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Biomedical subjects

L M Young

Publications and source records attributed to L M Young.

35 records · Page 2Linked to original sources
PubMed1987

Presence of salicylic acid in standardbred horse urine and plasma after various feed and drug administrations.

Plasma and urinary levels of salicylic acid were examined in Standardbred mares after administration of various feeds, containing different compositions of hay. In addition, horses were administered acetylsalicylic acid orally and methyl salicylate topically. Elevated salicylic acid levels were observed in horse urine and plasma in animals fed lucerne hay. The plasma and urinary elimination of salicylic acid exhibited a diurnal pattern which was related to the type of feed and the feeding schedule. Within 24 h after oral administration of acetylsalicylic acid, plasma and urine salicylic acid levels were consistent with residual levels observed after feeding lucerne hay. Elimination of salicylic acid was rapid and complete, with a half-life between 5 and 7 h. Topical administration of methyl salicylate (8.4 g) produced elevated urinary salicylic acid levels for 6 h. A smaller dose of methyl salicylate (3.4 g) did not elevate plasma or urine salicylic acid levels above those observed following administration of lucerne hay.

Administration, Oral↗
PubMed1987

Fetal biophysical profile and perinatal death.

Antepartum assessment of 5034 high-risk pregnancies to predict perinatal death included five biophysical variables (nonstress test, fetal breathing movements, fetal movements, fetal tone, and amniotic fluid volume) which combined to form a biophysical profile score. We assessed 4148 fetuses within seven days of delivery. The ability of each variable to predict perinatal death was expressed as the likelihood ratio, which incorporates sensitivity and specificity into one number. The predictive ability was most accurate with fetal movement (likelihood ratio 48.1) and the combined biophysical profile score (likelihood ratio 51.0). The biophysical profile score was more likely to predict perinatal death due to asphyxia (seven of eight) than lethal anomaly (six of 19). The overall perinatal mortality was 7.6 per 1000 total births. The perinatal mortality rate was 1.0 for a normal biophysical profile score, 31.3 for an equivocal score, and 200.0 for an abnormal score. The false-negative rate for the biophysical profile score was 0.7 per 1000.

Amniotic Fluid↗
PubMed1984

Antepartum fetal assessment using a fetal biophysical profile score.

The application of the fetal biophysical profile score in the management of 2,400 high-risk pregnancies was assessed. The negative predictive value for normal perinatal outcome was not improved compared to single variable tests. The positive predictive value for abnormal perinatal outcome was improved. The overall perinatal mortality in 2,485 fetuses was 9.2 per 1,000. In the 1,980 fetuses with a normal biophysical profile score within 7 days of delivery, excluding lethal anomalies, the perinatal mortality was 1 per 1,000. Fetal movement counting is supported as the most valid and appropriate test for universal fetal screening.

Amniotic Fluid↗
PubMed1984

Riboflavin use as a drug marker in Veterans Administration cooperative studies.

Most Veterans Administration (VA) cooperative studies have used only the pill count method to measure and describe patient adherence to a drug regimen. The use of a drug marker is considered when adherence is expected to be a problem in a study, especially if the therapeutic drug or metabolite cannot be measured in the blood or urine of all patients or if reliability of pill counts is open to serious question. In a VA-NHLBI hypertension study using riboflavin as a marker for assessing patient adherence, group data suggest that similar adherence scores can be expected when comparing pill counts and urine tests. However, when an individual patient's adherence was examined by each method at a particular visit, discrepancies were noted. In a VA cooperative study on disulfiram for the treatment of alcoholism, riboflavin used as a marker provided additional information that was needed to assess the adherence of the study population. By employing this second measure of adherence in this study, we were able to obtain at least one measure of adherence at 84% of all clinic visits. If the pill count method had been the sole adherence measure, only 60% of visits would have produced an adherence score. At 65% of clinic visits, the pill count and urine test were in agreement. Results of urine tests taken in the interval between visits were similar to those taken at the clinic visit. Patient cooperation in providing urine specimens or in returning pills to the clinic was slightly associated with positive adherence scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcoholism↗
PubMed1984

National survey of pharmacy-coordinated investigational drug services.

A national survey of 703 pharmacy departments was conducted to obtain information on the status and scope of investigational drug services (IDS). Questionnaires were mailed to the directors of pharmacy departments of general medical and surgical hospitals with 300 or more beds and a university affiliation. The survey consisted of 27 questions that were primarily based on the ASHP guidelines for the use of investigational drugs in institutions. A total of 403 questionnaires were returned, 386 of which could be evaluated, 386 of which could be evaluated. Only 33% of the pharmacy departments adopted a minimal subset (7 of 11) of the recommended procedures based on the ASHP guidelines. All pharmacy departments with more than 40 protocols reported having a research pharmacist or a need for one. Of all of the protocols, 43% were sponsored by the National Institutes of Health, 34% by pharmaceutical companies, 16% by investigators and physicians, and 7% by various other sponsors. Drug information, monetary reimbursement for services,a dn coordination and communication were the most frequently cited areas in need of improvement by the drug sponsors. The most common types of protocols involved cancer research (56%) and infectious disease and cardiovascular studies (12% and 13%, respectively). Directors of pharmacy departments should review their investigational drug policies and procedures for compliance with ASHP guidelines as the first step in developing the IDS concept.

Drug Information Services↗
PubMed1983

"Bare lymphocytes" without immunodeficiency.

"Bare lymphocytes," which cannot be typed for the HLA-A,B, and C antigens were observed in two siblings, nine and six years of age. The elder child presented with aplastic anemia and was being considered for bone marrow transplantation. The younger child was healthy. The inability to phenotype both children for these three gene products persisted throughout the 21-month period of observation. The DR antigens were demonstrable which rendered it possible to deduce their A, B, and C genotype from the typing of the other four family members. Although alloantisera failed to detect the antigens on peripheral blood lymphocytes, monoclonal antibodies demonstrated reduced amounts of the HLA-A,B, and C antigens on the cells. The reduced level was confirmed following EBV transformation of the cells. After prolonged culture, HLA antigens immunoprecipitated from the cell extracts were normal in amount, molecular weight, and polypeptide composition. Southern blot analysis did not reveal gross genomic rearrangements. A regulatory defect leading to the expression of these Class I antigens is postulated.

Anemia, Aplastic↗
PubMed1977

A field expander for patients with retinitis pigmentosa: a clinical study.

An inexpensive, commercially available optical device was tested on 10 patients with retinitis pigmentosa to determine its value as a field expander for scanning and as an aid to mobility. Visual acuity and visual fields were measured with and without the expander, and the patients' subjective responses were monitored by a questionnaire that was administered at regular intervals during a 2- to 4-week period between test sessions. Six of the 10 subjects considered the device helpful in at least 1 important visual task and planned to continue using it.

Adult↗
PubMedDate not supplied

Identification of metabolites of methylprednisolone in equine urine.

Methylprednisolone and three metabolites, 17,21-dihydroxy-6 alpha-methyl-1,4-pregnadiene-3,11,20-trione, 6 alpha-methyl-17,20 beta,21-trihydroxy-1,4-pregnadiene-3,11-dione, and 6 alpha-methyl-11 beta,17,20 beta,21-tetrahydroxy-1,4-pregnadien-3-one were detected in equine urine after intraarticular administration of methylprednisolone acetate. All four compounds were excreted both in the unconjugated form and as glucuronic acid conjugates. They were identified by comparing data obtained from analyses by high performance liquid chromatography, thin-layer chromatography, ultraviolet spectroscopy and gas chromatography/mass spectrometry to those of the synthesized standards. The presence of trace amounts of a fourth metabolite, 6 alpha-methyl-11 beta,17,20 alpha,21-tetrahydroxy-1,4-pregnadien-3-one, was indicated by high performance liquid chromatography but confirmation has not been attained by the other methods.

Animals↗
PubMedDate not supplied

A sensitive liquid chromatographic procedure for the analysis of camphor in equine urine and plasma.

A sensitive method was required to analyze low levels of camphor in equine urine and plasma. Camphorated oil (20% w/w camphor) was administered topically (6 g) and intratracheally (1 g) to standardbred mares. The drug was extracted from urine and plasma by diethyl ether and analyzed as its 2,4-dinitrophenylhydrazone derivative by reverse phase HPLC with UV detection. The UV detector was set at 368.5 nm and the samples were eluted from the C18 column by 82% acetonitrile in water. The detection limit achieved was about 10 ng/mL urine and about 20 ng/mL plasma. After topical administration, only trace amounts of camphor were found in urine, whereas in plasma detectable quantities appeared from 20 min to 12 hrs post-administration. After intratracheal administration, camphor appeared immediately in both urine and plasma and occurred in higher concentrations. The concentrations of camphor ranged from 11.4 to 21.6 ng/mL urine during 2 hrs post-administration and from 46.7 to 1650 ng/mL plasma during 1 hr. All traces of camphor disappeared from urine after 4 hrs and from plasma after 12 hrs. A GC/MS analysis of hydrolyzed urine extracts indicated two metabolites of camphor: trans-isoketopinic acid and an as yet uncharacterized hydroxycamphor.

Animals↗
PubMedDate not supplied

Characterization of metabolites of xylazine produced in vivo and in vitro by LC/MS/MS and by GC/MS.

The metabolic fate of xylazine, 2-(2,6-dimethylphenylamino)-5,6-dihydro-4H-1,3-thiazine, in horses is described. The major metabolites identified in the hydrolyzed horse urine were 2-(4'-hydroxy-2',6'-dimethylphenylamino)-5,6-dihydro-4H-1,3-thiazi ne, 2-(3'-hydroxy-2',6'-dimethylphenylamino)-5,6-dihydro-4H-1,3-thiazi ne, N-(2,6-dimethylphenyl)thiourea, and 2-(2',6'-dimethylphenylamino)-4-oxo-5,6-dihydro-1,3-thiazine. These metabolites were also produced by incubating xylazine with rat liver microsomes. The major metabolite produced in vitro by rat liver preparations was found to be the ring opened N-(2,6-dimethylphenyl)thiourea. The identities of these metabolites were confirmed by spectroscopic comparisons with synthetic standards. Phenolic metabolic standards were synthesized efficiently by the use of Fenton's reagent. This reagent was used to monohydroxylate multiply substituted aromatic ring systems. LC/MS/MS, with an atmospheric pressure chemical ionization source, was found to be particularly useful in confirming the presence of phenolic metabolites in hydrolyzed equine urine and microsomal extracts. These phenolic metabolites could not be analyzed by GC/MS even after derivatization with silylating agents. The advantage of LC/MS/MS was that no or little sample preparation of urine or microsomal extract was necessary prior to the analysis. A mechanism is also proposed for the formation of the major metabolite, N-(2,6-dimethylphenyl)thiourea, from xylazine.

Animals↗
PubMedDate not supplied

DIC: the insidious killer.

Disseminated intravascular coagulation (DIC) is not a disease but an abnormal syndrome that is always secondary to another process. Because its symptomatology is varied and subtle, frequent assessments of body systems must be conducted. This article and its plan of care are designed to assist the nurse in the effective management of the DIC patient.

Adult↗
PubMedDate not supplied

Validation of a method for determination of tetracycline antibiotics in salmon muscle tissue.

A method was validated for analysis of oxytetracycline (OTC), tetracycline (TC), and chlortetracycline (CTC) in fortified salmon muscle tissue. Recoveries of OTC were 100 +/- 6, 86 +/- 6, and 82 +/- 5% (n = 6) at fortification levels of 1.0, 0.5, and 0.2 ppm, respectively. Recoveries of TC were 68 +/- 4, 65 +/- 6, and 66 +/- 7%; recoveries of CTC were 45 +/- 9, 48 +/- 8, and 0%, respectively. Detection limits for OTC and TC were 0.08 and 0.09 ppm, respectively.

Animals↗
PubMedDate not supplied

Simultaneous liquid chromatographic screening of five coccidiostats in chicken liver.

A reverse-phase liquid chromatographic (LC) method is described for simultaneously determining 5 coccidiostats--aklomide, dinsed, ethopabate, nitromide, and zoalene in chicken liver. The method entails blender extraction of 10 g liver with ethyl acetate, column chromatography through Sephadex LH-20 and neutral alumina, and LC analysis on a C18 column with UV detection at 260 nm. The drugs were eluted from Sephadex with methanol-benzene (10 + 90), from alumina with methanol-dichloromethane (10 + 90), and from C18 with acetonitrile-water (linear gradient: 25% acetonitrile for 10 min, increasing to 55% over 15 min; flow rate 1 mL/min). Liquid chromatography was completed in 40 min and calculations were based on peak height measurements. Average recoveries of the coccidiostats from fortified liver ranged from 72 to 97%, except for dinsed, which showed a relatively constant average recovery of 57%. The detection limit for the standards was 2.5 ng on column. Levels as low as 50 ng/g were detected in fortified liver samples.

Animals↗