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The purpose of this exploratory study was to determine whether or not statistically significant relationships existed between adult patients' health locus or control beliefs and their progress in rehabilitation at a midwestern facility. This study was based primarily on social learning theory. Three tools were administered to determine their perceived health status, health locus of control beliefs, and perception of the value of health. Progress in therapy was determined from data recorded by health professionals using the facility's functional classification system. Demographic data, including life stage and geographic affiliation were coded from official records. Data for 93 adult inpatients, obtained through convenience sample selection, were analyzed utilizing chi-square; this revealed that individuals who expressed believing in internal health locus of control made the greatest progress in rehabilitation (chi-square = 82.353, P = .001). Further study is needed to validate these findings. [ABSTRACT FROM AUTHOR]

Qualitative methodologies are relative newcomers to health sciences education research. While they may look very different to their quantitative counterparts in terms of size and scope, when well-applied they offer a fresh perspective and generate valuable research findings. Although qualitative research is being increasingly conducted in veterinary medical education, there are few contextualized resources to assist those who would like to develop their expertise in this area. In this article, we address this by introducing the principles of qualitative research design in a veterinary medical education context. Drawing from a range of contemporary resources, we explore the types of research goals and questions that are amenable to qualitative inquiry and discuss the process of formulating a worthwhile research question. We explain what research paradigms are and introduce readers to some of the methodological options available to them in qualitative research. Examples from veterinary medical education are used to illustrate key points. In a second companion article, we will focus on the decisions that need to be made regarding data sampling, collection, and analysis. We will also consider how qualitative research is evaluated, and discuss how qualitative findings are applied. Taken together, the two articles build an understanding of qualitative research, illuminate its potential to contribute to the scholarship of teaching and learning in veterinary medical education, and equip readers with an improved capacity to appraise its value.

This is the second of two articles that together comprise an orientation and introduction to qualitative research for veterinary medical educators who may be new to research, or for those whose research experience is based on the quantitative traditions of biomedicine. In the first article ( Part 1-Principles of Qualitative Design ), we explored the types of research interests and goals suited to qualitative inquiry and introduced the concepts of research paradigms and methodologies. In this second article, we move to the strategies and actions involved in conducting a qualitative study, including selection and sampling of research sites and participants, data collection and analysis. We introduce some guidelines for reporting qualitative research and explore the ways in which qualitative research is evaluated and the findings applied. Throughout, we provide illustrative examples from veterinary and human medical education and suggest useful resources for further reading. Taken together, the two articles build an understanding of qualitative research, outline how it may be conducted, and equip readers with an improved capacity to appraise its value.

Working farm dogs are essential to many livestock farmers. Little is known about factors that influence dogs' risk of being lost from work. This paper explores risk factors for farm dogs being lost through death, euthanasia and retirement. All enrolled dogs were working and a minimum of 18 months old. Five data collection rounds were performed over four years. Data about dogs were collected from owners and dogs were given physical examinations by veterinarians. Dogs that were lost from work were counted and owner-reported reasons for loss were recorded. Multivariable logistic regression modelling was used to investigate risk factors for loss. Of 589 dogs, 81 were lost from work. Of these, 59 dogs died or were euthanized and 22 were retired. Farm dogs tended to reach advanced ages, with 38% being 10 years or older when last examined. Acute injury or illness was the most commonly owner-reported reason for loss. Age group ( p < 0.0001) and lameness ( p = 0.04, OR = 1.8) significantly affected dogs' risk of being lost. These results expand our knowledge about factors that affect health, welfare and work in farm dogs. Further investigation into reasons for lameness may help improve health and welfare in working farm dogs.

Qualitative methodologies are relative newcomers to health sciences education research. While they may look very different to their quantitative counterparts in terms of size and scope, when well-applied they offer a fresh perspective and generate valuable research findings. Although qualitative research is being increasingly conducted in veterinary medical education, there are few contextualized resources to assist those who would like to develop their expertise in this area. In this article, we address this by introducing the principles of qualitative research design in a veterinary medical education context. Drawing from a range of contemporary resources, we explore the types of research goals and questions that are amenable to qualitative inquiry and discuss the process of formulating a worthwhile research question. We explain what research paradigms are and introduce readers to some of the methodological options available to them in qualitative research. Examples from veterinary medical education are used to illustrate key points. In a second companion article, we will focus on the decisions that need to be made regarding data sampling, collection, and analysis. We will also consider how qualitative research is evaluated, and discuss how qualitative findings are applied. Taken together, the two articles build an understanding of qualitative research, illuminate its potential to contribute to the scholarship of teaching and learning in veterinary medical education, and equip readers with an improved capacity to appraise its value.

Musculoskeletal injury and disease are common in dogs, and a major cause of retirement in working dogs. Many livestock farmers rely on dogs for the effective running of their farms. However, the incidence of musculoskeletal disease has not been explored in working farm dogs. Here we explore the occurrence of musculoskeletal abnormalities in 323 working farm dogs that were enrolled in TeamMate, a longitudinal study of working farm dogs in New Zealand. All dogs were free of musculoskeletal abnormalities on enrolment to the study and were present for at least one follow-up examination. During the follow-up period, 184 dogs (57%, 95% confidence interval (CI) = 52%-62%) developed at least one musculoskeletal abnormality during 4,508 dog-months at risk, corresponding to 4.1 dogs (95% CI = 3.5-4.7) with recorded abnormalities per 100 dog-months at risk. The most common abnormalities were reduced range of motion and swelling of the carpus or stifle, while the hip was the most common site of pain. No major differences in incidence rate (IR) between sexes or types of dogs were observed, though Huntaways had a slightly lower rate of carpal abnormalities than Heading dogs (IR ratio = 0.6, 95% CI = 0.3-1.0). Eighty-one of 119 dogs (68%, 95% CI = 60%-76%) that had a first musculoskeletal abormality developed a second abnormality. The most common type of abnormality that was seen in the same dog more than once was reduced range of motion in the carpus (14 of 119 dogs, 12%, 95% CI = 6%-18%). Although we do not provide data on diagnoses, the high incidence rate of recorded musculoskeletal abnormalities and dogs' high activity mean it is likely that working farm dogs are at a high risk of conditions that could impair their welfare and reduce the lengths of their working careers. Preventing and managing musculoskeletal injury and illness should be a priority for owners and veterinarians caring for working farm dogs., (Copyright © 2020 Isaksen, Linney, Williamson, Cave, Norman and Cogger.)

Training measures, particularly those that examine the interactions between training volume, speed, and recovery, can improve understanding of training practices that contribute to success and avoid adverse horse welfare outcomes in endurance competitions. This study describes the training of Fédération Equestre Internationale (FEI) 100-160 km level horses in New Zealand. A convenience sample of 16 participants and 25 horses were surveyed before commencement of training. Participants then reported daily data for an entire nine-month season of training and competition. Participants began their season with predetermined goals and individual training plans for each horse. They intended to use competitions for training. Competitions contributed a median of 44% [IQR, 36%-49%] of total accumulated distance (in training and competition) for each horse for the season, despite being only 11% (207/1,933) of all days worked. Most starts (80%) were in domestic-level (CEN) competition ≤80 km. Speed ranged from 2-18 km/hour on home training days to 6-18.5 km/hour in CEN competitions and 10.9-16.9 km/hour in FEI competitions. Horses were worked 34% [IQR, 21-38] of days in training, ranging from 12% to 55% for individual horses. The most common horse health problem was lameness, affecting 12/25 horses, for a median of 9 (range, 1-78) days. This study highlights the potential for CEN data as a resource to improve understanding of training and competition load, speed, and recovery and therefore reduce adverse horse welfare outcomes in FEI competitions., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Horses are used in practical teaching classes in many equine and veterinary science degree programmes to develop and refine the handling and clinical skills of students. In this study, the activities of 24 teaching horses grouped in three herds were investigated over an entire calendar year. Although also used for research and general husbandry, teaching-related activities were the predominant use of the horses. Herd B was used for a greater number of teaching sessions (median = 28, IQR = 27-29.5 per year) than herds M (median = 21, IQR = 20-21 per year) and T (median = 19.5, IQR = 13.75-25.5 per year), which translates to a relatively low workload (one or two weekly sessions during the teaching semester). Sedation was used in dentistry classes (in alignment with national best practice standards) but was rarely required for other teaching activities. Mare reproductive rectal- and medical rectal examination practical classes (specific to 5th-year veterinary teaching and characterised by more restraint (in stocks)) were significantly shorter and had fewer students per horse than the other practical classes. Although the low workload reported suggests an opportunity to increase students' exposure to horses without compromising the horses' welfare, further investigation to determine specific stressors to the horses in the teaching environment may be required., Competing Interests: The authors declare no conflict of interest.

Background: Working farm dogs are invaluable on New Zealand sheep and beef farms. To date no study describing farm dog population and health has included information about incidence of illness and injury, or risk factors affecting health and career duration. This paper describes the methodology and initial results from TeamMate, a longitudinal study that was designed to address this gap. We describe the study population, husbandry practices, and prevalence of clinical abnormalities on enrolment., Methods: Data about the farms, owners, husbandry practices and dogs were collected on farm at approximately 6-month intervals. All dogs over 18 months old and in full work were enrolled. Dogs were given physical examinations by veterinarians. On examination all abnormalities were noted, regardless of clinical significance., Results: Six hundred forty-one working farm dogs and 126 owners were enrolled from the South Island of New Zealand. Forty-nine percent of dogs were Heading dogs (314 of 641) and 48% Huntaways (308 of 641). Median age of dogs was 4 years (range 1.5-14) and median body condition score (BCS) was four on a 9-point scale (interquartile range (IQR) 3-5). Fifty-four percent of dogs were male (345 of 641), and 6% (41 of 641) were neutered. Eighty-one percent of owners (102 of 126) fed dogs commercial biscuits and meat sourced on farm. Forty-four percent of dogs (279 of 641) had bedding in their kennel, 14% (55 of 393) had insulated kennels, 69% (442 of 641) had been vaccinated and 33% (213 of 641) were insured. Clinical abnormalities were found in 74% of dogs (475 of 641). Common abnormalities involved the musculoskeletal system (43%, 273 of 641), skin (including scars and callouses; 42%, 272 of 641), and oral cavity (including worn and broken teeth; 35%, 227 of 641)., Conclusions: Our results expand on those from previous surveys and indicate that musculoskeletal illness and injury, and skin trauma are the most commonly seen clinical abnormalities in working farm dogs. These results will provide a baseline for investigation of incidence and risk factors for illness, injury, retirement and death in New Zealand working farm dogs.

Horses are one of the most dangerous animals veterinarians have to work with. For many veterinary students, their first exposure to horses occurs during practical classes. To evaluate the level of knowledge students have of equine behaviour and their equine handling competency when entering the programme, 214 veterinary students (1st and 4th year) were recruited to participate in a questionnaire. Participants were asked to choose one out of 12 terms that best represented the affective state of a horse in a picture, and to self-assess their equine handling skills. Half (n = 56/115) of the first-year students correctly interpreted the horse's behaviour. The majority had (1) a poor understanding of equine learning mechanisms and (2) poor self-rated equine handling skills. A history of pet ownership ( p = 0.027) and the presence of horses on their family property ( p = 0.001) were significantly associated with a correct understanding of equine behaviour. Fourth-year students were three times more likely to accurately interpret the horse's behaviour ( p = 0.01) and rated their handling skills higher than first-year students ( p = 0.006). These results suggest that previous animal experience confers a considerable advantage to interpret equine behaviour and highlight the critical importance of practical training in the veterinary programme.

In-training evaluations are commonly used for assessing veterinary students during clinical training, but are criticised for being unable to discriminate dimensions of performance. This study investigated scores on an in-training evaluation in use at one veterinary school to determine the dimensions being assessed and the influence of the dimensions on the overall score awarded. Common factor analysis and ordinal logistic regression were conducted on a retrospective sample of 3466 evaluations of 197 final year veterinary students. The findings suggested a higher-order dimensional structure, with one overarching factor and two to four subfactors, consistent with the complex construct of competency that thSAS Institute e assessment was intended to assess. In the four -factor model, all dimensions were significantly related to overall grade, with the effects of the professional attitude factor and the knowledge factor dependent on the placement. The professional attitude factor had the strongest effect on overall grade (β=2.71, P=0.0004). There was a significant effect of placement on overall grade (P=0.021). Neither academic status of the supervisor nor grade point average had significant effects on the overall grade (P>0.49), and a student's overall grade did not significantly differ over time (P=1). The results suggest that the complexity of supervisor judgement is effectively represented in evaluation scores., Competing Interests: Competing interests: None declared., (© British Veterinary Association 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

This qualitative study investigated the qualities of veterinary student performance that inform a supervisor's impression of their competency. Semi-structured interviews were conducted with a purposive sample of 15 supervisors from different veterinary subdisciplines, to elicit descriptions of excellent, weak and marginal students. Thematic analysis of transcriptions revealed 12 themes, of which engagement was frequently discussed and of stated importance, and trustworthiness was a differentiator of weak and marginal students from excellent students. Other themes were knowledge, application of knowledge, technical and animal handling skills, communication, social interaction, personal functioning, caring for animals, impact, prospects and the difficulty in judging competency. Patterns of association of themes were found, however themes were also used independently in unique combinations for most students described. The findings show the range of abilities, behaviours, attitudes and personal characteristics of students that are considered by supervisors and how these are weighted and balanced. The key contribution of engagement and trustworthiness to the overall impression aligns with research indicating their importance for success in clinical practice, as both contributors to competency and indicators of it. The findings may inform future design and investigation of workplace-based learning and in-training evaluation, as well as conceptions of veterinary competency., (British Veterinary Association.)

Objective: To evaluate curettage and diathermy as a treatment for actinic dysplasia and superficial squamous cell carcinoma of the feline nasal planum., Methods: Thirty-four cats clinically assessed to have actinic dysplasia and superficial squamous cell carcinoma involving less than 50% of the nasal planum were treated with a three-cycle curettage and diathermy procedure. Degree of dysplasia, response to treatment, adverse effects, owner perceptions, time to recurrence and proportion disease free at 1 year were evaluated., Results: Lesions ranged from actinic keratoses to invasive squamous cell carcinoma. A complete response to treatment was obtained in all cats. The median follow-up time was 18 · 2 (IQR: 12 · 0-22 · 8) months. Two cats had a clinical recurrence of lesions at 161 and 192 days after treatment. The probability of remaining disease free after 12 months was 0 · 94 (95% CI: 0 · 85-1 · 0). Median time to recurrence was not reached. The procedure was well tolerated with a good cosmetic outcome and no significant post-operative complications., Clinical Significance: This study suggests that curettage and diathermy is an effective treatment for feline actinic dysplasia and for superficial squamous cell carcinoma involving less than 50% of the nasal planum. Curettage and diathermy is an easily mastered technique, requiring minimal equipment., (© 2013 British Small Animal Veterinary Association.)

Mucopolysaccharidosis type IIIA (MPS IIIA) results from lack of functional sulfamidase (SGSH), a lysosomal enzyme. Its substrate, heparan sulfate, and other secondarily-stored compounds subsequently accumulate primarily within the central nervous system (CNS), resulting in progressive mental deterioration and early death. Presently there is no treatment. As a potential therapeutic strategy, recombinant human sulfamidase (rhSGSH) was administered into the CSF (via the cerebellomedullary cistern) of three adult MPS IIIA dogs either twice with a 4 day interval, or weekly for up to 4 weeks. The dogs were euthanased 24 h post-injection along with one untreated unaffected and two MPS IIIA controls. We have examined the three dimensional pattern of distribution of enzyme in the CNS and its ability to reduce primary substrate storage. High concentrations of rhSGSH protein, with up to 39-fold normal enzyme activity levels were detected within widespread areas of the CNS. RhSGSH protein was also detectable by immunohistochemistry in neurons and glia in all three enzyme-treated dogs. In both weekly-treated dogs, relative levels of a heparan sulfate-derived disaccharide, measured using tandem mass spectrometry, were lower in many brain regions when compared to untreated MPS IIIA controls. A moderately severe meningitis was also present as well as antibodies to rhSGSH in CSF/plasma. These findings demonstrate proof of principle that MPS IIIA can be treated by intracisternal enzyme replacement warranting further experiments in animals tolerant to rhSGSH. This enzyme delivery method may represent a means of treating neuropathology in MPS IIIA and other lysosomal storage disorders affecting the CNS.

Dogs with mucopolysaccharidosis (MPS) IIIA were bred within an experimental colony. As part of characterizing them as a model for testing therapeutic strategies for the analogous disease of children, a pathologic study was undertaken. By histology, there were variably stained storage cytosomes within neurons, including many that stained for gangliosides. On ultrastructure examination, these cytosomes contained either moderately dense granular material, tentatively interpreted as precipitated glycosaminoglycan; a variety of multilaminar bodies, interpreted as being associated with secondary accumulation of gangliosides; or a mixture of both types. In the liver, storage vesicles also contained excess glycogen as a secondary storage product. In various tissues, there were large foamy macrophages. In the brain, many of these were in juxtaposition with neurons, and, on ultrastructure examination, they contained storage cytosomes similar to those in neurons. However, the neuron in association with such a macrophage frequently showed little such material.

Aggregation of feline platelets in vitro results in difficulty assessing platelet number. A citrate-based anticoagulant containing the platelet inhibitors theophylline, adenosine, and dipyridamole (CTAD; Diatube-H, Becton Dickinson, Oxford, UK) has been developed for use in human platelet studies and heparin assays. To evaluate the efficacy of CTAD in reducing platelet aggregation in feline blood samples, aliquots of blood from 51 cats were anticoagulated with EDTA, CTAD, and for 12 samples, citrate solution. Samples preserved in CTAD had significantly higher (P

True thrombocytopenia is uncommon in cats; however, low platelet counts frequently are found using automated cell counters. Although this discrepancy is a well known problem, the prevalence of low automated platelet counts in feline blood samples has not been documented. We retrospectively compared the prevalence of low automated platelet counts with low blood smear-estimated platelet counts in feline blood samples. Results of blood sample analysis from 359 cats during a 1-year period at the University of Glasgow Veterinary Haematology Laboratory were examined. Smear estimates of platelet number were done in those cases in which records did not indicate adequate platelet numbers. Platelet counts obtained with an impedance counter (Minos Vet, Abx Hematologie) were <200X10(9) cells/L in 256 samples (71%) and <50X10(9) cells/L in 43 samples (12%). However, based on estimation of platelet numbers from blood smears, only 11 samples (3.1%) had platelet counts of <200X10(9) cells/L and 9 samples (2.5%) had counts of <50X10(9) cells/L. Four cats with thrombocytopenia estimated by blood smear evaluation had clinical signs of a bleeding disorder. Disorders associated with thrombocytopenia included neoplasia, cytotoxic chemotherapy, and infectious diseases. There was no evidence that delay due to mailing of samples was associated with lower automated platelet counts than would have been obtained on the day of sampling. The high prevalence of apparent thrombocytopenia in automated platelet counts was attributed to a combination of platelet aggregation and the impedance method of cell differentiation by size. Vigilance and careful examination of blood smears is required to identify the few cats with true thrombocytopenia.

The results of adrenocorticotropin (ACTH) stimulation and low-dose dexamethasone suppression tests (LDDST) were evaluated retrospectively in eight dogs with clinical signs of hyperadrenocorticism arising from functional adrenocortical tumours, and compared with the results from 12 dogs with confirmed pituitary-dependent hyperadrenocorticism (PDH). The post-ACTH cortisol concentration in the dogs with adrenocortical tumours ranged from 61 to 345-6 nmol/litre (median 251.5 nmol/litre) and they were within the reference range (150 to 450 nmol/litre) in five and unexpectedly low (< 150 nmol/litre) in three dogs. Both the basal and post-ACTH cortisol concentrations were significantly lower in the dogs with adrenocortical neoplasia than in the dogs with PDH. Eight hours after the LDDST, only two of six dogs with adrenocortical tumours had a cortisol concentration above 30 nmol/litre, and the median resting, three, and eight-hour cortisol concentrations were 31.5, 23.0, and 22.7 nmol/litre respectively. There was no significant cortisol suppression during the LDDST, although interpretation was complicated by the low cortisol concentrations, but two dogs showed a pattern of apparent suppression. Two dogs with adrenal tumours showed a diagnostically significant increase in 17-OH-progesterone concentration in response to ACTH although their cortisol concentrations did not increase greatly. These results differ from previous reports of the response of functional adrenal tumours to dynamic endocrine tests.

Purpose: This study assesses the value of the urinary methylmalonic acid (MMA) assay by gas chromatography mass spectrometry as a screening procedure for detection of cobalamin (Cbl) deficiency and estimates the prevalence of undetected Cbl deficiency in elderly populations., Subjects and Methods: A total of 809 elderly individuals over age 65 were screened using random spot urine specimens from 4 different sites: a health fair, retirement apartments, a hospital-based elderly assessment center, and a nursing home. Follow-up tests included serum total Cbl, serum MMA, and normalization of urinary and serum MMA levels with Cbl intramuscular (IM) therapy., Results: The prevalence of elevated urinary MMA varied across population groups, from 3.0% in elderly visiting a health fair to 5.1% in elderly residing in retirement apartments. Follow-up on 35 of 36 subjects with elevated urinary MMA levels showed that 18 had low serum total Cbl (less than 180 pg/mL at Hospital 1 or less than 200 pg/mL at Hospital 2), 12 had low-normal Cbl (180 or 200 pg/mL to 350 pg/mL), and 5 had normal Cbl. Of the 12 subjects with low-normal Cbl on retesting, further assessment was performed in 7, and all 7 of these subjects had evidence of Cbl deficiency. Cbl IM therapy was initiated for 23 subjects; 16 were seen for follow-up and all had normal urinary MMA., Conclusion: The relatively high prevalence of undetected Cbl deficiency identified in the seniors warrants additional studies of elderly populations. The sensitivity, convenience, and noninvasive nature of the urinary MMA assay by gas chromatography mass spectrometry make it a practical screening test.

It is suggested that the thermic effect of protein be exploited as a means of hyperthermia therapy in the treatment of liver cancer. Oral ingestion of high amounts of protein or intravenous amino acid therapy could generate heat directly within the hepatocytes primarily through urea synthesis. This approach could enhance the effects of conventional hyperthermia or radiation therapy.

The question of possible circadian rhythm upon administration of 6,11-dimethyl-2,6-methano-3-(3-methyl-2-butenyl)-1,2,3,4,5,6-hexahydro-3- benzazocin-8-ol (pentazocine, Talwin) (which was found to exist in beagle dogs) was studied in eight healthy, male volunteers. Six of the subjects resided in the USA, and two subjects joined the study group the night before the morning experiment from Europe. All blood concentration-time data after i.v. injection starting between 8-9 a.m. and 8-9p.m., respectively, were best fit by biexponential curves. The derived pharmacokinetic parameters were essentially identical to those reported in the literature. Overall, no statistically significant differences were found for any of the parameters between the day and night study. However, the two volunteers from Europe demonstrated significant differences in the volume of distribution. Although the sample number is too small to draw final conclusions, it indicates the need for further studies regarding possible influences by offsetting the biologic clock, or "jet-lag" on drug disposition. No differences were found in clinical effects between the day and night study. However, all clinical effects were significantly more pronounced after the first than after the second dose, regardless of time of administration.

An isotope dilution mass spectrometry method is described for determining chenodeoxycholic acid pool size in children. The stable isotopically labeled tracer, (11,12-2H2) chenodeoxycholic acid, was administered orally to children, and the enrichment of bile was measured by selected ion monitoring gas chromatography mass spectrometry. The level of (11,12-2H2)chenodeoxycholic acid enrichment found in the patient samples was in the range of 0.5 to 5%. Data are presented illustrating the duplication of this method in two independent laboratories using standard quadrupole mass spectrometers. This procedure provides the clinician with a non-radioactive method for determining chenodeoxycholic acid pool size which is especially beneficial in studies involving children and pregnant women.

Drug disposition of pentazocine was studied in the beagle dog upon i.v. administration of 30 mg in a crossover design with the variable being the time of administration. The pharmacokinetic parameters for the volume of distribution at steady state (V dss) and during the beta-phase (V d beta) and the biological half-life (t 1/2 beta) are statistically significant increased during the night, documenting circadian rhythm for the disposition of pentazocine. The total clearance (Cltot), however, remains unchanged.

Gas chromatography/mass spectrometry was used for the detection of 3-hydroxy-3-methylglutaryl-CoA lyase (EC 4.1.3.4) deficiency in double first cousins. This enzyme is in the last step of leucine catabolism and is also involved in ketogenesis. Quantitation of urinary organic acids as their cyclohexyl esters demonstrated increased concentrations of 3-hydroxy-3-methylglutaric acid, 3-methylglutaconic acid, 3-methylglutaric acid, and 3-hydroxyisovaleric acid. The procedure is more rapid, sensitive, and specific than previously reported gas-chromatographic methods for acid quantitation. The affected children initially presented with symptoms similar to Reye's syndrome; the acids were quantitated during periods of altered intake of protein and fat. Both leucine and fat intake contributed to increased acid excretion. These studies suggest that life-threatening episodes of hypoglycemia are best prevented with a low-protein, low-fat diet.