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At least 919 records · Page 51Linked to original sources
PubMed2001

Cerebral hemodynamic parameters for patients with neurological improvements after extracranial-intracranial arterial bypass surgery: evaluation using positron emission tomography.

OBJECTIVE: The purpose of this study was to clarify the hemodynamic features of patients who experienced improved neurological function after extracranial-intracranial arterial bypass surgery. With this aim, we retrospectively analyzed the results of their pre- and postoperative positron emission tomographic studies. METHODS: This study included 16 patients who exhibited stable neurological dysfunction just before extracranial-intracranial bypass surgery. All underwent pre- and postoperative positron emission tomographic studies. They were divided into groups, i.e., patients who did (Group 1, n = 6) or did not (Group 2, n = 10) manifest postoperative improvements in neurological functions. Positron emission tomographic parameters obtained in the middle cerebral artery territories were compared between the two groups. RESULTS: Comparison of the preoperative hemodynamic values on the affected side and the contralateral side demonstrated that the mean regional cerebral blood flow values were significantly lower on the affected side in both groups (Group 1, P < 0.005; Group 2, P < 0.05). For Group 1 patients, the mean regional oxygen extraction fraction (rOEF) and regional cerebral blood volume values were significantly higher on the affected side than on the contralateral side (P < 0.01 and P < 0.05, respectively). For Group 2 patients, the mean regional cerebral metabolic rate of oxygen (rCMRO2) value was significantly lower on the affected side than on the contralateral side (P < 0.05). The mean rOEF and rCMRO2 values on the affected side were significantly higher for Group 1 patients, compared with Group 2 patients, before surgery (P < 0.05 and P < 0.05, respectively). The preoperative regional cerebral blood flow and regional cerebral blood volume values on the affected side were similar for the two groups. Postoperative changes in mean regional cerebral blood flow and mean rOEF on the affected side were statistically significant for both groups. The mean rCMRO2 on the affected side for Group 2 was significantly lower than that for Group 1, even after bypass surgery (P < 0.05). CONCLUSION: Bypass surgery may improve neurological function for patients with significantly elevated rOEF values and rCMRO2 values near the normal level. These hemodynamic parameters may be useful for the identification of candidates for extracranial-intracranial bypass surgery.

Adult↗
PubMed1993

System for quality management.

Total quality management will provide important benefits for organizations that are involved with the delivery of occupational and environmental health care. These organizations should shift from traditional medical management to the new paradigm. Identification of a set of relevant parameters for this new management system is necessary to implement the quality culture within our professional settings. An exhaustive literature search was undertaken on the topic of total quality management to delineate a framework for consideration by occupational and environmental health managers. Proposed are essential components of a management system for quality excellence which are derived from review of reported approaches among health care organizations and industry, various lists of quality principles and criteria, and classical systems theory.

Delivery of Health Care↗
PubMed2006

Reliability of radiological classifications used in Legg-Calve-Perthes disease.

Radiological assessment is a valuable tool in the assessment, management and prognostication of Perthes disease. Radiological assessment, however, is not an easy task and all classification systems used in Perthes disease have some degree of interrater and intrarater variabilities. In the past, there were some isolated studies to find the reliability of the classifications used in Perthes disease. In this study, we comprehensively studied three most commonly used radiological classifications (Salter-Thompson, lateral pillar and Catterall). We had 44 patients' radiographs (anteroposterior and lateral) taken in the fragmentation stage, and two experienced observers assessed and classified the radiographs on two separate occasions. In this study, we found that the average interrater reliability of the Salter-Thompson, lateral pillar and Catterall classifications was 0.163 (0.08-0.236), 0.722 (0.581-0.824) and 0.433 (0.280-0.546), respectively. The intrarater reliability was 0.313 and 0.699 for the Salter-Thompson, 0.707 and 0.658 for the lateral pillar and 0.38 and 0.577 for the Catterall classifications. Further, we tried to determine the possible reason for the low reliability associated with the Catterall classification. We think that the quantitative method of lateral pillar has better intrarater and interrater reliabilities than other classification systems, and the reliability of the Catterall classification can be significantly improved if some radiological parameters such as metaphyseal reaction and identification of the junction of involved to uninvolved region can be optimized.

Humans↗
PubMed1997

Simultaneous and nonlinear identification of mechanical and reflex properties of human elbow joint muscles.

The naturally coexisting intrinsic mechanical and reflex properties of the human elbow joint were identified simultaneously using nonlinear, time-delay, continuous-time, and dynamic models. Angular random perturbations of small amplitude and low bandwidth were applied to the joint using a computer-controlled servomotor, while the subject maintained various levels of mean background muscle torque. Joint neuromuscular dynamics were identified from the measured elbow angle and torque. Stretch reflexes were modeled nonlinearly with both dynamic and static reflex gains. A continuous-time system identification method was developed to estimate parameters of the nonlinear models directly from sampled data while retaining realistic physical or physiological interpretations. Results from six subjects showed that dynamic stretch reflex gains, joint stiffness, and viscosity generally increased with mean background muscle torque; and that dynamic stretch reflex gain was higher during muscle stretch than that during muscle shortening. More importantly, the study provided realistic simultaneous estimates of the relative contributions of intrinsic mechanical and reflex actions to net joint torque. In particular, reflexively-mediated stiffness generated a significant portion of the total joint stiffness and the percentage varied systematically with background muscle torque.

Biomechanical Phenomena↗
PubMed2006

Local image registration by adaptive filtering.

We propose a new adaptive filtering framework for local image registration, which compensates for the effect of local distortions/displacements without explicitly estimating a distortion/displacement field. To this effect, we formulate local image registration as a two-dimensional (2-D) system identification problem with spatially varying system parameters. We utilize a 2-D adaptive filtering framework to identify the locally varying system parameters, where a new block adaptive filtering scheme is introduced. We discuss the conditions under which the adaptive filter coefficients conform to a local displacement vector at each pixel. Experimental results demonstrate that the proposed 2-D adaptive filtering framework is very successful in modeling and compensation of both local distortions, such as Stirmark attacks, and local motion, such as in the presence of a parallax field. In particular, we show that the proposed method can provide image registration to: a) enable reliable detection of watermarks following a Stirmark attack in nonblind detection scenarios, b) compensate for lens distortions, and c) align multiview images with nonparametric local motion.

Algorithms↗
PubMed2002

Comparative and prospective study of different immune parameters in healthy subjects at risk for tuberculosis and in tuberculosis patients.

It has not been fully elucidated which of the components of the immune response against Mycobacterium tuberculosis is indicative of resistance or susceptibility. The aim of this study was to identify an immune parameter that could be indicative of either resistance or susceptibility to M. tuberculosis infection. We prospectively studied (three determinations, at months 0, 8, and 12) 15 patients with chronic pulmonary tuberculosis and 42 healthy individuals with a recent and frequent contact with tuberculosis patients. Peripheral blood mononuclear cells were stimulated with a whole-protein extract or the 30-kDa antigen of M. tuberculosis for 6 days, and several immune parameters were determined. No consistent differences between tuberculosis patients and healthy controls were detected in most immune parameters studied, including the expression of different activation antigens, cytokine secretion, lymphocyte proliferation, and nitric oxide production. However, the synthesis of tumor necrosis factor alpha, the intracellular detection of gamma interferon, and the apoptosis of monocytes under certain culture conditions tended to show clear-cut differences in cells from patients and controls (P < 0.05 in all cases for most determinations). Nevertheless, when results were analyzed on an individual basis, it was evident that a significant degree of overlapping of values from patients and controls occurred for all parameters studied. We conclude that although the immune parameters tested do not allow the identification of individuals susceptible to M. tuberculosis, the specificity and sensitivity of some of them could be improved through future studies.

Adenosine Triphosphate↗
PubMed1979

'On line' data handling in a routine haematology department.

The use of a ;stand alone' mini computer, on line, data acquisition system is described utilising a microprocessor as an adjunct to the main central processor to increase data transmission rates. Visual display units (VDU) provide on line flexibility of data input. The system acquires, on line, the Coulter S generated parameters together with the associated patient identification data and other requested tests. Erythrocyte sedimentation rate, platelet count, and B12 and folate results are fed in at will via the VDUs, using rapid entry subroutines. Percentage differential white cell count results and the absolute leucocyte count are calculated by the microprocessor, on line input being facilitated by remote keyboards associated with the VDUs. Total editing of all requests and results is available on all ;current' (unfiled) reports via the VDUs, and this facility includes the entry of film appearances using plus symbols and predetermined comments available against a code number. This editing function is also used to enter all other results that can be made available on the computer-printed report form. The computer system also provides quality control data, immediate printout of Coulter S results outside given limits, cumulative filing for all routine and designated ;priority' results, and a daily alphabetical listing of all patients from whom specimens have been examined together with full blood count, ESR, and platelet results on specimens examined that day.

Blood Cell Count↗
PubMed2002

Denaturation of collagen via heating: an irreversible rate process.

Heating therapies are increasingly used in cardiology, dermatology, gynecology, neurosurgery, oncology, ophthalmology, orthopedics, and urology, among other medical specialties. This widespread use of heating is driven primarily by the availability of new technology, not by a detailed understanding of the biothermomechanics. Without basic quantification of the underlying physical and chemical processes in terms of parameters that can be controlled clinically, identification of preferred interventions will continue to be based primarily on trial and error, thus necessitating large clinical studies and years of accumulative experience. Perusal of the literature reveals that much has been learned over the past century about the response of cells, proteins, and tissues to supra-physiologic temperatures; yet, the associated findings are reported in diverse journals and the underlying basic processes remain unidentified. In this review, we seek to contrast various findings on the kinetics of the thermal denaturation of collagen and to encourage investigators to consider the many open problems in part via a synthesis of results from the diverse literatures.

Collagen Type I↗
PubMed2006

Myeloperoxidase promoter polymorphism -463G is associated with more severe clinical expression of cystic fibrosis pulmonary disease.

The severity of cystic fibrosis (CF) pulmonary disease is not directly related to CFTR genotype but depends upon several parameters, including neutrophil-dominated inflammation. Identification of agents modulating inflammation constitutes a relevant goal. Myeloperoxidase (MPO) is involved in both microbicidal and proinflammatory neutrophil activities. The aim of this study was to evaluate whether the -463GA MPO promoter polymorphism is linked to clinical severity of CF-associated pulmonary inflammation. This polymorphism significantly affects the level of MPO gene expression in leukocytes and the G allele is more expressing than the A allele. We show that MPO genotype significantly influences the severity of pulmonary disease in early stages, prior to the development of chronic lung infections, with GG genotype being associated with more severe CF disease. Our findings indicate that the level of MPO gene expression influences the CF pathogenesis, presumably reflecting cellular damage by MPO-generated oxidants or other activity of MPO in airway inflammation.

Adolescent↗
PubMedDate not supplied

A real-time classification system of thalassemic pathologies based on artificial neural networks.

Thalassemias are pathologies that derive from genetic defects of the globin genes. The most common defects among the population affect the genes that are involved in the synthesis of alpha and beta chains. The main aspects of these pathologies are well explained from a biochemical and genetic point of view. The diagnosis is fundamentally based on hematologic and genetic tests. A genetic analysis is particularly important to determine the carriers of alpha-thalassemia, whose identification by means of the hematologic parameters is more difficult in comparison with heterozygotes for alpha-thalassemia. This work investigates the use of artificial neural networks (ANNs) for the classification of thalassemic pathologies using the hematologic parameters resulting from hemochromocytometric analysis only. Different combinations of ANNs are reported, which allow thalassemia carriers to be discriminated from normals with 94% classification accuracy, 92% sensitivity, and 95% specificity. On the basis of these results, an automated system that allows real-time support for diagnoses is proposed. The automated system interfaces a hemochromo analyzer to a simple PC.

Adolescent↗
PubMedDate not supplied

Primary care clinic size and patient satisfaction in a military setting.

Patient satisfaction is a fundamental parameter of quality in health care. Identification of aspects of care that influence patient satisfaction may be used to design changes in health delivery systems, thus improving quality of care. The objective of this study was to examine the relationship between the patient's assessment of quality of health care and the size of primary care clinics (PCCs) (measured as number of monthly patient visits) as well as the physician workload (measured as number of visits per physician per month). This study was a cross-sectional study using PCCs' characteristics and patient satisfaction surveys. One hundred one PCCs were evaluated. There was a negative correlation between all satisfaction indices and the number of primary care physicians in the clinic and the number of monthly visits to the clinic. In contrast, there was no significant correlation between the actual workload per physician. In general linear models, clinic size correlated significantly and negatively with patient satisfaction even after correction for other factors. The study concluded that patient satisfaction in the medical settings of the Israel Defense Forces is adversely affected by large clinic size but is not affected by physician workload.

Adolescent↗
PubMed2004

Limitations in the interpretation of biopsies in patients with penile squamous cell carcinoma.

Surgeons often perform small or superficial penile biopsies that are difficult to classify definitely with regard to a benign or malignant nature, and if malignant, cannot always be accurately subclassified. Staging and therapeutic decisions rely on the identification, in these materials, of pathologic parameters related to prognosis. In this study, we evaluated the accuracy and completeness of pathologic information obtained from biopsies of 57 consecutive patients with squamous cell carcinoma (SSC) of the penis, and compared it with the information obtained from penectomies. Diagnostic accuracy was determined by recording discordances of critical factors in biopsies and penectomies. The evaluated parameters were as follows: cancer diagnosis, histologic type, tumor grade, depth of invasion (anatomical levels), and vascular invasion. Histologic subtypes of SCC were the following: usual 37, verruciform 11, mixed 7, pseudohyperplastic 1, and sarcomatoid 1. Grades were 1, 2, and 3 (well, moderately and poorly differentiated). Levels of invasion were lamina propria, corpus spongiosum, and corpus cavernosum in the glans; and lamina propria, dartos, and skin in the foreskin. In 2 patients with well-differentiated tumors a diagnosis of cancer could not be established in biopsy material. In 17 cases (30%) there was a biopsy-penectomy discordance of histologic types, especially of verruciform and mixed carcinomas. Biopsies failed to identify the correct histologic grade in 30% of the cases. A higher grade was usually identified in penectomy specimens. Because biopsies were superficial, the deepest point of invasion could not be determined in 91% of the cases. Vascular invasion was identified in biopsies in only 1 of 8 patients. In summary, biopsies were useful for cancer diagnosis except in 2 differentiated variants of penile squamous cell carcinoma. However, important pathologic parameters related to prognosis were missed on biopsy materials, and they were more accurately evaluated in penectomy specimens. We conclude that clinical and pathologic staging of penile cancer, at least in our material, cannot depend on biopsy information alone. Data from biopsies may be insufficient to make a decision whether to perform a groin dissection, or for prognostic evaluation in those patients in whom other treatment modalities (such as radiotherapy or chemotherapy) are being considered.

Biopsy↗
PubMed1985

Determination of theophylline in saliva, using fluorescence polarization immunoassay (FPIA).

Theophylline concentrations were determined by fluorescence polarization immunoassay (FPIA) in saliva, serum and serum water of healthy volunteers and outpatients after administration of single theophylline doses, and after the administration of several doses in order to establish a steady state. The FPIA allowed rapid and reliable theophylline determinations in saliva and serum water (between-days coefficients of variation: less than 3%; recovery: 95-03%). Salivary theophylline concentrations measured by FPIA in 30 samples agreed well with those determined by HPLC. Furthermore the results obtained by ultrafiltration for the concentration of unbound theophylline in serum water were in good agreement with those determined by ultracentrifugation. The binding of theophylline by serum protein rose by about 25%, when the pH of the samples was increased from 7.0 to 8.0. After adjusting the pH to 7.4, average values for theophylline binding to proteins at 25 degrees C ranged from 48.5 to 52.2% in serum samples from outpatients and healthy adults. Salivary theophylline concentrations correlated well with total and free serum theophylline concentrations in healthy adults and outpatients (r = 0.90-0.98). The theophylline concentration in saliva was on average about 20-30% higher than the unbound theophylline concentration in serum water. The saliva/serum concentration ratio of theophylline showed some intersubject variation (0.68 +/- 0.08; range: 0.50-0.85). Using the mean saliva/serum concentration ratio of the patient group, steady state serum theophylline concentrations were predicted from salivary levels with a mean error of 7.6% (range: 0.0-26.8%). The salivary theophylline concentration appears to be a suitable parameter for assessment of compliance, for identification of patients with inappropriate dosage, and for consequent dosage adjustment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1997

Establishment of behavioral parameters for the evaluation of osteopathic treatment principles in a rat model of arthritis.

Unilateral arthritis was produced in rats by use of methylated bovine serum albumin in a model of antigen-induced arthritis. The progression of arthritis was measured by computerized motion analysis, bilateral joint circumference, voluntary extension force of the hindlegs, and length of ankle extension. Animals with induced arthritis were assigned to treated and untreated groups on the basis of approximately equal deficits by the parameters measured. A third group of rats, which did not have arthritis induced and received no treatment, served to establish mean normal parameters. Modified techniques of muscle energy, passive movement of the ankle and knee, and passive myofascial stretch were applied to the animals, and the animals were exercised in a mechanized exercise wheel. Parameters associated with gait were examined by computerized motion analysis of walking. Animals treated with manipulation and exercise improved significantly relative to untreated animals with antigen-induced arthritis in vertical ankle lift, ankle-based and foot-based stride lengths, knee circumference, and normalized extension of the ankle. The results demonstrate that the parameters identified can be used to detect functional deficits and significant improvement from those deficits can be derived from a nonpharmacologic treatment paradigm that includes osteopathic manipulation and exercise in an animal model of arthritis. These parameters may be useful in the identification of the relative benefits of independent treatment variables including frequency of osteopathic manipulation and exercise and the relative benefits of each in this model. Also, they may elucidate how these treatments produce their beneficial effects clinically.

Animals↗
PubMed1999

[Mathematical model of micturition allowing a detailed analysis of free urine flowmetry].

A mathematical model of micturition allowing precise analysis of uroflowmetry curves (VBN method) is described together with some of its applications. The physiology of micturition and possible diagnostic hypotheses able to explain the shape of the uroflowmetry curve can be expressed by a series of differential equations. Integration of the system allows the validity of these hypotheses to be tested by simulation. A theoretical uroflowmetry is calculated in less than 1 second and analysis of a dysuric uroflowmetry takes about 5 minutes. The efficacy of the model is due to its rapidity and the precision of the comparisons between measured and predicted values. The method has been applied to almost one thousand curves. The uroflowmetries of normal subjects are restored without adjustment with a quadratic error of less than 1%, while those of dysuric patients require identification of one or two adaptive parameters characteristic of the underlying disease. These parameters remain constant during the same session, but vary with the disease and/or the treatment. This model could become a tool for noninvasive urodynamic studies.

Diagnostic Techniques, Urological↗
PubMed1999

Effect of proteinuria reduction on prevention of focal glomerulosclerosis by angiotensin-converting enzyme inhibition is modifiable.

BACKGROUND: Proteinuria is associated with a progressive loss of renal function; we recently found that both intrarenal effects of proteinuria and the state of systemic nephrosis play an independent role in proteinuria-induced renal damage. Reduction of proteinuria is an important mechanism underlying the renoprotective effect of angiotensin-converting enzyme inhibition (ACEi). Both the reduction of proteinuria and the attenuation of the systemic state of nephrosis may be involved in the renoprotection by ACEi. METHODS: This article entails a post hoc analysis of a previous study on the renoprotective effect of ACEi lisinopril in adriamycin nephrosis. It was attempted to modify therapeutic efficacy of ACEi by increasing lisinopril dose and by dietary sodium restriction, respectively. In this analysis, we aimed to delineate the contribution of proteinuria reduction and the reduction of other intermediate parameters such as hyperlipidemia and blood pressure on the protection against focal glomerulosclerosis (FGS). RESULTS: We found that in adriamycin nephrosis, ACEi significantly reduced proteinuria, lipids, and blood pressure and provided protection against FGS. Treatment modification by increasing the lisinopril dose resulted in a further reduction of FGS without significant effects on intermediate parameters (proteinuria, hyperlipidemia, and blood pressure), whereas surprisingly, treatment modification by sodium restriction resulted in a further attenuation of intermediate parameters, without additional protection against FGS. CONCLUSIONS: The renoprotective benefit of an obtained attenuation of intermediate parameters is modified by other factors. Further optimization of renoprotective therapy requires identification of such factors and explicit consideration of therapeutic efficacy on intermediate parameters as well as hard end points.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2003

[Infection control and prevention in intensive care: environmental aspects].

Surveillance is understood as the monitoring over time of the onset of preventable infection and/or microbial colonization in patients in intensive care units (ICU), where the prevalence of nosocomial infections, particularly those caused by microorganisms multiresistant to antibiotics, is alarmingly high. Surveillance deals with: 1) pathogens responsible for infection and their patterns of antibiotic resistance; 2) epidemics; 3) endemic infections selected according to predictability; 4) frequency of use of specific invasive procedures, where the greater the use, the higher the frequency of nosocomial infections associated with them; 5) use of antibiotics. Surveillance is operated through: 1) the microbiology laboratory, which is responsible for accurate surveillance of hospital infections; 2) the active surveillance on the wards, which concerns: a) identification of infections either on admission or during hospitalization or both, b) use of invasive procedures, control of parameters, and data collection, c) type of patients treated, identification of infected patients and data analysis and interpretation. Infection prevention complementary to surveillance starts with the adoption of strategies and interventions based on the application of universal precautions and/or on the route of transmission. A crucial point is the sterilization and disinfection of medical devices. In recent years there has been a steady rise in the number of infections caused by medical devices, most likely because of the increasing use of sophisticated and complex equipment that is often difficult to decontaminate and because of the rise in the number of immunocompromised patients or those susceptible to infections.

Critical Care↗
PubMedDate not supplied

Evaluation of results of an interlaboratory comparison test on determination of acrylamide in crispbread samples.

The European Commission's Directorate General Joint Research Centre has organized several proficiency tests on the determination of acrylamide (AA) in food. This paper presents the results and outcome of a proficiency test that focused on the determination of AA in crispbread samples. One of the goals was the identification of the influence of different parameters such as analyte extraction or instrument calibration on the analytical results. A set of samples, containing 3 different crispbread samples as well as extracts of one crispbread sample and AA standard solutions, was shipped to each participant. A total of 42 European laboratories reported analytical results that were evaluated by applying internationally accepted protocols and procedures. The study found that, for each sample, the results of 4-8 laboratories were outside the range formed by the target value plus or minus the 2-fold of the target standard deviation; thus, they did not perform satisfactorily. In transferring this knowledge to the data of monitoring databases of AA in food, care must be taken that data are quality controlled, as it is likely that some of them may be biased.

Acrylamide↗