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PubMed1998

Entamoeba histolytica and Entamoeba dispar are distinct species; clinical, epidemiological and serological evidence.

The name of the causative organism of invasive amoebiasis, Entamoeba histolytica, was first introduced in 1903, even though this intestinal amoeba had been recognised since 1875. The marked disparity between the number of infected individuals and those with invasive amoebiasis resulted in a number of explanatory hypotheses being proposed. Although none of these were universally accepted, Brumpt's concept of two morphologically identical species gained increasing acceptance 50-60 years later when technology became available to investigate this anomaly. Sargeaunt spear-headed this drive by establishing the value of isoenzyme electrophoresis for studying the host-parasite relationship. From this foundation, incorporation of clinical, epidemiological and serological parameters to studies of the parasite resulted in the conclusion that a species complex comprising two morphologically identical amoebae was implicated with the disease. The two organisms have been named E. histolytica and Entamoeba dispar. The former is a pathogen and is responsible for invasive amoebiasis, while the latter is a gut commensal. Demonstration of the existence of this species complex has subsequently been confirmed by studies on the nucleic acids from several independent laboratories. The acceptance of E. histolytica and E. dispar as distinct species has had a major impact on our understanding of amoebiasis and its clinical management.

Animals↗
PubMed1986

Staging of non-small cell bronchogenic carcinoma. Relationship of the clinical evaluation to organ scans.

Organ scans are generally performed on patients with bronchogenic carcinoma only when clinical evaluation is suspicious for metastases. However, it is not clear whether the clinical abnormalities will direct attention to the single organ which should be scanned, or if all three organs (bone, brain, liver) should be evaluated if any clinical abnormality is present. We investigated the use of triple organ radionuclide scanning and computerized tomography (CT) of the brain in the initial staging of patients with non-small cell bronchogenic carcinoma with no obvious metastases. Of 122 patients with newly diagnosed lung cancer, 53 met our criteria for further study. Thirty-three (62 percent) of these had at least one clinical abnormality suggestive of metastasis. Bone scanning detected metastases in seven (21 percent) and head CT in two additional patients (6 percent). Brain and liver scanning had no yield. In only five of these nine patients did the clinical abnormality direct attention to the organ with detectable metastases. Twenty of the 53 (38 percent) patients had a negative routine clinical evaluation, yet bone scanning showed metastases in three (15 percent). We concluded that clinical abnormalities are not specific for the organ in which metastases may be detected, so three scans (bone, liver, CT of the brain) should be obtained if there is any suspicion of metastasis based on history, physical examination, and laboratory tests. The value of bone scanning in clinically normal patients deserves further study.

Adult↗
PubMed2000

Causes of unsatisfactory performance in proficiency testing.

BACKGROUND: Proficiency testing (PT) provides a measure of the effectiveness of laboratory quality assurance programs. Test reports are released from processes that the laboratory judges to be in conformance with quality specifications; an evaluation of unsatisfactory performance (UNSAT) by a PT provider is an unexpected outcome for the laboratory. An understanding of the root cause(s) of testing errors provides an opportunity for the continuous improvement of laboratory services. METHODS: We used participant data from the New York State Department of Health PT program to characterize the quality of testing in the toxicology specialty. Outcomes from laboratory investigations into causes of UNSAT and information on quality control practices collected from all program participants were used to identify the root causes of error. RESULTS: Two classes of error were encountered: spurious test results caused by lapses in standard operating procedures and instrument malfunctions (300 per million assays) and common-cause analytic error (7000 per million assays or 0.7% rate of UNSAT). Causes of spurious results included inaccurate mathematical correction for specimen dilution, misinterpretation of instrument codes, and instrument sampling errors. Calibration drift was most frequently cited as the common-cause analytic error. Approximately one-half of the laboratories used an allowable error for the quality control of analytical systems that exceeded the threshold error specified by manufacturers for stable instrument performance. CONCLUSIONS: The causes of spurious results suggest the need for ongoing competency testing of analysts where analyst intervention is required in an otherwise automated process, and for continued diligence in mistake-proofing instrument design. The intrinsic quality of laboratory testing is unlikely to improve until the allowable error in quality control is consistent with manufacturer specifications for stable system performance.

Clinical Chemistry Tests↗
PubMed2003

Understanding the characteristics of naturally shaded composite resins.

Composite resin formulations have proliferated in recent years, and clinicians are challenged to understand the nuances and technical requirements involved in the successful application of each individual system. Depending on the user's material of choice, the restorative protocol follows the resin layering sequence traditionally used by either clinicians or laboratory technicians. To clarify comprehension of each, this presentation discusses the characteristics of a naturally shaded composite resin and demonstrates their application in the direct restoration.

Color↗
PubMed1978

Interlaboratory comparison of results of erythrocyte protoporphyrin analysis.

Each of 65 laboratories analyzed 10 whole-blood samples for erythrocyte protoporphyrin by one or more of several analytical procedures. These procedures were of two types: (a) extraction of protoporphyrin from the erythrocytes into ethyl acetate/acetic acid, re-extraction into hydrochloric acid, and fluorometric measurement; or (b) direct reading in a portable fluorometer (hematofluorometer), with no pretreatment of the blood sample. Interlaboratory correlation was generally poor, especially between laboratories using extraction procedures. Hematofluorometric results intercorrelated better, but they had a low bias as compared to the extraction approach. Nationwide standardization of the test is required to assure satisfactory interlaboratory performance and to identify laboratories whose results are sufficiently accurate to be used for interpretations according to guidelines set forth by the Center for Disease Control for erythrocyte protoporphyrin testing.

Analysis of Variance↗
PubMed1995

Gonococcal opacity: lectin-like interactions between Opa proteins and lipooligosaccharide.

Previous evidence from our laboratory suggested that the tight intercellular adhesions between the outer membranes of gonococci displaying the opacity colony phenotype occurred because Opa proteins expressed on one gonococcus adhered to the lipooligosaccharide (LOS) of the opposing bacterium (M.S. Blake, p. 51-66, in G. G. Jackson and H. Thomas, ed., The Pathogenesis of Bacterial Infections, 1985, and M. S. Blake and E. C. Gotschlich, p. 377-400, in M. Inouye, ed., Bacterial Outer Membranes as Model Systems, 1986). A noncompetitive inhibition assay used previously to determine the carbohydrate structures recognized by the major hepatic asialoglycoprotein receptor was modified to determine the gonococcal LOS structures that bind Opa proteins (R. T. Lee, Targeted Diagn. Ther. Ser. 4:65-84, 1991). The LOS carbohydrates used in these assays were LOS structures purified from pyocin LOS mutants of Neisseria gonorrhoeae 1291 described by K. C. Dudas and M. A. Apicella (Infect. Immun. 56:499-504, 1988) and further characterized by C. M. John et al. (J. Biol. Chem. 266:19303-19311, 1991). Purified gonococcal Opa proteins were incubated with each of the parent and mutant LOS, and the amount of binding of Opa proteins was measured by a direct enzyme-linked immunosorbent assay using the Opa-specific monoclonal antibody 4B12. The affinities of the Opa proteins for each of the LOS were determined indirectly by measuring the concentrations of Opa proteins that noncompetitively inhibited 50% of the binding of LOS-specific monoclonal antibodies. This concentration is inversely proportional to the affinity of the inhibitor (R. T. Lee, Targeted Diagn. Ther. Ser. 4:65-84, 1991). Our data suggest that the gonococcal Opa proteins tested had the highest affinity for the Gal beta 1-4GlcNAc residue present on the gonococcal lactoneoseries LOS. This affinity was comparable to that reported for the binding of the major hepatic asialoglycoprotein receptor to glycoconjugates containing terminal galactose and N-acetylgalactosamine (R. T. Lee, Targeted Diagn. Ther. Ser. 4:65-84, 1991). After sialylation of the lactoneoseries LOS, presumably on the terminal galactose residue, the interaction with the Opa proteins was ablated. Therefore, the gonococcal Opa-LOS and mammalian epithelial cell asialoglycoprotein receptor-carbohydrate interactions have quite similar specificities.

Antigens, Bacterial↗
PubMed1997

Evaluation of the IITC tail cuff blood pressure recorder in the rat against intraarterial pressure according to criteria for human devices.

National standards govern the manufacture and marketing of medical devices in the United States, including those for indirect blood pressure measurement in man. There are no comparable standards for devices for recording in laboratory animals. Noninvasive tail cuff blood pressure (BP) recording in the rat is widely accepted, but beset by methodologic difficulties. Intraarterial recording is regarded as the "gold standard" but is invasive and also susceptible to methodologic error. We compared the IITC Mark 12 photoelectric/oscillometric tail cuff system (IITC Life Sciences, Woodland Hills, CA) versus simultaneous femoral intraarterial recordings in spontaneously hypertensive rats, during anesthesia and 1 to 2 days after recover (150 recordings under each condition), according to the guidelines for human data collection and analysis suggested the American National Standard for automated sphygmomanometers. Within- and between-observer disagreements in estimates made by two observers from 40 anesthetized recordings were less for intraarterial measurements than for the tail cuff method. Within-observer differences (mean +/- SD of differences [SDD]) for systolic, diastolic, and mean pressure were 0 +/- 1, 0 +/- 1, and 0 +/- 1 mm Hg for intraarterial versus -1 +/- 3, 0 +/- 8, and 0 +/- 5 mm Hg for tail cuff. Between-observer differences were 0 +/- 2, 0 +/- 1, and 6 +/- 2 mm Hg versus 5 +/- 4, 13 +/- 7, and 0 +/- 5 mm Hg, respectively. Differences between tail cuff and intraarterial methods were 16 +/- 13, -5 +/- 11, and 2 +/- 8 mm Hg in anesthetized animals and 8 +/- 14, -5 +/- 9, and 0 +/- 9 mm Hg in conscious animals (39% to 82% of differences exceeded 5 mm Hg). The upper limits of clinically acceptable disagreement in the American National Standard are: mean of 5 mm Hg, SDD of 8 mm Hg. The disagreement between tail cuff and intraarterial recordings cannot be ascribed to either method with certainty. These findings do not support the manufacturer's guarantee of tail-cuff readings within "5 mm Hg of intraarterial." Inaccuracy and unreliability of devices intended for laboratory animal use have considerable scientific, fiscal, and ethical implications. Marketing of these devices should also be governed by rigorous standards.

Anesthesia↗
PubMed2003

Upper extremity arterial injuries in athletes.

Upper extremity arterial injury resulting in hand and digit ischemia can occur in athletes who perform repetitive, high-stress, overhead arm motions. The initial presentation of these injuries often mimics the more common musculoskeletal injuries found in these athletes, and therefore, a high index of suspicion is essential to establish the diagnosis in a timely fashion. There are several described mechanisms of injury, most of which involve extrinsic compression and injury to the axillary artery or its branches from the humeral head. The clinical diagnosis is confirmed with noninvasive vascular laboratory testing, and the anatomy is generally confirmed using contrast arteriography. Surgical repair is almost always successful in these patients, allowing full recovery with return to competition.

Arteries↗
PubMed2005

A multicenter study of the pharmacokinetics of tacrolimus ointment after first and repeated application to children with atopic dermatitis.

The pharmacokinetics of tacrolimus after first and repeated application of 0.1% tacrolimus ointment were evaluated in 39 children, aged 6-12 y, with moderate to severe atopic dermatitis. The patients were grouped according to the size of the affected body surface area to be treated: Group 1< or =1500 cm(2); Group 2 >1500 cm(2) < or =3000 cm(2); Group 3 >3000 cm(2) < or =5000 cm(2). Serial blood samples to calculate pharmacokinetic parameters taken on Day 1 (first ointment application) and Day 14 (last application) showed minimal systemic exposure to tacrolimus. Overall, 92% of the blood samples assayed contained tacrolimus concentrations below 1 ng per mL and 17% of samples were below 0.025 ng per mL, the lower limit of quantification. Systemic exposure to tacrolimus varied between patients and tended to increase proportionally as the size of the treated body surface area increased. Absorption decreased with time as the skin lesions healed and there was no evidence of systemic accumulation. The mean apparent half-life of tacrolimus (t(1/2, z)) was 66+/-27 h (range 19-125 h). Most patients experienced substantial clinical improvement in their atopic dermatitis. There were no clinically relevant changes in laboratory values, and the most frequently reported adverse event was skin burning, which resolved quickly as the skin condition improved.

Administration, Topical↗
PubMed1985

External quality assurance in hematology. The programme of the Royal College of Pathologists of Australasia.

The Royal College of Pathologists of Australasia introduced a comprehensive national external quality assurance programme (QAP) in hematology in 1979. This now provides regular monthly trials of full blood counting, supplemented by 3-monthly sets of samples for a large variety of other tests for "state of the art" studies, together with case slides for diagnosis for 294 participants. In addition educational supplements are provided, based on one or other aspect of each major quarterly trial. The frequency and variety of tests and analysis of participants' results conform to suggested standards for similar national schemes elsewhere in the world. There is evidence that the programme has helped raise the standards of hematopathology in Australasia and has identified areas which require improvement. It is envisaged that the scheme will satisfy the requirements of state legislation designed to accredit pathology laboratories. Future development should include a refinement of objective methods of scoring performance, especially in areas such as morphology where participants' results cannot readily be expressed numerically.

Asia↗
PubMed2005

Automated Water Analyser Computer Supported System (AWACSS) Part II: Intelligent, remote-controlled, cost-effective, on-line, water-monitoring measurement system.

A novel analytical system AWACSS (Automated Water Analyser Computer Supported System) based on immunochemical technology has been evaluated that can measure several organic pollutants at low nanogram per litre level in a single few-minutes analysis without any prior sample pre-concentration or pre-treatment steps. Having in mind actual needs of water-sector managers related to the implementation of the Drinking Water Directive (DWD) [98/83/EC, 1998. Council Directive (98/83/EC) of 3 November 1998 relating to the quality of water intended for human consumption. Off. J. Eur. Commun. L330, 32-54] and Water Framework Directive (WFD) [2000/60/EC, 2000. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. Off. J. Eur. Commun. L327, 1-72], drinking, ground, surface, and waste waters were major media used for the evaluation of the system performance. The first part article gave the reader an overview of the aims and scope of the AWACSS project as well as details about basic technology, immunoassays, software, and networking developed and utilised within the research project. The second part reports on the system performance, first real sample measurements, and an international collaborative trial (inter-laboratory tests) to compare the biosensor with conventional anayltical methods. The systems' capability for analysing a wide range of environmental organic micro-pollutants, such as modern pesticides, endocrine disrupting compounds and pharmaceuticals in surface, ground, drinking and waste water is shown. In addition, a protocol using reconstitution of extracts of solid samples, developed and applied for analysis of river sediments and food samples, is presented. Finally, the overall performance of the AWACSS system in comparison to the conventional analytical techniques, which included liquid and gas chromatographic systems with diode-array UV and mass spectrometric detectors, was successfully tested in an inter-laboratory collaborative trial among six project partners.

Algorithms↗
PubMed2026

Saliva versus lesion swabs for PCR diagnosis of acute-phase clade Ib mpox in Uganda: a prospective matched hospital cohort study.

BACKGROUND: As clade Ib mpox expands through HIV-affected populations in east and central Africa, diagnostic specimen selection should balance accuracy, accessibility, and operational feasibility in outbreak settings. Here, we aimed to compare the diagnostic performance of matched plasma, saliva, genital, anal, and skin specimens during the acute rash phase of clade Ib mpox to identify clinically practical and high-yield sampling approaches for outbreak response and clinical care. METHODS: We conducted a prospective cohort study of 155 adults (median age 30 years, IQR 25-36) hospitalised at Uganda's national mpox referral hospital. The specimens were collected between March 3 and April 10, 2025, during the clade Ib outbreak. All participants were admitted with suspected mpox and were subsequently confirmed by MPXV PCR. We collected 836 clinical specimens (acid citrate dextrose plasma, saliva, genital swabs, anal swabs, and skin swabs) during the acute phase (visit 1; 14 days [SD 2] after systemic symptom onset) and at approximately 3 months (visit 2). A matched acute-phase subset (n=80) provided concurrent plasma, saliva, genital, and skin specimens for within-participant comparisons. MPXV DNA was quantified by F3L real-time quantitative PCR, and cycle threshold (Ct) values were compared using paired Wilcoxon signed-rank tests. Whole-genome sequencing of selected acute specimens confirmed clade assignment. FINDINGS: In the matched subset at visit 1, PCR positivity was high in saliva (78 [98%] of 80), skin swabs (78 [98%] of 80), and genital swabs (77 [96%] of 80). Results for the saliva closely mirrored genital and skin swab results, supporting saliva as a high-yield alternative when lesion sampling is painful, operationally difficult, or unacceptable. Plasma had substantially lower sensitivity (34 [43%] of 80) and showed poor agreement with mucocutaneous compartments. At 3 months, persistent MPXV DNA was rare (ten [9%] of 109) and clustered among people with HIV, including the only two participants with persistent plasma positivity. All sequenced genomes clustered within clade Ib. INTERPRETATION: During the established rash phase (14 days [SD 2] after onset), saliva provides diagnostic yield similar to that provided by lesion swabs for clade Ib mpox in this hospitalised cohort. These findings are restricted to this sampling window; further studies are needed to define performance in prodromal, pre-rash, and asymptomatic infection. FUNDING: CEPI through its Centralised Laboratory Network.

Adult↗
PubMed1972

Resistance of wild Norway rats in North Carolina to warfarin rodenticide.

Reports concerning the ineffectiveness of warfarin rodenticide, used at farms and stores in a rural area about 8 kilometers in diameter near Raleigh, North Carolina, prompted subsequent laboratory testing. All of the 25 Norway rats trapped from the area survived 6 days of no-choice feeding of bait containing 0.025 percent (by weight) warfarin.

Animals↗
PubMedDate not supplied

Creation of atheromatous plaques in experimental animals.

Research of the dissolution of atheromatous plaques requires animal testing before any delivery system can be used on human beings. Using Flemish Giant rabbits, atheromatous plaques are created in our radiology research laboratory by a surgical air drying technique and a high cholesterol diet. Plaque development is monitored by ultrasound scanning and serial angiography.

Animals↗
PubMed1986

Prediction of progressive joint damage in patients with rheumatoid arthritis receiving gold or D-penicillamine therapy.

Seventy two patients with classical or definite rheumatoid arthritis (RA) were randomly allocated to receive gold or D-penicillamine therapy (DPA) in a prospective study designed to evaluate whether it is possible to predict which patients will show radiological progression despite therapy. Forty five patients completed 12 months' treatment. There were no significant demographic or clinical differences between them and the 27 drop outs. Twenty of the 45 patients showed no radiological progression between six and 12 months. These patients had less severe initial radiological damage, lower levels of serum aspartate transaminase (serum AST) and lactic dehydrogenase (LDH), but higher levels of serum cholesterol. Twenty five patients did show progression during the six to 12 month period. This group included all the men with nodules. Of the 43 pretreatment clinical and laboratory variables examined, however, the majority failed to predict whether or not progression would subsequently occur. This included the acute phase response and seropositivity.

Arthritis, Rheumatoid↗
PubMed2006

Amygdala and ventromedial prefrontal cortex are inversely coupled during regulation of negative affect and predict the diurnal pattern of cortisol secretion among older adults.

Among younger adults, the ability to willfully regulate negative affect, enabling effective responses to stressful experiences, engages regions of prefrontal cortex (PFC) and the amygdala. Because regions of PFC and the amygdala are known to influence the hypothalamic-pituitary-adrenal axis, here we test whether PFC and amygdala responses during emotion regulation predict the diurnal pattern of salivary cortisol secretion. We also test whether PFC and amygdala regions are engaged during emotion regulation in older (62- to 64-year-old) rather than younger individuals. We measured brain activity using functional magnetic resonance imaging as participants regulated (increased or decreased) their affective responses or attended to negative picture stimuli. We also collected saliva samples for 1 week at home for cortisol assay. Consistent with previous work in younger samples, increasing negative affect resulted in ventral lateral, dorsolateral, and dorsomedial regions of PFC and amygdala activation. In contrast to previous work, decreasing negative affect did not produce the predicted robust pattern of higher PFC and lower amygdala activation. Individuals demonstrating the predicted effect (decrease < attend in the amygdala), however, exhibited higher signal in ventromedial prefrontal cortex (VMPFC) for the same contrast. Furthermore, participants displaying higher VMPFC and lower amygdala signal when decreasing compared with the attention control condition evidenced steeper, more normative declines in cortisol over the course of the day. Individual differences yielded the predicted link between brain function while reducing negative affect in the laboratory and diurnal regulation of endocrine activity in the home environment.

Age Factors↗
PubMed2001

High and low responding strains of laboratory opossums differ in sterol 27-hydroxylase and acyl-coenzyme A:cholesterol acyltransferase activities on a high cholesterol diet.

Two partially inbred strains of laboratory opossums exhibit extremely high or low levels of VLDL+LDL cholesterol concentrations, respectively, when challenged with a high cholesterol and high fat diet. The present studies were conducted to determine whether the high and low responding strains differ in activities of important enzymes that have been shown to affect lipemic responsiveness to diet. We measured plasma 27-hydroxycholesterol and hepatic activities of 27-hydroxylase and 7alpha-hydroxylase in high and low responding opossums while consuming the basal diet and cholesterol-enriched diets. Plasma 27-hydroxycholesterol concentration and 27-hydroxylase activity in liver did not differ between groups on the basal diet, but both were significantly higher in low responders than in high responders on the cholesterol-enriched diet with unsaturated fat (10.79 +/- 0.56 in low vs. 7.31 +/- 0.50 &mgr;g/dl in high responders for 27-hydroxycholesterol and 14.14 +/- 0.79 in low vs. 10.07 +/- 0.80 pmol/mg protein/min in high responders for 27-hydroxylase activity). On the other hand, 7alpha-hydroxylase activity was significantly higher in high responding opossums (75.72 +/- 6.81 pmol/mg protein/min) than in low responding opossums (51.39 +/- 6.18 pmol/mg protein/min) on the basal diet, but it did not differ on the high cholesterol and high fat diet. We measured hepatic ACAT and extrahepatic hepatic 27-hydroxylase activities in high and low responding opossums on the cholesterol enriched diet. Hepatic ACAT activity was significantly higher in high responding opossums (137.00 +/- 18.33 pmol/mg protein/min) than in low responding opossums (47.67 +/- 2.71 pmol/mg protein/min), whereas extrahepatic 27-hydroxylase activity was higher in low responding opossums (33.00 +/- 2.10 pmol/mg protein/min in lungs and 3.69 +/- 0.20 in kidneys) than in high responding opossums (21.17 +/- 1.54 pmol/mg protein/min in lungs and 2.82 +/- 0.31 in kidneys). We also compared the composition of bile between high and low responders. The concentration of taurine conjugates of cholic acid in bile of both groups was similar, but concentration of taurine conjugates of chenodeoxycholic acid in bile of low responding animals was higher than in high responding animals (124.9 +/- 17.3 in low vs. 59.2 +/- 13.2 &mgr;mol/ml in high responders). The results of these studies suggest two enzymes may affect the lipemic response to diet in laboratory opossums: sterol 27-hydroxylase and ACAT. Each of these enzymes may influence diet-induced hyperlipidemia at a different step of lipoprotein metabolism.

Journal Article↗