasia. Associated malformations included craniofacial dysmorphism in a patient diagnosed of trichorhinophalangeal syndrome and a case with a primary temporal arachnoid cyst. After a mean follow-up of 2 years (range, 3 months to 5 years), four patients showed resolution of their neurological symptoms, and two exhibited persisting ocular findings. Headaches and nuchalgia improved in four cases and persisted in four. Syringomyelia was resolved in four patients and improved in two. Patients harboring a posterior fossa arachnoid cyst may evolve with acquired Chiari malformation and syringomyelia. Initial management should be directed to decompressing the foramen magnum and should include the resection of the arachnoid cyst’s walls. A wait-and-see attitude can be implemented in selected cases. In our experience, hydrocephalus should be properly addressed before treating the arachnoid cyst.
Case Report
A 4-year-old boy with kaposiform lymphangiomatosis (KLA) developed progressive headaches and papilloedema and was diagnosed with pseudotumor cerebri initially treated with acetazolamide. ...Clinical deterioration prompted placement of a ventriculoperitoneal shunt. After the surgery, the child’s condition has markedly improved.
Discussion and conclusions
A network of intracranial lymphatics is presently being investigated. Neuroimaging excluded KLA infiltration of the skull and/or meninges, leaving as the most plausible explanation for the child’s pseudotumor cerebri the existence of an increase in intracranial venous pressure by venous compression at the thorax. To our knowledge, our case constitutes the first report of pseudotumor cerebri occurring in the context of KLA.
Background
Chiari type I malformation is a congenital disorder that is characterized by the caudal extension of the cerebellar tonsils through the foramen magnum into the cervical canal and by a ...reduced posterior fossa volume.
Methods
We report our surgical technique of reposition, reduction, or resection of the cerebellar tonsils for the management of Chiari I malformation. The procedure was performed in 22 adult patients, in three different centers, with a mean age of 37 years. Clinical complaints included headaches, nuchalgia, vertigo, and upper-limb weakness or numbness. Seven patients had cervical syringomyelia. Symptoms developed within a mean time of 36 months (range, 12–70 months).
Results
The cerebellar tonsils were exposed through a dura mater–arachnoid incision at the atlanto-occipital space after a 0.5-cm rimming craniectomy of the occipital bone in all patients. In seven patients the tonsils were resected, in other seven were reduced by subpial coagulation and aspiration, and in the remaining eight patients the tonsils were repositioned after coagulating their surfaces. Three patients had also a posterior fossa arachnoid cyst that was fenestrated in two of them. All patients improved postoperatively. Syringomyelia was reduced in five of seven patients. The mean length of the follow-up period was 12 months.
Conclusions
Selective reposition, reduction, or resection of herniated cerebellar tonsils may improve symptoms in adult patients with Chiari I malformation.
To analyze the association of diverse cerebral anomalies in a series of pediatric patients with cerebellar tonsillar ectopia.
We reviewed the medical records of 60 children diagnosed with Chiari type ...1 malformation (CM1), of these, 20 patients (11 boys and 9 girls; mean age 7.2 years, range 2-16 years) had an associated cerebral anomaly. Symptoms of tonsillar ectopia evolved over a mean of 12 months (range 3 months to 4 years). Syringomyelia was present in 5 cases. All patients underwent a posterior fossa decompression.
Disclosed anomalies included: congenital hydrocephalus (n = 11), cervicomedullary kinking (n = 5), focal cerebral heterotopia with epilepsy (n = 4), partial agenesis of the corpus callosum (n = 4), hypoplastic brain stem (n = 2), holoprosencephaly (n = 1), and subcortical dysplasia in the context of neurofibromatosis type 1 (n = 1). Other malformations included: subcortical hamartoma associated with neurofibromatosis type 1, craniofacial dysmorphism secondary to Noonan syndrome, congenital occipital plagiocephaly, os odontoideum, craniofacial cleft, juvenile rheumathoid arthritis with platybasia, and osteogenesis imperfecta with bathrocephaly and scoliosis.
Craniocerebral anomalies in children treated for CM1 may be found consistently. The association of hydrocephalus, which was the most common anomaly in this cohort, with cerebellar tonsillar ectopia may contribute to a poor outcome in regard to tonsillar herniation symptoms.
Background The definite diagnosis of hydrocephalus valve infection is generally made by cerebrospinal fluid (CSF) sampling via the valve reservoir, which is considered to be more dependable than that ...of the CSF obtained by lumbar puncture. Case report We treated a 17-year-old boy with an intra-abdominal pseudocyst due to ventriculoperitoneal shunt infection caused by Staphylococcus warneri whose ventricular CSF, obtained via the valve reservoir, was repeatedly sterile thus causing a considerable delay in the management of the complication. Discussion and conclusions S. warneri constitutes an emergent contaminant of catheters and prostheses. We found only a detailed report of S. warneri infection of a ventriculoatrial shunt. If manifestations of peritoneal involvement in shunted patients would occur, the attention should be shifted to the distal component of the shunt hardware, even in the presence of a normal ventricular CSF as happened in our case to avoid unnecessary delay in diagnosis and management.
Object
A previous study by computational fluid dynamics (CFD) of the three-dimensional (3-D) flow in ventricular catheters (VC) disclosed that most of the total fluid mass flows through the ...catheter’s most proximal holes in commercially available VC. The aim of the present study is to investigate basic flow patterns in VC prototypes.
Methods
The general procedure for the development of a CFD model calls for transforming the physical dimensions of the system to be studied into a virtual wire-frame model which provides the coordinates for the virtual space of a CFD mesh, in this case, a VC. The incompressible Navier–Stokes equations, a system of strongly coupled, nonlinear, partial differential conservation equations governing the motion of the flow field, are then solved numerically. New designs of VC, e.g., with novel hole configurations, can then be readily modeled, and the corresponding flow pattern computed in an automated way. Specially modified VCs were used for benchmark experimental testing.
Results
Three distinct types of flow pattern in prototype models of VC were obtained by varying specific parameters of the catheter design, like the number of holes in the drainage segments and the distance between them. Specifically, we show how to equalize and reverse the flow pattern through the different VC drainage segments by choosing appropriate parameters.
Conclusions
The flow pattern in prototype catheters is determined by the number of holes, the hole diameter, the ratio hole/segment, and the distance between hole segments. The application of basic design principles of VC may help to develop new catheters with better flow circulation, thus reducing the possibility of becoming occluded.
PDF
