Nanoparticles with smaller diameters have larger surface areas. Unfortunately, this fact is often neglected in their biomedical characterization, e.g. in the evaluation of their toxicity with cell ...viability tests. We here point out the different scientific conclusions drawn in such tests when considering the traditional mass or concentration of nanoparticles, or their surface areas.
Candida albicans promotes biofilm formation on dentures, which compromises the use of poly(methyl‐methacrylate) (PMMA) as a dental material. Farnesol (FAR), a natural compound that prevents C. ...albicans filamentation and biofilm formation, was incorporated into the PMMA matrix, to obtain antifungal PMMA_FAR materials. The tested concentrations (0·0125% and 0·4%) of FAR, 24 h after incubation on YPD agar, inhibited filamentation of C. albicans. PMMA was modified with different FAR concentrations (3–12%), and physicochemical properties, antifungal activity and cytotoxicity of these modified materials (PMMA_FAR) were tested. The presence of FAR in PMMA_FAR composites was verified by Fourier‐transform infrared spectroscopy (FT‐IR). Incorporation of FAR into the polymeric matrix significantly decreased hydrophilicity at all tested concentrations and significantly reduced biofilm and planktonic cells metabolic activity in the early stage of biofilm formation at ≥6% FAR in PMMA. PMMA_FAR composites with <9% FAR were non‐toxic. Modification of PMMA with FAR is a good strategy for reducing C. albicans biofilm formation on dentures.
To our knowledge, this is the first report of PMMA modification with FAR as a good strategy for preventing Candida‐related infection.
Herpes simplex virus 1 fuses with the plasma membrane of a host cell, and the incoming capsids are efficiently and rapidly transported across the cytosol to the nuclear pore complexes, where the ...viral DNA genomes are released into the nucleoplasm. Using biochemical assays, immunofluorescence, and immunoelectron microscopy in the presence and absence of microtubule depolymerizing agents, it was shown that the cytosolic capsid transport in Vero cells was mediated by microtubules. Antibody labeling revealed the attachment of dynein, a minus end-directed, microtubule-dependent motor, to the viral capsids. We propose that the incoming capsids bind to microtubules and use dynein to propel them from the cell periphery to the nucleus.
In this work, the novel fabrication and characterization of elastomeric piezoelectric nanocomposites are explored. Fabrication methods explored herein utilize ball milled barium titanate powder ...dispersions, along with double walled carbon nanotubes which are dispersed in toluene though the use of an ultrasonic probe. Test devices are then constructed with electrodes made from evaporated gold on polyimide foils and protective dielectrics of pristine PDMS. Two different device construction methods are explored utilizing both direct contact bonding and plasma bonding of the active composite layers to the dielectric electrode. Test samples are evaluated through the use of a dedicated Berlincourt type piezoelectric d33 meter.
The long-term outcome of cervical spondylitic myelopathy after surgical treatment was retrospectively reviewed and critically evaluated in 100 patients with documented cervical myelopathy treated ...between 1978 and 1988 at our institution. Eighty-four patients were available for long-term study. The median duration of follow up was 7.35 years (range 3 to 9.5 years). There were 67 men and 17 women; their ages ranged from 27 to 86 years. The duration of preoperative symptoms ranged from 1 month to 10 years. Preoperative functional grade as evaluated with the Nurick Scale for the group was 2.1. Thirty-three patients with primarily anterior cord compression, one- or two-level disease, or a kyphotic neck deformity were treated by anterior decompression and fusion. Fifty-one patients with primarily posterior or cord compression and multiple-level disease were treated by posterior laminectomy. There was no difference in the preoperative functional grade in these two groups. The patients in the posterior treatment group were older (59 vs 55 years). There was no surgical mortality from the operative procedures; morbidity was 3.6%. Of the 33 patients undergoing anterior decompression and fusion, 24 showed immediate functional improvement and nine were unchanged. Of the 51 patients who underwent posterior laminectomy, 35 demonstrated improvement, 11 were unchanged, and five were worse. Six patients, one in the anterior group and five in the posterior group, demonstrated early deterioration. Late deterioration occurred from 2 to 68 months postoperatively. Four (12%) patients who had undergone anterior procedures had additional posterior procedures, and seven (13.7%) patients who had undergone posterior procedures had additional decompressive surgery. The final functional status at last follow-up examination for the 33 patients in the anterior group was improved in 18, unchanged in nine, and deteriorated in six. Of the 51 patients who underwent posterior decompression, 19 benefited from the surgery, 13 were unchanged, and 19 were worse at last follow up than before their initial surgical procedure. Age, severity of disease, number of levels operated, and preoperative grade were not predictive of outcome. The only factor related to potential deterioration was the duration of symptoms preoperatively. The results indicate that with anterior or posterior decompression, long-term outcome is variable, and a subgroup of patients, even after adequate decompression and initial improvement, will have late functional deterioration.
Paragangliomas are rare tumors that arise from extraadrenal chromaffin cells. We examined the clinical characteristics, location, treatment, and outcome of 236 patients (141 females, 60%) with 297 ...benign paragangliomas evaluated at the Mayo Clinic during 1978-1998. The mean age (+/-SD) at diagnosis was 47 +/- 16 yr. Of the 297 paragangliomas, 205 were in the head and neck region, and 92 were below the neck. Paragangliomas were discovered and diagnosed incidentally on imaging studies in 9% of patients. Biochemical screening was performed in 128 patients; 40 patients (17% of the total and 31% of those screened) had hyperfunctional tumors. Of the 40 patients with tumoral catecholamine excess, 38 had documented hypertension. In patients identified with catecholamine-secreting paragangliomas, the sensitivities achieved by measurements in the 24-h urine collection were 74% for total metanephrines, 84% for norepinephrine, 18% for dopamine, and 14% for epinephrine. Multiple imaging modalities were used for tumor localization. The false negative rates were 0% for magnetic resonance imaging, 5.8% for computed tomography, 3.4% for angiography, 10.7% for ultrasonography, and 39% for radioactive iodine-labeled metaiodobenzylguanidine scintigraphy. Of 192 patients (81.4%) with follow-up data (mean, 43.9 months; range, 0.5-240), operative cure was achieved in 133 (69%). Of the 59 patients without cure, 23 had persistent disease, 5 had recurrent disease, 16 had multiple persistent synchronous tumors, and 15 subsequently developed metachronous tumors. In conclusion, most paragangliomas are nonhypersecretory and located in the head and neck region. Magnetic resonance imaging was associated with the lowest false negative rate, and metaiodobenzylguanidine was the least sensitive imaging study. A significant proportion of patients (31%) has persistent or recurrent disease, and long-term follow-up is important.
Post‐traumatic Cerebrospinal Fluid Leakage Friedman, Jonathan A.; Ebersold, Michael J.; Quast, Lynn M.
World journal of surgery,
August 2001, Letnik:
25, Številka:
8
Journal Article
Recenzirano
Posttraumatic cerebrospinal fluid (CSF) leakage frequently complicates skull base fractures. While most CSF leaks will cease without treatment, patients with persistent CSF leaks may be at increased ...risk for meningitis, and many will require surgical intervention. We reviewed the medical records of 51 patients treated between 1984 and 1998, with CSF leaks that persisted for 24 hours or longer after head trauma. Twenty-eight patients (53%) had spontaneous resolution of the leakage at an average of 5 days. Twenty-three patients (47%) required surgery. Eight patients (16%) had occult leaks presenting with recurrent meningitis at an average of 6.5 years posttrauma. Forty-three (84%) patients with CSF leaks had an associated skull fracture, most commonly involving the frontal sinus, while only 18 patients (35%) had parenchymal brain injury or extra-axial hematoma. Eight patients (16%) had delayed leaks at an average of 13 days posttrauma. Among patients with clinically evident CSF leakage the frequency of meningitis was 10% with antibiotic prophylaxis, and 21% without antibiotic prophylaxis. Thus, prophylactic antibiotic administration halved risk of meningitis. A variety of surgical approaches was used, with minimal morbidity. Three of 23 surgically treated patients (13%) required additional surgery for continued leakage. Patients with CSF leaks that persist greater than 24 hours are at risk for meningitis, and many will require surgical intervention. Prophylactic antibiotics may be effective and should be considered in this group of patients. Patients with skull fractures involving the skull base or frontal sinus should be followed for delayed leakage. Surgical outcome is excellent.
Adenovirus targets its genome to the cell nucleus by a multistep process involving endocytosis, membrane penetration and cytoplasmic transport, and finally imports its DNA into the nucleus. Using an ...immunochemical and biochemical approach combined with inhibitors of nuclear import, we demonstrate that incoming viral DNA and DNA‐associated protein VII enter the nucleus via nuclear pore complexes (NPCs). Depletion of calcium from nuclear envelope and endoplasmic reticulum cisternae by ionophores or thapsigargin blocked DNA and protein VII import into the nucleus, but had no effect on virus targeting to NPCs. Calcium‐depleted cells were capable of disassembling incoming virus. In contrast, inhibitors of cytosolic O‐linked glycoproteins of the NPC blocked virus attachment to the nuclear envelope, capsid disassembly and also nuclear import of protein VII. The data indicate that NPCs have multiple roles in adenovirus entry into cells: they contain a virus‐binding and/or dissociation activity and provide a gateway for the incoming DNA genome into the nucleus.
A retrospective study about the occurrence of spinal column deformity or instability after multilevel lumbar or thoracolumbar total laminectomy for removal of benign intraspinal tumors in children ...and young adults.
To analyze the long-term clinical and radiographic outcome of these patients, and to specify factors that affect the occurrence of postlaminectomy spinal column deformity and instability.
Spinal column deformity is not uncommon after multilevel cervical or thoracic laminectomies for removal of intraspinal tumors in children. Its incidence in the lumbar and thoracolumbar spine reportedly is low.
Thirty-six consecutive patients (23 male, 13 female) underwent multilevel lumbar or thoracolumbar total laminectomy for removal of benign intraspinal tumors from 1966 to 1989. Twelve patients were aged 17 years or younger ("children and adolescents"; mean age, 11 years), and 24 were aged 18-30 years ("young adults"; mean age, 24 years). All patients had preoperative, immediate postoperative, and follow-up clinical and radiographic examinations.
At a mean follow-up period of 14 years (range, 4-28 years), six patients (16.6%) had spinal deformity (lordosis or thoracolumbar kyphosis associated with scoliosis), and four (11%) had spondylolisthesis. Spinal column deformity occurred in 33% of children and adolescents and in 8% of young adults. Spondylolisthesis occurred in 16.6% of children and adolescents and in 8% of young adults. Three patients had fusion for spinal column deformity. Pain was present in eight patients, and other neurologic signs and symptoms were found in 18. There was an increased incidence of postoperative spinal deformity in patients who had more than two laminae removed (P < 0.01) or a facetectomy performed at the time of the initial operation (P < 0.05). There was no association between the occurrence of the deformity and sex, neurologic condition after laminectomy, or length of follow-up period.
Spinal deformity or instability after multilevel lumbar or thoracolumbar total laminectomy is not uncommon in children and adolescents. Limiting laminae removal and facet destruction may decrease this incidence. Fusion may be required to correct post-laminectomy deformity and to stabilize the spine.
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