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Biomedical subjects

A Isla

Publications and source records attributed to A Isla.

At least 19 recordsLinked to original sources
PubMed2006

Elimination of piperacillin and tazobactam by renal replacement therapies with AN69 and polysulfone hemofilters: evaluation of the sieving coefficient.

BACKGROUND/AIM: Piperacillin-tazobactam is commonly used to treat infections in ICU patients. Controversial data have been published about the sieving/saturation coefficient (Sc/Sa) of piperacillin during continuous renal replacement therapies (CRRT). The objective was to evaluate the Sc/Sa of piperacillin-tazobactam during continuous venovenous hemofiltration (CVVH) and continuous venovenous hemodialysis (CVVHD) using AN69 and polysulfone. METHODS: Ringer lactate, BSA-containing Ringer lactate and plasma were circulated at 150 ml/min. The ultrafiltrate/dialysis flow was kept at 1,500 ml/min. A bolus was injected and samples were taken. Drugs were measured using HPLC. Sc/Sa was calculated according to standard formula. RESULTS: Free passage of drugs through the membranes was reported with protein free solutions. In the presence of proteins the Sc/Sa lowered and correlated to protein free fraction. Polysulfone had a significantly higher permeability than AN69 during CVVH. CONCLUSION: Drug binding to albumin contributes to the decrease of the Sc/Sa of piperacillin but it does not completely justify the in vivo value obtained by some authors.

Acrylic Resins↗
PubMed2006

[Causes of reoperations in patients with lumbar spinal stenosis treated with instrumentations].

OBJECTIVE: In present study we analyze the causes leading to reoperation patients treated for lumbar spinal stenosis with laminectomy and lumbar instrumentation. MATERIAL AND METHODS: 74 patients operated between January of 1996 and December of 2000 with a minimum 4 year follow-up were seleted for the study. RESULTS: 16 patients (21.1%) underwent a new surgical intervention. The main cause for reoperation was stenosis of the adjacent level superiorly to the instrumentation (in 50%). Other causes were radicular fibrosis, persistence of stenosis after the surgery, neuropatic pain, failure of the instrumentation system, transpedicular screws misplacement and break of screws. CONCLUSIONS: Complications related with the initial surgical procedure are low, as half of the reoperations were due to stenosis of the segment superior to the fixation.

Adult↗
PubMed2006

Anatomical and functional connectivity of the transected ulnar nerve after accessory nerve neurotization in the cat.

AIM: The objective of this experimental study was to test the capacity of accessory nerve motoneurons to innervate muscles of the ulnar nerve territory after direct anastomosis. METHODS: This study used 22 cats in two groups: experimental group (15 cats) and control group (7 cats). The first one was followed during twelve months using electromyographic records every two months postsurgery; muscle and nerve histological assessment and counting horseradish peroxidase-labeled motoneurons. RESULTS: Our results showed that reinnervation was achieved in 12/15 nerves. The number of HRP labelled medullar motoneurons after anastomosis showed a significant statistic difference with a simple ulnar nerve transection; there was no significant statistic difference in labelling between the group with an anastomosis and the one with a simple accessory nerve transection. CONCLUSIONS: Direct anastomosis between the spinal accessory nerve and the ulnar nerve is achievable and thus, the accessory spinal nerve is another possible choice for correcting the motor deficit arising from lower brachial plexus avulsion, but the limited number of motoneurons would only allow partial reinnervation..

Accessory Nerve↗
PubMed2005

Laparoscopy for abdominal emergencies: evidence-based guidelines of the European Association for Endoscopic Surgery.

BACKGROUND: Emergency laparoscopic exploration can be used to identify the causative pathology of acute abdominal pain. Laparoscopic surgery also allows treatment of many intraabdominal disorders. This report was prepared to describe the effectiveness of laparoscopic surgery compared to laparotomy or nonoperative treatment. METHODS: A panel of European experts in abdominal and gynecological surgery was assembled and participated in a consensus conference using Delphi methods. The aim was to develop evidence-based recommendations for the most common diseases that may cause acute abdominal pain. RECOMMENDATIONS: Laparoscopic surgery was found to be clearly superior for patients with a presumable diagnosis of perforated peptic ulcer, acute cholecystitis, appendicitis, or pelvic inflammatory disease. In the emergency setting, laparoscopy is of unclear or limited value if adhesive bowel obstruction, acute diverticulitis, nonbiliary pancreatitis, hernia incarceration, or mesenteric ischemia are suspected. In stable patients with acute abdominal pain, noninvasive diagnostics should be fully exhausted before considering explorative surgery. However, diagnostic laparoscopy may be useful if no diagnosis can be found by conventional diagnostics. More clinical data are needed on the use of laparoscopy after blunt or penetrating trauma of the abdomen. CONCLUSIONS: Due to diagnostic and therapeutic advantages, laparoscopic surgery is useful for the majority of conditions underlying acute abdominal pain, but noninvasive diagnostic aids should be exhausted first. Depending on symptom severity, laparoscopy should be advocated if routine diagnostic procedures have failed to yield results.

Abdomen↗
PubMed2005

Determination of ceftazidime and cefepime in plasma and dialysate-ultrafiltrate from patients undergoing continuous veno-venous hemodiafiltration by HPLC.

We have developed and validated a new, rapid and reproducible HPLC method for the determination of cefepime and ceftazidime in plasma and dialysate-ultrafiltrate samples obtained from intensive care unit (ICU) patients undergoing continuous veno-venous hemodiafiltration (CVVHDF). The method for plasma samples involved protein precipitation with acetonitrile, followed by washing with dichloromethane to remove apolar lipophilic compounds. Dialysate-ultrafiltrate samples did not require any preparation. Separation was performed on a muBondapak C18 (30 cm x 3.9 mm x 10 microm) with UV detection. The mobile phase contained acetate buffer: ACN and was delivered at 2 ml/min. The coefficients of determination of the calibration curves were always > or = 0.998 and R.S.D.% of the response factors <10%. The intra and inter-assay precision and accuracy of the quality controls (QC) and limit of quantification (LOQ) were satisfactory in all cases. Plasma and dialysate-ultrafiltrate samples were stable at -20 and -80 degrees C for 2 months and also after three freeze/thaw cycles. Dialysate-ultrafiltrate samples were stable in the chromatographic rack for 24h at room temperature, but we recommend storing processed plasma samples at 4 degrees C until the analysis. The described method has proved to be useful to give accurate measurements of ceftazidime and cefepime in samples obtained from patients undergoing CVVHDF.

Anti-Bacterial Agents↗
PubMed2005

Quantitation and stability of piperacillin and tazobactam in plasma and ultrafiltrate from patients undergoing continuous venovenous hemofiltration by HPLC.

Simple and reproducible HPLC methods for the determination of piperacillin and tazobactam have been developed and a complete stability study carried out. The method for piperacillin plasma samples consisted of protein precipitation with methanol using penicillin G as internal standard. No sample preparation was needed for ultrafiltrate samples. Tazobactam sample preparation involved protein precipitation with acetonitrile and the removal of lipids with dichloromethane. Piperacillin separation was performed on a microBondapack C(18) column (300 x 3.9, 10 microm) and tazobactam on a Novapack C(18) column (150 x 3.9, 4 microm) with UV detection set at 229 and 225 nm, respectively. The mobile phase consisted of phosphate buffer-acetonitrile, delivered at 1.5 mL[sol ]min. Calibration curves determination coefficients were >or=0.999 and response factors CV% < 5%. Intra- and inter-assay precision and accuracy of the quality control and limit of quantification were satisfactory. Plasma and ultrafiltrate samples were stable at -20 and -80 degrees C for 2 months and after three freeze-thaw cycles. In the chromatographic rack, tazobactam ultrafiltrate samples were stable for 24 h and plasma samples for 12 h, piperacillin ultrafiltrate samples for 8 h, but plasma samples for only 4 h. Storage of piperacillin samples at 4 degrees C until analysis is recommended. Piperacillin was stable in the presence of tazobactam.

Anti-Bacterial Agents↗
PubMed2005

Molecular analysis of the EGFR gene in astrocytic gliomas: mRNA expression, quantitative-PCR analysis of non-homogeneous gene amplification and DNA sequence alterations.

The epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein with tyrosine kinase activity. This report investigates the presence of mutations, amplification and/or over-expression of the EGFR gene in 86 glial tumours including 44 glioblastomas, 21 anaplastic astrocytomas, and 21 WHO grade II astrocytomas, using polymerase chain reaction/single-strand conformation polymorphism, semiquantitative reverse-transcription-polymerase chain reaction (RT-PCR) and Southern Blot techniques. Gene amplification values were found in 34 tumours. Amplification levels were not uniform, as the transmembrane region presented lower amplification rates than extra- and intracellular domains. For the 19 samples with sufficient available tumour tissue we found over-expression in 11, and no EGFR mRNA expression in three. Ten cases showed deletion transcripts, and EGFR VIII was identified in all of these cases. One of the cases with EGFR vIII also presented a truncated form, C-958, while another showed an in frame tandem duplication of exons 18--25. We found 14 cases with sequence/structure gene alterations, including seven on which genomic novel DNA changes were identified: a missense mutation (1052C > T/Ala265Val), an insertion (InsCCC2498/Ins Pro748), three intronic changes (E6+72delG, E22--14C>G and E18--109T>C), a new polymorphic variant E12+ 22A > T, and one case that presented a 190 bp insertion, that was produced by the intron-7-exon-8 duplication and generated a truncated EGFR with intact exons 1--8 followed by an additional amino acidic sequence: Val-Ile-Met-Trp. These findings corroborate that EGFR is non-randomly involved in malignant glioma development and that different mutant forms participate in aberrant activation of tyrosine kinase pathways.

Astrocytoma↗
PubMed2005

Evaluation of antimicrobial treatments in children with acute otitis media in Spain: a pharmacokinetic-pharmacodynamic (PK/PD) approach.

Pharmacokinetic/pharmacodynamic (PK/PD) principles are priceless tools for evaluating the effectiveness of different antimicrobial treatments for different infections. However, very few studies deal with pediatric dosages and take into account the unbound drug serum levels. Our study is focused on the most frequent antibiotic dosing schedules used in Spain for the treatment of acute otitis media (AOM) in children, where high rates of penicillin and macrolide resistance exist among pneumococcal isolates. Pharmacokinetic parameters of antibiotics in children where obtained from the literature. The minimum inhibitory concentrations (MIC90) of antibiotics for pediatric strains of Streptococcus pneumoniae and Haemophilus influenzae were obtained from the SAUCE 2 project. Only ceftriaxone (50 mg/kg single intramuscular dose) and high doses of co-amoxiclav (27-33 mg/kg q8h) provided adequate efficacy indexes (tss(%)>MIC) for both S. pneumoniae and H. influenzae in AOM in children. These results are consistent with MEF (medium ear fluid) levels obtained from the literature. Our results confirm the utility of serum unbound levels to predict efficacy of antibiotics in children with AOM.

Acute Disease↗
PubMed2005

[Intramedullary spinal cord metastasis as the first manifestation of a renal carcinoma].

We present the case of a 69 year-old male without known antecedente who presented a clinical loss of distal force in his lower limbs during the last two months. Magnetic resonance imaging (MRI) showed an intramedullary spinal cord mass at the level of the medullaris cone. The patient was operated on; the histological diagnosis was clear cells carcinoma suggestive of metastasis from an unsuspected renal tumor that was later confirmed with an abdominal CT. When the patient's state is good, surgery can correct the neurological deficit produced by an intramedullary spinal cord lesion. The neurological state of our patient improved after the intervention, and 14 months after surgery, he has no neurological deficit in the lower limbs.

Aged↗
PubMed2004

[Paragangliomas of the cauda equina: report of two cases].

Extraadrenal paragangliomas involving the spinal cord are not common and usually take the compression of the cauda equine. Two cases of paraganglioma of the cauda equina with a different presentation are reported, and the clinical and histopathology findings of this tumor, as well as diagnosis, treatment and prognosis are review. We stress the importance of the high tumor vascularization form of intradural that can make impossible achieve a complete resection. Laminotomy and intraoperatory echography are very useful in the approach to intradural tumors, such as paraganglioma.

Adult↗
PubMed2004

[Anterior approach in low cervical fractures prodited by hyperflexion or tear drop].

Hyperflexion or teardrop fracture of low cervical vertebrae is characterised by ligament affectation of the entire intervertebral segment, the vertebral body, primarily its anteroinferior third and, frequently, spinal medullar affectation. This series presents the clinical symptoms, diagnosis, surgical approach, and post surgical evolution in 30 patients with tear drop fractures. Over the last 30 years, thirty patients with tear drop fractures at the low cervical spine (C3-C7) were admitted to our Neurosurgical Service. Diagnostic studies included simple radiographs, computerised axial tomography (CT), and magnetic resonance imaging (MRI), all of which evidenced the instability of the damaged segment due to osteoligamentous affectation, and a primarily vertebral body fracture. Patients' neurological status was according to the Frankel' scale adapted to the American Spinal Injury Association scale (ASIA). 11 patients were included in grade A, 5 in B, 3 in grade C, 2 in grade D and 9 grade E of neurological affectation. Surgery through an anterior approach was performed, an average of 5 days after placement of halo traction, which had been placed on admission to the hospital. Surgery consisted in vertebral corporectomy and placement of a plate and a graft from the iliac crest. The patients' neurological evolution was favourable in all cases with incomplete medullar lesions. There were 11 patients with complete lesions, or Frankel grade A affectation; two died due to other associated lesions and the other nine showed no neurological improvement after surgery. The degree of arthrodesis was good and only one patient required an a combined anterior-posterior approach. We conclude that teardrop fractures were associated with severe neurological affectation in more than 50% of our patients, and that these fractures provoke instability requiring arthrodesis, generally via an anterior approach.

Adolescent↗
PubMed2004

Cervical epidural hematoma without fracture in a patient with ankylosing spondylitis. A case report.

Ankylosing spondylitis (AS) is an inflammatory disease involving the axial spine. Alterations in vertebral biomechanics leave the spine sensitive to traumas which, though minimal, may cause serious neurological lesions, particularly in long term AS patients with a completely ankylosed spine, who are more prone to suffer spine fractures. A 62-year-old man with a long-term AS suffered a minor trauma resulting in a cervical epidural hematoma from C2 to C7, leading to paraplegia. On the diagnosis of hematoma, he underwent C3-C7 left hemilaminectomies, to remove the hematoma. We could find no cause for the hematoma. The patient's condition improved, and he was eventually able to perform all his activities independently. Even though traumatic spinal epidural hematoma (SHE) of the ankylosed spine may occur in the absence of fracture, it is commonly associated with traumatic fracture or dislocation of the spine, particularly the cervical spine. In all the published series of SEH in AS, we could only find one more case of this pathology at the cervical spine without a fracture. Neurologic recovery can be successful if decompression is performed early. SHE must be considered after trauma to an ankylosed spine when there is neurological deterioration despite the absence of fracture. A good outcome depends on the early diagnosis and surgery.

Cervical Vertebrae↗
PubMed2003

CpG island methylation status and mutation analysis of the RB1 gene essential promoter region and protein-binding pocket domain in nervous system tumours.

A series of 136 nervous system tumours were studied to determine the methylation status of the CpG island contained within the promoter region of the RB1 gene, as well as mutation analysis of the essential promoter region and exons 20-24 (and surrounding intronic regions) coding for the protein-binding pocket domain. Methylation of the RB1 CpG island was detected in 26 samples corresponding to nine glioblastomas, three anaplastic astrocytomas, one mixed oligo-astrocytoma, one ependymoma, two medulloblastomas, two primary central nervous system lymphomas, two neurofibrosarcomas, and six brain metastasis from solid tumours. No inactivating mutations were found within the RB1 promoter region, whereas one glioblastoma and one oligodendroglioma displayed similar sequence variations consisting of 12 and 8 base pair deletions at intron 21. These results suggest that RB1 CpG island hypermethylation is a common epigenetic event that is associated with the development of malignant nervous system tumours.

CpG Islands↗
PubMed2003

Single-stage definitive laparoscopic management in mild acute biliary pancreatitis.

BACKGROUND: Population-based studies have shown that nearly one third of patients with acute biliary pancreatitis undergo endoscopic retrograde cholangiopancreatography (ERCP) before undergoing laparoscopic cholecystectomy (LC) (two-stage approach). The present study was designed to evaluate the safety of single-stage laparoscopic management to avoid preoperative ERCP. MATERIALS AND METHODS: Between June 1998 and June 2002, 35 female patients and 10 male patients (median age, 59 years) with uncomplicated mild acute biliary pancreatitis were studied prospectively and reviewed retrospectively. LC with fluoroscopic intraoperative cholangiography (IOC) or with fluoroscopic IOC and laparoscopic CBD exploration in cases of concomitant choledocholithiasis was performed as the definitive treatment (single-stage approach). Patients underwent surgery electively when symptoms had subsided and laboratory parameters had improved. RESULTS: LC alone was performed in 39 patients, and an additional laparoscopic CBD exploration was performed in the remaining six. In one patient, IOC yielded a false-positive result. CBD stones were detected in four cases, and debris in the CBD in one case, for an 11% incidence of concomitant choledocholithiasis. The conversion rate was zero, and single-stage laparoscopic treatment was successful in all cases. The overall morbidity rate was 4%. The 30-day postoperative mortality rate was zero. CONCLUSION: Although preoperative ERCP and sphincterotomy still have a role in complicated cases of mild acute biliary pancreatitis, laparoscopic single-stage definitive treatment is feasible and safe in uncomplicated cases of disease when local experience is available.

Acute Disease↗
PubMed2003

A reservable antiadhesion barrier gel reduces the perineural adhesions in rats after anastomosis.

AIM: The objective of this experimental study was to assess the effectiveness of ADCON T/N in reducing perinerural adhesions when applied around a previously exposed and then anastomosed peripheral nerve in a rat model. METHODS: Sixteen adult 8-month-old male Wistar rats were used for this study. After the ulnar nerve was exposed bilaterally, the nerves were sectioned and anastomosised. ADCON T/N gel was applied around the nerve suture on 1 limb, while the contralateral limb was left untreated (sham operated control). Treatments were administered according to a randomised schedule revealed to the operator only after the perineural adhesions observed during the 2nd operation had been dissected and complete haemostasis achieved. In other group of 4 Wistar rats, the ulnar nerve was sectioned and the 2 ends connected with a 5 mm silastic tube that was placed bilaterally in each rat but on only one side, chosen randomly, was the nerve treated with ADCON TN and placed within the tube on that side. RESULTS: Three months after the 1st operation, the same nerves were exposed again in all animals under general anesthesia before microsurgical external neurolysis. The neurolysis sites in 16 rats were evaluated by blinded surgical dissection immediately before death. Parameters examined included: quality of wound healing, possible adverse effects, presence of residual implant material and perineural adhesions. Perineural adhesions around the ulnar nerve were visually scored using a 4-point qualitative scale (Mean 2.81 without gel, and 1.18 with ADCON T/N. p=0.017). There was no evidence of persistence of residual implant material in the ADCON T/N treated sites. No significant difference between the average density of myelinated axons was observed in either group. All ADCON T/N treated rats (4 animals) showed axonal growth through the tube connecting the 2 ends. CONCLUSION: ADCON-TN decreased fibrosis around the nerve anastomosis sites and did not impede growth between the severed ends of the axons. If reoperation becomes necessary, a reduction of fibrosis would facilitate access to the old site and decrease the risk of nerve lesions.

Animals↗
PubMed2001

Mutation analysis of the p73 gene in nonastrocytic brain tumours.

Loss of heterozygosity (LOH) involving the distal chromosome 1 p36 region occurs frequently in nonastrocytic brain tumours, but the tumour suppressor gene targeted by this deletion is unknown. p73 is a novel gene that has high sequence homology and similar gene structure to the p53 gene; it has been mapped to 1 p36, and may thus represent a candidate for this tumour suppressor gene. To determine whether p73 is involved in nonastrocytic brain tumour development, we analysed 65 tumour samples including 26 oligodendrogliomas, 4 ependymomas, 5 medulloblastomas, 10 meningiomas, 2 meningeal haemangiopericytomas, 2 neurofibrosarcomas, 3 primary lymphomas, 8 schwannomas and 5 metastatic tumours to the brain, for p73 alterations. Characterization of allelic loss at 1 p36-p35 showed LOH in about 50% of cases, primarily involving oligodendroglial tumours (22 of 26 cases analysed; 85%) and meningiomas (4 of 10; 40%). PCR-SSCP and direct DNA sequencing of exons 2 to 14 of p73 revealed a missense mutation in one primary lymphoma: a G-to-A transition, with Glu291Lys change. 8 additional cases displayed no tumour-specific alterations, as 3 distinct polymorphic changes were identified: a double polymorphic change of exon 5 was found in one ependymoma and both samples derived from an oligodendroglioma, as follows: a G-to-A transition with no change in Pro 146, and a C-to-T variation with no change in Asn 204: a delG at exon 3/+12 position was identified in 4 samples corresponding to 2 oligodendrogliomas, 1 ependymoma and 1 meningioma, and a C-to-T change at exon 2/+10 position was present in a metastatic tumour. Although both LOH at 1 p36 and p73 sequence changes were evidenced in 4 cases, it is difficult to establish a causal role of the p73 variations and nonastrocytic brain tumours development.

Brain Neoplasms↗
PubMed2001

[Spinal epidural fibrosis following lumbar diskectomy and antiadhesion barrier].

Although diskectomy after hemilaminectomy always produces some fibrosis, only few patients develop clinical symptoms. Fibrosis is one of the causes for failed lumbar disc surgery. Identification of fibrosis as the cause of recurring lumbar or sciatic pain requires the existence of a good clinical history and selective physical examination of the patient. MR is the imaging technique of choice although CT and myelography can be useful in some cases. Surgery can correct recurrent hernias, segmentary instability or spinal stenosis, but good results are less likely in patients with epidural fibrosis. When this exists, surgery should be directed to performing an arthrodesis of the vertebral space since the operation itself can destabilize the segment resulting in instability of the affected segment. Application of ADCON-L did not worse and in some cases improved the clinical condition of patients in double blind studies. Our multicentric double blind study showed no clinical differences among 253 patients at six months after surgery. Additionally, since this gel seems to avoid the development of fibrosis, it may prevent one of the main causes of failed disc surgery and, if reoperation is necessary due to disc remains or a lateral stenosis, the absence of fibrosis would facilitate surgery.

Diskectomy↗