Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Testing accessibility”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1988

Automation of routine coagulation testing using a random access centrifugal analyzer.

The results are reported of a clinical and laboratory evaluation of the use of a random-access centrifugal analyzer linked to a personal computer in the management of the routine workload of a hemostasis laboratory. Over a three-month period, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin clotting time (TCT), and derived fibrinogen (Fib) were performed on a total of 929 samples. Included in the study were 448 samples from patients receiving anticoagulants (oral anticoagulants, 228; heparin, 166; heparin and warfarin, 130) and 351 samples from patients requiring coagulation screens (PT, APTT, TCT, Fib). Tests were done in parallel with tilt-tube manual techniques and the results correlated. The correlation coefficients were PT, 0.99; TCT, 0.72; APTT, 0.96; Fib, 0.97. Discrepancies were analyzed and were due to hypofibrinogenemia and hyperlipidemia. The poorer correlation coefficient of TCT was attributable both to lower reproducibility of the manual test and the effect of dysfibrinogenemia or FDPs in liver disease. In no case was an abnormality or diagnosis missed using the centrifugal analyzer. In several cases the increased sensitivity of the analyzer improved the detection of the lupus anticoagulant. The use of automation was accompanied by a major reduction in workload and reagent costs. The machine has been used to assay a wide range of coagulation tests by clot based and chromogenic substrate methods. In conclusion, a programmed centrifugal analyzer is a safe, efficient, and flexible way of automating routine coagulation tests. It widens the reportoire of tests performed in the Hemostasis laboratory by using a machine capable of being used in other areas of pathology.

Blood Coagulation Tests↗
PubMed1979

Access to interproximal tooth surfaces by different bristle designs and stiffnesses of toothbrushes.

An in vitro model for the purpose of testing the access to interproximal tooth surfaces by toothbrushes is described. The model was used to compare the access of different bristle designs and stiffnesses. Two standardized brushing techniques were used: a horizontal and a vertical one. The test method discriminated significantly between different bristle designs and stiffnesses. With regard to interproximal access the V-shaped bristles were superior to the straight multitufted ones and soft bristles were better than medium and stiff ones. This study also indicated that the interproximal access increased with increasing pressure within the pressure range chosen. Of the two techniques used in this study the vertical one was superior to the horizontal. The results indicated that some current opinions with regard to mechanical cleaning should be re-evaluated and clinical testing methods be further developed to enable corresponding in vivo testing.

Efficiency↗
PubMed1992

Effect of the Clinical Laboratory Improvement Amendments of 1988 (CLIA '88) on the incidence of invasive cervical cancer.

The Clinical Laboratory Improvement Act of 1988 (CLIA '88) mandates strict, new quality-control measures for laboratories that interpret cervical cytology smears. Proposed regulations include proficiency testing of cytotechnologists and remediation for technologists and laboratories that fail to meet proposed proficiency standards. Proponents of the new regulations argue that these measures will reduce deaths from cervical cancer by reducing the false-negative rate of the Papanicolaou (Pap) test, but opponents argue that the regulations will increase the price of processing Pap tests and thereby reduce access to cervical cancer screening for high-risk, vulnerable populations. To examine these claims the authors used David Eddy's published simulation to model the natural history and detection of cervical neoplasia, and developed a new model to examine the health consequences of diminished access to Pap testing. The authors estimated the false-negative rate of the Pap test and the price elasticity of demand for preventive services on the basis of the published literature, and modeled the entire range of published or quoted predictions about the impact of CLIA '88 on accuracy and price. The results show that, if effects on access are ignored, reducing the false-negative rate from 15% to 5% would prevent 66 invasive cancers per 100,000 average risk women screened. However, under moderate assumptions regarding the effect of price on access, the regulations would prevent only 11 (instead of 66) cancers per 100,000 eligible women. The regulatory effect is very sensitive to the degree of improvement in the false-negative rate and increase in price that the regulations cause. Over the range of assumptions and predictions encountered in the literature and tested in our analysis, the proposed regulations could greatly reduce or greatly increase the incidence of invasive cancer, especially among high-risk and uninsured women. The implementation of the regulations should be delayed until new information regarding the actual false-negative rate of the Pap test allow a more precise estimate of the potential impact on the incidence of cervical cancer.

Clinical Competence↗
PubMed1986

Accessibility of the leading end of ribonucleic acid in transcription complexes.

A photoaffinity-protection technique has been developed to study the accessibility of the leading (5') end of nascent RNA as it passes through the transcription complex formed by Escherichia coli RNA polymerase and phage T7 DNA. The macromolecules contacted by the leading (5') end of the growing RNA chain in the transcription complex have been determined previously by photoaffinity labeling experiments using aryl azides attached to the leading end of nascent RNA [Hanna, M. M., & Meares, C. F. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 4238-4242]. By using thiols to reduce accessible photoprobes, we have modified the photoaffinity technique so that it tests the accessibility of the leading end of nascent RNA to small molecules in solution, as a function of RNA chain length. We examined in detail RNA molecules containing 11-50 nucleotides, whose 5' ends label the beta and beta' enzyme subunits with good yield. The thiol's accessibility to the leading end of each transcript was determined by comparing the RNAs cross-linked to beta beta' in thiol-treated samples to controls not treated with thiol. Incubation with 1 mM dithiothreitol for 5 min reduced approximately 36% of the 5'-azides on RNAs 11-13 bases long and approximately 43% on RNAs 28-37 bases long but practically none of the 5'-azides on RNAs 40-43 bases long. Also notable was the reduction of 34 +/- 1% of the 5'-azides on RNA 12 bases long but only 14 +/- 2% on the 14-base RNA; on the T7 A1 promoter, the leading end of the transcript diverges from the DNA template when the chain is between 12 and 14 bases long.

DNA, Viral↗
PubMed1991

Who seeks HIV testing? The impact of risk, knowledge, and state regulatory policy on the testing decision.

This study examines the determinants of an individual's decision to be tested for HIV infection. Using data from the 1988 AIDS Knowledge and Attitudes Survey we develop and test a conceptual model of the factors that impact the testing decision. We estimate the impact that individuals' risk characteristics, sociodemographic characteristics, knowledge about HIV infection, and access to testing have on their decision to be tested. We also examine the impact of state confidentiality policies on the testing decision. Our results indicate that risk group membership, knowledge about HIV infection, and the sociodemographic characteristics of the individual exert a significant impact on the decision to receive an HIV test. In addition, state policies that preserve confidentiality also have a significant effect on an individual's decision to be tested.

AIDS Serodiagnosis↗
PubMed1988

Schedule-induced polydipsia experience decreases locomotor response to amphetamine.

To investigate the influence of schedule-induced polydipsia (SIP) on central dopaminergic systems, rats trained in a SIP procedure were challenged with the psychostimulant and dopaminergic agonist, D-amphetamine. In a first experiment, rats that had access to water and developed SIP (SIP-positive) displayed a lower response to amphetamine than rats that had access to water but did not develop SIP (SIP-negative) and rats that had no access to water. There was no difference in the spontaneous activity of these different groups of animals. In a second experiment, SIP-positive rats displayed the same reduced response to amphetamine following only 10 min of SIP drinking. In addition, SIP-positive rats that were tested without access to water during the SIP test displayed an increased locomotor activity both after saline and amphetamine treatments. These results suggest that SIP has stress-reducing properties.

Animals↗
PubMed1975

Chemical accessibility of tyrosyl and lysyl residues in turnip yellow mosaic virus capsids.

The chemical accessibility of tyrosyl residues in TYMV capsids was studied by spectrophotometric titration and with the nitrating agent tetranitromethane. That of the lysyl residues was probed with trinitrobenzenesulfonate. Attempts to test their accessibility in virions were also made. Since some of these reactions were accompanied by structural changes, degradation of the particles were monitored with ultracentrifugation and light-scattering measurements. Alkaline titration of TYMV capsids induced ionization of two of the three tyrosyl residues per subunit at pH 11.3, but the third tyrosyl ionized with an apparent pK of 12.65, concomitantly with the degradation of the capsids. Reaction with tetranitromethane suggested that one tyrosyl residue per subunit can easily be nitrated and initiates degradation, after which the remaining residues also react. In intact capsids, five out of seven lysyl residues per subunit reacted readily with trinitrobenzenesulfonate. The other two lysyl residues were trinitrophenylated only after degradation of the capsids. On the other hand, all seven lysyl residues per subunit were easily trinitrophenylated in virions, during which reaction the virions disintegrated. The demonstrated chemical inaccessibility of specific numbers of tyrosyl and lysyl residues in TYMV capsids and the observed structural consequences to the capsids when the residues were made to react are consistent with previously published properties of the cysteinyl and tryptophanyl residues. The findings suggest that in the capsid the central region of the TYMV polypeptide chain is buried and might represent a site of contact between neighboring subunits.

Binding Sites↗
PubMed1978

On the accessibility and selection of the initiator site of mRNA in protein synthesis.

The specificity of the cell-free system of Escherichia coli for mRNA was examined, and the "accessibility" of some natural and synthetic RNAs to the ribosomes was determined by measurement of AcPhe-tRNA and fMet-tRNA binding, AcPhe-puromycin and fMet-puromycin formation, and polypeptide synthesis. The E. coli system effectively initiates the translation of various synthetic RNAs with AcPhe-tRNA or fMet-tRNA under conditions optimal for the translation of viral RNA. Poly(A,G,U) is accessible to the ribosomes according to all of the above criteria. Poly(A,C,G,U), 23 S rRNA, R17 RNA, and MS2 RNA, on the other hand, show limited accessibility when tested for initiator tRNA binding, or for AcPhe-puromycin and fMet-puromycin formation. MS2 and R17 RNA, but not poly(A,C,G,U) and 23 S rRNA, show accessibility when measured by polypeptide synthesis. The results suggest that, except at initiator sites of natural mRNA, an RNA containing about equal amounts of all four bases is inaccessible to E. coli ribosomes for polypeptide synthesis. Rate constants obtained for fMet-tRNA binding with MS2 RNA, poly(A,G,U), and poly(C,G,U) indicate that the ribosomes do not have any special affinity for the viral RNA. Thus, the selection of the initiator site in protein synthesis may be critically determined more by the accessibility of the initiator codon than by ribosomal recognition of the site.

Base Sequence↗
PubMed1985

Activation of fine articular afferent units by bradykinin.

The responses of single fine articular afferent units to close intra-arterial injection of KCl and bradykinin were recorded from filaments of the saphenous nerve of the cat's right hindlimb. All units included in this study were sensitive to local mechanical probing of the medial and anteromedial aspects of the knee joint. The units were identified by conduction velocity as belonging either to group III (2.5-20 m/s, 17 units) or group IV (less than 2.5 m/s, 23 units). Prior to bradykinin administration the responses of all units to passive limb movements were recorded in order to classify the units as belonging to one of the following 4 categories: activated by non-noxious movements; weakly activated by non-noxious movements; activated only by noxious movements; not activated by movements. Bolus injections of KCl were used to test the accessibility of the units via the blood vessels. Such injections elicited a rapid burst of impulses at short latencies of less than 1 s. If this discharge did not occur, no test with bradykinin was carried out. There was no difference in latency and time course between such discharges in group III and group IV units. With only 3 exceptions the 40 units excited by KCl were also activated by bradykinin which was applied in doses from 0.026 to 26 micrograms. Higher doses were not used. For most group III and IV units the minimal effective dose of bradykinin for a clear excitation was usually either 0.26 or 2.6 micrograms. In both groups of units the bradykinin-evoked discharge generally had a uniform latency and a time course with a total duration well under 1 min. In the course of repetitive injections at intervals of 3-5 min, the latency of the evoked discharge increased gradually and its magnitude became successively smaller. This tachyphylaxis was usually very pronounced, regardless of whether low or high doses of bradykinin were administered. No differences in the bradykinin sensitivity were found between units with very low to very high thresholds to local mechanical stimulation (tested with von Frey hairs) and between units belonging to the 4 different categories of response behavior to passive innocuous and noxious joint movements. These results indicate that the sensitivity to bradykinin is shared by all fine articular afferent units, regardless of their thresholds to local mechanical stimulation and joint movement and, hence, their functional role in signaling innocuous or noxious mechanical events at the knee joint.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

[An operating model for assessing the practical efficacy of screening tests: the case of amblyopia].

Standard for assessing the efficacy of screening programs are at present well-established. Nevertheless, the effectiveness of screening programs can reduced by several factors in real world conditions. The aim of this work is to check the feasibility of an operational model for the practical evaluation of the effectiveness of screening programs. In this model seven critical points are defined (recruitment, screening test sensitivity, access to diagnostic services, diagnosis, compliance to follow-up, treatment compliance, therapy) and their contribution to the reduction of potential effectiveness is calculated. For each point consequent problem(s) and possible solutions are predefined. The model was tested with the results of the screening program for amblyopia of the Community Health Service of USL 32 Treviglio (BG) assuming 40% and 97% sensitivity of the screening test. For this screening the reduction of effectiveness at the seven critical points ranged from 0 to 60%, with a total reduction of effectiveness to 15.6-37.8%. The operational model was used to identify causes of this reduction. This kind of analysis is proposed as a tool for evaluation and improvement of the effectiveness of efficacious screening program.

Amblyopia↗
PubMed1987

The accessibility of DNA to dimethylsulfate in complexes with recA protein.

recA protein coats DNA co-operatively to form filaments approximately 100 A thick, which in the presence of ATP, and more stably so in the presence of the non-hydrolyzable analog ATP gamma S, have a helical appearance with a deep cleft in the protein coat. This protein helix follows the DNA helix, to which it imparts a new helicity of 18.5 bp per turn of 97 A pitch. Here we test the accessibility of the DNA in the complex to modification by dimethylsulfate, and find that the complexed DNA is approximately 2-fold more reactive on the major groove side than it was in B-DNA (methylation of guanine N7), while it is protected approximately 2-fold on the minor groove side (methylation of adenine N3), suggesting that the protein coats the DNA along the minor groove. Furthermore, N3 of cytosine, a residue involved in base pairing, is found exposed in complexes with single strands as it is in naked single-stranded DNA, while it remains inaccessible in complexes with double strands, suggesting that the latter is not melted at this stage of the strand exchange reaction.

Alkylating Agents↗
PubMed2026

Tau proteoforms as plasma biomarkers in Alzheimer's disease: mechanisms, measurement, and medicine.

INTRODUCTION: Blood-based tau proteoforms have emerged as specific, scalable biomarkers of Alzheimer's pathology, addressing the limitations of symptom-based diagnosis, neuroimaging, and invasive cerebrospinal fluid (CSF) testing. This review synthesizes advances in tau phosphorylation and truncation biology, evaluates translation from CSF to plasma with state-of-the-art proteomics, and outlines the analytical standards and cross-matrix calibration needed for clinical adoption. AREAS COVERED: We conducted a literature search in PubMed and Google Scholar. We reviewed studies published between January 2005 and September 2025 investigating tau proteoforms in Alzheimer's disease. EXPERT OPINION: Blood-based tau proteoforms are poised to move Alzheimer's diagnostics from specialized imaging to accessible frontline testing, with plasma p-tau217 approaching positron emission tomography (PET) and CSF performance and multi-analyte panels with glial fibrillary acidic protein (GFAP) or neurofilament light (NfL) improving differential diagnosis while reducing invasiveness and cost. Building on the first FDA-cleared plasma assay (Lumipulse G p-tau217/Aβ1-42 Ratio) in May 2025, we anticipate a dual pathway over the next decade in which referral centers use high-plex mass spectrometry (MS) panels for phosphoforms and truncations, while primary care adopts automated high-throughput immunoassays (e.g. chemiluminescent enzyme immunoassay (CLEIA)) for triage, supported by harmonized standard operating procedures (SOPs), cross-matrix calibration, and robust reference materials.

Humans↗
PubMed1987

Dual fluorometric/colorimetric detection system for an automated random-access instrument utilizing standard polystyrene test tubes as precision cuvettes.

To attain the optical precision necessary to precisely quantify fluorescent or colorimetric signals, analytical systems have typically included quality-controlled cuvettes, flow cells, or dual-beam reference systems. We describe a system where a fluorescence or transmittance signal is quantified in single, standard, 12-mm-diameter polystyrene test tubes. Tube-to-tube variation is minimized by referencing the primary signal to a second reference signal. The tube is carefully oriented within a positioner that allows for the precise placement of the tube within a light path 7.6 mm in diameter. The detection system allows for use of either four pairs of fluorescence excitation/emission wavelengths or eight transmittance wavelengths, which are selected by using specific interference filters. The impact of temperature, tube imperfections, surface flaws, and distortions is minimized by using a reference ratio. Fluorescence is measured with an orthogonal photomultiplier tube, and transmittance with a photodiode; both are illuminated with an ordinary long-life tungsten-halogen lamp. This system is used with the Becton Dickinson AFFINITY system, an automated random-access analyzer with analyte-specific unit-package reagents. The polystyrene tube of the reagent package, which has an antibody-absorbed surface, serves as both the cuvette and the separation medium. Use of the reference ratio method reduces intertube imprecision of fluorometric or transmittance signals, for more precise quantification of various analytes.

Autoanalysis↗
PubMedDate not supplied

Pap tests of rural black women.

Cervical cancer is an important cause of cancer mortality in black women. Pap tests may prevent such deaths, but poor, rural black women are relatively less likely than others to be screened. In order to understand why that is so, the authors surveyed 149 women in three rural North Carolina counties. Thirty-three percent of the women interviewed had not had a Pap test in the preceding three years. Variables independently associated with not having a recent Pap test included: having no identifiable source of medical care; having more than one source of gynecologic care; having an internist provide gynecologic care; and perceiving psychological barriers to Pap tests and pelvic examinations. Income, educational level, and health insurance status were not associated with having a recent Pap test. Although access to care remains a problem for some, better use should be made of the medical care encounters available.

Adolescent↗
PubMed1991

Behavioral and biochemical studies in rats following prenatal treatment with beta-adrenoceptor antagonists.

Increased motor activity and poor performance in the active avoidance test were observed in the offspring of rats treated with dl-propranolol or sotalol during pregnancy, but not with atenolol and d-propranolol. All substances were administered in drinking water from days 8-22 of gestation. A significant increase in the density of muscarinic acetylcholine receptors in the hippocampus was found for dl-propranolol and sotalol, at 35 and 20 days of age, respectively. Twenty-day-old pups born to dl-propranolol-treated rats exhibited a non-significant decrease in the number of beta-adrenoceptors in the frontal cortex. Assuming that all the beta-adrenoceptor antagonists tested had access to the developing fetal brain, the effect of dl-propranolol and sotalol on behavior could stem from central beta 2-adrenoceptor blockade. In view of the lack of behavioral changes after atenolol, a beta 1-selective adrenoceptor antagonist, it is suggested that the clinical use of beta 1-selective adrenoceptor antagonists during pregnancy might be safer for the fetus than beta 2-adrenoceptor antagonists.

Administration, Oral↗
PubMed1992

Beliefs and behavioral intentions regarding human immunodeficiency virus testing among New York City runaways.

From 1988 to 1991, 139 runaways aged 11-19 years in the New York City area (n = 70 males, 69 females) were recruited from four shelters. Each runaway participated in a semistructured interview assessing beliefs and behavioral intentions regarding human immunodeficiency virus (HIV) testing. When asked how they would respond to being seropositive for HIV, 29% of runaways reported that they would engage in self-destructive acts and/or harm others (e.g., suicide, unprotected sex), 80% anticipated extreme distress, 47% expected difficulty securing housing and food, and 61% believed that friends were likely to avoid them. When presented with specific alternatives, fewer runaways anticipated self-destructive acts. Drug use, rather than sexual behaviors, would lead runaways to get tested for HIV. These results suggest that health-care providers must anticipate emotional distress and potential self-destructive behavior following receipt of documentation of HIV positive serostatus among runaways. Furthermore, prior to testing, youths' access to food, shelter, medical care, and social support must be secured.

Adolescent↗
PubMed1987

Resolution of racemic carbocyclic analogues of purine nucleosides through the action of adenosine deaminase. Antiviral activity of the carbocyclic 2'-deoxyguanosine enantiomers.

The action of adenosine deaminase on racemic carbocyclic analogues of 6-aminopurine nucleosides was investigated. When either racemic carbocyclic adenosine [(+/-)-C-Ado] or the racemic carbocyclic analogue [(+/-)-C-2,6-DAP-2'-dR] of 2,6-diaminopurine 2'-deoxyribofuranoside was incubated with this enzyme, approximately half of the material was deaminated rapidly. From the resulting solution, the D isomers of the deaminated carbocyclic analogues (D-carbocyclic inosine, D-C-Ino, or D-carbocyclic 2'-deoxyguanosine, D-2'-CDG) and the L isomers of the undeaminated carbocyclic analogues were isolated. At higher concentrations of the enzyme, deamination of L-C-Ado and L-C-2,6-DAP-2'-dR proceeded slowly, thus also making the other enantiomers accessible. In tests in vitro against herpes simplex virus, types 1 and 2, D-2'-CDG was as active and potent as (+/-)-2'-CDG, whereas L-2'-CDG displayed only modest activity. In contrast to the previously reported high activity and potency of (+/-)-C-2,6-DAP-2'-dR against these two viruses, L-C-2,6-DAP-2'-dR was inactive.

2-Aminopurine↗
PubMed1979

An archival system for clinical laboratory data.

A magnetic tape-based archival system that provides for generation of computer-output microfiche has been developed. Data from magnetic tapes written on a turnkey laboratory system are used as the basis for generating the archival tapes. Programmed searches of the tapes allow retrieval directly by name or test(s). Accessing the computer-output microfiche allows retrieval by name and is being used to supplant a traditional file system.

Archives↗