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At least 973 records · Page 54Linked to original sources
PubMed1977

Improved estrogen receptor assay in human mammary cancer. Technics for handling small tissue samples.

Studies of various technics that aid in performing estrogen receptor assays on small tissue samples from primary cancers of the breast are reported. It is shown how sufficient protein can be obtained from less than 100 mg of small primary tumor without ultracentrifugation to assay estrogen receptor by a simplified two-point Scatchard plot method. The resulting Kd and maximum binding site values with 36 tumor tissue samples approximated the values obtained with the more laborious, larger tissue sample-demanding six-point Scatchard plot. Target and nontarget tissue controls are easily included in an assay run of four to eight samples. For interpretive purposes the derivation of the characterizing value of the Kd for estrogen receptor is given and compared with nonspecific associating binders.

Animals↗
PubMedDate not supplied

Evaluation of sample handling in relation to levels of tissue inhibitor of metalloproteinases-1 measured in blood by immunoassay.

BACKGROUND: The possible effect of preanalytical conditions such as blood sample preparation and handling on TIMP-1 levels in blood needs thorough investigation. MATERIALS AND METHODS: Blood was collected in dry tubes and tubes containing EDTA and kept at 4 degrees C or 20 degrees C for 1, 3, 8, 24 or 72 hours before processing into serum or EDTA plasma. In addition, serum and EDTA plasma samples were frozen and thawed 1-8 times. TIMP-1 was measured by ELISA. RESULTS: Time to processing for up to 72 hours did not significantly affect TIMP-1 levels in serum. In EDTA plasma, TIMP-1 levels were stable for up to eight hours; however, if samples were kept for 24 hours or longer the TIMP-1 levels increased (p < 0.0001). Repeated freezing and thawing had a significant effect on TIMP-1 levels in serum (p = 0.04). In plasma, repeated freezing and thawing for up to six times did not influence TIMP-1. However, in plasma samples exposed to seven or eight freeze/thaw cycles TIMP-1 levels decreased, although not significantly (p = 0.23). CONCLUSIONS: Handling and processing of blood samples is crucial for TIMP-1 measurement by immunoassay. In serum, TIMP-1 levels are unaffected by time to processing. Plasma samples should be processed within eight hours to avoid a TIMP-1 increase. For the measurement of TIMP-1 in archival material, serum should not be used because TIMP-1 levels are significantly affected by repeated freezing and thawing; archival plasma can readily be used provided that samples have not been frozen and thawed more than six times.

Biomarkers, Tumor↗
PubMed1995

Universal precautions for the prevention of HIV and HBV infection in health care settings. Committee for Science and Education, Medical Association of South Africa.

OBJECTIVE: To outline the principles guiding the deliberate actions that should be taken in health care settings to prevent the spread of pathogens, especially HIV and hepatitis B virus (HBV), to patients and health care workers (HCWs). OUTCOMES: Universal precautions should be implemented in all health care settings. EVIDENCE: Based on similar international recommendations. VALUES: An adaptation of an existing guideline, it was sent to 87 organisations for comment. The comments received were included where possible in this guideline. It is the right of HCWs and patients to be protected from nosocomial HIV and HBV infection. BENEFITS, HARMS AND COSTS: The prevention of costly HIV and HBV infection by simple, rational precautions in the health care setting. The cost to the health care system has not been measured. The cost to individual patients or HCWs who acquire either infection is inestimable. RECOMMENDATIONS: The guideline recommends that the four basic elements of universal precautions be implemented appropriately in all health care settings: (i) body fluids should be handled with the same precautions as blood; (ii) avoidance of sharps (sharp objects); (iii) avoidance of skin or mucous membrane contamination; (iv) cleaning/disinfecting/sterilising. VALIDATION: The draft guideline was subjected to extensive external review by specialist, generalist and health professional groups. These included HIV activist groups. There were no major disputes about the content. The most important amendment to the draft guideline is the inclusion of HBV and other related pathogens together with the HIV. DEVELOPMENT AND FUNDING: The Medical Association of South Africa Committee for Science and Education. ENDORSEMENTS: The MASA and twenty national health care organisations and three provincial health authorities (see list at end of document).

Body Fluids↗
PubMed1984

Sperm antibodies in infertile women: a comparison of three methods for handling the cervical mucus for extraction of immunoglobulins.

Three procedures commonly employed in the extraction of soluble proteins from cervical mucus, for the application of the technique for the detection of sperm antibodies also in this biological fluid, were compared in order to establish which provided the highest yield. Studies were therefore carried out on 125 women with primary and secondary sterility characterized by good rheologic qualities of their mid-cycle cervical mucus and in presence of repeatedly poor PCTs, not justified by the seminal characteristics of their partners. The laboratory results and the statistical analysis have shown that as far as concerns IgG, liquefaction with bromelin and solubilization with Baker's buffer provide a better yield than ultracentrifugation; while bromelin alone has the best yield with IgA.

Agglutination Tests↗
PubMed1995

Multichannel PCR and serial transfer machine as a future tool in evolutionary biotechnology.

As an improved strategy for producing functional macromolecules by in vitro evolutionary optimization, we propose an automated machine that can process up to 960 samples in parallel. It consists of a 960-well PCR machine with special sealed plastic reaction vessels and appropriate handling devices. We show that the heat-sealing technique does not significantly affect the activity of Taq DNA Polymerase or that of the temperature-sensitive Q beta RNA polymerase but avoids cross-contamination and evaporation of the samples. Initial experiments demonstrate the suitability of the apparatus to uniformly process the samples and to perform the thermocycling. Serial transfer of reaction products into fresh reaction solution was used to initiate further rounds of amplification as a typical experimental setup for an evolutionary biotechnology application.

Allolevivirus↗
PubMed1999

Evaluation of hypothalamo-pituitary-adrenal activity in the tree shrew (Tupaia belangeri) via salivary cortisol measurement.

Saliva sampling is frequently used in humans for adrenal glucocorticoid hormone analysis because of advantages such as non-invasiveness, the ease of collection, and storing of the samples. To transfer this advantageous method to laboratory mammals, potentially confounding factors such as stressful handling procedures have to be excluded. In the present study we established a method for collecting saliva for cortisol measurement in freely moving adult male tree shrews (Tupaia belangeri). The practicability of the procedure was demonstrated (i) by stress-induced changes in cortisol levels revealing a significant increase during the stress phase (control = 0.91 nmol/l vs stress = 1.71 nmol/l), and (ii) by reporting no significant differences in salivary cortisol levels before and after performance of a learning task. The present study emphasizes the use of salivary cortisol analysis especially for monitoring acute changes in the hypothalamo-pituitary-adrenal axis activity in male tree shrews.

Adrenal Glands↗
PubMed2001

Nucleosomes in serum as a marker for cell death.

The concentration of nucleosomes is elevated in blood of patients with diseases which are associated with enhanced cell death. In order to detect these circulating nucleosomes, we used the Cell Death Detection-ELISAplus (CDDE) from Roche Diagnostics (Mannheim, Germany) (details at http:\\biochem.roche.com). For its application in liquid materials we performed various modifications: we introduced a standard curve with nucleosome-rich material, which enabled direct quantification and improved comparability of the values within (CVintraassay:3.0-4.11%) and between several runs (CVinterassay:8.6-13.5%), and tested the analytical specificity of the ELISA. Because of the fast elimination of nucleosomes from circulation and their limited stability, we compared plasma and serum matrix and investigated in detail the pre-analytical handling of serum samples which can considerably influence the test results. Careless venipuncture producing hemolysis, delayed centrifugation and bacterial contamination of the blood samples led to false-positive results; delayed stabilization with EDTA and insufficient storage conditions resulted in false-negative values. At temperatures of -20 degrees C, serum samples which were treated with 10 mM EDTA were stable for at least 6 months. In order to avoid possible interfering factors, we recommend a schedule for the pre-analytical handling of the samples. As the first stage, the possible clinical application was investigated in the sera of 310 persons. Patients with solid tumors (n=220; mean=361 Arbitrary Units (AU)) had considerably higher values than healthy persons (n=50; mean=30 AU; p=0.0001) and patients with inflammatory diseases (n=40; mean= 296 AU; p=0.096). Within the group of patients with tumors, those in advanced stages (UICC 4) showed significantly higher values than those in early stages (UICC 1-3) (p=0.0004).

Anti-Bacterial Agents↗
PubMed1987

Orbital lymphoproliferative and inflammatory lesions.

We reviewed the records and biopsy specimens of 38 patients with clinically similar orbital lymphoproliferative and low-grade inflammatory lesions referred to one ophthalmologist at the University of British Columbia between 1977 and 1984. Twenty-six patients had lymphoproliferative lesions, the main feature being a densely cellular population of small lymphocytes. This group was further divided into reactive lymphoid hyperplasia, malignant lymphoma, Hodgkin's disease and atypical lymphoid hyperplasia. Symptoms and signs were similar within the subgroups. The mean length of follow-up was 3.7 years. Of the 26 patients 14 had extraorbital lymphoproliferative disease, 9 had orbital recurrences and 2 died of widespread disease. Twelve patients had inflammatory lesions with distinctly different histologic features from those of the lymphoproliferative group. Symptoms and signs were similar to those in the latter group. The mean length of follow-up was 2.1 years. Four of the 12 had orbital recurrences; none had extraorbital disease or died of their disease. We feel that orbital lymphoproliferative lesions can easily be separated from clinically similar low-grade inflammatory lesions histologically and that they should be staged and followed like small lymphocytic lymphomas. Guidelines are given for handling these specimens in the laboratory.

Adult↗
PubMed1987

Determination of molecular forms of brain acetylcholinesterase: technical considerations.

Sucrose density centrifugation has been used to characterize the relative levels of AChE molecular forms in different parts of the brain, during development, or in various disease states. We have examined the influence of various tissue or sample storage and handling techniques on the abundance of the 4S and 10S molecular forms of AChE in rat forebrain. Our results demonstrate that freezing either a subcellular fraction or the intact tissue causes dramatic shifts in the level of the 4S and 10S molecular forms as compared to the values obtained in fresh tissue. Total AChE activity was unchanged suggesting that 4S and 10S forms are equally active and that 4S AChE is easily dissociated from 10S. These observations suggest that 4S and 10S molecular forms in brain are extremely labile and that great care should be taken when studying the factors that regulate these forms.

Acetylcholinesterase↗
PubMed1997

Sample collection, processing and storage.

We review issues related to the inclusion of biospecimens in epidemiological studies. Technical advances and the revolution in molecular biology have rendered the use of biomarkers increasingly feasible in epidemiological investigations, however the cost and complexity require interdisciplinary expertise and careful attention to methodological detail in order to ensure validity. The widespread banking of biospecimens for long-term (cohort) studies requires special attention to be paid to these issues. Blood, urine and tumour tissue are in common use in medicine and at least some aspects of sample handling derives directly from this clinical experience, although special considerations apply in the epidemiological setting. An increasingly broad array of biospecimen types have been studied, including exhaled air, nail clippings, buccal cells, saliva, semen, faeces and breast milk. Relevant issues in the processing, storage, shipping, timing of collection and safety procedures are examined in terms of their potential to distort results. The role of carefully developed quality control protocols is emphasized. In order to take full advantage of the opportunities afforded by the use of biomarkers in epidemiological studies, careful attention to biospecimen processing, the stability of the biomarker and the precautions to be taken during transportation and storage of samples is necessary.

Biomarkers, Tumor↗
PubMed2001

Critical assessment of the performance of electronic moisture analyzers for small amounts of environmental samples and biological reference materials.

Two electronic moisture analyzers were critically evaluated with regard to their suitability for determining moisture in small amounts (< or = 200 mg) of various environmental matrices such as leaves, needles, soil, peat, sediments, and sewage sludge, as well as various biological reference materials. To this end, several homogeneous bulk materials were prepared which were subsequently employed for the development and optimization of all analytical procedures. The key features of the moisture analyzers included a halogen or ceramic heater and an integrated balance with a resolution of 0.1 mg, which is an essential prerequisite for obtaining precise results. Oven drying of the bulk materials in a conventional oven at 105 degrees C until constant mass served as reference method. A heating temperature of 65degrees C was found to provide accurate and precise results for almost all matrices investigated. To further improve the accuracy and precision, other critical parameters such as handling of sample pans, standby temperature, and measurement delay were optimized. Because of its ponderous heating behavior, the performance of the ceramic radiator was inferior to that of the halogen heater, which produced moisture results comparable to those obtained by oven drying. The developed drying procedures were successfully applied to the fast moisture analysis (1.4-6.3 min) of certified biological reference materials of similar provenance to the investigated the bulk materials. Moisture results for 200 mg aliquots ranged from 1.4 to 7.8% and good agreement was obtained between the recommended drying procedure for the reference materials and the electronic moisture analyzers with absolute uncertainties amounting to 0.1% and 0.2-0.3%, respectively.

Adsorption↗
PubMed2002

Simulation analysis of pneumatic tube systems.

Pneumatic tube systems play an important material handling role in many hospitals. These systems are costly and complex to design and operate, yet little exists in the way of analytical methodologies for them. We present a decision support framework based on defining relevant system performance metrics, traffic analysis reporting, as well as discrete event simulation modeling. We have used this approach to analyze numerous pneumatic tubes systems in the United States and present a representative case study from a large tertiary care hospital. Our general approach can be generalized to other computer controlled hospital operational systems such as elevators, track vehicles, automatic guided vehicles, workflow enabled processes, and laboratory automation systems.

Computer Simulation↗
PubMed2006

Rapid and simple screening of transgenic mice: novel extraction-free, filter-based PCR genotyping from blood samples.

We evaluated the effectiveness of using Flinders Technology Associates (FTA) filter paper for the polymerase chain reaction (PCR) genotyping of transgenic mice. Tail prick blood sample dried on an FTA filter disc was processed for genomic PCR. It is easy and rapid to prepare DNA templates because the protocol is extraction-free and only requires minimal handling of wash briefly bloodstained FTA filter discs. Progeny of a transgene-positive founder mated with wild-type mice was screened for the presence of the transgene by the filter-based PCR using transgene-specific primers. The resulting amplicons with expected sizes of 3134 bp, 1152 bp, 877 bp and 688 bp were robust and reproducible, allowing a distinction between transgenic (n=44) and wild-type (n=47) mice showing no signal. The filter-based PCR screening took only half a day. The present study confirmed the validity and usefulness of the novel rapid extraction-free genotyping method.

Animals↗
PubMed2004

Rapid analysis of docetaxel in human plasma by tandem mass spectrometry with on-line sample extraction.

A simple, rapid, and sensitive analytical method for the measurement of docetaxel in human plasma was developed and validated. The method is based on positive electrospray ionization tandem mass spectrometry (ESI+-MS-MS) with on-line sample extraction. It uses paclitaxel as internal standard for calibration. The on-line sample extraction minimizes sample handling and is readily adopted for automation. Quantitation of plasma docetaxel was done by the multiple reaction monitoring (MRM) mode. The method had a linear calibration range of 1.00-3000 ng/mL with a correlation coefficient >0.9999. The limit of quantitation (LOQ) for docetaxel in plasma was 1.00 ng/mL. The on-line extraction recovery of docetaxel was between 86.1-94.7%, with %CV < or = 6.1%. This method has high accuracy (90.1-96.3%), and excellent intra-assay (0.6-3.8%) and inter-assay (2.0-5.7%) precision. Its applicability to clinical samples was demonstrated by measuring patient plasma samples after treatment of weekly docetaxel at 25 mg/m2 as 60-min infusion.

Calibration↗
PubMed1988

Importance of correct handling of samples for the results of blood gas analysis.

The importance of correct handling of samples for blood gas analysis was studied in 100 patients. Sixty minutes storage in iced water lowered pH by 0.02 pH-units. Storage at room temperature caused considerable changes in PCO2 and PO2 (+0.45 kPa and -1.05 kPa). Air bubbles in the syringes increased PO2 if not expelled within 30 s. Thirty minutes storage with air trapped inside the syringe caused an increase in PO2 of 1.8 kPa and a decrease in PCO2 of 0.16 kPa. The use of plastic syringes induced significant changes in PCO2 and PO2, of which the latter (+1.0 kPa) may be clinically significant. The findings indicate that sample collection and storage must be guarded by strict rules in order to avoid false results.

Blood Gas Analysis↗
PubMed1997

A comparison of sampling methods for airborne fungal spores during an outbreak of aspergillosis in the forest aviary of the North Carolina Zoological Park.

An outbreak of aspergillosis with the death of six birds in the North Carolina Zoological Park R. J. Reynolds Forest Aviary in the spring of 1993 led to an investigation of the concentration of Aspergillus fumigatus spores in the air. No Aspergillus sp. was found in the facility through use of the drop plate method (gravitometric sampling) along with swab-sampling of selected surfaces within the exhibit and plating of food samples and nesting material onto petri dishes of nutrient media. A number factors that could stress the avian population were identified. These included excessive heat in the upper portion of the aviary due to the failure of an air handling system, a malfunctioning cooling tower, and large numbers of visitors to the facility (an average of 3,500/day). In addition, the outbreak occurred during a period of increased nesting behavior. Sampling of the fungal population of the air was conducted 1 year later, when no disease was noted, to compare the sensitivity of the commonly used drop plate method (open plates of nutrient media) with a volumetric impaction method (Andersen N-6 Air Sampler). The volumetric method delivered quantitative as well as qualitative data and exhibited more sensitivity for fungal spores of size similar to those of Aspergillus sp.

Air Microbiology↗
PubMed2006

The German Competence Net Dementias: standard operating procedures for the neurochemical dementia diagnostics.

Aging of population results in an increasing number of patients with dementia. Therefore, recently a BMBF-supported project, Competence Net Dementia, was launched to reveal diagnostic, therapeutic, and epidemiologic aspects of demential disorders. In this project, our task was to establish and maintain human body fluids (HBF) bank to collect cerebrospinal fluid, plasma, serum, and full blood of patients enrolled into the study. As the pre-analytical sample handling is a prerequisite of all studies aiming at finding novel disease biomarkers, standard operating procedures (SOPs) were launched by our group to allow standardized collection, storage, and shipment of the samples among all 14 University centers involved in HBF collection. Currently, to our best knowledge the CND HBF bank represents one of the largest prospectively collected set of the samples from subjects with mild cognitive impairment and early dementias. With the samples collected in the HBF bank, recently introduced analytical technologies (like e.g. surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS), differential gel electrophoresis (DIGE), and multiplexing) can be promptly tested with regard to their potential usefulness in neurochemical dementia diagnostics.

Brain Chemistry↗
PubMed2006

Pre-analytic considerations for the proper assessment of hormones of the hypothalamic-pituitary axis in epidemiological research.

There is growing epidemiological interest in hormones as predictors of chronic diseases. The correct handling and analysis of hormones can be cumbersome, and great care must be taken in these processes in order to gain the most information possible. Given differences in sampling, processing, and stability of the various hormonal assays, we sought to provide a comprehensive review to aid future epidemiological research. We have coupled a thorough literature search with our own analytical experience to outline common laboratory problems one must consider in analyzing the hormones of the hypothalamic-pituitary axis. In addition, we describe the benefits and limitations of using alternative media--including urine, saliva, and blood spots on filter paper--to measure endocrine hormones in epidemiological studies.

Biological Assay↗