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At least 397 records · Page 22Linked to original sources
PubMed1977

[Sources of error in the interpretation of bone scans with 99mTc-diphosphonate (author's transl)].

Errors in the interpretation of bone scans with 99mTc-diphosphonate may be due to summation of radio-activity from superimposition of various bone structures. Lesions with increased bone turn-over as well as reactive hyperaemia result in increased uptake. The possibility of extraosseous uptake of diphosphonate must be borne in mind during the evaluation of bone scans. The kidneys and lower urinary tract must be considered. Absent or slight uptake by the kidneys with good demonstration of bone suggests increased diphosphonate uptake by the bones. Special attention should also be paid to zones of decreased uptake, since these are also due to abnormalities in the bone.

Bone Diseases↗
PubMed1985

[The interparietal hepatic fat pad--a source of error in the diagnosis of a hematoma of the musculus rectus abdominis].

Some patients, even subjects with normal weight, have a fatty tissue pad located behind the xyphoid appendix between the peritoneum, the liver and the abdominal wall muscles. The wall fatty pad is encapsulated. It is sonographically transsonic, but with high-level internal echoes, and may deform the anterior face of the liver. It can be from 8 to 13 cm wide, 5 to 10 cm high and 3 to 5 cm thick. This fatty structure may be mistaken for a parietal abscess or haematoma. The sonographical exploration of the abdominal wall with short-focussed high-frequency transducers and the knowledge of this normal variance of human anatomy should avoid such pitfalls.

Abdominal Muscles↗
PubMed1984

[Failure of puncture sonographic diagnosis of focal liver lesions--the influence of possible sources of error].

A correct diagnosis was obtained in 92 cases (87.6%) of 105 sonographically monitored fine-needle punctures of focal lesions of the liver; in 13 cases (12.4%) the diagnosis was wrong. Both groups were compared with each other in respect of the anatomic and sonographic properties of the puncture targets and the technique of biopsy employed. Reflexibility and definability of the lesions did not influence the number of wrong diagnoses in puncture sonography; likewise, the following factors did not affect the quota of errors: the macroscopic structure of the punctate; the outer diameter of the fine needle; and the fact whether puncture was effected by means of a special biopsy sound head or by free-hand technique. Limited influence was exercised by the size and depth position of the intrahepatic space-occupying growths and by the number of punctures.

Biopsy, Needle↗
PubMed1992

[Electroconvulsive therapy--sources of error and aids in insufficient duration of convulsions].

Modern electroconvulsive therapy (ECT) involves the administration of six to ten convulsions of sufficient duration (25 seconds) by unilateral electrical stimulation of the non-dominant hemisphere. Missed or abortive seizures are a common clinical problem but may often be accounted for by concurrent medication and technical problems with unilateral ECT seizure induction. In the absence of such factors, controlled hyperventilation and intravenous caffeine are adjunctive means to achieve an adequate unilateral ECT treatment course.

Caffeine↗
PubMed1991

[Color-coded duplex sonography of the extracranial arteries supplying the brain: diagnostic significance and sources of error in comparison with i.a. DSA].

The findings of color Doppler flow imaging of the extracranial cerebral arteries in 75 patients were compared with i.a. DSA. Carotid stenoses greater than 50% and carotid occlusions were shown by sonography with a sensitivity of 91% and a specificity of 97%. The severity of the stenosis was in agreement in 88% of cases using the two methods. Sonography of the vertebral arteries achieved a sensitivity of only 65% and a specificity of 88%. Sonographic examination of the ophthalmic artery in order to demonstrate carotid stenosis achieved a sensitivity of only 29% and provided no additional information. Retrobulbar kinking of the ophthalmic artery was found in 30/178 vessels and may be a cause of misinterpretation.

Angiography, Digital Subtraction↗
PubMed1981

[On-target accuracy of tumour punctures in the breast. Possible sources of error in puncture cytology (author's transl)].

Puncture cytology can yield false results if the tumour to be explored is not definitely located by the puncture needle. The risk of missing the tumour is particularly great if the tumour is small. We do not know of any safe method to control and ensure on-target accuracy. In the course of 3 years we punctured in 203 women 665 palpable and also non-palpable cysts, using compound scanner Multiplanar-MS-3. 38 further individual punctures failed despite repeated attempts under visual control of this device which supplies a spatial impression of the target during puncture. Some of the small tumours will evade the advancing needle time and again.

Biopsy, Needle↗
PubMed1980

[Measurement of urethral closure pressure profiles with stress performed by CO2-infusion in stressincontinent women: sources of error in methodology and modes of clinical application (author's transl)].

The measurement of urethral closure pressure with stress is limited by the compressibility of gasiform mediums, which causes damping of intraurethral pressure spikes. In this study damping could be reduced by alterations of the catheter and the connecting tubes of an aircystometer. With this modified technique 55 incontinent women were examined. The differentiation between stress- and urgeincontinence was clinically sufficient.

Adult↗
PubMed1992

[Sources of error in planimetry of the optic nerve].

No matter how "sophisticated" they may seem to have become, contemporary methods for bioplanimetry of the optic disc vary in precision; easily overlooked or neglected optical influences must, indeed, be taken into consideration; and, of greatest detriment to the meaningfulness of any and all such results is the fact that even "experts" have difficulty in uniformly and reproducibly indicating where the boundaries of the optic disc and its excavation actually lie.

Fluorescein Angiography↗
PubMed1986

[Instrument myopia as a possible source of error in nyktometer examinations].

In comparative studies covering 142 eyes a "night myopia" of 0.5 to 1.5 D was found in 33 eyes with the Nyktometer (Rodenstock) and in 23 eyes with the Mesoptometer I (Oculus). In 17 eyes the same degree of "night myopia" was determined with both instruments, while in 16 eyes it was found to be more severe when measured with the Nyktometer than with the Mesoptometer. In one eye this myopia was only found with the Mesoptometer. This more severe "night myopia" measured with the Nyktometer is probably attributable to "instrument myopia."

Adolescent↗
PubMed1984

[Fundus asymmetry--supertraction of the papilla and posterior sclera staphyloma--as a source of error in the calculation of intraocular lenses].

The evaluation of 404 consecutively implanted posterior-chamber intraocular lenses after extra-capsular cataract extraction revealed a mean post-operative refractive error of + 0.52 diopters with a standard deviation of +/- 1.27 diopters. Four calculations attracted attention because of their unusually high refractive error of + 3.4 diopters. A post-operative refractive balance excluded measurement or calculation errors. On the other hand, repeated axial length measurements on these four eyes showed a very high mean variation of 3.27 mm. This high variation can be correlated to such typical elevation changes of the central fundus as a tilted disc or posterior staphyloma. High axial length measurements which do not correspond to appropriate amounts of axial myopia should be handled carefully to avoid high amounts of hyperopia following intraocular implantation.

Fundus Oculi↗
PubMed1988

Sources of error in the Piagetian water-level task.

Task materials were devised which allowed two different explanations of the Piagetian water-level task to be distinguished. Two experiments are reported with 5-6 and 7-8 year olds in which both a predictive and a perceptual task were used. The results support Ibbotson and Bryant's explanation that the performance of young children is affected by a perpendicular bias. This effect was weaker, particularly among 7-8 year olds, in the perceptual task.

Attention↗
PubMed1997

Ancient mtDNA sequences in the human nuclear genome: a potential source of errors in identifying pathogenic mutations.

Nuclear-localized mtDNA pseudogenes might explain a recent report describing a heteroplasmic mtDNA molecule containing five linked missense mutations dispersed over the contiguous mtDNA CO1 and CO2 genes in Alzheimer's disease (AD) patients. To test this hypothesis, we have used the PCR primers utilized in the original report to amplify CO1 and CO2 sequences from two independent rho degrees (mtDNA-less) cell lines. CO1 and CO2 sequences amplified from both of the rho degrees cells, demonstrating that these sequences are also present in the human nuclear DNA. The nuclear pseudogene CO1 and CO2 sequences were then tested for each of the five "AD" missense mutations by restriction endonuclease site variant assays. All five mutations were found in the nuclear CO1 and CO2 PCR products from rho degrees cells, but none were found in the PCR products obtained from cells with normal mtDNA. Moreover, when the overlapping nuclear CO1 and CO2 PCR products were cloned and sequenced, all five missense mutations were found, as well as a linked synonymous mutation. Unlike the findings in the original report, an additional 32 base substitutions were found, including two in adjacent tRNAs and a two base pair deletion in the CO2 gene. Phylogenetic analysis of the nuclear CO1 and CO2 sequences revealed that they diverged from modern human mtDNAs early in hominid evolution about 770,000 years before present. These data would be consistent with the interpretation that the missense mutations proposed to cause AD may be the product of ancient mtDNA variants preserved as nuclear pseudogenes.

Alzheimer Disease↗
PubMed2005

Detection of scavenged material in the guts of predators using monoclonal antibodies: a significant source of error in measurement of predation?

Molecular detection systems used to analyse the gut contents of invertebrate predators have enhanced our understanding of trophic interactions, but do not distinguish between the methods of consumption. Many predators regularly scavenge, which could have profound implications for quantitative analyses of the dynamics of predation. We report the first quantified assessment of the potential error caused by scavenging in post-mortem measurements of predation in a slug-carabid system. An anti-slug monoclonal antibody was able to detect antigens from decayed slugs after surprisingly long periods, significantly longer on relatively sterile peat than on natural soil. On soil the half-life of antibody-detectable slug proteins was 8.2 days while on peat it was 11.5 days. When slugs that had decayed on soil for 100 h were fed to the carabid predator Pterostichus melanarius, slug proteins could still be identified after 6 h (but not 12 h) digestion. Fresh and decayed slug was eaten in equal quantities by the beetles suggesting no aversion to the latter. The results suggest that significant errors may be caused by scavenging leading to inaccurate interpretation of predation rates in the field.

Animals↗