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Biomedical subjects

D Raines

Publications and source records attributed to D Raines.

13 recordsLinked to original sources
PubMed2001

Expedient microdetermination of itraconazole and hydroxyitraconazole in plasma by high-performance liquid chromatography with fluorescence detection.

The authors describe a useful and rapid micromethod for the analysis of itraconazole (ITZ) and its active metabolite hydroxyitraconazole (HIT) in human plasma. After a simple deproteinization of 100 microL plasma with acetonitrile, the drug, its metabolite, and an internal standard (IS, ketoconazole) were separated on an 8 mm x 10 cm NovaPak (Waters Associates; Milford, MA) C(18) 4-microm particle-size radial compression cartridge. The compounds of interest were detected using a fluorescence detector with the excitation wavelength set at 260 nm and the emission at 365 nm. The mobile phase consisted of 420 mL water adjusted to a pH of 2.5 with phosphoric acid, 580 mL acetonitrile, and 100 microL triethylamine, which was delivered at a flow rate of 3.0 mL/min. This expedient and rugged method is being used to monitor therapeutic levels in bone marrow transplant recipients who are taking the drug for prophylaxis.

Antifungal Agents↗
PubMed2001

Caffeine metabolism in premature infants.

Caffeine has been used frequently in the treatment and prevention of apnea of prematurity. The metabolism of caffeine depends on the activities of the hepatic enzymes that vary from one infant to another. The objective of this study was to determine the influence of postnatal age (PNA), birth weight (BW), study weight (SW), gestational age (GA), postconceptual age (PCA), and gender on the maturation of caffeine metabolism in premature infants. The caffeine base was administered orally as a loading dose of 10 mg/kg, followed by a maintenance dose of 2 mg/kg every 24 hours. The steady-state concentration of caffeine and metabolites was measured in plasma taken on the 5th-day postloading dose. The molar concentration ratios for the N3 (N3-), N7 (N7-), N1 (N1-), and all methyl (Nall-) demethylation processes; clearance (CL); and the percentage of molar concentration of caffeine found in plasma to that of the total caffeine and metabolites (%CAF) were calculated from samples collected from 80 neonatal infants. The 48 male and 32 female premature infants had median (range) BW (g), GA (weeks), SW (g), PCA (weeks), and PNA (days) of 1300 (650-2260), 30 (24-34), 1630 (980-2670), 34 (29-40), and 28 (5-60), respectively. The median (range) of the ratios for the %CAF, CL, and the N3-, N7-, N1-, and Nall- were 86.9 (52.9-99.0), 0.127 (0.046-0.503) ml.kg-1.min-1, 0.032 (0-0.438), 0.070 (0.007-0.471), 0.026 (0-0.283), and 0.0463 (0.003-0.303), respectively. When the patients were stratified into four PNA age groups, each older group showed a consistently higher level of caffeine metabolic activity for the N3-, N7-, and Nall- pathways with a corresponding decrease in the %CAF, whereas no significant differences were seen for the N1-pathway or for CL. No pattern of significant differences between the demethylation process ratios, %CAF, or CL was seen between groups of infants when they were stratified according to BW, SW, PCA, or GA. The female infants were found to have significantly higher rates of caffeine metabolism as shown by %CAF, N1-, N3-, and Nall- processes but not the N7-. Multivariate linear regression analysis by two methods demonstrated that PNA is significantly related to %CAF and Nall-, whereas the female patients had higher levels of metabolic activity for the %CAF and N1- process. The authors conclude that the N7-demethy-lation process is the predominate caffeine metabolic process in premature infants. Furthermore, the maturation of the caffeine metabolism in premature infants with a PNA of less than 60 days increases with postnatal age, regardless of birth weight, gestational age, postconceptual age, and study weight. The female neonatal patients demonstrated a higher rate of caffeine metabolism than the males.

Age Factors↗
PubMed1999

Simplified high-performance liquid chromatographic method for the determination of gentamicin sulfate in a microsample of plasma: comparison with fluorescence polarization immunoassay.

The authors describe a simplified high-performance liquid chromatographic (HPLC) method for the determination of gentamicin sulfate (GEN) in microsamples of plasma using 9-fluorenylmethyl chloroformate (FMOC) as a derivatizing agent and neomycin sulfate as the internal standard (IS). The drug and IS were separated on a 4 microm (particle size), 8 x 100 mm Nova-Pak C18 radial compression cartridge using a mixture of 84.5% acetonitrile and 15.5% water at a flow rate of 2.5 mL/min. The compounds were detected fluorometrically in the effluent at excitation and emission wavelengths of 260 nm and 315 nm, respectively. Sample preparation was performed on 50 microL of plasma using a simple liquid-liquid extraction followed by a room-temperature derivatization procedure. No interference from any endogenous substance or concurrently used drug was observed, and the retention times of the IS and three major components of GEN were 12.4, 19.5, 23.6, and 27.6 min, respectively. The concentration of the GEN in plasma for the range of 0.2-20.0 microg/mL was linearly (r > .997) related to the peak height ratio of the sum of the three major GEN peaks to that of the IS, with CV value at 0.3, 7.5, and 15 microg/mL being <3.61%. A comparison of the results from this assay versus fluorescence polarization immunoassay (TDx) showed a close agreement between the two methods with r = 0.994. This assay is currently being used to monitor GEN and investigate its pharmacokinetics in pediatric patients.

Chromatography, High Pressure Liquid↗
PubMed1999

Pharmacokinetics of azithromycinin rabbit lacrimal glands and conjunctiv a.

PURPOSE AND BACKGROUND: To measure azithromycin levels in rabbit lacrimal and Harder glands, conjunctiva and plasma after a single oral dose of 20 mg/kg. Drug levels in lacrimal gland tissue are significant in trachoma because the gland may be involved in the disease process and it is the source of tears by which the drug is carried to the external eye. METHODS: Lacrimal and Harder glands, conjunctiva and plasma were collected from New Zealand white female rabbits at 24, 48, 72, 96 and 144 h following a single oral dose of azithromycin (20 mg/kg). Azithromycin levels in tissue and plasma were measured using high-performance liquid chromatography (HPLC) electrochemical detection. RESULTS: Azithromycin levels peaked within the first 24 h in all tissues and plasma assayed. The highest concentration was in the lacrimal gland (6.2 microg/g, SD +/- 0.8), followed by Harder gland (4.4 microg/g, SD +/- 0.8), conjunctiva (0. 9 microg/g, SD +/- 0.5) and plasma (0.06 microg/g, SD +/- 0.03). These concentrations reached their lowest measured levels at 120 and 144 h. CONCLUSION: Azithromycin levels measured throughout the 144 h after dosing were consistently above the minimum inhibitory range (MIC) for Chlamydia trachomatis (0.03-0.25 microg/ml) in the lacrimal glands, while the conjunctiva maintained a concentration above the MIC for 96 h and stayed within MIC levels for 144 h.

Administration, Oral↗
PubMed1998

Ocular penetration of oral clarithromycin in humans.

Clarithromycin has a wide spectrum of activity against many gram-positive and gram-negative organisms, intracellular pathogens, and opportunistic pathogens. To examine the penetration of clarithromycin in the ocular tissues, 21 patients who underwent elective cataract surgery (Group I) received a single 500-mg dose of clarithromycin orally either 4, 8, 10, 12, or 22 hours before cataract surgery, and 21 patients who underwent elective retina/vitreous surgery (Group II) received 500 mg every 12 hours orally for 3 days before the surgery with the last dose given either 3, 6, 8, 11, or 24 hours before the surgery. Serum from all patients was assayed for clarithromycin prior to drug administration and at the time ocular specimen was taken. Aqueous, iris, and vitreous samples were also assayed for clarithromycin concentration. The concentrations of clarithromycin in the aqueous fluid 4, 8, 10, 12, and 22 hours after administration were: (mean +/- SD) 0.13+/-0.05, 0.137+/-0.11, 0.074+/-0.03, 0.06+/-0.02, and 0.074+/-0.04 microg/ml, respectively. Concentration of clarithromycin in vitreous 3, 6, 8, 11, and 24 hours after administration were: (mean +/- SD) 0.11+/-0.02, 0.257+/-0.13, 0.27+/-0.21, 0.307+/-0.26 and 0.108+/-0.07 microg/ml, respectively. The mean concentration of clarithromycin in the iris was 6.2 microg/g. In conclusion, this data suggest that clarithromycin widely penetrates and adequately concentrates in the aqueous humor, vitreous humor, and iris tissue after oral administration and therefore is effective in the management of many infectious ocular conditions.

Administration, Oral↗
PubMed1998

Medicaid managed care partnerships to improve perinatal outcomes.

New York State's Prenatal Care Assistance Program, and enhanced care program based on public health principles, is in the process of being transformed into Medicaid managed care. The program described in this article, namely, a Medicaid managed care health maintenance organization and its interaction with one hospital's care of women, especially pregnant women, serves to illustrate how traditional public health values and managed care principles may be linked. This linkage is a starting point to developing a community's involvement in its own health, although it is too early from our experience to note a lasting effect on improved pregnancy outcomes.

Adult↗
PubMed1993

Deciding what to do when the patient can't speak: a preliminary analysis of an ethnographic study of professional nurses in the neonatal intensive care unit.

The role of patient advocate is not easily implemented with infants in the neonatal intensive care unit because there is no way of knowing what the infant would wish to be done. Many of the nurse's actions are based on the concept of the "best interests of the infant." However, although widely used, this concept is rarely defined or described for the neonatal population. The purpose of this qualitative study was to identify themes related to the professional nurse's interpretation of the concept of advocacy. A case study design and inductive data analysis consisting of constant comparison and triangulation methodologies were used. This research resulted in multiple perspectives of a single phenomenon based on the similarities and differences in the nurse's perspective related to the concept of interest.

Humans↗
PubMed1982

Childhood accidents in a rural community: a five-year study.

Childhood accidents were monitored over a five-year period in a rural West Virginia primary care center. A population of 1,410 families with children up to 12 years of age was followed. Lacerations, musculoskeletal injuries, and head injuries were the most common injuries. Accidents were relatively more frequent within families with lower income levels and in single-parent households. The data suggest specific preventive strategies for this rural population.

Accident Prevention↗
PubMed1979

Laboratory-based surveillance of influenza virus in the United States during the winter of 1977--1978. II. Isolation of a mixture of A/Victoria- and A/USSR-like viruses from a single person during an epidemic in Wyoming, USA, January 1978.

At a time when outbreaks and sporadic cases of influenza caused a A/Victoria/3/75-like and A/Texas/1/77-like H3N2 strain of influenza were occurring in the Rocky Mountain region of the USA, about 60% of the students of a high school in Cheyenne, Wyoming, were involved in an outbreak of influenza-like illness. Six influenza A(H1N1) virus isolates were obtained from throat swabs collected from 12 of these students. Virus isolated from a seventh student, however, contained a mixture of H1 and H3 (A/Victoria/3/75-like) hemagglutinins and N1 and N2 neuraminidases, as shown by the ability to clone from the mixture viruses with antigenic components H1N1, H3N1, and H3N2. An antigenic hybrid virus with H3N1 composition was re-isolated from the original throat swab. The results show that one student was shedding a mixture of A/Victoria/3/75(H3N2)-like and A/USSR/90/77(H1N1)-like viruses at the time his throat swab was taken.

Adolescent↗
PubMed1975

Clinical, haemodynamic, and coronary angiographic correlates of angina pectoris in patients with severe aortic valve disease.

Of 88 consecutive patients aged 20 to 77 years with severe symptomatic aortic valve disease requiring surgery, 51 patients had angina pectoris; of these 51, 41 had predominant aortic stenosis and 10 had severe aortic regurgitation. All patients with angina pectoris underwent coronary angiography; significant coronary arterial disease was encounted in 24 per cent of those with aortic stenosis and 20 per cent of those with aortic regurgitation. By contrast, of 37 patients without angina pectoris 19 underwent coronary arteriography; none showed significant coronary artery disease (P smaller than 0.05). Among patients with angina pectoris, 17 per cent of those with aortic stenosis experienced prolonged, rest or nocturnal pain, compared to 70 per cent of those with aortic regurgitation (P smaller than 0.005). At the time of onset of angina pectoris, there were features of heart failure in 34 per cent of those with aortic stenosis, and in 90 per cent of those with aortic regurgitation (P smaller than 0.005). Nitroglycerin promptly relieved angina pectoris in 56 percent of patients with aortic stenosis and in 50 per cent of those with aortic regurgitation (P smaller than 0.05). Neither the pattern of angina pectoris nor the response to nitroglycerin was dependent upon the coexistence of significant coronary artery disease. In patients with aortic stenosis, there was not significant difference between those with angina pectoris, and those without angina with regard to left ventricular end-diastolic volume, end-diastolic pressure, ejection fraction, peak systolic pressure, wall thickness, cardiac index, or the product of these factors. In patients with aortic regurgitation, cardiac index was significantly lower (P smaller than 0.05), left ventricular end-diastolic volume tended to be larger, and ejection fraction tended to be lower in patients with angina pectoris as opposed to those without angina pectoris.

Adult↗