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Effect of lesions in visual cortical area V4 on the recognition of transformed objects.

The primate visual system has a remarkable capability for recognizing objects irrespective of the multitude of images they form on the retinal surface by virtue of changes in size, perspective, contrast, colour and partial obstruction by other stimuli in the visual scene. There is increasing evidence that this remarkable capacity is brought about by processes that occur earlier in the visual system than had previously been thought. Here I show that after ablation of area V4 in the rhesus monkey, major deficits arise in the recognition of objects that have been transformed in size, in the degree of occlusion, and in the amount of contour information provided. The ability to detect these objects when presented individually was unaffected by these lesions.

Animals↗

Antibody responses to recombinant Epstein-Barr virus antigens in nasopharyngeal carcinoma patients: complementary test of ZEBRA protein and early antigens p54 and p138.

Serological tests based on the antibodies directed against the Epstein-Barr virus early antigen (EA) and viral capsid antigen (VCA), which have been recognized as tumor markers for nasopharyngeal carcinoma (NPC), are routinely used to help in the diagnosis of this malignancy. The detection of these antibodies reveals very low titers, found only in a small proportion of young compared with older NPC patients. This is a problem for the diagnosis of NPC, especially among Maghrebians, among whom young people are also affected, and emphasizes the necessity to search for more reliable markers. The present study reports results of immunoglobulin G (IgG) and IgA responses of NPC patients to recombinant EA antigens p54 (BMRF1) and p138 (BALF2), VCA complex antigens p18 (BFRF3) and p23 (BLRF2), and EBNA antigen p72 (BKRF1). Our results show that IgA-EA-p54 and -p138 (IgA-EA-p54+138) antibodies have a diagnostic value for detection of NPC (70%), compared with IgA-VCA-p18+23 and IgA-EBNA-p72, which have limited diagnostic value, especially in young patients. It is also noteworthy that IgA-EA-p54+138 can detect a high percentage (64%) of NPC cases negative by immunofluorescence. These results, however, clearly show that a single test cannot achieve the objective of detecting all NPC patients, and it seems advisable to combine different tests for the diagnosis of NPC. The combination of IgG-ZEBRA with IgA-EA-p54+138 improved the sensitivity of detection of NPC to 95% in the overall NPC population. The use of IgA-EA-p54+138 in combination with IgG-ZEBRA will facilitate detailed studies on the pattern of antibody response, which may result in the development of useful serological markers to guide the treatment of NPC.

Adolescent↗

A simple, focused, computerized query to detect overutilization of laboratory tests.

CONTEXT: Although there is nearly universal agreement that laboratory tests are overutilized, the degree of overutilization in a given institution is difficult to quantify and monitor across time. OBJECTIVE: To detect and clearly document repetitive daily ordering of a commonly ordered laboratory test (serum sodium) by employing a simple, focused, computerized query of a test result database followed by chart review and validation. DESIGN: A retrospective computerized query of our clinical data repository was performed to find inpatients who displayed normal serum sodium test results on 4 or more consecutive days, without any abnormal values during the same admission. The search was limited to a 1-month period. A subset of these patients was selected for chart review. RESULTS: One hundred sixteen patients met our criteria, and the tests ordered for those patients comprised 5.1% of the monthly volume of serum sodium tests ordered in our institution. Chart review revealed a consistent lack of documentation of medical necessity for repeat testing as well as persistence of repeat serum sodium orders until the end of the patients' hospital course. CONCLUSIONS: We conclude that a focused query of data derived from a clinical data repository can detect and document overutilization of a common laboratory test in a convincing fashion within a given institution.

Clinical Laboratory Techniques↗

The accuracy of prenatal ultrasonography in detecting congenital anomalies.

OBJECTIVES: The purpose of this study was to evaluate the accuracy of prenatal ultrasonography in detecting congenital anomalies. STUDY DESIGN: We studied all singleton births or fetal deaths with one or more congenital defects delivered during the study period who had had one or more ultrasonographic examinations performed at or after 16 weeks' gestation and a random sample of defect-free newborns similarly examined by ultrasonography. Congenital anomalies reported on either the infants' postdelivery medical record or the fetal autopsy report were our standard. Prenatal ultrasonographic findings reported during gestation and therefore "blind" to the postdelivery outcome were then compared with the standard. RESULTS: The overall sensitivity of ultrasonography in detecting defects was 53%. The overall specificity was 99%. Ultrasonography proved to be highly sensitive (89%) for prevalent lethal malformations. However, serious cardiac defects, microcephalus, and many musculoskeletal deformities were missed by ultrasonography. CONCLUSION: Ultrasonography is sensitive in detecting many lethal malformations. However, a negative prenatal ultrasonographic examination does not provide absolute assurance that a fetus is defect free.

Congenital Abnormalities↗

Prognostic importance of palpability as a feature of screen-detected breast cancers.

OBJECTIVES: To determine epidemiological characteristics of palpability as a feature of asymptomatic invasive breast cancers detected through screening mammography, and to determine whether palpability is predictive of case survival after adjusting for conventional prognostic indicators such as diameter, grade and nodal status. SETTING: The University of Adelaide, South Australian Department of Health, and The Cancer Council South Australia, Adelaide, South Australia. METHODS: Sociodemographic and clinical characteristics of 2108 screen-detected invasive breast cancers were compared by tumour palpability using univariate and multiple logistic regression analysis. Survival outcomes from breast cancer were compared using Kaplan-Meier product-limit estimates. Multivariable proportional hazard regression was employed to assess the association of palpability with survival after adjusting for conventional prognostic indicators. RESULTS: Palpability was associated with year of diagnosis, ductal histology type, and unfavourable prognostic indicators such as larger tumour diameter, higher grade and nodal involvement. After adjusting for these variables, no associations were found with age at diagnosis, place of residence or socioeconomic status, or with presence of multifocal disease or presence of an extensive in situ component. Palpability was predictive of death from breast cancer in an unadjusted analysis, the relative risk (95% confidence limits) being 1.75 (1.12, 2.74). After adjusting for nodal involvement and larger tumour size, the relative risk no longer was elevated, reducing to 0.99 (0.60, 1.64). DISCUSSION: Palpability is associated with unfavourable prognostic indicators, such as larger diameter, higher grade and nodal involvement, and is not an independent indicator of survival outcome for screen-detected female-breast cancers after accounting for nodal involvement and diameter.

Adult↗

[Combination PCR of mecA, femA genes for detection of MRSA].

OBJECTIVE: To make a comparison of PCR assay, Agar Dilution and Disk Diffusion as for detecting Staphylococcal mecA, femA genes. METHODS: A total of 178 strains of Staphylococci were isolated from three large scale hospitals in Chengdu. Disk Diffusion and staphylococcal mecA, femA gene PCR assay for detecting MRSA were compared with Agar Dilution. RESULTS: The sensitivity and specificity of Disk Diffusion for detecting MRSA were 94.4% and 92.4% respectively. The sensitivity and specificity of Disk Diffusion for detecting MRCNS were 89.5% and 73.7% respectively. Compared with Agar Dilution, Staphylococcus aureus mecA gene PCR assay's sensitivity and specificity were 91.7% and 95.5% respectively. In all the 178 strains of Staphylococci, mecA gene combining with femA gene PCR assay's specificity was up to 97.9%. CONCLUSION: The detection of femA gene together with mecA gene by PCR is not only an approach for differentiating MRSA from MRCNS, but also a rapid, highly specific method which can be used as an auxiliary method in clinical microbiological laboratory.

Bacterial Proteins↗

[The use of FQ-PCR in detecting condyloma acuminata].

OBJECTIVE: To assess the value of flurogenic quantitative polymerase chain reaction (FQ-PCR) in detecting condyloma acuminatum(CA). METHODS: Thirty-six samples of CA pathologically diagnosed as positive cases and 84 samples of healthy controls were tested with FQ-PCR, and another 273 samples of clinical cases were examined using both pathological method and FQ-PCR. Then FQ-PCR as a diagnostic test was evaluated. RESULTS: FQ-PCR detected HPV6, HPV11 DNA in all the 36 CA samples, the mean copy being 1.0 x 10(7) +/- 10(2)/ml; the 84 samples of the healthy group ware all negative, the mean copy being 3 x 10(1) +/- 2 x 10(1)/ml. The coincidence rate of FQ-PCR with the pathological diagnosis was 100%. There was significant differnce in copy amount between the CA group and the healthy group, (P < 0.05). At the second stage, comparison between FQ-PCR and the pathological diagnosis showed: Se was 100%, Sp 92%, alpha was 0.08, beta 0, accuracy was 98.9%, positive predictive value was 98.8%, negative predictive value 100%; positive likelihood ratio was 12.5, and negative likelihood ratio 0. CONCLUSION: FQ-PCR as a rapid and simple method could accurately detect and quantify CA and its Se and Sp were high; it can be taken as an index in early CA diagnosis.

Adolescent↗

Contrast-detail analysis characterizing diffuse optical fluorescence tomography image reconstruction.

Contrast-detail analysis is used to evaluate the imaging performance of diffuse optical fluorescence tomography (DOFT), characterizing spatial resolution limits, signal-to-noise limits, and the trade-off between object contrast and size. Reconstructed images of fluorescence yield from simulated noisy data were used to determine the contrast-to-noise ratio (CNR). A threshold of CNR=3 was used to approximate a lowest acceptable noise level in the image, as a surrogate measure for human detection of objects. For objects 0.5 cm inside the edge of a simulated tissue region, the smallest diameter that met this criteria was approximately 1.7 mm, regardless of contrast level, and test field diameter had little impact on this limit. Object depth had substantial impact on object CNR, leading to a limit of 4 mm for objects near the center of a 51-mm test field and 8.5 mm for an 86-mm test field. Similarly, large objects near the edge of both test fields required a minimum contrast of 50% to achieve acceptable image CNR. The minimum contrast for large, centered objects ranged between 50% and 100%. Contrast-detail analysis using human detection of lower contrast limits provides fundamentally important information about the performance of reconstruction algorithms, and can be used to compare imaging performance of different systems.

Algorithms↗

Medicolegal investigation of death in custody: a postmortem procedure for detection of blunt force injuries.

Death in custody frequently raises suspicion of ill-treatment on the part of the custodians. The meticulous postmortem search for evidence of injury is the paramount consideration in objective investigation. Detection and evaluation of hidden subcutaneous hemorrhages facilitates reconstruction of antemortem circumstances. We describe a new postmortem technique for accurate examination of the subcutaneous tissues utilizing a simple X-shaped incision of the back and limbs and reflecting the skin. This technique leaves no noticeable disfigurement.

Cause of Death↗

Classification of microcalcifications in radiographs of pathologic specimens for the diagnosis of breast cancer.

RATIONALE AND OBJECTIVES: Early detection of breast cancer depends on accurate classification of microcalcifications. We have developed a computer vision system that has the potential to classify microcalcifications objectively and consistently to aid radiologists in diagnosing breast cancer. METHODS: A convolution neural network (CNN) was used to classify benign and malignant microcalcifications in radiographs of pathologic specimens. Digital images were acquired by digitizing radiographs at a high resolution of 21 microns x 21 microns. RESULTS: Eighty regions of interest selected from digitized radiographs of pathologic specimens were used for training and testing of the neural network system. The CNN achieved an Az value (area under the receiver operating characteristic curve) of 0.90 in classifying clusters of microcalcifications associated with benign and malignant processes. CONCLUSION: Classification of microcalcifications in pathologic specimens for diagnosis of breast cancer was achieved at a high level in our computer vision system, which consists of high-resolution digitization of mammograms and a CNN.

Breast Neoplasms↗

Myocardial Doppler tissue velocity improves following myocardial gene therapy with VEGF-A165 plasmid in patients with inoperable angina pectoris.

BACKGROUND: Myocardial tissue velocity and perfusion were studied in patients with severe angina pectoris following gene therapy by intramyocardial injection of phVEGF-A165 via thoracotomy. Plasma concentrations of VEGF-A increased postoperatively. Two months after treatment anginal status and myocardial tissue velocity improved and perfusion showed a tendency to improve. Tissue velocity imaging appears to be a sensitive, objective method for detecting changes in myocardial function following gene therapy. OBJECTIVE: To study effects on myocardial tissue velocity and perfusion in patients with angina pectoris following intramyocardial injection of phVEGF-A165 via thoracotomy. DESIGN: Open label, phase I/II. METHODS: Six patients with Canadian Cardiovascular Society (CCS) angina pectoris functional class III - IV and with major defects at adenosine stress single-photon emission computerized tomography (SPECT) were studied. In addition to SPECT, coronary angiography and dobutamine stress echocardiography with tissue Doppler velocity imaging were performed before and two months after gene transfer. RESULTS: Plasma concentrations of VEGF-A increased 2 to 3 times (P < 0.04) over baseline from 2 to 14 days after injection with normalization after 4 weeks. The CCS class improved about 40%, from 3.3 +/- 0.2 to 2.0 +/- 0.3 (P < 0.02) and nitroglycerine consumption decreased 30 - 40%, from 44 +/- 17 to 15 +/- 5 tablets per week (P < 0.05). The maximal systolic myocardial tissue velocity increased in all patients about 25% (P < 0.02) but did not reach the reference range. Myocardial perfusion at SPECT improved in four of the six patients. CONCLUSIONS: Anginal status, myocardial tissue velocity and perfusion can be improved by phVEGF-A165 intramyocardial injection. Tissue velocity imaging appears to be a sensitive, objective method for detecting changes in myocardial function following gene therapy.

Aged↗

Risks of hazardous waste sites versus asteroid and comet impacts: accounting for the discrepancies in U.S. resource allocation.

Approximately $6 billion is spent annually in the United States on the cleanup of sites regulated under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA, or Superfund). The current health risks posed by such sites are thought to be quite small; the expenditures are justified primarily as protecting hypothetical future residents of these sites. Approximately 0.05% of this amount, or $3 million, is spent annually by the U.S. government on the detection of asteroids or comets that could strike the earth. Such damaging impacts do occur from time to time--most recently in 1908 in an unpopulated region of Siberia--but no person is confirmed ever to have died as a result. Anticipated impacts over the course of 1 million years would yield deaths that, when annualized, total approximately 4,000 per year. The risk reduction goal for CERCLA is 15 orders of magnitude greater than that for asteroid/comet detection. A modest increase in resources devoted to asteroid detection would greatly increase the chances of early detection of a threatening object, allowing an effective defense to be attempted. This article argues that the much lower risk-to-resources ratio for CERCLA cleanups than for asteroid and comet detection can be explained by four primary factors: (1) the regard for future generations, since CERCLA benefits mainly the unborn; (2) concrete fears, since toxics are much more feared than asteroids or comets; (3) the source of the threat, since toxic contamination is caused by human beings, unlike impacts from space objects; and (4) the greater political constituencies for hazardous waste cleanup than for space object detection.

Journal Article↗

Role of digital rectal examination and prostate specific antigen in detecting carcinoma prostate.

OBJECTIVE: To investigate the ability of digital rectal examination (DRE) and prostate specific antigen (PSA) in detecting carcinoma prostate. DESIGN: Descriptive cross-sectional study. PLACE AND DURATION OF STUDY: The study was conducted in the Department of Urology and Renal Transplantation from December 1996 to December 1999. PATIENTS AND METHODS: Two hundred patients entered the protocol. They presented with complaint of prostatism or retention of urine. The patients were evaluated with estimation of serum prostate specific antigen and digital rectal examination was performed. Prostatic tissue biopsy was also done. RESULTS: Digital rectal examination has shown sensitivity of 63% and specificity of 73.22%. The sensitivity of PSA was 87% and specificity was 70.8%. The positive predictive value for DRE and PSA was 57.5% and 78.04% respectively. Negative predictive value was 73.22% and 85.22% respectively. P value was statistically significant <0.037. In the second part of study a baseline serum PSA level in age-matched 200 patients without history of prostatism was estimated. CONCLUSION: It was concluded that PSA represent an important adjunct to DRE for detection of prostate carcinoma.

Aged↗

The impact of gestational age on the sonographic detection of aneuploidy.

OBJECTIVE: The purpose of this study was to identify the influence of gestational age on the detection of sonographic markers of aneuploidy. STUDY DESIGN: Using a retrospective chart review, cases of trisomy 13, 18, and 21 with fetal ultrasounds between 14 1/7 and 36 4/7 weeks' gestation were identified. Sonographic markers were subdivided into major abnormalities and "soft" sonographic markers: nuchal thickening > or = 5 mm, humerus or femur length <10th percentile, intracardiac echogenic focus, echogenic bowel, pyelectasis > or = 4 mm, and choroid plexus cysts. Markers were stratified by karyotype and gestational age. RESULTS: Fifteen fetuses with trisomy 13, 32 with trisomy 18, and 49 with trisomy 21 were identified. There was no difference in the prevalence of ultrasound markers by gestational age (P = .40). Soft markers were more common in the second trimester of pregnancy (P = .006) with a trend toward increased prevalence of major anomalies with advancing gestation (P = .22). CONCLUSION: Although sonographic markers change with gestational age, these markers are present throughout gestation and can provide clinically useful information to guide patient counseling.

Adult↗

Tremor-correlated cortical activity detected by electroencephalography.

OBJECTIVE: In this study we investigated whether cortical activity related to Parkinsonian resting tremor can be detected by electroencephalography (EEG). METHODS: Seven patients with idiopathic Parkinson's disease suffering from unilateral tremor participated in the study. Electromyography (EMG) signals arising from the wrist extensor and flexor muscles as well as a high resolution EEG were recorded simultaneously. Coherencies between EEG and EMG were calculated. RESULTS: In all patients, we found highly significant coherencies at the tremor frequency or its first harmonic between the tremor EMG and contralateral EEG channels. There were no significant coherencies between the tremor EMG and ipsilateral EEG channels. Isocoherency maps illustrating the topography of the coherencies over the scalp showed that the maximum coherencies were situated over the cortical motor areas. In one case, a high coherency was also found over the parietal cortex. CONCLUSIONS: The results show for the first time that tremor-correlated cortical activity can be detected by electroencephalography. The findings underline that motor areas of the cerebral cortex are involved in the neuronal network generating resting tremor in Parkinson's disease.

Aged↗

Early hydrogen peroxide-induced pulmonary endothelial cell dysfunction: detection and prevention.

OBJECTIVES: To determine a) whether hydrogen peroxide-induced, early lung endothelial cell dysfunction can be detected in an isolated, perfused, rat lung model; and b) whether the organic phosphothioate N-(2-mercaptoethyl)-1,3-propanediamine, which protects cells in culture against hydrogen peroxide-mediated damage, can exert the same protection in this model. DESIGN: Intervention study; before-after trial. SETTING: Research laboratory. MODEL: Isolated, perfused, rat lung model. INTERVENTION: Continuous hydrogen peroxide infusion at increasing concentrations and infusion times, preceded or not by a N-(2-mercaptoethyl)-1,3-propanediamine infusion. MEASUREMENTS AND MAIN RESULTS: Early pulmonary endothelial cell alterations, assessed by the lung extraction (% extraction) of 123I-metaiodobenzylguanidine. Permeability edema by % extraction of 125I-human serum albumin and the lung dry-to-wet weight ratio. Control experiments: % extraction-123I-metaiodobenzylguanidine: 21.7 +/- 3.8% (n = 7). With increasing concentrations of hydrogen peroxide (0.025, 0.125, 0.5, and 2 mmol), % extraction-123I-metaiodobenzylguanidine was progressively depressed (n = 28, ANOVA, p < .05), significantly decreased from controls at 2 mmol (10.2 +/- 5.0%, n = 7, p < .05). When the 2-mmol hydrogen peroxide infusion was preceded by the N-(2-mercaptoethyl)-1,3-propanediamine (2 mmol) infusion, % extraction-123I-metaiodobenzylguanidine (19.9 +/- 2.9%, n = 5) was not significantly different from controls (n = 7) and was significantly greater than after the 2-mmol hydrogen peroxide infusion alone (8.7 +/- 7.4%, p < .05, n = 8). In all experiments, % extraction of human serum albumin ratio and dry-to-wet weight ratio were not significantly different from that of controls. CONCLUSIONS: a) Hydrogen peroxide-induced lung endothelial cell dysfunction was detected at an early stage, before any permeability defect appeared; b) N-(2-mercaptoethyl)-1,3-propanediamine protected against such damage.

Amifostine↗

[Validation of a short questionnaire to use in clinical consultations to detect gender violence].

OBJECTIVE: To validate a Spanish-language questionnaire to be used in primary care consultations to detect cases of violence against women. METHODS: The validation study was carried out between October 2002 and October 2003 in the Program of General Internal Medicine of the Clinical Hospital of the University of Buenos Aires, in the city of Buenos Aires, Argentina. The original version of this Spanish-language questionnaire had been developed in sexual and reproductive health clinics of five countries of Latin America and the Caribbean. The questionnaire covered the most frequent forms of gender-based violence (emotional, physical, sexual, and sexual abuse during childhood); explored how and when the violence occurred and who perpetrated it; and investigated the patient's perception of her current risk. In the research in Buenos Aires the format and theoretical content of the survey were evaluated, and linguistic and psychometric validations were also carried out. The reliability of the tool was assessed in terms of its reproducibility, stability, and internal consistency. RESULTS: The study found that the women surveyed in Buenos Aires had a good understanding of the questions, the examples given with the questions, and the response options. The women did not perceive the survey as being intimidating or as an intrusion into their private lives. The women generally regarded the use of the survey in primary care settings as a key opportunity for them to express their suffering and to receive assistance. The level of agreement for the answers to the questions in all five areas (psychological violence, physical violence, sexual violence, sexual abuse during childhood, and perception of current risk) was very high, in terms of both reproducibility (kappa values of 0.63 to 1.00) and stability (kappa values of 0.62 to 1.00). The alpha correlation coefficient for internal consistency was 0.755 for psychological violence and physical violence, 0.498 for psychological violence and sexual violence, 0.596 for physical violence and sexual violence, and 0.715 for the different manifestations of violence (psychological, physical, sexual, and abuse during childhood). CONCLUSION: This research demonstrated the soundness of the brief questionnaire, in terms of its format, content, comprehensiveness, and reliability. This instrument can be used in clinical consultations to detect situations of psychological violence, physical violence, sexual violence, and sexual abuse during childhood.

Argentina↗

Multicenter evaluation of the Micral-Test II test strip, an immunologic rapid test for the detection of microalbuminuria.

OBJECTIVE: To assess the performance of the Micral-Test II immunologic test strip for the detection of microalbuminuria, a multicenter evaluation in eight European study sites was performed. RESEARCH DESIGN AND METHODS: Using both the Micral-Test II test strip and the routine method for the determination of albumin concentration, we investigated 2,228 urine samples from diabetic patients. Additionally, interperson variability, color stability, and possible interfering factors (temperature, pH, leucocyturia, erythrocyturia, and drugs) were tested. RESULTS: For a cutoff concentration of 20 mg/l with respect to the routine methods, a sensitivity of 96.7% and a specificity of 71% were calculated for the Micral-Test II test strip. The negative predictive value was 0.95, and the positive predictive value was 0.78, with a prevalence of positive samples (laboratory method) of 52%. The interperson variability of color interpretation showed 93% concordant readings. The interference study showed an influence of oxytetracycline, leading to higher readings. There was no interference from pH. A sample temperature of < 10 degrees C led to lower readings. In the case of samples with massive leucocyturia and erythrocyturia that may delete the chromatographic process, waiting an additional 1-2 min is needed before reading. CONCLUSIONS: The results of the multicenter evaluation show that the Micral-Test II test strip permits an immediate and reliable semiquantitative determination of low albumin concentrations in urine samples with an almost user-independent color interpretation.

Albuminuria↗