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At least 487 records · Page 27Linked to original sources
PubMed1994

Operative sepsis in neurosurgery: a method of classifying surgical cases.

Neurosurgical operations have traditionally been classified along the lines of general surgical procedures. A prospective study, during an 18-month period, was undertaken in 2249 patients undergoing neurosurgical procedures to establish and evaluate a method of classifying surgical cases by the use of specific neurosurgical criteria. Patients were placed in one of five categories according to the level and type of contamination at the time of surgery. Infection included all abnormal wounds and was documented as deep when infection occurred beneath the galea (subgaleal pus, osteitis, abscess/empyema, ventriculomeningitis) and as superficial if only the scalp (including wound erythema) was involved. A statistically significant difference in the sepsis rate was found in the different categories (P < 0.0001). Of the 342 "dirty cases," 9.1% of patients developed further wound sepsis. Concomitant cerebrospinal fluid fistulae (44%), second operations (11.8%), and patients with penetrating injuries (9.2%) were the major factors implicated in sepsis in the "contaminated" category (9.7%). In the "clean contaminated" category, a sepsis rate of 6.8% was found. Prolonged surgery (longer than 4 hours) was also implicated in higher infection rates (13.4%). This study strongly supports the separation of patients who have foreign materials implanted (sepsis rate = 6.0%) from "clean" patients, essentially cases categorized as having no known risk factors that may affect sepsis, in whom a sepsis rate of 0.8% was found (P < 0.001). Importantly, surgery for the repair of so-called "clean" neural tube defects in neonates requires separate consideration. An infection rate of 14.8% existed in this subgroup. A uniform system of reporting wound abnormalities is also proposed.

Bacteriological Techniques↗
PubMed2000

Reference values of plasma lipoprotein (a) in newly classified apolipoprotein(a) phenotype groups in the Japanese population.

We tried to establish the reference values of plasma lipoprotein (a) [Lp(a)] concentration in phenotype groups of apoliprotein(a) [apo A] classified by a new criterion. Lp(a) concentration was determined by latex agglutination immunoassay, and apo A was analysed by electrophoresis in sodium dodecyl sulphate-polyacrylamide gel and a Western blotting technique. According to the relative mobility to the apo B-100 band, apo A was classified into 11 isoforms, i.e. F, B, and S1-S9, and the phenotype was defined by their apparent combination. The frequency ratio of single-band versus double-band was approximately 2:1. In 382 cases of single-band, the most frequent phenotype was S5 (24.3%), followed by S4 (17.3%), S6 (15.4%) and S3 (14.4%). In 181 cases of double-band, S5/S6 phenotype was observed most frequently (12.2%). followed by S4/S5 (10.5%) and S3/S6 (7.2%). The reference value was determined between antilogs of the mean +/- 1.96 standard deviation by logarithmic transformation of all observed values for individual phenotype cases. These results suggest that the reference values shown to be variable with apo A phenotypes should be useful for evaluating Lp(a) values in diagnosis of atherosclerosis.

Arteriosclerosis↗
PubMedDate not supplied

[Clinical and radiological study of swallowing in patients with deglutition disorders, classified into two age groups: adults and older people].

BACKGROUND: The abnormalities of swallowing process have multifactor and complex etiologies. The videofluoroscopy has been pointed as the exam of greater utility in diagnostic investigation for these cases. This method, when preceded of an adequate anamnesis, can characterize conveniently the level of the dysfunction and usually identify the cause of abnormality with great precision. AIMS: To study the clinical complaints and findings of the videofluoroscopy examination in patients with deglutition disorders and no clinical evidence associated with neurological disorder, classified into two age groups: adults and older people, and to analyze: symptomatic manifestations, kinds of disorders (oropharyngeal or esophageal) and the capacity of clarifying the clinical complaints through the method of images. MATERIALS AND METHODS: Seventy patients with complaint of the capacity of deglutition were analyzed. They had no clinical evidence of associated neurological syndromes or disorders and were classified into two age groups: adults (GI)-- < or = 65 years (n = 36) and older (GII) > 65 years (n = 34). All patients were submitted to anamnesis to obtain the information about their complaints concerning deglutition. The complaints were characterized as high or low, according to their predominant location of manifestation. All the patients were submitted to videofluoroscopy of the deglutition; these alterations were characterized as oropharyngeal or esophageal. The capacity of clarifying the clinical complaints by videofluoroscopy was evaluated in both groups. RESULTS: Among the complaints analyzed, the only one in which the statistical analysis presented a significant difference between the groups was the complaint of heartburn, which occurred more often in the group GI-- eight patients (22.2%) and GII--one patient (2.9%). In the study of videofluoroscopy, it was observed a higher incidence in the oropharyngeal disorder in group GII--41.2% while in group GI--13.9%. As for the esophageal disorder, the incidence was similar in both groups GI - 35.3% and GII--33.3%. Nineteen patients (52.8%) in GI and 23 (67.6%) in GII had their complaints clarified through the videofluoroscopy. CONCLUSIONS: Under the conditions of this study, it can be concluded that: 1. The clinical complaints associated with the difficulty of deglutition occur at a similar frequency in adults and older people, with the exception of heartburn that occurs in larger number among adults; 2. Older people present a higher incidence of oropharyngeal deglutition problems; 3. The videofluoroscopy of the deglutition represents a method of great importance for the diagnosis, because it allows the identification of morphofunctional disorders that cannot be adequately identified by anamnesis; 4. The capacity of clarifying diagnosis of the videofluoroscopy of the deglutition is higher in the older people group.

Adult↗
PubMed2026

A MAGIBU-based model for pediatric and juvenile CNS tumors: an in-house epigenetic decision-support framework compared with online DNA methylation classifiers.

Background: DNA methylation profiling is a tool that provides key support for central nervous system (CNS) tumor classification. However, diagnostically ambiguous pediatric cases may result in discordant outputs across classifiers. We developed MAGIBU, a cross-platform, projection-based framework that embeds individual methylomes into a fixed CNS reference landscape, ranking diagnostic entities by local epigenetic proximity to support clinician-led integrative diagnosis. Methods: As a proof-of-concept, we evaluated MAGIBU in eight morphologically challenging pediatric/juvenile CNS tumors with unresolved diagnoses after institutional and central pathology review. To establish a benchmark in the absence of a definitive histopathological ground truth, a consensus epigenetic reference was defined a priori for cases showing concordant results between the Heidelberg CNS Tumor Methylation Classifier and Methylscape Analysis. Comparisons were also performed with Epigenomic Digital Pathology (EpiDiP). To validate MAGIBU beyond this discovery cohort, performance was assessed at the family level across the CNS methylation spectrum (n = 678, 28 methylation families), on non-array platforms (whole-genome bisulfite sequencing and Oxford Nanopore), and in a focused analysis of the low-grade glioma and diffuse midline glioma compartment across four independent cohorts (n = 670). Results: In the discovery cohort, MAGIBU achieved high concordance with the consensus reference (Cohen's &#x3ba; = 0.855), outperforming EpiDiP (&#x3ba; = 0.278), which frequently placed low-grade tumors in proximity to higher-grade reference regions. Conclusions: MAGIBU provides a stable, quantitative differential diagnosis framework that mitigates the limitations of rigid categorical assignments. By leveraging a distance-based proximity metric, it offers a transparent decision-support tool that integrates effectively with clinical, radiological, and molecular data. While performance is inherently dependent on reference atlas composition, MAGIBU represents a robust complementary approach for the diagnostic workup of ambiguous CNS tumors.

Brain↗
PubMed2005

Promoter classifier: software package for promoter database analysis.

Promoter Classifier is a package of seven stand-alone Windows-based C++ programs allowing the following basic manipulations with a set of promoter sequences: (i) calculation of positional distributions of nucleotides averaged over all promoters of the dataset; (ii) calculation of the averaged occurrence frequencies of the transcription factor binding sites and their combinations; (iii) division of the dataset into subsets of sequences containing or lacking certain promoter elements or combinations; (iv) extraction of the promoter subsets containing or lacking CpG islands around the transcription start site; and (v) calculation of spatial distributions of the promoter DNA stacking energy and bending stiffness. All programs have a user-friendly interface and provide the results in a convenient graphical form. The Promoter Classifier package is an effective tool for various basic manipulations with eukaryotic promoter sequences that usually are necessary for analysis of large promoter datasets. The program Promoter Divider is described in more detail as a representative component of the package.

Algorithms↗
PubMedDate not supplied

Making classifying selectors work for foam elimination in the activated-sludge process.

Classifying selectors are used to control the population of foam-causing organisms in activated-sludge plants to prevent the development of nuisance foams. The term, classifying selector, refers to the physical mechanism by which these organisms are selected against; foam-causing organisms are enriched into the solids in the foam and their rapid removal controls their population at low levels in the mixed liquor. Foam-causing organisms are wasted "first" rather than accumulating on the surface of tanks and thereby being wasted "last", which is typical of the process. This concept originated in South Africa, where pilot studies showed that placement of a flotation tank for foam removal prior to secondary clarifiers would eliminate foam-causing organisms. It was later simplified in the United States by using the aeration in aeration tanks or aerated channels coupled with simple baffling and adjustable weirs to make continuous separation of nuisance organisms from the mixed liquor.

Bioreactors↗
PubMed2004

Combining nearest neighbor classifiers versus cross-validation selection.

Various discriminant methods have been applied for classification of tumors based on gene expression profiles, among which the nearest neighbor (NN) method has been reported to perform relatively well. Usually cross-validation (CV) is used to select the neighbor size as well as the number of variables for the NN method. However, CV can perform poorly when there is considerable uncertainty in choosing the best candidate classifier. As an alternative to selecting a single "winner,'' we propose a weighting method to combine the multiple NN rules. Four gene expression data sets are used to compare its performance with CV methods. The results show that when the CV selection is unstable, the combined classifier performs much better.

Journal Article↗
PubMed1979

Proficiency examination of physicians for classifying pneumoconiosis chest films.

An examination has been developed to test the proficiency of physicians classifying chest radiographs with pneumoconiosis in accordance with the classification system promulgated by the International Labor Office in Geneva. The examination, prepared by Johns Hopkins University under contract with the National Institute of Occupational Safety and Health, was commissioned to identify physicians qualified to serve in national pneumoconiosis programs directed both to epidemiological research and to the compensation of coal miners and others who suffer from dust-related illness. The examination, consisting of 125 chest radiographs, includes examples of a broad range of disease extending from normal to far advanced pneumoconiosis. An examinee passes or fails by ability to classify the films, within prescribed limits, in the same manner as an expert panel of radiologists. The examination is open to radiologists, chest physicians, occupational health specialists, and other physicians interested in pneumoconiosis. By the end of 1978, the examination had been given to 202 candidates, including 116 radiologists 30 chest physicians, three candidates certified in preventive medicine, two family practitioners, and 51 others. Of the 202 candidates, 118 (58.4%) passed and 84 (41.6%) failed. Among the candidates taking the examination for the first time, 74 radiologists (63.8%) and 18 chest physicians (60%) received passing grades. Of the remainder, 21 physicians (37.5%) were successful. Early experience indicates the examination is quite successful in meeting its primary objectives, which suggests that this type of examination may be applicable in other situations to separate those who meet certain standards of performance in radiology from those who do not.

Clinical Competence↗
PubMed2001

Interrater reliability for the basic categories of the AO/ASIF's system as a frame of reference for classifying distal radial fractures.

This study is about agreement on the assignment into the three basic classes or categories (A, B, C) of the Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation's (AO/ASIF) classification system for distal radial fractures. A random sample of 124 distal radial fractures was classified by two experienced observers. Their agreement was calculated according to Cohen's kappa statistic. To investigate the possible bases for disagreement, all conflicting X-ray assessments were discussed in a consensus meeting. It appeared that the kappa value was .65 (good agreement) before the meeting; kappa rose to .86 (excellent agreement) after the consensus meeting. It appeared that the undisplaced fractures were a major source of disagreement. Further, the presence of articular involvement was an important issue. It was frequently noted that one observer classified the fracture as extraarticular (basic Class A), while the other observer chose classification as an intra-articular fracture (basic Class C) or vice versa. This phenomenon has been called the A/C reversal shift. It is concluded that radiological innovations might enhance agreement on articular involvement, and a separate category for undisplaced fractures should be defined in the Arbeitsgemeinschaft für Osteosynthesefragen (AO) system. However, agreement on relevant distinctive features and discussion of conflicting assessments may also be important in achieving excellent agreement.

Adolescent↗
PubMed1998

New composite ('quadrant') standard films for classifying radiographs of pneumoconioses.

120 chest radiographs of dust exposed persons were classified twice by each of 39 physicians, and three times by 37 of them. All film readers used both the 22 standard films accompanying the current International Labour Office's (1980) Classification of Radiographs of Pneumoconioses, and a modified set that reproduced selected parts from some of them as quadrants of full-size films. Variability within and between readers in small opacity profusion classifications was high, but similar when using the two sets of standards. Some readers recognised irregularly shaped small opacities more frequently, in low profusion categories, when using the quadrant standards. Small rounded opacities were classified more frequently higher on the scale when using the current standards. The effects found were small although the test films included a high proportion with some small opacities. It is concluded that use of the new quadrant standards is unlikely to introduce any important bias into results from occupational health surveys.

Bias↗
PubMed2005

Knee and hip angle and moment adaptations during cutting tasks in subjects with anterior cruciate ligament deficiency classified as noncopers.

STUDY DESIGN: Two-factor mixed-design study, with factors including group (control and noncoper) and task (sidestep, crossover, and straight). OBJECTIVES: To compare the knee and hip joint angles and moments of control subjects and subjects with an anterior cruciate ligament (ACL) deficient knee classified as noncopers, during a sidestep, crossover, and straight-ahead task. BACKGROUND: Subjects with ACL deficiency primarily note difficulty with cutting tasks as opposed to straight-ahead tasks. Yet, previous studies have primarily focused on straight-ahead tasks. METHODS AND MEASURES: Fifteen subjects with ACL deficiency classified as noncopers, based on the number of giving-way episodes (>1) and global question of knee function (<60%), were included in this study. These subjects (10 male, 5 female; age range, 18-49 years) were compared to a healthy control group (7 male, 7 female; age range, 19-47 years). Position data collected at 60 Hz were combined with anthropometric and ground reaction force data collected at 420 Hz to estimate 3-dimensional knee and hip joint angles and moments. All subjects performed 3 tasks including a step and 45 degrees sidestep cut, step and 45 degrees crossover cut, and step and proceed straight. Two-way mixed-model ANOVAs were used to compare peak angle and moment variables between 10% to 30% of stance. RESULTS: The ACL-deficient noncoper group had 1.8 degrees to 5.7 degrees less knee flexion angle compared to the control group across tasks (P<.043). The ACL-deficient noncoper group used 22% to 27% lower knee extensor moment during weight acceptance compared to the control group (P<.001). The sagittal plane hip extensor moments were 34% to 39% higher in the ACL-deficient noncoper group compared to the control group (P<.025). Hip frontal (P<.037) and transverse plane (P<.04) moments also distinguished the ACL-deficient noncoper from the control group. CONCLUSIONS: This study suggests that individuals who do not cope well after ACL injury rely on a hip control strategy during cutting tasks.

Adaptation, Physiological↗
PubMed2005

The centralization phenomenon and fear-avoidance beliefs as prognostic factors for acute low back pain: a preliminary investigation involving patients classified for specific exercise.

STUDY DESIGN: Secondary analysis of a prospective cohort of patients with acute low back pain (LBP). OBJECTIVES: To determine if the centralization phenomenon and fear-avoidance beliefs predict measurement of pain and disability 6 months after entering the study. BACKGROUND: The centralization phenomenon and fear-avoidance are predictive of future pain and disability. However, previous prognostic studies have not routinely included both measures in homogenous subgroups of patients with acute LBP. METHODS AND MEASURES: Patients completed self-report questionnaires and were evaluated and treated with treatment-based classification guidelines. Only the patients classified for specific exercise were included in this analysis (n = 28). Measures of disability and pain intensity were reassessed at 6 months by mail. Separate hierarchical regression models predicted measures of disability and pain intensity with the centralization phenomenon, fear-avoidance beliefs, and prespecified covariates. RESULTS: There were no significant differences in duration of symptoms, fear-avoidance beliefs, and history of LBP based on the centralization phenomenon (P > .05). Patients reporting the centralization phenomenon were significantly more likely to have leg pain (P < .01). A regression model including initial disability, the centralization phenomenon, and fear-avoidance beliefs about work significantly predicted 6-month disability, explaining 49% of the total variance (P < .001). A regression model that included initial pain intensity and the centralization phenomenon significantly predicted 6-month pain intensity, explaining 29% of the total variance (P < .016). These factors also appeared to be clinically meaningful predictors of outcome, but lacked precision for immediate use in clinical settings. The following covariates were not included in the final regression models: presence of leg pain, history of LBP, and duration of LBP. CONCLUSIONS: Baseline elevation in fear-avoidance beliefs about work and lack of centralization phenomenon predicted higher disability. Baseline lack of centralization phenomenon predicted higher pain intensity. These results can only be generalized to patients with acute LBP classified for specific exercise. It will be necessary to independently validate these prediction models before they can be implemented in clinical settings.

Acute Disease↗
PubMed1975

Some preliminary observations on a questionnaire technique for classifying depressive illness: its relationship with clinical diagnosis and a biological technique for depressive classification.

A questionnaire designed to assist in the classification of depressive illness, was administered to 20 acute depressive patients and 10 normal controls. Patient classification according to the decision rules employed by the questionnaire, were compared with patient classification arrived at by symptomatic (diagnostic) and physiological (G.S.R. inhibition threshold) means. It was found that a preponderance of patients classified as "endogenous depressives" by the questionnaire technique, also had clinical diagnoses of endogenous depression, and had low G.S.R. inhibition thresholds relative to normals. Furthermore a preponderance of patients classified as "non-endogenous depressives" by the questionnaire technique, had clinical diagnoses of neurotic depressive illness, and had high G.S.R. inhibition thresholds relative to normals. This supports the assertion that the questionnaire technique has some validity in the classification of depressive illness.

Adjustment Disorders↗
PubMed1991

The multi-crossover model for classifying patients as responders to a given treatment.

The strength and the validity of the multi-crossover model (MCO model) were investigated to optimalize the procedure for correctly classifying individual responders to a given therapy. One hundred and fifteen patients with non-ulcer dyspepsia from seven Norwegian hospitals were included in a 6-week double-blind MCO-designed trial with alternating weekly treatments with ranitidine and placebo. An individual effect score (X score) was calculated on the basis of the number of times the active drug was associated with less symptoms than the preceding or following placebo period. Patients categorized as responders (X score greater than or equal to 4) or unclassifiables (X scores = 2 or 3) after the MCO period continued single-blind active treatment for 4 weeks and were then reclassified by means of cross-tabulation of efficacy and adverse effects. Eighty-five per cent of the MCO responders and 62% of the 42 MCO unclassifiables were reclassified as responders. The reclassified responders were then included in a single-blind follow-up placebo period until relapse or for a maximum of 8 weeks. The relapse rate was significantly greater (p less than 0.01) and the time to relapse significantly shorter (p less than 0.01) in the group of MCO responders than in the MCO unclassifiables. The large response and relapse rates in the group of MCO responders verify that the MCO model is a reliable method for correctly classifying responders to treatment. Our results indicate that by including patients with an X score of 3 in the definition of 'responder', the MCO model could be modified to optimalize the procedure for correct classification.

Clinical Trials as Topic↗
PubMedDate not supplied

Screening of angiotensin II dependent hypertensive patients using a linear classifier.

The screening of renovascular hypertensive patients can be performed on the basis of the blood-pressure response of the patients to saralasin (Sarenin) infusion. A new approach is proposed here for the screening. The blood-pressure responses to the saralasin are modelled first, using autoregressive time series models. The constant parameters of the models are then used as the features for classifying the hypertensive patients. A linear classifier is constructed to perform the dichotomy between the angiotensin II dependent hypertensive and the rest of the hypertensive patients. Computational results on the testing of the method are presented. Although the sample size available for this study was small, the results are encouraging.

Angiotensin II↗
PubMed2000

A quantitative approach to classifying Holstein cows based on antibody responsiveness and its relationship to peripartum mastitis occurrence.

A quantitative approach was developed to classify Holstein cows and heifers based on phenotypic variation of serum antibody response and to determine associations with peripartum mastitis. Using an index, 136 cows and heifers were classified into high (Group 1), average (Group 2), or low (Group 3) antibody groups following immunization with ovalbumin at wk -8, -3, and 0 relative to parturition. The ranking of groups based on the quantitative index of serum antibody response to ovalbumin were similar for sera and whey antibody such that Group 1 > Group 2 > Group 3. Animals were also vaccinated with Escherichia coli J5 (Rhône Mérieux, Lenexa, KS) at wk -8 and -3 relative to parturition. The ranking of groups for E. coli J5 was similar to that observed for serum and whey antibody to ovalbumin. Serum and whey IgG1 and IgG2 concentrations were measured at wk 0, 3, and 6 but differences between groups were not significant. There was no occurrence of mastitis for Group 1 animals in two of the herds. In contrast, Group 1 animals from the third herd had the highest occurrence of mastitis; however, these cases all occurred in first-parity heifers. According to pooled data across all herds, Group 3 animals had the highest occurrence of mastitis. Heritability estimates of serum antibody response to ovalbumin varied between 0.32 to 0.64 depending on week relative to parturition. Heritability estimates of serum antibody response to E. coli J5 also varied between 0.13 to 0.88 depending upon week relative to parturition. These results indicate that high peripartum antibody may be beneficial in some herds.

Animals↗
PubMed1992

Cost-benefit evaluation of on-farm milk progesterone testing to monitor return to cyclicity and to classify ovarian cysts.

The effect of using on-farm milk progesterone testing to monitor return to cyclicity after parturition and to classify correctly and to treat cystic cows was evaluated using modeling and simulation. The test was evaluated assuming low and high accuracies of progesterone measurement, first breeding policy of 40 d, average estrus detection rate of 55%, and an average fertility rate of 55%. Three testing schemes (starting milk progesterone testing on d 30, 40, or 50 after parturition) were compared against a control to evaluate the effect of monitoring return to cyclicity on cows' reproductive and economic performance. For this purpose, the use of the test was an economically justifiable management intervention. Starting to test on d 30 after parturition was the most effective scheme, reducing days open by 18 d, replacement rate by 2.4%, and increasing net return per cow per year by $11. Starting to test on d 50 postpartum was not economically justifiable. Accuracy of the test, within the range used in this study, was unimportant. Testing was most profitable in herds with low fertility and low efficiency of estrus detection. The use of the test to classify follicular and luteal cysts and to select the appropriate therapy was not economically justifiable because of the low proportion of cystic cows and the high variation in response to therapy.

Animals↗