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Biomedical subjects

C Green

Publications and source records attributed to C Green.

At least 343 records · Page 19Linked to original sources
PubMedDate not supplied

Retroviral gene transfer into porcine keratinocytes following improved methods of cultivation.

We embarked on a program examining the application of cultured epithelial sheets to skin wounds in pigs using retroviral gene transfer as a means to follow the grafted cells. In the past similar studies have been hampered by an inability to grow porcine keratinocytes without seeding at an extremely high density. In this study we found that excellent results could be achieved with Opti-MEM-1 (Gibco BRL Life Technologies) containing 1 per cent foetal calf serum, 0.5 mM Ca2+ and no other growth factors or stimulants. Keratinocytes were plated on gamma-irradiated 3T3 feeders on surfaces which had previously been coated with rat tail collagen I. Keratinocyte cultures were established at a seeding density of 5 x 10(4) cm-2. The yield of cells from 1 cm2 of skin was sufficient to set up a 75 cm2 flask. Cultures reached 80-90 per cent confluence in 7-10 days, after which they were passaged 1:3 multiple times, taking 3-4 days to reach the same confluency. Allowing cultures to remain confluent for 1 week was sufficient to allow Dispase removal of an intact sheet. Using these techniques porcine keratinocytes were transduced at an average frequency of 25.3 per cent (+/- 14.0 SEM) with the retroviral vector MFG lacZ nls by growth on the gamma-irradiated retroviral producer line GP + envAm12.

Animals↗
PubMedDate not supplied

A hyaluronic acid membrane delivery system for cultured keratinocytes: clinical "take" rates in the porcine kerato-dermal model.

The clinical take rates of cultured keratinocyte autografts are poor on a full-thickness wound unless a dermal bed is provided. Even under these circumstances two important problems are the time delay in growing autografts and the fragility of the grafts. A laser-perforated hyaluronic acid membrane delivery system allows grafting at early confluence without requiring dispase digestion to release grafts from their culture dishes. We designed this study to investigate the influence of this membrane on clinical take rates in an established porcine kerato-dermal grafting model. The study demonstrated a significant reduction in take as a result of halving the keratinocyte seeding density onto the membrane. The take rates, however, of grafts grown on the membrane at half or full conventional seeding density and transplanted to a dermal wound bed were comparable, if not better, than those of keratinocyte sheet grafts.

Animals↗
PubMedDate not supplied

Comprehensive team care.

Explore the source record for details and available documents.

Adaptation, Psychological↗
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Nipple feeding for preterm infants with bronchopulmonary dysplasia.

OBJECTIVE: To examine the influence of an infant's physical condition on nipple-feeding practices and the contribution of the infant's age at complete nipple feeding to dietary intake and somatic growth outcomes. DESIGN: A retrospective, correlational study. SETTING: Two Level III nurseries. PARTICIPANTS: Records of 55 preterm infants with bronchopulmonary dysplasia. MAIN OUTCOME MEASURES: The infant's intake of kcal/kg on Day 1 of complete nipple feeding and the weight gain per day between complete nipple feeding and discharge. RESULTS: Gestational age and days on mechanical ventilation, continuous positive airway pressure, or supplementary oxygen influenced age at start and at completion of nipple feeding (p < .05). The infant's weight when nipple feeding was introduced was the primary determinant of age at introduction of nipple feeding (B = .50, p < .001). The physical condition variables did not influence the transition time from introduction of nipple feeding to complete nipple feeding. Neither the physical condition variables nor the feeding practice variables contributed to caloric intake. Weight gain between the time of complete nipple feeding and hospital discharge was less for infants who were on supplementary oxygen longer and who were older when completely nipple fed (p < .01).

Age Factors↗
PubMedDate not supplied

Transition time to full nipple feeding for premature infants with a history of lung disease.

OBJECTIVE: To (a) explore the contribution of infant, environmental, and historical factors to the number of days from initiation to achievement of full nipple feeding (transition time) for premature infants with a history of lung disease; (b) examine differences in the contribution of infant and environmental factors to transition time made by historical era, either earlier (in the 1980s) or later (in the 1990s); and (c) compare, within eras, the contribution to transition time of infant and environmental factors for infants with each lung diagnosis, respiratory distress syndrome (RDS) without bronchopulmonary dysplasia (BPD) or BPD. DESIGN: Data were collected at two midwestern hospitals from the records of premature infants with a diagnosis of either RDS without BPD or BPD. The influence on transition time of infant, environmental and historical factors was assessed with the Cox proportional hazards model. This analytic model, a form of regression analysis, also was used to explore how era influenced the contribution to transition time of infant and environmental factors. Finally, the contribution to transition time of infant and environmental factors was examined within diagnostic group for each era. SAMPLE: The hospital records audited were for infants who were 32 weeks gestational age or less with weight appropriate for gestational age. The number in each diagnostic group for each era was (a) BPD--Early, n = 35; (b) RDS--Early, n = 21; (c) BPD--Late, n = 21; and (d) RDS--Late, n = 15). RESULTS: All three types of factors (infant, environmental, and historical) contributed significantly (p < .05) to shortening or lengthening transition time. A diagnosis of BPD lengthened transition time only in the early era. Across both eras, the number of days on tube feedings significantly lengthened transition time, and the older the infant in postconceptional age (PCA) at initiation of nipple feeding, the shorter the transition time. CONCLUSION: The contribution of infant, environmental, and historical factors to transition time confirmed the basic structure of the theoretical model of transition time for premature infants with a history of lung disease. The influence of era on the contributions to transition time of infant and environmental factors suggests that care policy and practice have shortened the transition time. Although the current findings support the basic structure of the theoretical model for infants with either RDS or BPD, the marginally significant (p < .10) shortening effect of PCA on transition time for infants with BPD in both eras suggests that advancement to full nipple feeding may be limited by neurodevelopmental capacities, including respiratory control. How these capacities can be supported for advancement to full nipple feeding is a challenge for nursing practice and research.

Adult↗
PubMedDate not supplied

Fine needle aspiration cytodiagnosis of sialadenitis with crystalloids.

OBJECTIVE: To assess the utility of fine needle aspiration cytology in the diagnosis of sialadenitis with crystalloid formation in four patients that presented with a swelling of the parotid gland. STUDY DESIGN: The swelling was aspirated in all the cases using a 22-gauge needle, and aspirates were submitted as needle and syringe washings in a cytology fixative (30% ethyl alcohol in physiologic saline). From these washings filter preparations were made on Sartorius or Gelman filters (pore size, 3 microns) and stained by the Papanicolaou method. Additionally, cell block preparations were made from the aspirate. After processing, sections were cut and stained by hematoxylin-eosin, Prussian blue, alcian blue, mucicarmine, and Von Kossa and congo red stain. No air-dried smears were made, and no electron microscopic studies were done. RESULTS: Stained cytologic preparations and cell blocks showed numerous nonbirefringent crystalloids of varying sizes and shapes appearing as rectangles, needles, squares and rods mixed with neutrophils and rare multinucleated giant cells. No salivary gland components were seen, and all special staining was negative. CONCLUSION: Fine needle aspiration cytology not only provided an accurate diagnosis of sialadenitis with crystalloids but also resulted in adopting conservative management and avoiding unnecessary surgery.

Adolescent↗
PubMedDate not supplied

Study of moving and handling practices on two medical wards.

This small exploratory pilot study was undertaken to explore the moving and handling practices of nurses working on two medical wards and to determine nurses' perceptions of factors that might influence those practices. Data were collected by means of non-participant observation and semi-structured interviews. The results suggest that risk assessment of the task, load, environment and individual capabilities, carried out in the clinical area, was often incomplete. Factors influencing moving and handling practice included insufficient equipment, lack of space, unsuitable uniforms, and negative attitudes towards changing practice. In view of changing practices, nurses need to be aware of the factors that promote or hinder moving and handling practice if they are to address these issues.

Attitude of Health Personnel↗
PubMedDate not supplied

Electron microscopic analysis of the normal and the activated pleural macrophage.

Despite an apparent role in pleural pathophysiology, little information is known about pleural macrophage morphology. Intrapleural tetracycline (TCN) results in pleural macrophage influx and pleural fibrosis; intrapleural carrageenan (CAR) induces macrophage influx without ensuing fibrosis. Pleural macrophages collected from normal (NL) and TCN- or CAR-exposed rabbit pleural spaces were examined with electron microscopy. Cellular size; number of microvilli; pseudopods; coated pits (CP) and coated vesicles (CV); and prevalence of golgi, rough endoplasmic reticulum (RER), and intermediate filaments (IF) were determined. The means of each variable in each group were assessed by one-way analysis of variance, with post hoc testing performed by Scheffe F test; p < or = .05 was considered significant. TCN-stimulated pleural macrophages were characterized by their small perimeters. CAR-induced pleural macrophages were marked by their large size and abundant intracellular amorphous material. They had larger perimeters, areas, and diameters than the TCN-induced or normal macrophages and thus smaller numbers of CV + CP per area. The normal pleural macrophages were characterized by more IF, microvilli, and microvilli per perimeter than either the CAR- or TCN-induced pleural macrophages. No differences between groups were found in nuclear cytoplasmic ratios, number of pseudopods, and content of golgi or of RER. The results suggest that normal pleural macrophages and TCN- and CAR-induced pleural macrophages differ morphologically and that these morphologic differences reflect functional differences.

Animals↗
PubMedDate not supplied

Mammalian hibernation: lessons for organ preparation?

The adaptations to low environmental temperatures exhibited in mammalian hibernation are many and varied, and involve molecular and cellular mechanisms as well as the systematic physiology of the whole organism. Natural torpidity is characterised by a profound reduction in body temperature and other functions lasting from a few hours to several weeks. Controlled reduction of heart rate, respiration and oxygen consumption is followed by the fall in body temperature. However, thermoregulation persists such that a decrease in ambient temperature below dangerous levels typically triggers arousal, and shivering and non-shivering thermogenesis from brown fat provide the heat to restore body temperature to normal levels. Many of the cellular mechanisms for survival are similar to those brought into play during medium-term storage of organs destined for transplantation. For example maintenance of ionic regulation and membrane fluxes is fundamental to cell survival and function at low body temperatures. Differences between hibernating and non-hibernating species are marked by differences in Na+/K+ transport and Ca++pumps. These in turn are probably associated with alterations in the lipoproteins of the plasma membrane and inner mitochondrial membrane. We have accordingly conducted a series of pilot studies in captured Richardson's ground squirrels kept in laboratory conditions as a model for hypothermic organ preservation. Tissue function was compared during the summer (non-hibernating season) with that in the winter when the animals could be: (i) in deep hibernation in a cold chamber at 4 degree C; (ii) maintained in an ambient temperature of 4 degree C but active and awake; or (iii) active at an ambient temperature of 22 degree C. The studies involved: whole animal monitoring of standard physiological parameters; whole organ (kidney) storage and transplantation for viability assessment; storage and functional assessment on an ex vivo test circuit with capacity for perfusion at normothermic and hypothermic temperatures; measurement of thyroid function; measurements of total nucleotides (ATP, ADP and AMP)and ratios by standard techniques after freeze-clamping of organs; similar nucleotide and pH measurements using31P-NMR as a non-invasive whole animal technique; and measurement of O2 uptake and gluconeogenesis using isolated renal tubules and isolated hepatocytes. Marked differences in cold tolerance were demonstrated between organs taken from hibernating versus non-hibernating individuals. In particular kidneys transplanted from animals in deep hibernation were capable of withstanding up to 72 hours of cold storage as compared with up to 24 hours in non-hibernating squirrels or in comparable sized rats. Adaptations which might provide valuable clues in our attempts to better preserve human organs for transplantation are explored in some depth in this report.

Journal Article↗
PubMedDate not supplied

Radiation from ultraviolet phototherapy sources results in photodegradation of 12(R) and 12(S)-hydroxy-eicosatetraenoic acid: high-performance liquid chromatography and polymorph migration studies.

The effect of irradiation from Sylvania PUVA lamps (emitting predominantly in the ultraviolet (UVA) region) and broadband Philips TL-12 lamps (peaking in the UVB region) on two inflammatory mediators, 12(R)- and 12(S)-hydroxy-eicosatetraenoic acid (HETE) was studied. A high-performance liquid chromatography study showed significant photodegradation of both enantiomers at a concentration of 5 micrograms/ml in phosphate-buffered saline following irradiation with 10 J.cm-2 UVA or 0.375 J.cm-2 UVB. The in vitro chemokinetic microdroplet migration response of human peripheral polymorphonuclear leukocytes from normal and psoriatic subjects was significantly reduced following irradiation of 12(R)-HETE at a concentration of 1 micrograms/ml in medium with 40 J.cm-2 UVA and 1.5 J.cm-2 UVB respectively. No such effect was seen with 12(S)-HETE. The effect of ultraviolet on skin physiology, and in particular in the successful phototherapy of a range of inflammatory skin disorders, is not fully understood. The photodegradation of inflammatory mediators such as 12-HETE, as shown in this study, provides another factor of possible therapeutic significance.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗