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At least 721 records · Page 40Linked to original sources
PubMed1995

Brucella melitensis: an unexpected isolate from cerebrospinal fluid.

A specimen of cerebrospinal fluid was initially handled with 'category 3' precautions because the patient came from Somalia, where tuberculosis and HIV infection are endemic. An isolate from the specimen, initially thought to be a Neisseria species, was subsequently handled on the open bench. It was later identified as Brucella melitensis. Laboratory procedures should allow for the possibility of brucella in such specimens until a positive identification has been made.

Brucella melitensis↗
PubMed2001

Reline materials--handle with care? An investigation into the effect of varying the powder/liquid ratio on some properties of auto-polymerising acrylic resin materials.

INTRODUCTION: The fit of the denture base to the alveolar ridge progressively declines with alveolar ridge resorption. Once a denture becomes ill-fitting there are two main treatment options: to construct a new denture or to restore the fit of the existing denture. A denture may be relined as a laboratory procedure or at the chairside in the dental clinic. The chairside reline technique involves the direct application of auto-polymerising acrylic resin materials to the prepared denture base and the material is allowed to polymerise in the patient's mouth. The reline materials are generally supplied as a powder and a liquid. Clinicians and laboratory dental staff do not always follow manufacturers' recommended guidelines and the tendency can be simply to add varying quantities of powder and liquid until the desired consistency is achieved. This method however may have deleterious effects on the properties of the resultant material. MATERIALS AND METHOD: The aim of the study was to investigate the effect of varying the powder/liquid ratio on some properties of three auto-polymerising acrylic resin reline materials. The properties investigated were the flow characteristics in terms of the manipulation and setting time and the hardness. Four powder and liquid ratios were chosen. RESULTS AND CONCLUSIONS: For all the materials studied, a clinically useful lengthening of the manipulation time can be achieved by increasing the amount of liquid added to the powder. However, this is perhaps offset by the fact that it is associated with a corresponding increase in the setting time and resultant increase in clinical chairside time. There were significant differences in surface hardness when the powder/liquid ratio was altered.

Acrylic Resins↗
PubMed2001

[Cytopathology--current trends].

Modern imaging techniques help to detect minute tumours, even in remote locations of the body. This increases the demand to sample cellular material by minimal invasive procedures, such as fine needle aspiration (FNA). For optimal treatment, tumour cells should be characterized for prognostically relevant features. Primary and metastatic neoplasms, and individual disseminated cells of solid tumours are targets for FNA and exfoliative cytology. Recognition and typing of tumour cells is aided by immunochemistry and PCR based molecular studies. Especially immunostaining requires laboratory procedures adapted to cytology samples. Screening for precancerous lesions, highly successful in cervical cancer prevention, extends into areas such as bladder and lung cancer in selected patient groups. Cell image analysis, especially for DNA ploidy, and chromosomal FISH of interphase cells can have predictive value enhancing the information derived from the purely morphologic assessment. Prognostic tumour cell markers are studied using immunochemistry and PCR on cytological material. Cytology has to foster translational research and test the results from molecular cytogenetics, including comparative genomic hybridisation (CGH) and cDNA microarray techniques on dissociated solid tumour cells. Newly identified genetic abnormalities can be evaluated for their functional relevance and may correlate with distinct structural alterations of the tumour cells. Proper training, dedication to diagnostic cytologic work and molecular studies, and sufficient staffing will enable cytology to get the most for the patient out of limited cell material. This approach helps to distinguish genetically defined tumour subtypes by recognizing properties of the cell gestalt.

Biopsy, Needle↗
PubMed2006

The place of molecular genetic methods in the diagnostics of human pathogenic anaerobic bacteria. A minireview.

Anaerobic infections are common and can cause diseases associated with severe morbidity, but are easily overlooked in clinical settings. Both the relatively small number of infections due to exogenous anaerobes and the much larger number of infections involving anaerobic species that are originally members of the normal flora, may lead to a life-threatening situation unless appropriate treatment is instituted. Special laboratory procedures are needed for the isolation, identification and susceptibility testing of this diverse group of bacteria. Since many anaerobes grow more slowly than the facultative or aerobic bacteria, and particularly since clinical specimens yielding anaerobic bacteria commonly contain several organisms and often very complex mixtures of aerobic and anaerobic bacteria, considerable time may elapse before the laboratory is able to provide a final report. Species definition based on phenotypic features is often time-consuming and is not always easy to carry out. Molecular genetic methods may help in the everyday clinical microbiological practice in laboratories dealing with the diagnostics of anaerobic infections. Methods have been introduced for species diagnostics, such as 16S rRNA PCR-RFLP profile determination, which can help to distinguish species of Bacteroides, Prevotella, Actinomyces, etc. that are otherwise difficult to differentiate. The use of DNA-DNA hybridization and the sequencing of special regions of the 16S rRNA have revealed fundamental taxonomic changes among anaerobic bacteria. Some anaerobic bacteria are extremely slow growing or not cultivatable at all. To detect them in special infections involving flora changes due to oral malignancy or periodontitis, for instance, a PCR-based hybridization technique is used. Molecular methods have demonstrated the spread of specific resistance genes among the most important anaerobic bacteria, the members of the Bacteroides genus. Their detection and investigation of the IS elements involved in their expression may facilitate following of the spread of antibiotic resistance among anaerobic bacteria involved in infections and in the normal flora members. Molecular methods (a search for toxin genes and ribotyping) may promote a better understanding of the pathogenic features of some anaerobic infections, such as the nosocomial diarrhoea caused by C. difficile and its spread in the hospital environment and the community. The investigation of toxin production at a molecular level helps in the detection of new toxin types. This mini-review surveys some of the results obtained by our group and others using molecular genetic methods in anaerobic diagnostics.

Bacteria, Anaerobic↗
PubMedDate not supplied

Fabrication of a meatus obturator on a titanium framework with a 1-step impression.

The fabrication of meatal obturator prosthesis with titanium framework using a 1-step final impression procedure is described in the case of a 44-year-old woman with congenital absence of the soft palate. The meatus obturator results in a more stable maxillary prosthesis and permits acceptable speech for a patient with total absence of the soft palate. The fabrication technique is relatively easy and saves time by eliminating some laboratory procedures.

Adult↗
PubMed2004

Pseudoepidemic of Q fever at an animal research facility.

Serum samples from people exposed to sheep at a research facility were evaluated by a commercial laboratory and resulted in an overall Coxiella burnetii seroprevalence of 75%. We interviewed individuals to determine exposure history and compatible illness, and retested their sera. Analysis indicated that the commercial laboratory was misinterpreting its results; when corrected, the seroprevalence dropped to 27%. Test kits of the brand used by the commercial laboratory gave equivalent results to the in-house CDC assay when tested in parallel at CDC. Upon final analysis, only the attending veterinarian was confirmed as a Q fever case. This event resulted in increased risk reduction protocols at the research facility and improved public health communication among health authorities. This pseudoepidemic resulted from a lapse in laboratory quality control for testing. Similar errors can be avoided through standardization and improved review of laboratory procedures.

Animals↗
PubMed2006

Rehabilitation of failing dentition with immediate denture prostheses: technique for a predictable esthetic and functional outcome.

The goal of this article is to describe the clinical and laboratory procedures used in the fabrication of immediate complete and removable partial denture prostheses. In this type of treatment, achieving optimal esthetic and functional outcomes is complicated because of the absence of the try-in stage. To overcome this limitation, a technique that predictably transfers the information obtained during esthetic dentofacial analysis from the patient to the laboratory in the form of an incisal-occlusal plane guide is described. Stability, support, and retention of the immediate partial denture prosthesis can be improved with the incorporation of cast clasp assemblies, and its fabrication technique is presented in this article.

Adult↗
PubMedDate not supplied

Adherence to universal precautions among laboratory personnel in Lebanon.

To evaluate the present situation and plan future directions with regard to implementation of universal precautions in laboratories testing blood samples, we carried out a national cross sectional study in 2003 on a representative sample of laboratories in Lebanon. We compared the results with those of a 1993 study. We found that the education profile of staff had improved, being now more specialized in laboratory science. The discrepancies between what technicians knew, believed in and practised and what was observed in the field improved to some extent in most variables. Disposal of needles and syringes had improved greatly but disposal of blood-contaminated material had not. Given the risks of improper practice, a policy of universal precautions is essential and regular training should be carried out so that staff know and practise the universal precautions and correct laboratory procedures.

Attitude of Health Personnel↗
PubMed1988

Testing for drug use, Part 1: Analytical methods.

Issues surrounding the screening and testing of individuals for drug use, including analytical and legal aspects of the procedures and social, political, and ethical problems and concerns, are reviewed. Historically, professional and societal debate regarding drug taking, drug-use problems, and the utility of drug testing programs occurs in cycles. Analytical methods commonly used to test for drug use include breath analysis for alcohol and urine drug assays. Blood alcohol concentrations are determined by laboratory assay methods or by portable devices used in the field. While poor laboratory procedures can invalidate test results for both breath and urine tests, urine screening test results can be further invalidated by improper handling of specimens or by tampering on the part of the subject. Also, test results are meaningful only if they are correlated with a clinical state. Legal issues have been raised concerning the validity of testing procedures used and the reliability of evidence obtained, especially in relation to pre-employment drug screening. From an ethical standpoint, drug testing tends to focus efforts to combat drug abuse on the drugs themselves instead of on the social context of the problem. With a recycled interest in drug-use testing and screening, primarily attributable to technological advances, little attention is being given to other approaches to controlling drug use. Additional research is needed to better describe the nature and extent of our drug-use problems and their impact on society.

Humans↗
PubMed1992

Detection of antibody to immunodeficiency viruses by dot immunobinding assay.

The dot immunobinding assay (DIA), a modified enzyme immunoassay (EIA), has been demonstrated to be a highly sensitive and specific assay for the detection of antibody to a number of viruses. Different laboratory procedures are available for detecting antibody to the immunodeficiency viruses; however, these procedures require a certain amount of sophisticated equipment and trained personnel. Further, commercial kits for detecting antibody to human immunodeficiency virus, as now available, are not easy to use in the nonlaboratory setting. The DIA, as described herein, may be formatted to test up to 30 serum samples and is designed to be used in the absence of laboratory equipment. To determine the effectiveness of the DIA as a test kit for the detection of HIV and human T-cell leukemia virus type I (HTLV-I) antibodies, the kit was compared with commercial EIA and Western blot (WB; immunoblot) kits. Testing approximately 1,000 human serum samples for HIV antibody by DIA and EIA revealed a total agreement of 98.1%, a specificity of 99.0%, and a sensitivity of 95.9%. For 804 serum samples tested (200 were tested independently in two laboratories), eight results were discrepant: four DIA negatives which were EIA borderline positive and four DIA positives which were EIA negative. Testing the eight discrepant sera by immunofluorescence assay and WB resulted in their being either negative or indeterminate. The four DIA positives were indeterminate by WB. Close agreement was obtained when the remaining sera were compared by DIA, EIA, and WB. Of interest was finding that the DIA results compared favorably with those obtained by WB. Twenty-six suspect HTLV-I-positive serum samples tested by DIA also gave results comparable to those obtained by EIA and WB.

Blotting, Western↗
PubMed1999

Randomized comparison of hemostasis techniques after invasive cardiovascular procedures.

BACKGROUND: The arterial access required during most invasive vascular procedures provides a common source of complications and morbidity. This problem has been made worse by recent trends in earlier ambulation and more aggressive antihemostatic drug regimens. Despite these trends, no randomized trials have been reported comparing the 3 most commonly used techniques in achieving hemostasis at the arterial puncture site. METHODS: A cohort of 400 patients undergoing catheterization laboratory procedures were randomly assigned to 1 of 3 groups of arterial compression: manual compression, mechanical clamp, and pneumatic compression device. Standard requirements of the trial included uniformity in initial compression times, patient instructions, nursing follow-up, and timing of ambulation as well as a structured interview and physical examination at 24 hours. RESULTS: Prolonged compression was required in 13% of the manual group, 20% of the clamp group, and 35% of the pneumatic group (P <.0001). In-lab bleeding was more common in the pneumatic group (3%, 4%, and 16%, respectively, P <.0001), as was the need for an alternate compression technique (1%, 1%, and 27%, P <.0001). The groups also differed in respect to mean hematoma size (3.9 cm(2), 7.8 cm(2), and 19.8 cm(2), P =.036) and level of discomfort during compression (1.9, 2.2, and 3.1 on a 1- to 10-point scale, P <.0001). Comparable findings were observed in the subgroup of patients eligible for outpatient procedures. CONCLUSIONS: Use of the pneumatic compression device leads to longer compression times, greater discomfort, more bleeding, and larger hematomas. Differences between manual compression and the mechanical clamp were more subtle but tend to favor use of the manual technique.

Cardiac Catheterization↗
PubMed1994

[Ex vivo procedures associated with autologous hematopoietic stem cell transplantation].

In the last 15 years, autologous cryopreserved bone marrow has been extensively used to reestablish hematopoiesis after myeloablative therapies in patients with leukemia, lymphomas or solid tumors. Recently, the use of stem cells obtained from peripheral blood has become an additional source of autologous stem cells for patients, with bone marrow diseases as well as for patients with mammary or ovarian cancer, after high dose chemotherapy. The use of this therapy has created the need of implementing laboratory procedures (ex vivo) to concentrate, purify, cryopreserve and evaluate the hematopoietic stem cell and eliminate tumoral cells. This article reviews these procedures, available in Chile at the present time, and comments on the impact of its use in autologous bone marrow or peripheral blood stem cell transplantations in an estimated population of 300 patients per year.

Hematopoietic Stem Cell Transplantation↗
PubMed1985

Disk diffusion antimicrobial susceptibility testing for clinical and epidemiologic purposes.

Antimicrobial susceptibility testing is one of the most important and useful tests performed by the clinical microbiology laboratory. The value of disk susceptibility testing in epidemiology is enhanced by its simplicity of performance, reproducibility of results, and ability to indicate whether a single strain is likely to be the cause of many infections. By using a specific set of antimicrobials for either gram-positive or gram-negative bacterial susceptibility testing and by following recommended testing procedures, laboratories can reliably identify similarities and differences in strains. We propose a list of antimicrobial agents chosen specifically for their value in disk susceptibility testing for clinical and epidemiologic purposes and describe the recommended methods of testing.

Anti-Bacterial Agents↗
PubMed2003

Towards error-free HIV diagnosis: guidelines on laboratory practice.

Error can have multiple causes. These guidelines set out the most common reasons for inaccuracies in HIV testing and indicate how they can be avoided. Emphasis is placed on laboratory procedures as during over 15 years experience they, rather than the kits and reagents, have proved to be the most frequent source of error.

AIDS Serodiagnosis↗
PubMed2000

Root canal treatment and general health: a review of the literature.

REVIEW: The focal infection theory was prominent in the medical literature during the early 1900s and curtailed the progress of endodontics. This theory proposed that microorganisms, or their toxins, arising from a focus of circumscribed infection within a tissue could disseminate systemically, resulting in the initiation or exacerbation of systemic illness or the damage of a distant tissue site. For example, during the focal infection era rheumatoid arthritis (RA) was identified as having a close relationship with dental health. The theory was eventually discredited because there was only anecdotal evidence to support its claims and few scientifically controlled studies. There has been a renewed interest in the influence that foci of infection within the oral tissues may have on general health. Some current research suggests a possible relationship between dental health and cardiovascular disease and published case reports have cited dental sources as causes for several systemic illnesses. Improved laboratory procedures employing sophisticated molecular biological techniques and enhanced culturing techniques have allowed researchers to confirm that bacteria recovered from the peripheral blood during root canal treatment originated in the root canal. It has been suggested that the bacteraemia, or the associated bacterial endotoxins, subsequent to root canal treatment, may cause potential systemic complications. Further research is required, however, using current sampling and laboratory methods from scientifically controlled population groups to determine if a significant relationship between general health and periradicular infection exists.

Arthritis, Rheumatoid↗
PubMed1981

A technique for the production of standard test specimens of aluminous dental porcelain.

A technique has been developed for the preparation of test bars of the different types of aluminous porcelains using the standard laboratory procedures for the preparation of aluminous porcelain jacket crowns. Up to now the investigation of the properties of dental porcelain has been conducted using test specimens produced either by vibration of a slurry of porcelain powder without platinum foil or by grinding from the solid brock. These techniques are far removed from the methods used for the production of porcelain restorations in the laboratory. This might lead to a variation in the results achieved by testing porcelain jacket crowns on the one hand and test specimens on the other.

Aluminum↗
PubMed1998

A study of laboratory based faecal occult blood testing in Melbourne, Australia. The Faecal Occult Blood Testing Study Group.

Faecal occult blood tests (FOBT) are widely used in clinical practice and are under increasing scrutiny as a tool for colorectal cancer screening. However, there is little information regarding the quality of testing performed in pathology laboratories. Therefore, we asked 13 pathology laboratories in Melbourne, Australia, to test coded contrived faecal samples prepared from a composite stool specimen which had been spiked to various concentrations of haemoglobin. The samples were provided to the laboratories in two forms: (i) on/in the sample collection device appropriate for the faecal occult blood test they normally used; and (ii) as a moist faecal sample. Some variation in threshold analytical sensitivity between laboratories for the same FOBT was observed for Hemoccult SENSA, ColoRectal, Hematest, MonoHaem and Hemolex suggesting that, at least for those tests, technician training could be improved. Two tests, Hematest and an in-house FOBT did not perform as well as the other FOBT. When samples were sent in moist form, Hemoccult SENSA (P = 0.0002), ColoRectal (P = 0.02) and MonoHaem (P = 0.04) had significantly lower overall positivity rates; for Hemolex the decrease was not significant (P = 0.3). The lower positivity rate with moist samples is important, given that 11 of the 13 laboratories in the study stated that they receive at least some samples in moist form. Thus, technician training and laboratory procedure need to be reviewed to maximize the benefits of faecal occult blood testing in clinical practice, especially with its expanding role in colorectal cancer screening.

Australia↗