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At least 1,135 records · Page 63Linked to original sources
PubMed1998

[Spiral CT in arytenoid cartilage dislocation: the optimization of the study parameters with a cadaver phantom and its clinical evaluation].

PURPOSE: To evaluate an optimal scan protocol in a cadaver phantom and its clinical assessment in 40 patients. MATERIALS AND METHODS: In a cadaver larynx phantom helical CT (HiSpeed Advantage; GE, Milwaukee, Wis) was performed with increasing collimation (1-10 mm) and pitch (1.0-3.0). 40 patients with an immobile vocal cord were randomly assigned to undergo CT with a certain protocol. RESULTS: Best resolution was obtained with a collimation of 1 mm and pitch 1. The pitch could be increased up to 2 without losing information. With a collimation of 3 mm and higher, anatomical details were missed. In the patient studies a combination of 1 mm collimation with a pitch of 2.0 showed less motion artifacts than a pitch of 1.0. CONCLUSION: The quality of CT imaging of the arytenoid cartilage depends greatly on the scanning parameters, the compliance of the patients and the mineralisation of the cartilage. For clinical assessment a collimation of 1 mm with a pitch of 2 is recommended. The increase pitch has the advantage of shorter acquisition times and decreased radiation exposure.

Artifacts↗
PubMed1994

In-vivo evaluation of the "HIA-VAD": a new German ventricular assist device.

Helmholtz Ventricular Assist Devices (VAD) are pneumatically driven polyurethane membrane pumps with various volumes. The pumps are placed paracorporeally and connected with commercially available cannulas between the left atrium and aorta (left ventricular assist device) and/or right atrium and pulmonary artery (right ventricular assist device, bi-ventricular assist device). The pumps can be driven with a stand-alone driving system or with a Helmholtz IABP-console interface. Seventeen animal experiments (on calves) with Helmholtz VAD's were performed to evaluate experimental protocols, to optimize surgical techniques, and to improve design and manufacturing techniques. Blood chemistry and cell counts demonstrated that the tested HIA-70 produces low mechanical blood damage. In the course of the animal experiments the Helmholtz VAD's were made totally transparent, whereby they became easy to de-air, efficient, and affordable.

Animals↗
PubMed1997

Ethical issues in the management of chronic nonmalignant pain.

Chronic pain represents a challenge to patients, families, employers, and the physicians who care for these individuals. Opioids remain the mainstay of the analgesic medications for the treatment of both acute and chronic pain. Controlled release preparations of morphine, oxycodone, fentanyl and long acting opioid agents such as methadone and levorphanol have been medically and ethically accepted in managing chronic cancer pain. However, the continued use of these medications for patients with chronic noncancer pain has been fiercely debated. This article attempts to reconcile the medical and ethical dilemma of using opioid medications for chronic noncancer pain. Growing clinical experience in the field of pain medicine has helped to clarify: (1) the misunderstanding of addiction, physical dependence and analgesic tolerance, (2) the misconception that chronic opioid therapy inevitably causes personality changes, depression, and impairment of cognitive and physical function, (3) the lack of information on the correct use of opioid analgesics with regard to titration and management of related side effects. The behavioral management of pain patients undergoing chronic opioid therapy is also discussed. A protocol for optimal patient management is proposed. Particular emphasis is given to the consent form, behavioral contracting, and the consequences of noncompliance. The importance of psychologic evaluation before a long-term opioid trial, to minimize future complications, is stressed. Although most patients on the opioid regimen do well, special attention must be given to patients with current addiction, a past history of addiction, or current misuse of opioid medications. Pharmacologic and conservative interventions are often warranted in those patients with significant behavioral problems. If such strategies fail, and chronic opioid therapy is deemed necessary, some treatment guidelines are offered.

Analgesics, Opioid↗
PubMed2003

Detection of dioxygenase genes present in various activated sludge.

GOAL, SCOPE AND BACKGROUND: Activated sludge from refineries contains various microorganisms that could utilize aromatics under aerobic conditions due to the oxygenase enzymes. Dioxygenase enzymes are oxygenases, which are involved in the ring cleavage step of aromatic hydrocarbons. In this study, the selected catabolic loci involved in ring cleavage have been monitored in the activated sludge samples at different time intervals. The investigation of the dioxygenase genes in the Effluent Treatment Plants (ETPs) and evaluation of their presence at different time points provides a clue for the aromatic utilizing potential of the inherent microbial flora. METHODS: The catabolic gene loci pheB, xylE, tod-isp, bed and nahG responsible for the enzymes catechol 1,2-dioxygenase, catechol 2,3-dioxygenase, toluene dioxygenase-iron-sulphur protein component, benzene dioxygenase and naphthalene dioxygenase were used respectively. The time dependent change in eubacterial population was demonstrated by the amplification of 16S rDNA product, followed by restriction digestion. The template DNA was obtained from the activated sludge collected from ETPs. The supporting physiological data for the overall performance of sludge was developed using respirometric analysis. The on-site COD and MLSS analysis for ETP was used in final evaluation. The study was carried out with samples collected from three different ETPs and also from a selected ETP at different time intervals. RESULTS AND DISCUSSION: The respirometric studies were carried out with phenol, catechol, toluene, and naphthalene to arrive at the target genotypes for further study by PCR protocol. The respirometric analysis coupled with the COD and MLSS analysis represented the physiological capacity of the various sludges. Initially, the tracking protocol was optimized by using different sludge samples, which were collected from refineries. The selected genotypes were amplified and their presence has been confirmed using Southern analysis. The gene loci tod-isp, bed and xylE were commonly observed at various time intervals of the sludge from the same source. The gene loci pheB and nahG were found to be relatively rare. CONCLUSION: The 16S rDNA PCR products after restriction digestion produced different DNA fingerprint patterns, suggesting that the microbial community composition was diverse in the three sources. Similarly, the presence of the catechol 2,3-dioxygenase, benzene dioxygenase and toluene dioxygenase genes confirmed the aromatic degrading potential in the various sludges. The probes could not pick the nahG and pheB genes. However, the respirometeric assay suggested that the oxidative capacity to use naphthalene as a substrate exists. RECOMMENDATION AND PERSPECTIVE: Our study of the diversity at various time points from the ETP provided an overview of the shifts of the catabolic composition of the sludge. This also depends on the influential parameters like the incoming pollutant level and the environmental conditions that are prevailing and often changing from time to time. The results of direct DNA extraction and PCR amplification do reflect the relative abundance of a particular catabolic genotype, which could be used to monitor the efficiency of treatment.

DNA Fingerprinting↗
PubMed2006

Discovering antibiotic efficacy biomarkers: toward mechanism-specific high content compound screening.

As current antibiotic therapy is increasingly challenged by emerging drug-resistant bacteria, new technologies are required to identify and develop novel classes of antibiotics. A major bottleneck in today's discovery efforts, however, is a lack of an efficient and standardized method for assaying the efficacy of a drug candidate. We propose a new high content screening approach for identifying efficacious molecules suitable for development of antibiotics. Key to our approach is a new microarray-based efficacy biomarker discovery strategy. We first produced a large dataset of transcriptional responses of Bacillus subtilis to numerous structurally diverse antibacterial drugs. Second we evaluated different protocols to optimize drug concentration and exposure time selection for profiling compounds of unknown mechanism. Finally we identified a surprisingly low number of gene transcripts (approximately 130) that were sufficient for identifying the mechanism of novel substances with reasonable accuracy (approximately 90%). We show that the statistics-based approach reveals a physiologically meaningful set of biomarkers that can be related to major bacterial defense mechanisms against antibiotics. We provide statistical evidence that a parallel measurement of the expression of the biomarkers guarantees optimal performance when using expression systems for screening libraries of novel substances. The general approach is also applicable to drug discovery for medical indications other than infectious diseases.

Anti-Bacterial Agents↗
PubMed2004

Role of human papillomavirus in the development of head and neck squamous cell carcinomas.

OBJECTIVE: To review the literature on the role of oncogenic human papillomaviruses (HPVs) in the carcinogenesis of the head and neck mucosa. MATERIAL AND METHODS: Molecular and epidemiological studies concerning the high-risk HPV types and their role in carcinogenesis in the head and neck region were screened. RESULTS: Different studies revealed that: (i) 15-25% of head and neck squamous cell carcinomas (HNSCCs) are clonally associated with high risk HPV types (type 16); (ii) the oropharynx and particularly the tonsils are the most susceptible sites; (iii) patients with HPV-positive tumours present with more advanced stages of disease, are relatively younger, do not have extravagant tobacco and alcohol intake and seem to have a better survival; (iv) HPV-positive tumours are characterized by poor differentiation grade and a basaloid appearance; and (v) HPV-positive tumours exhibit integrated HPV DNA, wild-type p53, pRb downregulation and overexpression of p16INK4A. CONCLUSION: Taken together, these data support the view that HPV-harbouring HNSCC can be considered a discrete tumour entity with, moreover, a favourable prognosis. Screening of patients, especially those with tonsillar cancers, for the presence of HPV may help to further optimize treatment protocols and to provide more accurate prognostic information.

Alcohol Drinking↗
PubMed2005

Bedside monitoring of CBF with xenon-CT and a mobile scanner: a novel method in neurointensive care.

Combining previously independently established techniques our objective was to develop and evaluate a method for bedside qualitative assessment of cerebral blood flow in neurointensive care (NICU) patients. The CT-protocol was optimized using phantoms and comparing a mobile CT-scanner (Tomoscan-M, Philips) with two stationary CT scanners. Thirty-two per cent xenon was delivered with standard equipment (Enhancer 3000). Mean cortical flow in volunteers was 48 ml/min/100 g, with the mean vascular territorial flow varying between 45 and 66 ml/min/100 g. The potential clinical usefulness was illustrated in three patients with vasospasm following subarachnoid haemorrhage. Our conclusion is that quantitative bedside measurements of CBF can be repeatedly performed in an easy and safe way in a standard NICU-setting, using xenon-inhalation and a mobile CT-scanner. The method is useful for the decision-making, and is a good example of how the quality of multi-modality monitoring in the NICU can be developed and further diversified.

Adult↗
PubMed2026

Dynamic lysine acetylation and succinylation of platelet proteins regulates platelet storage lesion: mechanistic insights from multi-omics.

OBJECTIVES: Platelet storage lesion (PSL) severely impairs platelet function during storage, presenting a major hurdle in transfusion medicine; however, the dynamic interplay between global proteomic changes and post-translational modifications (PTMs) underlying these functional deteriorations remains insufficiently characterized. Here, we report the first comprehensive multi-omics analysis integrating global proteomics, acetylomics, and succinylomics to dissect the molecular dynamics during platelet storage. METHODS: We performed quantification of global proteomics, acetylome and succinylome based on TMT-labeled LC-MS/MS analysis, combined with antibody-affinity enrichment and purification. Dynamic molecular changes and functional transformation of platelet were also characterized under proper conditions stored for 1, 3, 5, 7 days, respectively. RESULTS: We systematically characterized 3,609 proteins, 1,308 acetylation sites, and 1,947 succinylation sites across multiple storage time points (D1, D3, D5, D7). We distinct temporal patterns of post-translational modifications, with succinylation showing more extensive coverage than acetylation in platelets. Pathway enrichment analysis revealed extensive metabolic reprogramming involving complement activation, energy metabolism, and cellular detoxification processes. The identification of specific motif patterns provided mechanistic insights into the functional specificity of these modifications. Random forest machine learning identified 20 core regulatory proteins representing critical nodes in PSL development. Furthermore, we employed real - time quantitative polymerase chain reaction (RT - QPCR) to measure the expression levels of key genes related to platelet function and PTM - associated pathways. CONCLUSION: By mapping the interplay between proteomic abundance shifts and PTM dynamics, this study provides a multidimensional understanding of PSL, establishing a foundational framework for optimizing storage protocols and enhancing transfusion safety.

Blood Platelets↗
PubMedDate not supplied

Association between the change in nutritional status in response to tube feeding and the occurrence of infections in children with a solid tumor.

In 32 children with a solid tumor, the association between the change in weight for height, in response to 4 weeks of tube feeding during the intensive phase of treatment, and the occurrence of leukopenia, leukopenic infections, and nonleukopenic infections in a period thereafter (4-10 weeks) was studied. Factors possibly influencing the change in weight for height during the first 4 weeks of tube feeding were also assessed. A statistically significant negative correlation (rho = -0.59; p < .001) was found between the change in z-score of weight for height in response to the first 4 weeks of tube feeding, and the occurrence of nonleukopenic infections between 4 and 10 weeks. A reduced occurrence of nonleukopenic infections resulted in a significant reduction of the number of days of infection-related hospital admission (rho = .45; p = .009), which, besides providing advantages for the patient, also had economical benefits. The change in weight for height in response to tube feeding was mainly influenced by the incidence of therapy-induced vomiting (r = -.45; p = .02) and by the amount of energy provided by tube feeding (r = .47; p = .007). Based on these findings, it is recommended that naso-gastric tube feeding be used in children with a solid tumor during the early intensive phase of treatment, and that one should aim for a considerable increase in weight for height during the first 4 weeks of administration, since this has been shown to reduce the number of nonleukopenic infections in a subsequent period. The increase in weight for height may be improved by providing an optimal antiemetic protocol, which will increase energy uptake, and an energy-enriched formula, which will increase energy intake.

Adolescent↗
PubMed2002

Chronic lymphocytic leukaemia--the haematologic basis for diagnosis and treatment.

Clinically diagnosis may be incidental when absolute lymphocytosis is uncovered at routine medical examination. More usually there is a recurrent sinopulmonary infection reflecting a varying degree of humoral and cellular immune deficiency. Autoimmune phenomena may result in haemolytic anaemia or thrombocytopenia. Expanding tumour bulk underlies the lymphadenopathy which may be prominent. Diagnosis is confirmed on morphology of the smear where atypical variants need to be distinguished from other indolent lymphoproliferative disorders. Immunophenotyping is indispensable in classification. Prognosis is predicated by cytogenetics and markers of tumour biology that include beta-2 microglobulin and peripheral blood lymphocyte doubling time. Management is dictated by symptoms and signs of progression superimposed upon performance status that includes age. Disease that is asymptomatic and truly indolent, particularly in the elderly, qualifies for a careful watch-and-wait policy. In other circumstances stratification to therapy requires entry into peer-reviewed protocols if optimal outcome is to be achieved. Established regimens, of demonstrably equal efficacy, are pulsed single-agents exemplified by chlorambucil or combinations of cyclophosphamide with vincristine and prednisone. The purine analogues, particularly when administered with an alkylating agent and mitoxantrone, are emerging as superior options. In selected patients any properly accredited program will make provision for escalation in chemotherapy requiring haematopoietic stem cell transplantation on the one hand or use of serotherapy with CD52 antibodies on the other. Less commonly, but in a defined subgroup, immunoglobulins directed against membrane CD20 may be effective. Perspective for the generalist is anchored in recognising that the previous cavalier approach to drug medication, with or without radiotherapy, is unwise whereas integrated management is now the international standard of practice. The previous anachronism of dabbling by occasional therapists is to be deprecated since this will generally deny patients access to proper diagnosis and risk-adjusted multi-disciplinary treatment.

Antineoplastic Agents↗
PubMed2002

A comparison of two surface sample collection devices for use in polymerase chain reaction based detection of Pneumocystis carinii in house dust.

A polymerase chain reaction assay was optimized to detect P. carinii cysts in composite dust samples. The optimal assay was capable of detecting as few as 10(3) P. carinii cysts in 50 mg of dust. Two dust collection devices were evaluated for efficiency and precision of collection of bulk dust and compatibility with the optimized PCR protocol for P. carinii DNA detection. A handheld vacuum cleaner equipped with a high-retention bag was found to be superior to a 37-mm filter cassette attached to an electrically powered vacuum pump in terms of dust collection efficiency (87% [n = 37] versus 81% [n = 35]), although the precision of the two devices as assessed by the standard deviation was similar (6.2% versus 6.3%). However, the vacuum cleaner method was not as compatible with the PCR-based detection assay as the filter cassette method. The filter cassette appears to be a better device for use in conjunction with PCR-based detection of P. carinii DNA in bulk dust samples from both smooth and carpeted surfaces.

DNA, Fungal↗
PubMed2000

Development of a purification procedure for the isolation of nucleosides from urine prior to mass spectrometric analysis.

A chromatographic separation of nucleosides from urine has been developed in order to facilitate their mass spectrometric analysis for clinical diagnosis. A number of chromatographic resins were studied in order to develop an effective and efficient purification procedure. The optimized sequential protocol comprises a centrifugation, acidification and neutralization step, followed by application of an affinity chromatographic column and finally further separation on an acidic cation exchange column and a basic anion exchanger. This scheme shows effective clean-up of a standard radiolabelled nucleoside with a recovery of 92.5%, and recovery of nucleosides added to urine samples before extraction showed recoveries of 72-82%.

Acrylic Resins↗
PubMed1992

Review of respirator performance testing in the workplace: issues and concerns.

Performance capability of respirators has traditionally been evaluated by testing components of the respirator (e.g., filter efficiency), facepiece fit, total inward leakage, or some other measure of performance evaluated under laboratory conditions. In recent years, increased emphasis has been placed on development of test methods suitable for evaluating respirator performance in the workplace. The goal of such testing is to evaluate the level of protection provided by respirators in the work environment. The AIHA Respiratory Protection Committee believes that workplace testing of respirators has the potential to be an excellent tool for increasing knowledge about the effectiveness of respiratory protection. However, a number of technical issues remain to be addressed before optimal test protocols and data analysis methods can be defined. The progress made to date in workplace testing will be reviewed, and broader discussion about key elements that must be considered when developing guidelines for testing respirators in the workplace will be initiated.

Air Pollution, Indoor↗
PubMed2003

A study on arsenic removal from household drinking water.

Arsenic removal from household drinking water has been receiving considerable attention in the field of water supply engineering. To develop the optimal coagulation protocol, the effectiveness of several operation options such as coagulants, coagulant aids and additives, as well as flocs separation systems were investigated in this study through the use of orthogonal array experiment based on Taguchi method. Arsenic removal mechanism during household coagulation (via manual mixing) was also discussed. The results showed that the addition of kaoline and powder activated carbon (PAC) did not enhance arsenic removal efficiency of ferric sulfate or aluminum sulfate. Similarly, mixture of ferric sulfate and aluminum sulfate (MFA) as well as polymeric ferric silicate sulfate (PFSiS) was also unable to improve the overall arsenic removal efficiency. The mechanism of arsenic removal during coagulation was somewhat different from those experienced in conventional processes. Coprecipitation appeared to be the crucial mechanism for arsenic removal. It is noted from this study that arsenic adsorption isotherm under household operation condition could be described by Langmuir equation. An efficient flocs separation system subsequent to coagulation was essential to achieve the effectiveness of overall arsenic removal. The results obtained from field experiment demonstrated that the method of ferric sulfate coagulation/sand filtration for arsenic removal from household drinking water was acceptable and affordable.

Alum Compounds↗
PubMed2001

Optimization of retroviral gene transfer protocol to maintain the lymphoid potential of progenitor cells.

We have attempted to improve retrovirus-mediated gene transfer efficacy into hematopoietic progenitor cells (HPCs) without causing them to lose their lymphoid potential. Highly purified CD34(+) cells on CH-296 fibronectin fragments have been transduced with three different cytokine combinations. Murine CD2 was used as a marker gene. Transgene expression was assayed by FACS analysis shortly after transduction of CD34(+) cells and after long-term culture (LTC) extended by differentiation of various lymphoid lineages: NK cells, B cells, and dendritic cells. Compared with the historical cytokine mix, i.e., SCF (stem cell factor) + IL-3 (interleukin 3) + IL-6, the combination SCF + FL (Flt-3 ligand) + M-GDF (megakaryocyte growth and differentiation factor) + IL-3 significantly improved the total number of viable cells and CD34(+) cells after transduction and the long term-cultured progenitors after 6 weeks. In addition, the combination of SCF + FL + M-GDF + IL-3 maintained more efficiently the lymphoid potential of the progeny of transduced long term-cultured CD34(+) cells, as attested by the significantly higher number of CD56(+), CD19(+), and CD1a(+) cells recovered when FL and M-GDF were added to SCF + IL-3. Thus, even though additional improvements may still be needed in transduction of HPCs, these conditions were adopted for a clinical trial of gene therapy for X-linked severe combined immunodeficiency.

Animals↗
PubMed2002

Somatic cell nuclear transfer: recent progress and challenges.

Somatic cell nuclear transfer (NT) offers new and exciting opportunities in many areas of research and biotechnology. However, the field as a whole is still in its infancy, with continuing inefficiencies in the process proving many early expectations premature. The technical steps of NT are complex, and success is highly susceptible to minor variations. Furthermore, the biological process of reprogramming is not fully understood, making it difficult to optimize the protocols for providing ideal recipient oocytes and donor cells. In this paper, we describe recent advances and novel approaches, which resulted in progress during the last year, including the birth of cloned piglets and farm animals with precise genetic changes. Key problems hindering further progress are addressed.

Animals↗
PubMed2002

Metabolomics of plant saponins: bioprospecting triterpene glycoside diversity with respect to mammalian cell targets.

One of the goals of cancer chemotherapy and prevention is the discovery of compounds that are relatively selective to tumor cells and, therefore, have reduced effects on normal cell growth. In previously published studies, it was shown that certain triterpene saponins (called avicins) from a desert tree, Acacia victoriae, are selectively toxic to tumor cells at very low doses (IC(50): 0.2 microg/mL for Jurkat cells). To extend this research to human clinical studies, we needed to find a reliable supply of avicins and have developed a transformed "hairy root" culture as a means of biomass production. Protocols were optimized for A. victoriae micropropagation; after a boiling water treatment, A. victoriae seeds were maintained under in vitro conditions on defined media. Embryo-axis explants from shoot tips were removed and infected with Agrobacterium rhizogenes Conn (R 1000) for hairy root induction. Plasmid integration was confirmed by PCR analysis with a primer set for a segment of the rol B gene. Culture conditions have been optimized for root biomass production, and various inducers have been investigated for enhancement of avicin production. Hairy root cultures were compared with intact pod tissue from field-grown sources for avicin content following partial purification of triterpene glycosides and HPLC separation of the secondary metabolites. From bioassays of the collected HPLC fractions, we have identified putative triterpene "metabolic clusters" with enhanced activity against tumor cells. This now provides a system for both production of clinical trial lots of active samples, but also a means to correlate structure of individual triterpene glycosides with specific cellular target activity in mammalian cells.

Acacia↗
PubMed2003

Demyelination and axonal loss in multifocal motor neuropathy: distribution and relation to weakness.

Multifocal motor neuropathy (MMN) is characterized by a slowly progressive, asymmetric weakness of the limbs without sensory loss. The arms are usually affected to a greater extent than the legs, and distal muscles more than proximal muscles. The distribution of electrophysiological abnormalities and its correlation with weak muscle groups in MMN have not been investigated systematically. The aim of the present study was to assess whether electrophysiological abnormalities have a preferential or random distribution, whether electrophysiological abnormalities in a nerve correlate with weakness in the innervated muscles, and whether these results are relevant for the development of optimal electrodiagnostic protocols. We compared the pattern of weakness and electrophysiological abnormalities in 39 patients with a lower motoneuron syndrome and a positive response to intravenous immunoglobulins. All patients underwent an extensive standardized electrophysiological examination. Electrophysiological evidence of demyelination was found more often in the nerves of the arms and was distributed randomly over lower arm, upper arm and shoulder segments. Electrophysiological evidence of axonal loss presented more frequently in longer nerves, occurring most often in the leg nerves. For the arm nerves, it is possible that the length dependence of axonal loss is due to the random distribution of demyelinating lesions that lead to axonal degeneration. Weakness was associated with features of demyelination and axonal loss in the nerves of the arm, and with features of axonal loss in leg nerves. However, a substantial number (approximately one-third) of electrophysiological abnormalities were found in nerves innervating non-weakened muscles. These results imply that in MMN, conduction block is most likely to be found in long arm nerves innervating weakened muscles, but if conduction block cannot be detected in these nerves, the electrophysiological examination should be extended to other arm nerves including those innervating non-weakened muscles.

Action Potentials↗