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1.
Rural Remote Health ; 8(2): 937, 2008.
Article in English | MEDLINE | ID: mdl-18489239

ABSTRACT

In recent times remote medical practice has been developed into a unique discipline in its own right with telehealth one of the eight defining key features. Since 1942, the telemedicine consultation service provided by the Royal Flying Doctor Service in Australia has been supported by a tele-pharmacy program known as the Medical Chest Program. The contents of the chest comprise more than 85 items, including medications and equipment which can be prescribed during a telehealth consultation to cover both emergency care and definitive treatment for less serious conditions. By 2006 there were 3500 medical chests placed throughout Australia. Specifically, the state of Queensland had 21 470 telehealth consultations from 1 July 2005 to 30 June 2006, resulting in the prescription of at least one medical chest item in 2938 (13.7%) consultations. Queensland data regarding medication indicate that antibiotics (26%), analgesics (23%) and gastrointestinal medications (12%) were the most common categories of dispensed medications, and that the most common clinical diagnostic categories for the consultation resulting in dispensed medications were respiratory (17%), skin (15%) and abdominal conditions (13%). In summary, the RFDS medical chest program continues to be a successful large scale provider of medications to those living in remote Australia, enabling early access to medications for both emergencies and definitive care, while minimising the need for mail-order pharmacy or patient travel. This model of care may provide an important template for those designing service delivery models in other remote jurisdictions.


Subject(s)
Clinical Pharmacy Information Systems/supply & distribution , Community Pharmacy Services/supply & distribution , Drug Prescriptions , Health Services, Indigenous/supply & distribution , Rural Health Services/supply & distribution , Telemedicine/organization & administration , Clinical Pharmacy Information Systems/organization & administration , Community Pharmacy Services/organization & administration , Health Services Accessibility , Health Services Research , Health Services, Indigenous/organization & administration , Humans , Organizational Innovation , Program Evaluation , Queensland , Rural Health Services/organization & administration , Telemedicine/statistics & numerical data
2.
Rural Remote Health ; 6(2): 527, 2006.
Article in English | MEDLINE | ID: mdl-16764503

ABSTRACT

Medical education has undergone significant changes globally. Calls for the revitalisation of centuries old pathways of learning have resulted in innovative medical curricula. Didactic modes of teaching which involved the learning of copious amounts of facts have given way to curricula that focus on the horizontal and vertical integration of basic and clinical sciences. Increasing concern for patient care and safety has led to a 'gap' between the needs of medical students to acquire necessary psychomotor skills and the safety and wellbeing of the patient. This has resulted in alternate teaching methods that include non-patient based training for the acquisition of clinical skills. The use of computerised, full-sized human simulators provides medical students with the necessary psychomotor and clinical reasoning skills in a realistic learning environment, while remaining risk free to patients. These clinical simulators are powerful learning tools that have applications at all levels of medical education across multiple disciplines, emphasising the multidisciplinary approach required in many medical situations. This article reviews the literature on medical simulation and provides the contextual basis for the establishment of a Clinical Simulation Learning Centre (CSLC) in a rural clinical school in Australia. The educational program, as well as the design, layout and equipment of the CSLC are described, as well as implications for rural practitioners. The CSLC has been a major capital investment in a relatively under-resourced part of regional Australia and has provided opportunities for ongoing education across a range of healthcare professionals in the community.


Subject(s)
Computer Simulation , Curriculum , Education, Medical, Continuing/methods , Education, Medical, Undergraduate/methods , Models, Biological , Rural Health , Australia , Clinical Competence , Education, Medical, Continuing/trends , Education, Medical, Undergraduate/trends , Humans
3.
Med Teach ; 28(1): 3-18, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16627313

ABSTRACT

REVIEW DATE: Review period January 1992-December 2001. Final analysis July 2004-January 2005. BACKGROUND AND REVIEW CONTEXT: There has been no rigorous systematic review of the outcomes of early exposure to clinical and community settings in medical education. OBJECTIVES OF REVIEW: Identify published empirical evidence of the effects of early experience in medical education, analyse it, and synthesize conclusions from it. Identify the strengths and limitations of the research effort to date, and identify objectives for future research. SEARCH STRATEGY: Ovid search of: BEI, ERIC, Medline, CINAHL and EMBASE Additional electronic searches of: Psychinfo, Timelit, EBM reviews, SIGLE, and the Cochrane databases. Hand-searches of:Medical Education, Medical Teacher, Academic Medicine, Teaching and Learning in Medicine, Advances in Health Sciences Education, Journal of Educational Psychology. EXPERIENCE: Authentic (real as opposed to simulated) human contact in a social or clinical context that enhances learning of health, illness and/or disease, and the role of the health professional. Early: What would traditionally have been regarded as the preclinical phase, usually the first 2 years. Inclusions: All empirical studies (verifiable, observational data) of early experience in the basic education of health professionals, whatever their design or methodology, including papers not in English. Evidence from other health care professions that could be applied to medicine was included. EXCLUSIONS: Not empirical; not early; post-basic; simulated rather than 'authentic' experience. DATA COLLECTION: Careful validation of selection processes. Coding by two reviewers onto an extensively modified version of the standard BEME coding sheet. Accumulation into an Access database. Secondary coding and synthesis of an interpretation. HEADLINE RESULTS: A total of 73 studies met the selection criteria and yielded 277 educational outcomes; 116 of those outcomes (from 38 studies) were rated strong and important enough to include in a narrative synthesis of results; 76% of those outcomes were from descriptive studies and 24% from comparative studies. Early experience motivated and satisfied students of the health professions and helped them acclimatize to clinical environments, develop professionally, interact with patients with more confidence and less stress, develop self-reflection and appraisal skill, and develop a professional identity. It strengthened their learning and made it more real and relevant to clinical practice. It helped students learn about the structure and function of the healthcare system, and about preventive care and the role of health professionals. It supported the learning of both biomedical and behavioural/social sciences and helped students acquire communication and basic clinical skills. There were outcomes for beneficiaries other than students, including teachers, patients, populations, organizations and specialties. Early experience increased recruitment to primary care/rural medical practice, though mainly in US studies which introduced it for that specific purpose as part of a complex intervention. CONCLUSIONS: Early experience helps medical students socialize to their chosen profession. It helps them acquire a range of subject matter and makes their learning more real and relevant. It has potential benefits for other stakeholders, notably teachers and patients. It can influence career choices.


Subject(s)
Clinical Clerkship/methods , Clinical Clerkship/organization & administration , Curriculum/trends , Family Practice/education , Health Knowledge, Attitudes, Practice , Health Services Research/trends , Socialization , Attitude of Health Personnel , Clinical Competence , Empathy , Forecasting , Physician-Patient Relations , Primary Health Care , United Kingdom
4.
East Mediterr Health J ; 8(2-3): 409-15, 2002.
Article in English | MEDLINE | ID: mdl-15339131

ABSTRACT

Changes in use by the elderly of the emergency department of a major hospital in Al-Ain in the years 1989 and 1999 were examined. All patients aged 65 years or older who attended the emergency room were included in this cross-sectional survey. Patient numbers rose from 321 in 1989 to 1347 in 1999 with no significant change in the female to male ratio of 0.78 or the mean age of the elderly attendees 72.9 +/- 7.4 years. Attendance rose 5.4 fold while non-urgent attendance rose 14.7 fold, demonstrating rising use but falling illness severity over time.


Subject(s)
Aged/statistics & numerical data , Emergency Service, Hospital/statistics & numerical data , Health Transition , Patient Acceptance of Health Care/statistics & numerical data , Age Distribution , Aged/psychology , Analysis of Variance , Cross-Sectional Studies , Delivery of Health Care/organization & administration , Developing Countries , Emergency Service, Hospital/trends , Emergency Treatment/methods , Emergency Treatment/trends , Female , Health Care Surveys , Health Knowledge, Attitudes, Practice , Humans , Length of Stay/trends , Life Expectancy , Male , Morbidity , Organizational Innovation , Patient Acceptance of Health Care/psychology , Seasons , Severity of Illness Index , Time Factors , Triage , United Arab Emirates/epidemiology
5.
East Mediterr Health J ; 8(4-5): 566-73, 2002.
Article in English | MEDLINE | ID: mdl-15603039

ABSTRACT

We evaluated a diabetic mini-clinic by assessing adherence to American Diabetes Association guidelines and changes in glycosylated haemoglobin levels. Of 1063 patients, 721 were multiple attenders. Single and multiple attenders showed no significant differences in age, sex, time since diagnosis or body mass index. Female and male multiple attenders showed significant declines in glycosylated haemoglobin levels over the first 12 and 18 months respectively. After 2 years, these levels were similar to those at entry to the clinic. The clinic's compliance with standard measurement guidelines was high. The diabetic mini-clinic model, which is effective in industrialized countries, was equally effective in this setting.


Subject(s)
Ambulatory Care Facilities/standards , Diabetes Mellitus/therapy , Family Practice/standards , Guideline Adherence/standards , Practice Guidelines as Topic , Primary Health Care/standards , Total Quality Management/organization & administration , Analysis of Variance , Body Mass Index , Chi-Square Distribution , Developed Countries , Developing Countries , Diabetes Mellitus/epidemiology , Diabetes Mellitus/metabolism , Female , Glycated Hemoglobin/metabolism , Health Services Research , Humans , Life Style , Male , Medical Audit , Middle Aged , Models, Organizational , Outcome Assessment, Health Care/organization & administration , Social Change , United Arab Emirates/epidemiology , Urban Health Services/standards
6.
(East. Mediterr. health j).
in English | WHO IRIS | ID: who-119201

ABSTRACT

We evaluated a diabetic mini-clinic by assessing adherence to American Diabetes Association guidelines and changes in glycosylated haemoglobin levels. Of 1063 patients, 721 were multiple attenders. Single and multiple attenders showed no significant differences in age, sex, time since diagnosis or body mass index. Female and male multiple attenders showed significant declines in glycosylated haemoglobin levels over the first 12 and 18 months respectively. After 2 years, these levels were similar to those at entry to the clinic. The clinic's compliance with standard measurement guidelines was high. The diabetic mini-clinic model, which is effective in industrialized countries, was equally effective in this setting


Subject(s)
Ambulatory Care Facilities , Body Mass Index , Chi-Square Distribution , Family Practice , Health Services Research , Glycated Hemoglobin , Life Style , Practice Guidelines as Topic , Primary Health Care , Total Quality Management , Diabetes Mellitus
7.
(East. Mediterr. health j).
in English | WHO IRIS | ID: who-119180

ABSTRACT

Changes in use by the elderly of the emergency department of a major hospital in Al-Ain in the years 1989 and 1999 were examined. All patients aged 65 years or older who attended the emergency room were included in this cross-sectional survey. Patient numbers rose from 321 in 1989 to 1347 in 1999 with no significant change in the female to male ratio of 0.78 or the mean age of the elderly attendees 72.9 +/- 7.4 years. Attendance rose 5.4 fold while non-urgent attendance rose 14.7 fold, demonstrating rising use but falling illness severity over time


Subject(s)
Age Distribution , Aged , Analysis of Variance , Delivery of Health Care , Emergency Treatment , Health Knowledge, Attitudes, Practice , Health Transition , Length of Stay , Morbidity , Patient Acceptance of Health Care , Severity of Illness Index , Emergency Service, Hospital
8.
Anal Chem ; 73(20): 4787-92, 2001 Oct 15.
Article in English | MEDLINE | ID: mdl-11681452

ABSTRACT

Water in oil has been measured by tubular oven evaporation and by azeotropic distillation into a coulometric moisture analyzer. The results of these measurements were compared to the results obtained by volumetric titration of water in oil. The volumetric measurements were consistently higher than the measurements made by tubular oven evaporation or azeotropic distillation. A mass balance study was performed by volumetric Karl Fischer titration of the water in the oil that remained in the tubular oven and in the distillation apparatus. This study indicated that measurable amounts of water were not removed after exhaustive evaporation or distillation. The sum of the water removed by distillation from toluene and that remaining in the distillation chamber was equal to the amount of water measured in the oil by the volumetric method. The data are consistent with the existence of an oil-water azeotrope that does not release water upon evaporation at 160 degrees C or upon dissolution in toluene and distillation of the water-toluene azeotrope. These results were obtained for oils varying in viscosity from 8 to 850 m2/s, and the amount of water remaining associated with the oil appears to be dependent upon the composition of the oil and the method of analysis.

10.
Gerontology ; 47(3): 161-7, 2001.
Article in English | MEDLINE | ID: mdl-11340323

ABSTRACT

BACKGROUND: Little is known about the rate of institutionalization and health status of nursing home (NH) type patients living in the Middle East. This study was set in the Al-Ain Medical District, a geographically discrete region of the United Arab Emirates, a country with a developing economy located on the shores of the Arabian Gulf. NH-type patients were defined as people aged 60 years and older who were admitted to a hospital or a long-term institutionalized setting for at least 6 weeks and with no evidence of an expectation of discharge at the time of the evaluation. OBJECTIVE: To determine the clinical, functional, cognitive, and nutritional status of NH-type patients living in a defined community within a developing country. METHOD: Cross-sectional survey. RESULTS: All NH-type patients were identified, and all were included in this study (n = 47, 100% participation rate). All were located within three public institutions, none of which was a dedicated NH facility. The rate of institutionalization was 7.0-14.0 per 1,000 people aged 65 or older. The age distribution was 30% (60-74 years), 49% (75-84 years), and 21% (85+ years). The length of stay was 3.8 years. The female:male ratio was 1.6. All except 1 had a neurological disorder, and 89% had dementia. The cognitive deficits were severe with only 61% alert, 41% able to speak, 17% orientated in place, and 15% orientated in time. The functional status was also poor: 98% received assistance with all instrumental activities of daily living, 85% received assistance with five activities of daily living, and 94% were bed bound. The nutritional status was also impaired with a mean body weight of 45 +/- 14 kg and a mean albumin level of 3.1 +/- 0.6 g/dl. When compared with the USA data from the National Center for Health Statistics, the study population was younger, had a longer length of stay, a lower female:male ratio, a higher rate of neurological diseases and dementia, and were far more dependent and disoriented. The rate of institutionalization was one sixth to one third of that in the USA. CONCLUSION: From these data we concluded that this region has a distinctly different population of institutionalized older people who demonstrate greater impairments in all domains of health status.


Subject(s)
Geriatric Assessment/statistics & numerical data , Health Status , Health Surveys , Homes for the Aged/statistics & numerical data , Nursing Homes/statistics & numerical data , Activities of Daily Living , Age Distribution , Aged , Aged, 80 and over , Chi-Square Distribution , Cross-Sectional Studies , Developing Countries , Female , Humans , Institutionalization/statistics & numerical data , Male , Probability , Sex Distribution , United Arab Emirates/epidemiology
11.
J Chromatogr B Biomed Sci Appl ; 765(2): 141-50, 2001 Dec 25.
Article in English | MEDLINE | ID: mdl-11767307

ABSTRACT

Liquid chromatography (LC) in direct combination with mass spectrometry (MS) has been shown to be a good analytical technique for the selective separation and detection of labile folate monoglutamates. Reversed-phase LC and electrospray-ionization MS conditions were developed and optimized for the separation and detection of 5-methyltetrahydrofolic acid, 5-formyl tetrahydrofolic acid, tetrahydrofolic acid, dihydrofolic acid and folic acid in aqueous samples. Representative and reproducible positive ion mass spectra were generated for each folate under mild MS conditions. The selective MS detection and identification of endogenous 5-methyltetrahydrofolic acid in human plasma was accomplished through the development of a straightforward C18-based solid-phase extraction procedure. This procedure allows for the qualitative assessment of 5-methyltetrahydrofolic acid in plasma. Based upon an isotope-dilution internal standard calibration study with standards, the LC-MS limit of quantitation for 5M-THF was estimated to be 0.39 ng/mnl.


Subject(s)
Chromatography, Liquid/methods , Spectrometry, Mass, Electrospray Ionization/methods , Tetrahydrofolates/blood , Humans
12.
J Chromatogr A ; 881(1-2): 403-10, 2000 Jun 09.
Article in English | MEDLINE | ID: mdl-10905723

ABSTRACT

This article reviews recent developments in the methodology for the measurement of anthocyanins that offer several advantages over classical methods of analysis. The use of UV-diode array and mass spectrometric (MS) detectors, with improved methods of liquid chromatography analysis has facilitated identification of these analytes. The use of capillary electrophoresis (CE) analysis of the anthocyanins under acid conditions has significantly increased peak resolution and improved the detection limits by several orders of magnitude. CE offers the advantage of economies of very small sample size, very small solvent consumption, and short analysis times along with the future possibility of being combined with MS detection.


Subject(s)
Anthocyanins/analysis , Chromatography, Liquid/methods , Electrophoresis, Capillary/methods , Food Analysis , Mass Spectrometry/methods , Spectrophotometry, Ultraviolet
13.
J Mass Spectrom ; 35(4): 540-9, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10797650

ABSTRACT

Reversed-phase liquid chromatography with atmospheric pressure chemical ionization mass spectrometry (LC/APCI-MS) in the positive-ion mode was utilized to analyze crude ether extracts from the root bark of Maclura pomifera, a tree known to have a high content of prenylated xanthones and flavanones. Identification of three xanthones and two flavanones was based on their unique mass spectra. Under optimum conditions peaks corresponding to the [MH](+) ion and characteristic fragments for each compound were observed. (1)H NMR data were used to confirm the identities of two xanthones that had the same molecular mass and similar fragmentation patterns. Fragmentation of the analytes was achieved by application of an electrostatic potential at the entrance of the single quadrupole mass spectrometer. The optimum voltage for fragmentation was found to be related to the class of compounds analyzed and, within each class, to be dependent on the structure of the prenyl moiety. Collision-induced pathways consistent with precedent literature describing the MS characterization of similar compounds and with the observed fragmentation patterns are tentatively proposed.


Subject(s)
Flavonoids/chemistry , Plant Extracts/chemistry , Trees/chemistry , Xanthenes/chemistry , Chromatography, Liquid , Magnetic Resonance Spectroscopy , Mass Spectrometry
14.
Fresenius J Anal Chem ; 367(1): 1-7, 2000 May.
Article in English | MEDLINE | ID: mdl-11227426

ABSTRACT

The calibration of Karl Fischer instruments and reagents and the compensation for instrumental bias are essential to the accurate measurement of trace levels of water in organic and inorganic chemicals. A stable, nonhygroscopic standard, Water Saturated Octanol, which is compatible with the Karl Fischer reagents, has been prepared. This material, Standard Reference Material (SRM) 2890, is homogeneous and is certified to contain 39.24 +/- 0.85 mg water/mL (expanded uncertainty) of solution (47.3 +/- 1.0 mg water/g solution, expanded uncertainty) at 21.5 degrees C. The solubility of water in -octanol has been shown to be nearly constant between 10 degrees C and 30 degrees C (i.e., within 1% of the value at 21.5 degrees C). The results of an interlaboratory comparison exercise illustrate the utility of SRM 2890 in assessing the accuracy and bias of Karl Fischer instruments and measurements.

15.
J AOAC Int ; 82(2): 276-87, 1999.
Article in English | MEDLINE | ID: mdl-10191534

ABSTRACT

The preparation of the recently released Standard Reference Material (SRM) 2383 Baby Food Composite and the process used for value assignment of nutrient concentrations are reported. SRM 2383 can be used as a control material when assigning values to in-house control materials and when validating analytical methods for measuring proximates, vitamins, and minerals in baby food and similar matrixes. The SRM was prepared as a commercial baby food would be prepared, with the same ingredients. The Certificate of Analysis for SRM 2383 provides assigned values for concentrations of proximates, vitamins, and minerals for which product labeling is required by the Nutrition Labeling and Education Act of 1990. These assigned values were based on measurements by the National Institute of Standards and Technology (NIST) and/or collaborating laboratories. Assignment of analyte concentrations based solely on analyses by collaborating laboratories is described in this paper. Certified values are provided for retinol, tocopherols, and several carotenoids including total beta-carotene; the certification of and methodology used for measurement of these analytes is discussed in a companion paper (this issue, page 288). Reference values are provided for solids, ash, fat, nitrogen, protein, carbohydrate, calories, vitamin B1, vitamin B2, vitamin B6, niacin, biotin, calcium, phosphorus, magnesium, manganese, iron, zinc, copper, sodium, potassium, and chloride. Reference values for additional carotenoids are reported in the companion paper (this issue, page 288). Information values are provided for iodine, selenium, molybdenum, vitamin D, vitamin B12, folic acid, pantothenic acid, choline, inositol, sugars, total dietary fiber, and 3 classes of fats.


Subject(s)
Infant Food/analysis , Laboratories/standards , Carbohydrates/analysis , Carotenoids/analysis , Energy Intake , Fats/analysis , Minerals/analysis , Nitrogen/analysis , Proteins/analysis , Reference Standards , Reference Values , Vitamin A/analysis , Vitamin E/analysis , Vitamins/analysis
16.
Anal Chem ; 71(9): 1728-32, 1999 May 01.
Article in English | MEDLINE | ID: mdl-21662813

ABSTRACT

The disparity between the volumetric and coulometric Karl Fischer methods for the measurement of water in hydrocarbons and hydrocarbon mixtures (oils) has been resolved. The amount of water detected by the volumetric method when the titration vessel solution is homogeneous is higher than that measured coulometrically or volumetrically when the titration vessel solution is heterogeneous. Water in oil that is not measured by the coulometric method when the oil is incompletely dissolved has been shown to reside in the oil phase of the heterogeneous (multiphasic) coulometric vessel suspension. Water that is not measured volumetrically under relatively low chloroform concentrations after the point of transition to a heterogeneous titration vessel solution is reached also appears to reside in the nonaqueous phase of the titration vessel solution. It appears that this water is retained in the hydrocarbon phase in a manner such that it is completely inaccessible to the volumetric or coulometric Karl Fischer reagents.

17.
Anal Chem ; 69(23): 4864-71, 1997 Dec 01.
Article in English | MEDLINE | ID: mdl-9406534

ABSTRACT

The sources of systematic bias in the measurement of moisture by the volumetric and coulometric Karl Fischer methods were assessed. Using water-saturated octanol as a moisture standard, the measurement accuracy of five coulometric instruments was evaluated. Six possible sources of systematic bias were examined: accuracy of the moisture standard, nonadjustable instrumental bias, operator-adjustable instrumental bias, solvent composition, cell design, and sample composition. The published water content of water-saturated octanol was confirmed by the method of standard additions. The nonadjustable instrumental bias consisted of two types, one that was variable and was observed at water levels below 200 micrograms of water, and one that represented a constant percentage of the total water over the tested range from 40 to 400 micrograms of water. The adjustable instrumental parameters, if set incorrectly, may cause a small but significant negative bias (< 7%). Solvent composition as a function of both solvent type and titration vessel design can introduce a negative bias of up to 10%. Finally, the nature of the sample introduces a negative bias as demonstrated by the results obtained from titrating water in four different oil samples. Under optimum conditions, different amounts of water were measured in each oil using different Karl Fischer titration procedures and five different instruments.


Subject(s)
Water/chemistry , Electrochemistry/methods , Models, Chemical , Oils/chemistry
18.
J AOAC Int ; 80(3): 611-21, 1997.
Article in English | MEDLINE | ID: mdl-9170657

ABSTRACT

In 1996, the National Institute of Standards and Technology (NIST) released Standard Reference Material 1846 (Infant Formula), which can be used as a control material for assigning values to in-house control materials and for validating analytical methods for measurement of proximates, vitamins, and minerals in infant formula and similar matrixes. The SRM was manufactured by preparing a spray-dried formula base containing fat, protein, carbohydrates, and minerals and then combining that formula base with a dry-blend vitamin premix that supplied the vitamins. The Certificate of Analysis for SRM 1846 provides assigned values for concentrations of proximates (fat, protein, etc.), vitamins, and minerals for which product labeling is required by the Infant Formula Act of 1980 and by the Nutrition Labeling and Education Act of 1990. These assigned values were based on agreement of measurements by NIST and/or collaborating laboratories. Certified values are provided for vitamins A (trans), E, C, B2, and B6 and niacin. Noncertified values are provided for solids, ash, fat, nitrogen, protein, carbohydrate, calories, vitamin D, delta-tocopherol, gamma-tocopherol, vitamin B1, vitamin B12, folic acid, pantothenic acid, biotin, choline, inositol, calcium, phosphorus, magnesium, iron, zinc, copper, sodium, potassium, and chloride. Information values are provided for iodine, manganese, selenium, and vitamin K.


Subject(s)
Infant Food/standards , Nutritional Requirements , Food Analysis , Humans , Infant , Iodine/analysis , Manganese/analysis , Reference Standards , Selenium/analysis , Vitamin K/analysis
19.
J Chromatogr B Biomed Sci Appl ; 690(1-2): 25-33, 1997 Mar 07.
Article in English | MEDLINE | ID: mdl-9106026

ABSTRACT

D- and L-Ascorbic acids have been separated using liquid chromatography (LC) on a polymer-coated silica-based NH2 column and the L-isomer has been quantified in human serum, rat serum, rat lung, rat lung perfusate, infant formula (SRM 1846) and mixed food sample (SRM 2383). The D-isomer was observed only in trace amounts in the mixed food sample. The results demonstrate that ascorbic acid was stable on the column and completely recovered from supplemented samples of human serum and that this method of analysis is accurate, precise and has broad application exhibiting no dependence on the nature of the matrices evaluated herein.


Subject(s)
Ascorbic Acid/analysis , Animals , Ascorbic Acid/blood , Chromatography, Liquid , Dehydroascorbic Acid/analysis , Dehydroascorbic Acid/blood , Food, Formulated/analysis , Humans , In Vitro Techniques , Infant , Infant Food/analysis , Lung/chemistry , Rats , Stereoisomerism
20.
Clin Chem ; 42(8 Pt 1): 1257-62, 1996 Aug.
Article in English | MEDLINE | ID: mdl-8697586

ABSTRACT

We demonstrate that total ascorbic acid (TAA, the sum of ascorbic acid and dehydroascorbic acid) in properly prepared human plasma is stable at -70 degrees C for at least 6 years when preserved with dithiothreitol. TAA in human plasma or serum preserved with metaphosphoric acid degrades slowly, at the rate of no more than 1% per year. As assessed from our stability data and from data obtained from 23 laboratories over a period of > 2 years, the intralaboratory repeatability of TAA measurement is approximately 2 mumol/L, irrespective of TAA concentration. Nonchromatographic analytical methods involving dinitrophenylhydrazine and 0-phenylenediamine yield biased results relative to chromatographic methods. Within groups of laboratories that use roughly similar analytical methods, the interlaboratory measurement reproducibility CV for TAA is 15%.


Subject(s)
Ascorbic Acid/blood , Laboratories/standards , Chromatography/methods , Chromatography/statistics & numerical data , Dehydroascorbic Acid/blood , Dithiothreitol , Drug Stability , Freezing , Humans , Kinetics , Phenylenediamines , Phenylhydrazines , Phosphorous Acids , Plasma , Reproducibility of Results , Specimen Handling , Stereoisomerism , Time Factors
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