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1.
Appl Clin Inform ; 6(1): 27-41, 2015.
Article in English | MEDLINE | ID: mdl-25848411

ABSTRACT

OBJECTIVE: To understand emergency department (ED) physicians' use of electronic documentation in order to identify usability and workflow considerations for the design of future ED information system (EDIS) physician documentation modules. METHODS: We invited emergency medicine resident physicians to participate in a mixed methods study using task analysis and qualitative interviews. Participants completed a simulated, standardized patient encounter in a medical simulation center while documenting in the test environment of a currently used EDIS. We recorded the time on task, type and sequence of tasks performed by the participants (including tasks performed in parallel). We then conducted semi-structured interviews with each participant. We analyzed these qualitative data using the constant comparative method to generate themes. RESULTS: Eight resident physicians participated. The simulation session averaged 17 minutes and participants spent 11 minutes on average on tasks that included electronic documentation. Participants performed tasks in parallel, such as history taking and electronic documentation. Five of the 8 participants performed a similar workflow sequence during the first part of the session while the remaining three used different workflows. Three themes characterize electronic documentation: (1) physicians report that location and timing of documentation varies based on patient acuity and workload, (2) physicians report a need for features that support improved efficiency; and (3) physicians like viewing available patient data but struggle with integration of the EDIS with other information sources. CONCLUSION: We confirmed that physicians spend much of their time on documentation (65%) during an ED patient visit. Further, we found that resident physicians did not all use the same workflow and approach even when presented with an identical standardized patient scenario. Future EHR design should consider these varied workflows while trying to optimize efficiency, such as improving integration of clinical data. These findings should be tested quantitatively in a larger, representative study.


Subject(s)
Documentation/methods , Electronic Health Records , Emergency Medicine/methods , Internship and Residency , Physicians , Workflow , Emergency Service, Hospital , Humans , Male , Middle Aged , Time Factors
2.
Rozhl Chir ; 90(9): 496-8, 2011 Sep.
Article in Czech | MEDLINE | ID: mdl-22320111

ABSTRACT

Ileus caused by small intestinal obturation due to an enterolith, as a complication of jejunal diverticulosis, is rare, however, a number of case reviews describing the conditions can be found in literature. The presented case review documents difficulties with entherolith ileus diagnostics and its management together with a growing abdominal aneurysm, as a single step procedure.


Subject(s)
Aortic Aneurysm, Abdominal/complications , Calculi/complications , Diverticulum/complications , Ileus/complications , Jejunal Diseases/complications , Aged , Aortic Aneurysm, Abdominal/surgery , Calculi/surgery , Chronic Disease , Diverticulum/surgery , Humans , Ileus/surgery , Jejunal Diseases/surgery , Male
3.
Rozhl Chir ; 88(12): 730-4, 2009 Dec.
Article in Czech | MEDLINE | ID: mdl-20662438

ABSTRACT

THE INTRODUCTION: Biliary cystadenomas of the liver are less often complicated cystic lesions of the liver with a malignant potential. THE AIM: The aim of the work was to assess the results of the set of an own working place emphasising new findings in the diagnostics and the treatment of benign tumours of the liver. THE SET OF THE PATIENTS AND THE METHOD: From 2004 till 2009 three patients were operated on biliary cystadenomas of the liver at the Surgical Clinic of Medical Faculty of Charles University and Faculty Hospital in Plzen. In all cases these patients were women with the average age 42 years of the age category 36-58 years. In all cases the formation was located centrally close to the branching of the big biliary ducts. The diagnosis was established preoperativelly in 66% of cases. An enucleation was performed two times and the right hepatectomy once. Mortality was 0% and morbidity was 33%. THE CONCLUSION: Regarding to the fact that cystadenomas of the liver as benign tumours have a malignant potential for rising the cystadenocarcinoma, it is always necessary to perform their surgical removing--resection or the enucleation. With respect to their central location their surgical treatment belongs to more difficult performances carried out on the liver parenchyma. Long-term results after the surgical treatment are very good.


Subject(s)
Cystadenoma/surgery , Liver Neoplasms/surgery , Adult , Cystadenoma/diagnosis , Diagnosis, Differential , Female , Humans , Liver Neoplasms/diagnosis , Middle Aged
4.
Rozhl Chir ; 81(7): 340-5, 2002 Jul.
Article in Czech | MEDLINE | ID: mdl-12197167

ABSTRACT

The authors evaluated the results achieved in 47 patients with injuries of the acral vesels where they performed a total of 50 vascular operations during the five-year period from 1998-2001. 21.3% injuries were part of multiple injuries. The mean period of hospitalization was 14.7 days. The 30-day mortality was 6.4% and the morbidity 12.8%. The upper extremity was saved in all instances (100%), the lower extremity in 77.3% of the injured. The reason for high amputations of the lower extremity were most frequently injuries of the popliteal artery associated with skeletal injury and extensive contusion of the soft tissues of the extremity. The authors discuss the optimal diagnostic and therapeutic procedures in injuries of the acral vessels. They emphasize a multidisciplinary approach without delay with early, frequently during the primary operation indicated fasciotomy, to prevent the development of compartment syndrome. The order of operations in concurrent injuries of the acral skeleton depends on the stage of ischaemia, type of injury and solution of the skeletal fractures. This type of injury frequently calls for repeated redressing in the operation theatre with repeated necrectomies of soft tissues to prevent infection which may prove fatal for the extremity. Injuries of the acral vessels should be nowadays treated in specialized departments with a 24-hour diagnostic and therapeutic traumatological service which comprises a highly specialized team of vascular surgeons.


Subject(s)
Arm Injuries/surgery , Blood Vessels/injuries , Extremities/blood supply , Leg Injuries/surgery , Adolescent , Adult , Aged , Child , Female , Humans , Male , Middle Aged , Plastic Surgery Procedures , Vascular Surgical Procedures
6.
JAMA ; 286(22): 2839-44, 2001 Dec 12.
Article in English | MEDLINE | ID: mdl-11735759

ABSTRACT

CONTEXT: Usual drug-prescribing practices may not consider the effects of renal insufficiency on the disposition of certain drugs. Decision aids may help optimize prescribing behavior and reduce medical error. OBJECTIVE: To determine if a system application for adjusting drug dose and frequency in patients with renal insufficiency, when merged with a computerized order entry system, improves drug prescribing and patient outcomes. DESIGN, SETTING, AND PATIENTS: Four consecutive 2-month intervals consisting of control (usual computerized order entry) alternating with intervention (computerized order entry plus decision support system), conducted in September 1997-April 1998 with outcomes assessed among a consecutive sample of 17 828 adults admitted to an urban tertiary care teaching hospital. INTERVENTION: Real-time computerized decision support system for prescribing drugs in patients with renal insufficiency. During intervention periods, the adjusted dose list, default dose amount, and default frequency were displayed to the order-entry user and a notation was provided that adjustments had been made based on renal insufficiency. During control periods, these recommended adjustments were not revealed to the order-entry user, and the unadjusted parameters were displayed. MAIN OUTCOME MEASURES: Rates of appropriate prescription by dose and frequency, length of stay, hospital and pharmacy costs, and changes in renal function, compared among patients with renal insufficiency who were hospitalized during the intervention vs control periods. RESULTS: A total of 7490 patients were found to have some degree of renal insufficiency. In this group, 97 151 orders were written on renally cleared or nephrotoxic medications, of which 14 440 (15%) had at least 1 dosing parameter modified by the computer based on renal function. The fraction of prescriptions deemed appropriate during the intervention vs control periods by dose was 67% vs 54% (P<.001) and by frequency was 59% vs 35% (P<.001). Mean (SD) length of stay was 4.3 (4.5) days vs 4.5 (4.8) days in the intervention vs control periods, respectively (P =.009). There were no significant differences in estimated hospital and pharmacy costs or in the proportion of patients who experienced a decline in renal function during hospitalization. CONCLUSIONS: Guided medication dosing for inpatients with renal insufficiency appears to result in improved dose and frequency choices. This intervention demonstrates a way in which computer-based decision support systems can improve care.


Subject(s)
Decision Support Systems, Clinical , Medication Systems, Hospital , Pharmaceutical Preparations/administration & dosage , Renal Insufficiency/metabolism , Health Care Costs , Humans , Length of Stay , Pharmaceutical Preparations/metabolism , Renal Insufficiency/physiopathology , United States
7.
Stud Health Technol Inform ; 84(Pt 2): 1207-11, 2001.
Article in English | MEDLINE | ID: mdl-11604922

ABSTRACT

Computerized physician order entry (CPOE) has been shown to improve quality, and to reduce resource utilization, but most available data suggest that it takes longer to enter orders using CPOE. We had previously implemented a CPOE system, and elected to evaluate its impact on physician time in the new setting. To do this, we performed a prospective study using random reminder methodology. Key findings were that interns spent 9.0% of their time ordering with CPOE, compared to 2.1% before, although CPOE saved them an additional 2% of time, so that the net difference was 5% of their total time. However, this is counterbalanced by decreased time for other personnel such as nursing and pharmacy, and by the quality and efficiency changes. We conclude that while CPOE has many benefits, it represents a major process change, and organizations must factor this in when they implement it.


Subject(s)
Hospital Information Systems , Medical Records Systems, Computerized , User-Computer Interface , Medical Records , Practice Patterns, Physicians' , Prospective Studies , Time Factors
8.
J Gen Intern Med ; 16(10): 663-7, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11679033

ABSTRACT

CONTEXT: Although few data are available, many believe that part-time primary care physicians (PCPs) are less productive and provide lower quality care than full-time PCPs. Some insurers exclude part-time PCPs from their provider networks. OBJECTIVE: To compare productivity, quality of preventive care, patient satisfaction, and risk-adjusted resource utilization of part-time and full-time PCPs. DESIGN: Retrospective cohort study. SETTING: Boston. PARTICIPANTS: PCPs affiliated with 2 academic outpatient primary care networks. MEASUREMENTS: PCP productivity, patient satisfaction, resource utilization, and compliance with screening guidelines. RESULTS: Part-time PCP productivity was greater than that of full-time PCPs (2.1 work relative value units (RVUs)/bookable clinical hour versus 1.3 work RVUs/bookable clinical hour, P< .01). A similar proportion of part-time PCPs (80%) and full-time PCPs (75%) met targets for mammography, Pap smears, and cholesterol screening (P = .67). After adjusting for clinical case mix, practice location, gender, board certification status, and years in practice, resource utilization of part-time PCPs (138 dollars [95% confidence interval (CI), 108 dollars to 167 dollars]) was similar to that of full-time PCPs (139 dollars [95% CI, 108 dollars to 170 dollars], P = .92). Patient satisfaction was similar for part-time and full-time PCPs. CONCLUSIONS: In these academic primary care practices, rates of patient satisfaction, compliance with screening guidelines, and resource utilization were similar for part-time PCPs compared to full-time PCPs. Productivity per clinical hour was markedly higher for part-time PCPs. Despite study limitations, these data suggest that academic part-time PCPs are at least as efficient as full-time PCPs and that the quality of their work is similar.


Subject(s)
Efficiency/classification , Internal Medicine , Patient Satisfaction/statistics & numerical data , Physicians, Family/statistics & numerical data , Quality of Health Care/statistics & numerical data , Academic Medical Centers , Adult , Benchmarking , Boston , Female , Guideline Adherence , Health Resources/statistics & numerical data , Humans , Internal Medicine/statistics & numerical data , Male , Middle Aged , Personnel Staffing and Scheduling , Preventive Health Services/standards , Primary Health Care/statistics & numerical data , Retrospective Studies , Workforce
9.
J Rheumatol ; 28(9): 2090-5, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11550979

ABSTRACT

OBJECTIVE: To examine factors associated with musculoskeletal referral and determine whether referral influences clinical outcomes. METHODS: Patients included in the study presented with knee or shoulder pain to primary care physicians affiliated with an academic teaching hospital. The primary clinical outcome was change in pain or function measured up to 12 months after initial presentation. Covariates included baseline pain and function, duration of complaint, initial diagnosis, insurance status, and several demographic factors. RESULTS: Forty-one percent (65 of 160 patients) were referred for knee or shoulder conditions, 47 (29%) patients were referred only to an orthopedic surgeon, and 12 (8%) only to a rheumatologist; 6 (4%) patients saw both specialists. For patients with knee pain, the only variable correlated with referral was an initial diagnosis of internal derangement (p = 0.02). No variable was significantly associated with referral for shoulder pain. Baseline pain, baseline function, duration of complaint, age, and insurance status were not associated with referral for either knee or shoulder pain (all p values > 0.05). The variables most associated with improvement in pain and function were more severe pain and function at baseline (all p values < 0.0001). In multivariate analyses controlling for clinical and demographic factors among patients with shoulder complaints, referral was associated with significantly less improvement in clinical outcomes than non-referral (p = 0.02). Referral was not associated with clinical outcomes for patients with knee pain. CONCLUSIONS: Referral was common for patients with knee or shoulder conditions. The only baseline variable correlated with referral was a diagnosis of knee internal derangement. Referral was not associated with improvement in pain or function and may actually be correlated with worse outcomes among patients with shoulder pain, although this is likely due to unmeasured factors contributing to the referral decision.


Subject(s)
Joint Diseases/diagnosis , Joint Diseases/therapy , Referral and Consultation/statistics & numerical data , Adult , Cohort Studies , Female , Humans , Incidence , Knee Joint/physiopathology , Male , Middle Aged , Musculoskeletal Diseases/diagnosis , Musculoskeletal Diseases/therapy , Predictive Value of Tests , Probability , Recovery of Function , Risk Factors , Shoulder Joint/physiopathology , Shoulder Pain/diagnosis , Shoulder Pain/therapy , Treatment Outcome
10.
Med Care ; 39(7): 705-15, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11458135

ABSTRACT

OBJECTIVES: To examine the resource utilization of patients with high levels of somatization and health-related anxiety. DESIGN: Consecutive patients on randomly chosen days completed a self-report questionnaire assessing somatization and health-related, hypochondriacal anxiety. Their medical care utilization in the year preceding and following completion of the questionnaire was obtained from an automated patient record. The utilization of patients above and below a predetermined threshold on the questionnaire was then compared. PATIENTS AND SETTING: Eight hundred seventy-six patients attending a primary care clinic in a large, urban, teaching hospital. OUTCOME MEASURES: Number of ambulatory physician visits (primary care and specialist), outpatient costs (total, physician services, and laboratory procedures), proportion of patients hospitalized, and proportion of patients receiving emergency care. RESULTS: Patients in the uppermost 14% of the clinic population on somatization and hypochondriacal health anxiety had appreciably and significantly higher utilization in the year preceding and the year following completion of the somatization questionnaire than did the rest of the patients in the clinic. After adjusting for group differences in sociodemographic characteristics and medical comorbidity, significant differences in utilization remained. In the year preceding the assessment of somatization, their adjusted total outpatient costs were $1,312 (95% CI $1154, $1481) versus $954 (95% CI $868, $1057) for the remainder of the patients and the total number of physician visits was 9.21 (95% CI 7.94, 10.40) versus 6.33 (95% CI 5.87, 6.90). In the year following the assessment of somatization, those above the threshold had adjusted total outpatient costs of $1,395 (95% CI $1243, $1586) versus $1,145 (95% CI $1038, $1282), 9.8 total physician visits (95% CI 8.66, 11.07) versus 7.2 (95% CI 6.62, 7.77), and had a 24% (95% CI 19%, 30%) versus 17% (95% CI 14%, 20%) chance of being hospitalized. CONCLUSIONS: Primary care patients who somatize and have high levels of health-related anxiety have considerably higher medical care utilization than nonsomatizers in the year before and after being assessed. This differential persists after adjusting for differences in sociodemographic characteristics and medical morbidity.


Subject(s)
Health Care Costs , Health Resources/statistics & numerical data , Health Services Misuse , Hypochondriasis/therapy , Somatoform Disorders/therapy , Adult , Aged , Boston , Case-Control Studies , Female , Health Services Misuse/economics , Humans , Hypochondriasis/diagnosis , Hypochondriasis/economics , Male , Middle Aged , Multivariate Analysis , Prospective Studies , Regression Analysis , Retrospective Studies , Risk Factors , Somatoform Disorders/diagnosis , Somatoform Disorders/economics
12.
Am J Med ; 108(1): 28-35, 2000 Jan.
Article in English | MEDLINE | ID: mdl-11059438

ABSTRACT

PURPOSE: Previous studies have suggested that specialists may achieve better clinical outcomes for patients, albeit often at greater cost. We sought to compare outcomes of care and resource utilization among patients with shoulder or knee problems who were treated by general internists, rheumatologists, and orthopedic surgeons. SUBJECTS AND METHODS: Outpatients with knee or shoulder complaints who were seen by general internists, rheumatologists, or orthopedic surgeons at an academic medical center were administered questionnaires at enrollment in the study and again 3 months later. The questionnaires included validated measures of satisfaction, functional status, and pain severity, as well as resource utilization. We compared baseline clinical characteristics, satisfaction with care, resource utilization, and changes in function and symptoms during 3 months of follow-up among patients who were cared for by the three different types of providers. RESULTS: A total of 534 patients responded to the baseline survey and 436 (82%) to the 3-month follow-up survey. About 60% (n = 323) had knee pain. Orthopedists cared for 40% (n = 211) of the patients, with the remainder treated in approximately equal numbers by general internists or rheumatologists. At baseline, patients of internists had less severe pain (differences of 0.3 to 0.6 points on a 1 to 5 scale, P <0.05) and functional limitations (differences of 0.4 to 0.6 points on a 1 to 5 scale, P <0.0006) than patients of rheumatologists and orthopedic surgeons. Adjusting for baseline differences, there were no significant differences among provider groups in pain relief or functional improvement during follow-up. However, in adjusted analyses, patients with shoulder pain who were cared for by orthopedic surgeons were least satisfied with the office environment [adjusted mean (+/- SD) satisfaction score of 1.6 +/- 0.8 on a 1 to 4 scale for orthopedic surgeons vs 1.3 +/- 0.8 for rheumatologists and 1.4 +/- 0.8 for internists, P = 0.004]. Among patients with knee pain, those treated by rheumatologists and orthopedic surgeons were more satisfied with the doctor-patient interaction (adjusted mean satisfaction scores of 1.1 +/- 0.9 for rheumatologists and 1.2 +/- 0.7 for orthopedic surgeons on a 1 to 4 scale vs 1.4 +/- 0.8 for general internists, P = 0.003). Orthopedic surgeons obtained significantly more radiographs of the knee or shoulder and more magnetic resonance imaging scans of the knee. Rheumatologists performed significantly more aspirations or injection procedures. Among all patients, those treated by rheumatologists were most satisfied with the physician interaction, and those treated by orthopedic surgeons were most satisfied with treatment results. CONCLUSION: The relative benefits of specialist compared with generalist care for patients with knee or shoulder pain depend on the importance attached to resource utilization, patient satisfaction, and health outcomes.


Subject(s)
Health Resources/statistics & numerical data , Internal Medicine/statistics & numerical data , Joint Diseases/therapy , Knee Joint , Orthopedics/statistics & numerical data , Practice Patterns, Physicians'/statistics & numerical data , Rheumatology/statistics & numerical data , Shoulder Joint , Academic Medical Centers , Adult , Aged , Boston , Female , Humans , Joint Diseases/surgery , Male , Middle Aged , Outcome and Process Assessment, Health Care , Pain Measurement , Patient Satisfaction , Severity of Illness Index , Surveys and Questionnaires , Treatment Outcome
13.
J Chromatogr A ; 891(1): 201-6, 2000 Sep 01.
Article in English | MEDLINE | ID: mdl-10999640

ABSTRACT

A simple and general method suitable for the determination of cyclodextrin content in various matrices is described. The proposed method involves selective cleavage of C-C bonds with vicinal hydroxyl groups by means of periodate (Malaprade's reaction). The amount of produced iodate is monitored by capillary electrophoresis. Optimized electrophoretic conditions (20 mM disodium tetraborate with 1 mM tetradecyltrimethylammonium bromide, direct UV detection lambda = 200 nm) ensure complete separation of periodate and iodate ions and sufficient sensitivity towards iodate. Under optimized reaction conditions (2-fold excess of periodate, temperature 70 degrees C) reproducible quantitative results were obtained for alpha-, beta- and gamma-cyclodextrins as model samples. The proposed method was tested on a real sample of acrylamide--2'-O-allyl-beta-CD copolymer. The values of beta-cyclodextrin content were compared with those obtained by reference NMR measurement and were found to be identical.


Subject(s)
Cyclodextrins/analysis , Electrophoresis, Capillary/methods , Periodic Acid/chemistry , Magnetic Resonance Spectroscopy , Oxidation-Reduction , Reproducibility of Results , Spectrophotometry, Ultraviolet
14.
Med Care ; 38(4): 383-91, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10752970

ABSTRACT

BACKGROUND: The medical record serves as an important source of information regarding the care process, but few studies have examined whether thoroughness of documentation is associated with outcomes. OBJECTIVE: The objectives of this study were to analyze the initial visit note for 513 patients presenting with acute musculoskeletal pain, compare thoroughness of documentation by physician specialty, and determine whether thoroughness of documentation was associated with clinical improvement or patient satisfaction. METHODS: A structured medical record abstraction was performed to examine whether treating physicians documented key historical and physical exam findings. Satisfaction with care, symptom relief, and functional improvement were assessed after 3 months with validated survey instruments. RESULTS: In the initial visit note, 43+/-16% of selected historical findings and 28+/-17% of physical examination findings were documented. Orthopedic surgeons documented 2 to 4 more historical and physical examination items (P <0.01) and assigned more specific diagnoses (P <0.01) than rheumatologists and general internists. Multivariate models showed a very weak association between all aspects of documentation and patient satisfaction with the provider-patient interaction (all partial R2 <0.016) and no association between documentation and 3-month pain relief or functional status. Patients' perception of physician communication was more highly associated with patient satisfaction (P = 0.0001) than was documentation. CONCLUSIONS: No provider types consistently documented many important historical items and physical examination findings. While thoroughness of documentation was not associated with clinical outcomes, there was a very weak relationship between documentation and patient satisfaction with provider-patient interactions.


Subject(s)
Medical History Taking , Physical Examination , Quality Assurance, Health Care , Acute Disease , Documentation , Female , Humans , Knee Injuries/diagnosis , Male , Medical Records, Problem-Oriented , Medicine , Middle Aged , Osteoarthritis, Knee/diagnosis , Pain/etiology , Patient Satisfaction , Shoulder Pain/etiology , Specialization
15.
Arthritis Care Res ; 12(2): 96-100, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10513497

ABSTRACT

OBJECTIVE: To test the hypothesis that 3 distinct domains of patient satisfaction with musculoskeletal care--satisfaction with the office environment, provider-patient interaction, and treatment outcomes--can be measured reliably and, when considered separately, are more valid indicators of satisfaction than global measures. METHODS: Three hundred ninety-nine outpatients who presented with knee or shoulder pain were enrolled in a prospective cohort study. We measured patient satisfaction with musculoskeletal care by adapting a widely used generic satisfaction survey. RESULTS: Each domain of the scale was internally consistent, with Cronbach's alphas for satisfaction with the office environment, provider-patient interaction, and treatment outcome subscales of 0.68, 0.95, and 0.93, respectively. Validity correlations demonstrated the greater specificity of the subscales than global measures for particular aspects of musculoskeletal care. CONCLUSIONS: The musculoskeletal-specific satisfaction scale has excellent reliability and good discriminant validity. From a policy perspective, the distinct subscale structure is critical because problems within each domain may have different remedies.


Subject(s)
Knee Joint , Musculoskeletal Diseases/psychology , Musculoskeletal Diseases/therapy , Pain Management , Pain/psychology , Patient Satisfaction , Shoulder Pain/psychology , Shoulder Pain/therapy , Surveys and Questionnaires/standards , Discriminant Analysis , Female , Humans , Male , Middle Aged , Office Visits , Physician-Patient Relations , Prospective Studies , Reproducibility of Results , Treatment Outcome
16.
Biochemistry ; 37(38): 13194-202, 1998 Sep 22.
Article in English | MEDLINE | ID: mdl-9748326

ABSTRACT

The role of the beta-93 cysteine residue in the hemoglobin autoxidation process has been delineated by electron paramagnetic resonance. At low temperatures (8 K) after incubation at 235 K, free radical signals were detected. An analysis of the free radical spectrum produced implies that, besides the superoxide radical expected to be formed during autoxidation, an isotropic free radical is produced with a giso of 2.0133. This g value is consistent with that expected for a sulfur radical. Blocking the beta-93 sulfhydryl group with N-ethylmaleimide was found to eliminate the formation of the isotropic radical, but not the superoxide. This finding confirms the assignment of the isotropic radical as a thiyl radical originating from the oxidation of the cysteine SH group. A kinetic analysis of the time course for the formation of both the superoxide and thiyl radicals is consistent with a reversible electron transfer process between superoxide in the heme pocket of the beta-chains and the cysteine residue. This reaction is expected to produce both a thiyl radical and a peroxide. Direct evidence for peroxide production comes from the detection of a transient Fe(III) heme peroxide complex. The significance of the electron transfer process producing a thiyl radical is discussed. It is shown that the formation of the thiyl radical decreases the rate of autoxidation for the beta-chain and reduces heme degradation attributed to the reaction of superoxide with the heme. The insights gained from these low-temperature studies are believed to be relevant to room-temperature autoxidation.


Subject(s)
Cysteine/blood , Heme/metabolism , Hemoglobins/metabolism , Sulfhydryl Compounds/blood , Superoxides/blood , Cysteine/chemistry , Electron Spin Resonance Spectroscopy , Ethylmaleimide/pharmacology , Free Radicals/blood , Hemoglobins/chemistry , Humans , Kinetics , Macromolecular Substances , Models, Chemical , Peroxides/blood , Spectrometry, Fluorescence
17.
J Pharm Sci ; 85(1): 96-100, 1996 Jan.
Article in English | MEDLINE | ID: mdl-8926593

ABSTRACT

The solubility of the lipophilic carcinogens benzo[a]pyrene and aflatoxin B1 in water increases linearly and substantially with the concentration of hydroxypropyl beta-cyclodextrin present. Results of a kinetic study of naphthalene, a model for more potent carcinogens, indicate that the increase in the dissolution rate and in the transport through the aqueous phase into a nonpolar phase is on the same order of magnitude as the increase in solubility. Consequently, hydroxypropyl beta-cyclodextrin, when used in pharmaceutical formulations, has the potential to increase the absorption of carcinogens which enter the gastrointestinal tract either as food components or from air pollution through saliva. Only the above mechanism's simple proportionality needs be considered for estimating the increases in carcinogen absorption in the upper gastrointestinal tract and in the colon. In the presence of bile, however, additional factors are involved and the proportionality does not apply. Bile micelles, which themselves are effective solubilizers of lipophilic carcinogens, were disrupted by hydroxypropyl beta-cyclodextrin because of the formation of complexes with bile salts. Thus, in the presence of bile, two systems for delivery of carcinogens may coexist: that of cotransport with lipids and that of delivery through solubilization by hydroxypropyl beta-cyclodextrin.


Subject(s)
Carcinogens/chemistry , Cyclodextrins/chemistry , beta-Cyclodextrins , 2-Hydroxypropyl-beta-cyclodextrin , Aflatoxin B1/chemistry , Aflatoxin B1/pharmacokinetics , Benzo(a)pyrene/chemistry , Benzo(a)pyrene/pharmacokinetics , Bile/chemistry , Bile/metabolism , Chemical Phenomena , Chemistry, Physical , Cyclodextrins/pharmacology , Drug Synergism , Kinetics , Lipid Metabolism , Lipids/chemistry , Mathematical Computing , Naphthalenes/chemistry , Naphthalenes/pharmacokinetics , Solubility , Water/chemistry
18.
Demografie ; 38(3): 165-72, 1996.
Article in Czech | MEDLINE | ID: mdl-12292134

ABSTRACT

PIP: The author discusses family formation and characteristics in Bohemia from the sixteenth to the eighteenth century. Aspects considered include living arrangements, family status by age, marriage age, and ethnicity. (SUMMARY IN ENG)^ieng


Subject(s)
Age Factors , Demography , Ethnicity , Family Characteristics , Marriage , Residence Characteristics , Culture , Czechoslovakia , Developed Countries , Europe , Europe, Eastern , Geography , Population , Population Characteristics , Social Sciences
19.
Article in Czech | MEDLINE | ID: mdl-1842302

ABSTRACT

The location and properties of brain exopeptidase activities are determined with the method of so-called natural substrates. The activities of enzymes cleaving dipeptides (leu-leu, tyr-tyr, tyr-phe, met-ala, met-arg and gly-pro) are compared with both the activities and character of enzymes cleaving chromogenic leu-4M2NA substrate. The present work demonstrates a broad spectrum of exopeptidase activities localized in glia, neurons, neuropile and cerebral vessels. The cleavage of tyr-tyr and tyr-phe substrates is preferred with exopeptidases localized in neurons and their fibrillar protrusions. The leu-leu and leu-4M2NA substrates are cleaved in some definite portions of capillaries and thicker vessels. In the present work the question is discussed of substrate specificities of determined enzymatic activities in relation with detection specificity of M aminopeptidase.


Subject(s)
Brain/enzymology , Histological Techniques , Peptide Hydrolases/analysis , Animals , Exopeptidases , Histocytochemistry , Male , Rats
20.
Folia Morphol (Praha) ; 38(1): 24-7, 1990.
Article in English | MEDLINE | ID: mdl-2341077

ABSTRACT

The authors describe the localization of monoaminooxidases oxidizing the protoxin MPTP to the active neurotoxic MPP+ ion, which induces parkinsonism by destroying the dopaminergic neurons of the nigrostriatum. Apart from some types of magnocellular neurons of the hypothalamus, enzymatic activity is localized in the endothelium of segments of the circumventricular vascular bed communicating with the enzymatically equally positive processes of the tanycytes of the third brain ventricle. The findings are briefly discussed from the aspect of the pathogenesis of experimental parkinsonism.


Subject(s)
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/metabolism , Cerebral Ventricles/enzymology , Endothelium, Vascular/enzymology , Parkinson Disease, Secondary/chemically induced , Animals , Biotransformation , Cerebral Ventricles/blood supply , Cerebral Ventricles/cytology , Female , Male , Rats
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