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1.
Arch Esp Urol ; 67(9): 764-9, 2014 Nov.
Article in English, Spanish | MEDLINE | ID: mdl-25407150

ABSTRACT

OBJECTIVES: To analyze the influence of the different pre - cystectomy factors, both clinical and pathological, in the follow up of patients with no residual tumor ( pT0) in the pathological examination of the radical cystectomy specimen as predictors of tumor recurrence. Secondly we intend to compare overall survival, disease free survival and cancer-specific survival with the rest of cystectomy patients in our series. METHODS: Between 1985 and 2010, radical cystectomy was performed in 280 patients with bladder cancer, being 41 pT0 (14.6%). We analyzed potential predictors for overall survival and disease-free survival: age, sex , number of transurethral resections of bladder tumor before cystectomy , tumor type , tumor grade, tumor stage, tumor size, number of tumors, associated Cis and previous instillations. We used univariate analysis of Cox regression. Survival analysis was performed using Kaplan - Meier curves and log-rank test. RESULTS: Mean age was 61.7 years and 37 patients were males (90.2%). Stages before cystectomy were pT1 in eight (19.5%) , pT2 in 31 (75.6%) and Cis in two (4.9 %) with tumor grade III in 37 (90.2%). Cystectomy specimens revealed the presence of papillary transitional cell carcinoma in 38 (92.7%) cases. The median number of pre-cistectomy-TURBT was one. Eleven patients (26.8%) received intravesical instillations. Six patients (14.63 %) had tumor recurrence and 10 (24.4 %) died from causes unrelated to the disease. None of the variables analyzed was statistically significant in the univariate analysis as a predictor of tumor recurrence. With a median follow up of 70 months (3-272) disease-free survival and overall survival at five years were 85.9% and 72.8% respectively. Compared to the non pT0 cystectomies in our series, pT0 had a statistically significant difference for better recurrence-free survival (63.4 % and 36.8%, respectively in pT0 and no-pT0 patients) (p〈0,05). CONCLUSIONS: According to the results, we have found a better outcome for pT0 patients after cystectomy compared to those with residual tumor. We have not found any pre - cystectomy predictive factor related to disease-free survival and overall survival.


Subject(s)
Carcinoma, Transitional Cell , Cystectomy , Urinary Bladder Neoplasms , Carcinoma, Transitional Cell/surgery , Disease-Free Survival , Humans , Male , Middle Aged , Neoplasm Staging , Neoplasm, Residual , Retrospective Studies , Urinary Bladder Neoplasms/surgery
2.
Arch Esp Urol ; 66(1): 180-5, 2013.
Article in Spanish | MEDLINE | ID: mdl-23406814

ABSTRACT

Renal graft neoplasias are a rare complication,possibly due to the immunosuppressive therapy itself and increased susceptibility to potentially oncogenic viruses. Few case series have been reported in the literature on the treatment of such tumors, so far there is no clear consensus on how to deal with them. We conducted an exhaustive review of the literature to examine the treatment performed by different authors.


Subject(s)
Kidney Neoplasms/etiology , Kidney Neoplasms/therapy , Kidney Transplantation/adverse effects , Carcinoma, Renal Cell/diagnosis , Carcinoma, Renal Cell/etiology , Carcinoma, Renal Cell/therapy , Humans , Immunosuppressive Agents/adverse effects , Kidney Neoplasms/diagnosis , Kidney Neoplasms/surgery , Minimally Invasive Surgical Procedures
3.
Langmuir ; 26(15): 12540-7, 2010 Aug 03.
Article in English | MEDLINE | ID: mdl-20604541

ABSTRACT

Fluorescent silica and alumina-like spherical particles with almost equal sizes are synthesized. Dilute aqueous suspensions are prepared with various ratios of those colloidal particles that exhibit opposite surface charges. These suspensions undergo heteroaggregation for a wide range of compositions. The structure of the formed aggregates is analyzed by means of confocal microscopy. The experimental results are compared to those of Brownian dynamics simulations in which the interactions between colloids are modeled by the DLVO potential. Good agreement between experiments and simulations is obtained.


Subject(s)
Aluminum Oxide/chemistry , Colloids/chemistry , Silicon Dioxide/chemistry , Microscopy, Confocal , Models, Theoretical
4.
Hum Genet ; 123(4): 429-32, 2008 May.
Article in English | MEDLINE | ID: mdl-18340466

ABSTRACT

The dominant negative effect of mutations is rare in metabolic diseases and its mechanism has not been studied much. Hypophosphatasia, a bone inherited metabolic disorder, is a good model because the disease can be dominantly transmitted. The gene product activity depends on a homodimeric configuration and many mutations have been reported in the ALPL gene responsible for the disease. Using CFP/YFP-tagged-TNSALP plasmids, transfections in COS cells and confocal fluorescence analyses, we studied the point mutation G232V (c.746G>T). We showed that the G232V protein sequestrates some of the wild-type protein into the cells and prevents it from reaching the membrane where it plays its physiological role.


Subject(s)
Alkaline Phosphatase/genetics , Alkaline Phosphatase/metabolism , Genes, Dominant , Hypophosphatasia/enzymology , Hypophosphatasia/genetics , Mutation, Missense , Alkaline Phosphatase/chemistry , Amino Acid Substitution , Animals , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , COS Cells , Chlorocebus aethiops , Female , Green Fluorescent Proteins/chemistry , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Heterozygote , Humans , Infant , Infant, Newborn , Luminescent Proteins/chemistry , Luminescent Proteins/genetics , Luminescent Proteins/metabolism , Male , Microscopy, Fluorescence , Models, Genetic , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Subcellular Fractions/enzymology , Transfection
5.
J Chromatogr A ; 1141(1): 98-105, 2007 Feb 02.
Article in English | MEDLINE | ID: mdl-17188700

ABSTRACT

A vanguard/rearguard analytical strategy for the monitoring of the degradation of yoghurt samples is proposed. The method is based on the headspace-gas chromatography-mass spectrometry (HS-GC-MS) instrumental coupling. In this combination, the chromatographic column is firstly used as an interface between the HS and the MS (vanguard mode) avoiding separation of the volatile components by maintaining the chromatographic oven at high, constant temperature. By changing the thermal conditions of the oven, the aldehydes can be properly separated for individual identification/quantification (rearguard mode). In the vanguard method, the quantification of the volatile aldehydes was calculated through partial least square and given as a total index. The rearguard method permits the detection of the aldehydes at concentrations between 12 and 35 ng/g. Both methods were applied to the study of the environmental factors favouring the presence of the volatile aldehydes (C(5)-C(9)) in the yoghurt samples. Principal component analysis of the total concentration of aldehydes with the time (from 0 to 30 days) demonstrates the capability of the HS-MS coupling for the estimation of the quality losses of the samples. The results were corroborated by the HS-GC-MS which also indicates that pentanal was present in the yoghurt from the beginning of the study and the combination of light/oxygen was the most negative influence for sample conservation.


Subject(s)
Aldehydes/analysis , Gas Chromatography-Mass Spectrometry/methods , Yogurt/analysis , Calibration , Fluorescence , Multivariate Analysis , Principal Component Analysis , Reproducibility of Results , Time Factors , Volatilization
6.
J Chromatogr A ; 1158(1-2): 234-40, 2007 Jul 27.
Article in English | MEDLINE | ID: mdl-17395192

ABSTRACT

This article presents the state of the art of qualitative analysis in the framework of the chromatographic analysis. After establishing the differences between two main classes of qualitative analysis (analyte identification and sample classification/qualification) the particularities of instrumental qualitative analysis are commented on. Qualitative chromatographic analysis for sample classification/qualification through the so-called chromatographic fingerprint (for complex samples) or the volatiles profile (through the direct coupling headspace-mass spectrometry using the chromatograph as interface) is discussed. Next, more technical exposition of the qualitative chromatographic information is presented supported by a variety of representative examples.


Subject(s)
Chromatography/methods
7.
Bioresour Technol ; 98(18): 3561-9, 2007 Dec.
Article in English | MEDLINE | ID: mdl-17196816

ABSTRACT

The biological oxidation of elemental sulphur (S(o)) added to three alkaline composts prepared with a range of organic wastes (CC, melon crop residues; MC, mixed manures; and BC, pine bark) to reduce their pH was studied. The titration curves showed that to achieve an equivalent pH drop, compost CC needed a larger dose of S(o) than did composts MC and BC. The acidification efficiency was high in the three composts (53%), but the pH reduction obtained from the titration curves in MC and BC composts was lower than expected. S(o) oxidation in amended composts was found to be related to pH and CaCO(3) content decreases, and to the rise in CaSO(4) and electrical conductivity levels. A remarkable increase in the autotrophic bacteria population and a slight increase in heterotrophic bacteria along with S(o) oxidation were recorded. Actinomycetes, fungi and yeasts were not affected by the addition of S(o) to composts.


Subject(s)
Agriculture , Soil/analysis , Sulfur/chemistry , Hydrogen-Ion Concentration , Oxidation-Reduction , Sulfur/metabolism
8.
Water Res ; 124: 290-297, 2017 11 01.
Article in English | MEDLINE | ID: mdl-28772141

ABSTRACT

Antibiotics-bacteria interactions depend on antibiotic concentration at the scale of bacteria. This study investigates how vancomycin penetrates into activated sludge flocs and can be sorbed on the bacteria and extracellular polymeric substances (EPS). The 3D structure of flocs was imaged using EPS autofluorescence. The green fluorescent BODIPY® FL vancomycin was introduced in a microscopic chamber containing activated sludge and penetration of vancomycin into the flocs by diffusion was observed using time-lapse microscopy. The penetration depended on the floc structure, as long and large pores could go through the whole flocs making preferential path. The antibiotic concentration into the flocs was also found to depend on the sorption rate. BODIPY® FL vancomycin was found to bind preferentially into Gram+ bacteria than on EPS. The vancomycin adsorption constant on bacteria according to the linear adsorption model, Kdbacteria was estimated to be 5 times higher (SD 2.6) than the adsorption constant on EPS KdEPS. These results suggest that antibiotic removal by sorption into wastewater treatment plants could change according to the amount of bacteria in the sludge. Moreover, antibiotic concentration at the scale of bacteria could be significantly higher than the concentration in the bulk solution and this should be taken into account when studying antibiotic activity or biodegradation.


Subject(s)
Gram-Positive Bacteria , Sewage , Vancomycin/chemistry , Water Pollutants, Chemical/chemistry , Bacteria , Flocculation , Microscopy, Confocal , Sewage/chemistry , Sewage/microbiology , Time-Lapse Imaging , Waste Disposal, Fluid
9.
Chem Commun (Camb) ; 52(7): 1311-26, 2016 Jan 25.
Article in English | MEDLINE | ID: mdl-26671042

ABSTRACT

Fluorescent nanodots have become increasingly prevalent in a wide variety of applications with special interest in analytical and biomedical fields. The present overview focuses on three main aspects: (i) a systematic description and reasonable classification of the most relevant types of fluorescent nanodots according to their nature, quantum confinement and crystalline structure is provided, starting with a clear distinction between semiconductor and carbon-based dots (graphene quantum dots, carbon quantum dots and carbon nanodots). A new set of abbreviations and definitions for them to avoid contradictions found in literature is also proposed; (ii) a rational classification allows the establishment of clear-cut differences and similarities among them. From a basic point of view, the origins of the photoluminescence of the different nanodots are also established, which is a relevant contribution of this overview. Additionally, the most outstanding similarities and differences in a great variety of criteria (i.e. year of discovery, synthesis, the physico-chemical characteristics like structure, nature, shape, size, quantum confinement, toxicity and solubility, the optical characteristics including the quantum yield and lifetime, limitations, applications as well as the evolution of publications) are thoroughly outlined; and (iii) finally, the promising future of fluorescent nanodots in both analytical and biomedical fields is discussed using selected examples of relevant applications.


Subject(s)
Carbon/chemistry , Nanostructures , Semiconductors , Fluorescence
10.
Actas Urol Esp ; 40(3): 195-200, 2016 Apr.
Article in English, Spanish | MEDLINE | ID: mdl-26748843

ABSTRACT

INTRODUCTION: Microcytic carcinoma of the urinary bladder or bladder Small Cell Carcinoma (SCC) is a rare entity, characterised by an aggressive behaviour, with a poor prognosis, elevated metastatic potential, and is commonly found in older patients and in advanced disease stages. Here we present our experiences with the behaviour of the disease and the treatments applied. MATERIAL AND METHOD: This was a retrospective study on patients diagnosed with bladder SCC in our hospital between February 1992 and February 2014. We analysed the demographic and clinical characteristics of the tumour, the applied treatments and survival. We performed a descriptive statistical analysis of the median follow-up time, Overall Survival (OS) and Cancer-Specific Survival (CSS), using the SPSS statistical package v. 15.0. RESULTS: Over 22 years, 20 patients with an average age of 75 years were diagnosed with bladder SCC (2 female). The predominant symptom was macroscopic haematuria (75%). After the first transurethral resection (TUR) of the bladder and the histological diagnosis, 35% (7 patients) did not receive additional treatment, 15% (3 patients) were treated with chemoradiotherapy (CRT), 10% (2 patients) with TUR, 15% (3 patients) with chemotherapy (QT), 5% (1 patient) with TUR associated to CRT, 5% (1 patient) with radical surgery, 5% (1 patient) with radical surgery treatment followed by adjuvant CRT, 5% (1 patient) with palliative surgery (hypogastric arteriae ligation) followed by adjuvant QT and 5% (1 patient) with hemostatic radiotherapy (RT). With a median follow-up time of 13.8 months, the OS was 14.48 months (95% CI: 6.22 - 22.75) and the CSS 18.04 months (95% CI: 6.51-29.57). Only 10% (2 patients) survived till the end of the study. CONCLUSION: Microcytic carcinoma of the urinary bladder is a rare and aggressive entity commonly diagnosed in males of advanced age and in advanced disease stages. It has a poor prognosis and reduced survival. Due to its aggressiveness previous to the initial diagnosis, a cystectomy is only possible in very few cases; therefore multimodal treatment is necessary. This treatment is yet to be defined.


Subject(s)
Carcinoma, Small Cell , Urinary Bladder Neoplasms , Adult , Aged , Aged, 80 and over , Carcinoma, Small Cell/diagnosis , Carcinoma, Small Cell/therapy , Female , Humans , Male , Middle Aged , Retrospective Studies , Time Factors , Urinary Bladder Neoplasms/diagnosis , Urinary Bladder Neoplasms/therapy
11.
Biochim Biophys Acta ; 1371(1): 17-23, 1998 Apr 22.
Article in English | MEDLINE | ID: mdl-9565652

ABSTRACT

The My-10 monoclonal antibody has facilitated the search of haematopoietic stem cells by recognizing selectively the human CD34 antigen. In the present work, My-10 immunoliposomes directed specifically against CD34+ cells were prepared, characterized and tested in vitro. Binding to target cells at 4 degreesC of immunoliposomes containing carboxyfluorescein as aqueous marker was evaluated by flow cytometry and fluorescence microscopy. These immunoliposomes demonstrated their capacity to bind specifically to CD34+ cells. Studies have shown that 9 antibodies/vesicle were sufficient to obtain a good binding efficiency. The product was stable over one month at 4 degreesC in terms of leakage of encapsulated carboxyfluorescein, particle size and antigen binding capacity.


Subject(s)
Antibodies, Monoclonal , Antigens, CD34/analysis , Hematopoietic Stem Cells/chemistry , Liposomes , Cell Line , Flow Cytometry , Fluoresceins , Fluorescent Dyes , Humans , Microscopy, Fluorescence
12.
Mol Plant Microbe Interact ; 13(4): 421-9, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10755305

ABSTRACT

We have investigated the role of bacterial resistance to oxidative stress in pathogenesis. The oxyR gene from the pathogenic bacterium Erwinia chrysanthemi has been characterized. It is closely related to that found in Escherichia coli (88% overall amino acid identity). An E. chrysanthemi oxyR mutant strain was constructed by marker exchange. After induction with a sublethal dose of H2O2, this mutant was more sensitive to H2O2 and showed reduced levels of catalase and glutathione reductase activities, compared with the wild type. The oxyR mutant was unable to form individual colonies on agar plates unless catalase was added exogenously. However, it retained full virulence in potato tubers and tobacco leaves. These results suggest that the host-produced H2O2 has no direct antimicrobial effect on the interaction of E. chrysanthemi with the two plant species.


Subject(s)
DNA-Binding Proteins , Dickeya chrysanthemi/genetics , Hydrogen Peroxide/pharmacology , Plant Diseases/microbiology , Repressor Proteins/genetics , Transcription Factors/genetics , Amino Acid Sequence , Catalase/biosynthesis , Catalase/metabolism , Cloning, Molecular , Dickeya chrysanthemi/enzymology , Dickeya chrysanthemi/pathogenicity , Glutathione Reductase/biosynthesis , Glutathione Reductase/metabolism , Molecular Sequence Data , Mutagenesis, Insertional , Plants, Toxic , Repressor Proteins/metabolism , Sequence Alignment , Nicotiana/microbiology , Transcription Factors/metabolism
13.
FEBS Lett ; 498(2-3): 219-22, 2001 Jun 08.
Article in English | MEDLINE | ID: mdl-11412861

ABSTRACT

Genes encoding plant antibiotic peptides show expression patterns that are consistent with a defence role. Transgenic over-expression of defence peptide genes is potentially useful to engineer resistance of plants to relevant pathogens. Pathogen mutants that are sensitive to plant peptides in vitro have been obtained and a decrease of their virulence in planta has been observed, which is consistent with their hypothetical defence role. A similar approach has been followed to elucidate the potential direct anti-microbial role of hydrogen peroxide. Additionally, a scavenger of peroxynitrite has been used to investigate its involvement in plant defence.


Subject(s)
Anti-Bacterial Agents/metabolism , Defensins/metabolism , Hydrogen Peroxide/metabolism , Nitrates/metabolism , Plant Physiological Phenomena , Plants/microbiology , Bacterial Physiological Phenomena , Defensins/genetics , Oxidants/metabolism , Plant Leaves/metabolism , Plants/genetics , Pseudomonas/metabolism , Pseudomonas/pathogenicity , Uric Acid/pharmacology
14.
Neurosurgery ; 25(3): 462-5, 1989 Sep.
Article in English | MEDLINE | ID: mdl-2771018

ABSTRACT

Caudal regression syndrome involves absence of the sacrococcygeal vertebrae with or without lumbar vertebral defects. Since the neurological condition of infants with this syndrome deteriorates, radiographic studies are important to rule out any surgically correctable lesion. A paraplegic male neonate with a vertebral canal ending at T11 is presented. This is the first report of using magnetic resonance imaging to evaluate the spinal cord and surrounding soft tissues involved in this syndrome. Magnetic resonance imaging provides more anatomical details than myelogram with computed tomography, which greatly aids in determining whether surgery is necessary.


Subject(s)
Lumbar Vertebrae/abnormalities , Magnetic Resonance Imaging , Sacrum/abnormalities , Abnormalities, Multiple/diagnosis , Humans , Infant, Newborn , Lumbar Vertebrae/pathology , Male , Sacrum/pathology , Spinal Cord/abnormalities , Syndrome
15.
Neurosurgery ; 16(6): 850-2, 1985 Jun.
Article in English | MEDLINE | ID: mdl-4010912

ABSTRACT

Intraspinal synovial cysts are rare. Those reported have occurred in the lumbar region. We report a case of an extradural true synovial cyst of the cervical spine causing spastic paraparesis. The cyst occurred after a cervical spine fracture and, hence, was probably related to trauma. Surgical therapy resulted in a satisfactory recovery.


Subject(s)
Cervical Vertebrae/surgery , Synovial Cyst/surgery , Adult , Cervical Vertebrae/injuries , Fractures, Bone/complications , Humans , Male , Muscle Spasticity/surgery , Paraplegia/surgery , Spinal Cord Compression/surgery
16.
J Neurosurg ; 89(4): 649-52, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9761062

ABSTRACT

In this report the authors describe the use of continuous venovenous hemodialysis (CVVHD) in a medically unstable patient who suffered from a spontaneous cerebellar hemorrhage. Conventional dialysis techniques carry the risk of developing the dialysis disequilibrium syndrome (DDS) when performed in the presence of a variety of intracranial diseases. The CVVHD technique was used successfully in a morbidly obese, short-statured woman with a spontaneous hypertensive intraparenchymal cerebellar hemorrhage. The woman experienced acute renal failure several days after her hemorrhage and her general medical condition prevented her from undergoing surgical evacuation. The CVVHD did not result in elevations in intracranial pressure (ICP) and the patient made a full recovery from both acute renal failure and life-threatening posterior fossa hemorrhage. This case is noteworthy because of the absence of abnormally high ICP elevations or development of DDS in a patient with a large acute posterior fossa intraparenchymal brain hemorrhage and acute renal failure whose case was managed with CVVHD in the acute period.


Subject(s)
Acute Kidney Injury/therapy , Cerebellar Diseases/complications , Cerebral Hemorrhage/complications , Renal Dialysis/methods , Brain Edema/etiology , Female , Follow-Up Studies , Humans , Hypertension/complications , Intracranial Hypertension/prevention & control , Middle Aged , Obesity, Morbid/complications , Renal Dialysis/adverse effects , Risk Factors , Subarachnoid Hemorrhage/complications , Syndrome , Ventriculostomy
17.
J Neurosurg ; 90(6): 1129-32, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10350262

ABSTRACT

Infantile myofibromatosis involving the skull is a benign disease if there is a solitary lesion. However, the multifocal form with skull involvement may portend a lethal course in the 1st year of life if there is involvement of the heart, lungs, or gastrointestinal tract. The authors report the case of a 3-year-old boy with an enlarging left parietal skull lesion that had been present since infancy. Increasing pain and the need to obtain tissue for diagnosis led to resection of the lesion by means of a small craniectomy. Further evaluation revealed no other lesions. A distinctly rare disease is presented, and the need for staging in children younger than 2 years of age is suggested to rule out cardiac, pulmonary, or gastrointestinal involvement.


Subject(s)
Myofibromatosis/surgery , Skull Neoplasms/surgery , Child, Preschool , Craniotomy , Humans , Male , Myofibromatosis/diagnostic imaging , Myofibromatosis/pathology , Parietal Bone/diagnostic imaging , Parietal Bone/pathology , Parietal Bone/surgery , Skull Neoplasms/diagnostic imaging , Skull Neoplasms/pathology , Tomography, X-Ray Computed
18.
Life Sci ; 75(3): 313-28, 2004 Jun 04.
Article in English | MEDLINE | ID: mdl-15135652

ABSTRACT

The expression of CD34 antigen in acute myelogenous leukemias is considered an unfavourable prognosis marker for response to anticancer drugs and duration of remission. This study investigated the applicability of long-circulating immunoliposomes loaded with doxorubicin targeted to CD34 antigen present on MDR(+) human myelogenous leukemia KG-1a cell line. Immunoliposomal doxorubicin showed a higher cytotoxicity against KG-1a cells than non-targeted liposomal doxorubicin, but it did not improve over that of free drug. Although no reversal of doxorubicin resistance was found to occur through its liposomal encapsulation, a therapeutic benefit can be obtained by the selective cytotoxicity observed. Endocytosis studies demonstrated that, after binding to CD34 antigen, the immunoliposomes are not internalized by the KG-1a cells and so the cytotoxic effect might be due to drug released into the space near the cell membrane. Thus, immunotargeting of liposomal doxorubicin to CD34(+) leukemic cells may only provide an ex vivo strategy for site-selective CD34(+) leukemia cell killing.


Subject(s)
Antibiotics, Antineoplastic/pharmacology , Antigens, CD34/immunology , Doxorubicin/pharmacology , Leukemia, Myeloid, Acute/drug therapy , Antibiotics, Antineoplastic/administration & dosage , Antibiotics, Antineoplastic/pharmacokinetics , Antibodies, Monoclonal , Capsules , Cell Division , Cell Line, Tumor , Cell Survival/drug effects , Chemistry, Pharmaceutical , Doxorubicin/administration & dosage , Doxorubicin/pharmacokinetics , Drug Carriers , Drug Delivery Systems , Endocytosis/drug effects , Flow Cytometry , Humans , Immunochemistry , Leukemia, Myeloid, Acute/pathology , Liposomes , Microscopy, Confocal , Particle Size
19.
Chem Phys Lipids ; 113(1-2): 97-110, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11687230

ABSTRACT

Poly(ethylene glycol)-coated liposomes were prepared with two new synthesised pegylated cholesterol (Chol) derivatives linked via carbamate bond. Poly(ethylene glycol) (PEG) was directly linked to Chol (PEG-Chol) or through a space arm of diaminebutane (PEG-L-Chol). In buffer, the physicochemical properties of PC/Chol liposomes (2/1, molar ratio) containing up to 10 mol% of pegylated Chol derivatives did not change significantly and the PEG layer at liposome surface inhibited the agglutination of biotin-liposomes induced by streptavidin. On the other hand, in serum, PEG-L-Chol seemed to reduce the interactions of liposomes with serum proteins, much more than PEG-Chol. The low steric hindrance of PEG-Chol derivative may be due to the slow conformational transition rate of the polymer, since PEG may be deeper located in the membrane. The coupling efficiency of the ligand to the functionalised amino group at the polymer end was also affected, but, its antigen-binding activity was preserved. The basic physical-chemical characteristics studied in this work are relevant to assess the application of pegylated Chol liposomes as drug delivery systems.


Subject(s)
Antibodies, Monoclonal/immunology , Cholesterol/analogs & derivatives , Cholesterol/chemistry , Liposomes/immunology , Polyethylene Glycols/chemistry , Antibodies, Monoclonal/chemistry , Antigen-Antibody Reactions/drug effects , Antigens, CD34/immunology , Blood Proteins/metabolism , Cholesterol/pharmacology , Cross-Linking Reagents/chemistry , Drug Delivery Systems , Humans , Liposomes/chemistry , Liposomes/metabolism , Permeability/drug effects , Phosphatidylethanolamines/chemistry , Phosphatidylethanolamines/pharmacology , Phospholipids/chemistry , Polyethylene Glycols/pharmacology , Protein Binding/drug effects
20.
JSLS ; 2(2): 177-80, 1998.
Article in English | MEDLINE | ID: mdl-9876734

ABSTRACT

OBJECTIVE: The authors report the first documented case of laparoscopically induced ventriculoperitoneal (VP) shunt failure. SUMMARY BACKGROUND DATA: Laparoscopic surgery has become a preferred method of accessing and treating a variety of intraperitoneal pathology. Surgeons can expect to encounter patients who have previously undergone placement of cerebrospinal fluid (CSF) shunts who present as candidates for laparoscopic procedures. Currently, the presence of a CSF shunt is not considered to be a contraindication to laparoscopy. We report the first documented case of laparoscopically induced VP shunt failure. CLINICAL HISTORY: A patient with shunt-dependent hydrocephalus underwent laparoscopic placement of a feeding jejunostomy. Postoperatively, clinical and radiographic evidence of shunt failure was noted. The patient underwent emergent shunt revision. Intraoperatively, an isolated distal shunt obstruction was encountered. Gentle irrigation cleared the occlusion. We believe that this shunt dysfunction was secondary to impaction of either soft tissue or air within the distal catheter as a consequence of peritoneal insufflation. CONCLUSIONS: It is concluded that laparoscopic surgery may represent a potential danger in patients with pre-existing CSF shunts. The risk of neurological injury faced by this patient population during laparoscopy is derived from peritoneal insufflation and relates to two primary concerns. The first is impaired CSF drainage due to a sustained elevated distal pressure gradient or, as in our case, an acute distal catheter obstruction. The second concern relates to the potential for retrograde insufflation of the CSF spaces through an incompetent shunt valve mechanism. Distal shunt catheter externalization performed in conjunction with a neurosurgeon during the laparoscopic procedure would prevent these complications. Internalization of the distal shunt catheter would then be performed at the completion of the laparoscopic procedure.


Subject(s)
Jejunostomy/instrumentation , Laparoscopy/adverse effects , Ventriculoperitoneal Shunt , Equipment Failure , Humans , Hydrocephalus/surgery , Jejunostomy/adverse effects , Male , Middle Aged , Treatment Failure
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