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Biomedical subjects

L Young

Publications and source records attributed to L Young.

At least 325 records · Page 18Linked to original sources
PubMedDate not supplied

Determination of procaine in equine plasma and urine by high-performance liquid chromatography.

The variability in plasma and urine equine procaine measurement between three independent laboratories using current methods led to the development of a sensitive, reliable, and reproducible high-performance liquid chromatographic method. Standardbred mares were administered either a penicillin G procaine preparation intramuscularly or procaine hydrochloride subcutaneously, and blood and urine were collected at defined time intervals. By HPLC the detection limits for procaine in plasma and urine were 1 and 10 ng/mL, respectively. In contrast procaine in plasma could not be detected by GC-NPD, while the urinary detection limit was 50 ng/mL. The concentration of fluoride in the collection tubes and repetitive freeze-thawing modified plasma procaine measurement. Urinary pH was a factor in estimation of urine procaine levels with greater recovery and reproducibility of results at pH 5 as compared to pH 7. This HPLC method provides a simple, sensitive, and reliable quantitation of procaine in equine plasma and urine.

Animals↗
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Telopeptides as markers of bone turnover in rheumatoid arthritis and osteoarthritis.

AIMS: The aim of the present study was to determine if urinary excretion of type I collagen N-terminal telopeptides (UrNTx) and deoxypyridinoline (UrDPD) and serum levels of type I collagen C-terminal telopeptides (SeCTx) differed in patients with rheumatoid arthritis (RA) compared with populations matched for age and gender with and without osteoarthritis (OA). The correlation of markers of bone turnover with disease activity in patients with RA or radiographic severity in patients with OA was also examined. METHODS: Patients with RA aged >50 years (men) and >60 years (women) were identified from computer databases at two tertiary referral centres for rheumatology. Strict exclusion criteria were applied to avoid the effects of factors known to influence markers of bone turnover. Patients with RA and OA were matched for age and sex with a control population free of known arthritic disease and a population with OA. Bone markers were assayed in serum and urine. Urine markers were measured on three consecutive days and mean values used to minimize day-to-day variability of these analytes. RESULTS: The level of UrNTx was elevated in patients with RA compared with normal controls and patients with OA. UrNTx and UrDPD correlated with markers of disease activity in patients with RA (erythrocyte -sedimentation rate and C-reactive protein), but not with -clinical signs of inflammation (swollen and tender joint counts). Patients with OA failed to show any correlation between markers of bone turnover and radiographic severity. CONCLUSIONS: These data support a role for the use of UrNTx and UrDPD in further studies of the patho-physiology of RA and in longitudinal studies designed to modify the course of clinical disease.

Aged↗
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Action of alcohol on vestibular compensation and habituation in the cat.

Several effects of alcohol on vestibular nystagmus are well known, including positional alcoholic nystagmus, a depressive effect on post-rotatory nystagmus, and an inhibition of visual fixation. This study concerns the influence of alcohol on central vestibular compensatory phenomena. In one experiment, hemilabyrinthectomized cats were allowed to compensate for the postoperative spontaneous nystagmus and directional preponderance of post-rotatory nystagmus. Following alcohol injection, spontaneous nystagmus reappeared toward the intact side, positional nystagmus was unidirectional, and post-rotatory nystagmus was profoundly more depressed than for normals. Normal cats subjected to repeated accelerations showed less habituation of post-rotatory nystagmus with alcohol than without.

Animals↗
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Reciprocal epithelial: fibroblast interactions in the control of fetal and adult rat lung cells in culture.

Intercellular communication between epithelial cells and fibroblasts of the alveolar wall has been postulated from studies of lung development and repair. We examined the epithelial cell-fibroblast interactions with respect to growth control and epithelial cell function using cultured fetal and adult lung cells. The role of diffusing factor(s) as compared to direct cell-to-cell contact was studied by culturing epithelial cells either on a permeable culture well insert over fibroblasts or in co-culture with fibroblasts. The results show that the normal low proliferative rate of epithelial cells in culture is increased when exposed to fibroblast supernatants. In contrast, epithelial cells (particularly from adult lung) secrete a factor that suppresses fibroblast growth when cultured with a filter between the cell types. However, when cell-cell contact occurs in co-culture, the growth rate of fibroblasts is greatly increased. Synthesis of disaturated phosphatidylcholine by epithelial cells is increased under serum-free conditions and further rises when fetal epithelial cells are exposed to steroid-treated fibroblasts, when the cell types are separated, and when cells are in contact. This indicates that a fibroblast-derived factor stimulates epithelial differentiation, and morphologic evidence relating the appearance of lamellar bodies to the areas of direct epithelial cell-fibroblast contact was found. The results indicate the complex interdependence of these two types of cell where a secretory product of one cell or direct cell-cell contact may alter when regulatory control of the other cell type. These interactions are likely to be important in orderly development and in the reparative response of the lung to injury.

Animals↗
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Fibroblast inhibition does not promote normal lung repair after hyperoxia.

Severe alveolar epithelial injury disrupts the normal epithelial cell-fibroblast relationship, leading to abnormal repair and the uncontrolled growth of fibroblasts. It is postulated that selective inhibition of fibroblasts growth after injury may allow epithelial regeneration to occur, reestablish fibroblast control, and reduce fibrosis. This hypothesis was studied using organ cultures after lung injury was induced in vivo by exposing mice to 90% oxygen for 6 days to produce necrosis of Type 1 epithelium. When explants of this lung tissue were cultured, proliferation of cuboidal epithelial cells was reduced, whereas fibroblast growth and hydroxyproline (HYP) levels were significantly higher than in controls. In attempts to inhibit fibrosis, explants were also cultured in the presence of a proline analog, L-azetidine carboxylic acid (LACA). At concentrations that reduced fibroblast proliferation, epithelial repair was also inhibited. The explants appeared fibrotic, and reduced HYP/DNA was due to lower DNA synthesis. Using pure cell cultures, LACA reduced fibroblast but not epithelial growth, and also abolished the usual increase in epithelial cell proliferation that control cells show when exposed to fibroblast supernatants. These results provide further evidence of interdependence between epithelial cells and fibroblasts such that agents that inhibit fibroblast growth after lung injury either directly or indirectly retard regeneration of the overlying epithelium, and so fail to produce normal repair.

Animals↗
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Metastatic anaerobic orbital subperiosteal abscess: value of CT scanning.

A case of subperiosteal abscess associated with acute sinusitis is reported. The case is remarkable in that anaerobic organisms played a major role in the pathologic process. In addition, the unusual superolateral position of the abscess in the absence of any defect in the bony sinus walls suggests the hematogenous spread of the sinus infection. The use of Ct scanning proved to be essential in determining the true nature of the orbital pathology.

Abscess↗
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Aiming high.

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Community Health Nursing↗
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Tribalism is out.

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Community Health Nursing↗
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In the driving seat.

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Family Practice↗
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Transitions: A new model for nursing curricula.

Nurses in the next millennium will be asked to adopt new, broader roles across a wider variety of practice settings. The Healing Community is a consortium of nurse educators at six schools of nursing who formed a partnership to address these needs and explore solutions. The result is a shared curriculum, based on the concept of transitions. The authors describe the transitions model and the transitional process experienced by members of the Healing Community.

Adaptation, Psychological↗
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New world--new nurse.

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Delivery of Health Care↗