Multi-method evaluation of a paediatric ambulatory care unit (PACU): impact on families and staff.

AIM: To assess the impact of a purpose-built, short stay paediatric ambulatory care unit (PACU) on the patient journey and perceptions of parents, staff and referrers. METHODS: Multi-method evaluation, including a parent survey (n = 104), patient journey mapping (n = 10), staff interviews (n = 10), a referrer survey (n = 16), routine activity analysis, and a comparison with the A&E service (A&E parent survey: n = 41). RESULTS: Almost all parents attending PACU (94%) were satisfied with the service and significantly more likely to feel "very" satisfied than parents attending A&E (PACU: 51%, A&E: 31%; p = 0.03). Further, over three quarters (77%) of PACU parents preferred the new model to traditional A&E services. They reported receiving sufficient information (93%), reduced anxiety (55% anxious before service, 13% anxious after; p<0.001), "quick" waiting times (median: 35 min), and enhanced confidence (87%) and understanding (89%) in dealing with their ill child. The number of stages in the patient journey was reduced from six ("traditional" A&E pathway) to four (PACU pathway). Staff and referrers reported this was a "superior" model to A&E, but that improvements were required around appropriate referrals and the need for more multi-disciplinary protocols and liaison. CONCLUSION: Our study suggests that the PACU model is perceived to be an effective alternative to standard A&E services for the assessment and early management of acutely ill children and their families attending a hospital. It is highly valued by users, staff and referrers and enhances the patient journey. Lessons learnt include the need to enhance multi-disciplinary processes and clarify the role of this form of acute care provision in the wider healthcare system.

Angiomorphology of the pigmented Bomirski melanoma growing in hamster eye.

An melanotic line of Bomirski Hamster Melanoma (BHM Ma) was implanted into the anterior chamber of the hamster eye and the ensuring vascular system was studied using scanning electron microscopy (SEM) of vascular corrosion casts. The tumor vasculature, induced mainly from the host iris vessels, showed generally disorganized and irregular patterns. Tortuous tumor capillaries of uneven contour with local dilatations and constrictions were drained by markedly dilated, thin-walled, venous vessels connected with the eye veins. Vascular sprouting and, less frequently, intussusceptive formation of new vessels were observed at the periphery and also within the tumor mass. The presence of numerous nodular outgrowths, varying in size, on the surface of dilated venules and venous vessels represent morphological evidence for continuous remodeling of the tumor vasculature. The observed features of the vascular system seem to provide a pathway for further tumor expansion. Our study showed that BHM Ma line, originating from an aggressive skin melanotic melanoma, implanted to the eye anterior chamber gave rise to rapidly growing tumors with the capability of inducing abundant vasculature which allows metastasis to the lungs, kidneys and regional lymph-nodes.

Experimental ruthenium plaque therapy of amelanotic and melanotic melanomas in the hamster eye.

The effects of beta-radiation on melanoma implanted into the hamster's eye were investigated. Two Bomirski hamster melanomas (BHMs), differing in their melanin content, were compared with regard to their radiosensitivity to ruthenium-106 (106Ru) radiation. Tumours growing in the iris were irradiated with 3, 6 or 10 Gy of 106Ru given as a single dose or in four fractions at 24 h Intervals. Tumour growth kinetics and distant metastases were studied, and the eyeballs were examined histologically. Dose-dependent delay of tumour growth was observed in both melanomas. After treatment with a dose of 6 Gy, the Ab amelanotic tumours grew 2.6 times slower, and the Ma melanotic tumours 1.4 times slower than untreated ones. The location of metastases differed in the two tested lines--pigmented metastases were found mainly in the lungs, while unpigmented metastases were found mainly in the kidneys. Histopathological analysis showed signs of blood vessel damage such as endothelial cells swelling, erythrocyte extravasation and tumour necrosis. This last finding increased with the rising dose of beta-radiation. Pigmented tumours were found to be two times more resistant to beta-radiation than amelanotic ones. The pattern of metastases of BHMs is determined by the type of melanoma (Ab or Ma). Exposure to beta-radiation from 106Ru did not significantly affect either the number or size of metastases except at a dose of 10 Gy. This dose caused a statistically significant decrease in the number of metastases in the Ma melanotic subline.

Transplantable melanomas in gerbils (Meriones unguiculatus). I. Origin, morphology and growth rate.

A family of serially transplanted melanomas in gerbils is described. These tumors were derived from the cutaneous melanotic melanoma that arose in 1 of 44 gerbils injected postnatally with N-ethyl-N-nitrosourea. It consists of a slow growing heavily melanotic parental line and two fast growing melanotic (FGM) and amelanotic (A-FGM) lines that appeared abruptly during serial transplantation of the parental tumor. The FGM melanotic line originated after a sudden acceleration of growth of the parental line during the 4th in vivo passage that was accompanied by a decrease in both pigmentation and metastasizing potential. The A-FGM derived from the depigmented tissue of the 7th in vivo passage of the FGM line and has been characterized by an amelanotic phenotype, an increased metastasizing potential and similar growth rate to that of the FGM. Once established, both lines expressed considerable phenotypic stability during serial transplantation in gerbils. Thus, the Zeman UJ melanomas represent the first established family of transplantable melanomas in gerbils, which serve as a model for pigmented cell and melanoma research and as a subject for a retrospective analysis of the phenomenon of tumor evolution.

Effect of melanin on radiation response of CHO cells.

The effect of the presence of melanin on the response of mammalian cells to ionizing radiation was investigated in a model system utilizing the ability of Chinese hamster ovary cells to incorporate melanin by endocytosis. Cells were incubated in monolayer cultures from 2 to 20 hours with melanin prepared from 'beef eye' or synthesized by air oxidation of 3,4-dihydroxyphenylalanine. For asynchronous cultures, the survival curve parameters for cells incubated with both types of melanin were indistinguishable from those of the same cells without added melanin. The radiation response to fractionated doses of 6 Gy separated by various periods did not indicate any effect of melanin on the extent or kinetics of repair of sublethal damage. Likewise, the repair of potentially lethal damage in plateau phase cultures was unaffected by the presence of melanin. Thus the explanation for the clinical radiation resistance of melanomas in the absence of a direct radiation effect might more likely be found in consideration of other factors such as the role of melanin in oxygen consumption or in differentiation.

Melanin endocytosis by cultured mammalian cells. A model for melanin in a cellular environment.

The incorporation of natural eumelanin from bovine eyes and synthetic 3,4-dihydroxy-phenylalanine (dopa) melanin into Chinese hamster ovary (CHO) cells is reported. The process is linear for at least 8 h. Electron microscopy showed phagocytosis of melanin, either as a single granule or in groups of granules, into cell lysosomes with subsequent degradation of the granule. The general features of the ingestion and degradation processes mimic those of the incorporation of melanosomes into keratinocytes. CHO cells with ingested melanin in general revealed properties very similar to those of the pigment-free CHO cell: cell division, oxygen consumption and plating efficiency were not greatly altered by moderate concentrations of pigment. This suggests that the CHO cell system may be useful for the study of pigment in a cellular environment; pigment-free CHO cells are well characterized and can serve as a good control. Preliminary applications are reported: demonstrations of (1) incorporation of metal ions (Al3+) into CHO cells using melanin as a carrier; (2) the ability of melanin to enhance the rate of oxygen consumption during photo-irradiation of the cells.

Detectability of radiation damage to melanoma cells using ESR spectroscopy. A review.

Comparison of indirect and direct methods applicable for the examination of radiation damage to melanoma cells leads to the conclusion that the only method useful for its detection appears to be the indirect method. The paper describes the principle, examples of radiobiological applications, and perspectives of future development of a new indirect method of measuring oxygen consumption by neoplastic cells under in vitro conditions. The method is based on the use of a spin label technique.

Rate of oxygen consumption of hamster melanoma cells as a factor influencing their radioresistance.

It has been reported in recent years that the level of radiosensitivity of neoplastic cells in vivo and of sphaeroids in vitro can be modified by controlling their rate of oxygen consumption. Thus, an attempt was made to compare this rate in the case of the melanotic and amelanotic lines of Bomirski hamster melanoma in vitro, as it is known that these two lines distinctly differ in their reactivity to ionizing radiations. The measurements carried out by the use of a new ESR method revealed that pigmented and pigmentless cells consume oxygen at significantly different rates. This means that oxygen utilization may contribute to the overall level of radioresistance of melanoma cells.