Spleen pigmentation in young C57BL mice is caused by accumulation of melanin

Heijden, A. van der; Dijk, J. E. van; Lemmens, A. G.; Beynen, A. C.

doi:10.1258/002367795780740113

Cited by 15 publications

(15 citation statements)

References 3 publications

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“…A consequence of this is that 123 I-MEL037 uptake values observed in the spleen of some C57BL/6J mice correlated well with the black coloration of the organ. The pigmentation, occurring in 30% of the young animals was attributed to the accumulation of melanin in melanocytes (29). In metabolite studies, the recovery of the radioactivity in the tumor dropped from 85% at 0.25 h after injection to 37% at 24 h after injection despite the 2 extractions with acetonitrile.…”

Section: Discussionmentioning

confidence: 98%

Preparation and Biologic Evaluation of a Novel Radioiodinated Benzylpiperazine, 123I-MEL037, for Malignant Melanoma

Pham¹,

Berghofer²,

Liu³

et al. 2007

Journal of Nuclear Medicine

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Radiopharmaceuticals that can target the random metastatic dissemination of melanoma tumors may present opportunities for imaging and staging the disease as well as potential radiotherapeutic applications. A novel molecule, 2-(2-(4-(4-123 Iiodobenzyl)piperazin-1-yl)-2-oxoethyl)isoindoline-1,3-dione (MEL037), was synthesized, labeled with 123 I, and evaluated for application in melanoma tumor scintigraphy and radiotherapy. Methods: The tumor imaging potential of 123 I-MEL037 was studied in vivo in C57BL/6J female mice bearing the B16F0 murine melanoma tumor and in BALB/c nude mice bearing the A375 human amelanotic melanoma tumor by biodistribution, competition studies, and SPECT. Results: 123 I-MEL037 exhibited high and rapid uptake in the B16F0 melanoma tumor at 1 h (13 %ID/g [percentage injected dose per gram]), increasing with time to reach 25 %ID/g at 6 h. A significant uptake was also observed in the eyes (2 %ID, at 3-6 h after injection) of black mice. No uptake was observed in the tumor or in the eyes of nude mice bearing the A375 tumor. Because of high uptake and long retention in the tumor and rapid body clearance, the mean contrast ratios (MCR) of 123 I-MEL037 were 30 and 60, at 24 and 48 h after injection, respectively. At 24 h after injection of mice bearing the B16 melanoma, SPECT indicated that the radioactivity was located predominately in the tumor followed by the eyes, whereas no specific localization of the radioactivity was noted in mice bearing the A375 human amelanotic tumor. In competition experiments, uptake of 123 I-MEL037 in brain, lung, heart, and kidney-organs known to contain s-receptors-was not significantly different in haloperidol-treated animals compared with control animals. Therefore, reduction of uptake in tumor and eyes of the pigmented mice bearing the B16F0 tumor suggested that the mechanism of tumor uptake was likely due to an interaction with melanin. Conclusion: These findings suggested that 123 I-MEL037, which displays a rapid and very high tumor uptake, appeared to be a promising imaging agent for detection of most melanoma tumors with the potential for development as a therapeutic agent in melanoma tumor proliferation.

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Section: Discussionmentioning

confidence: 98%

Preparation and Biologic Evaluation of a Novel Radioiodinated Benzylpiperazine, 123I-MEL037, for Malignant Melanoma

Pham¹,

Berghofer²,

Liu³

et al. 2007

Journal of Nuclear Medicine

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“…The fact that the caecum‐colon region of the gastrointestinal tract plays a significant role in mineral absorption, is in agreement with the findings of Drochner (1984), Bruce & Sundsto‐L (1995), Kienzle et al . (1995) , Van Der Heijden et al . (1995) and O'Quinn et al .…”

Section: Discussionmentioning

confidence: 99%

“…Partridge (1978), Partridge (1986), Larsen (1993) and Mroz (1995) reported positive disappearances of P in the ileum but negative values post‐ileally. On the other hand, Drochner (1984), Bruce (1995), Kienzle (1995), Van Der Heijden (1995) and O'Quinn (1997) reported substantially higher total tract than precaecal P and Ca disappearances. The first aim of this study was to investigate the importance of the Ca/P ratio on precaecal and total tract disappearances at two P levels, and with or without phytase supplementation.…”

Section: Introductionmentioning

confidence: 98%

Effects of dietary Ca/P ratio, P level and microbial phytase supplementation on nutrient digestibilities in growing pigs: precaecal, post‐ileal and total tract disappearances of OM,

Seynaeve

Janssens

Hesta

et al. 2000

Animal Physiology Nutrition

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Eight female pigs (26–61 kg) provided with a simple T‐cannula about 10 cm proximal to the ileo‐caecal valve, were used in two experiments to investigate the effects of Ca/P ratio, P level and supplementation with phytase (500 FTU/kg) on precaecal, post‐ileal and total tract disappearances of organic matter (OM), phosphorus (P) and calcium (Ca). In experiment 1, two Ca/P ratios and two P levels were tested according to a 2 × 2 factorial arrangement within a Latin square design. In experiment 2, the diets of experiment 1 were supplemented with phytase (500 FTU/kg). There was a substantial absorption of OM, P and Ca in the post‐ileal tract for all diets. Precaecal and total tract disappearances of OM were reduced by phytase addition (−4.4 and −0.8%, respectively). Supplementation with phytase resulted in an improvement of total tract and post‐ileal P disappearances by 10.3 and 12.1%, respectively, without affecting precaecal P disappearance. Addition of feed phosphate resulted in a higher precaecal disappearance of P (+10.8%), resulting in a higher total tract disappearance of P (+5.9%). Addition of limestone had little effect on disappearances of OM, P and Ca, but reduced activity of supplemental phytase and had a negative influence on growth performance. Precaecal, post‐ileal and total tract Ca disappearances were hardly affected by the examined dietary factors. The results might indicate that P from feed phosphate is absorbed primarily prececally and that P from phytate, liberated by microbial phytases, is dominantly absorbed post‐illeally.

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“…Moreover, even in the presence of melanocytes, melanin and melanosomes can be generated ab ovo in other types of cells (9–11).…”

Section: Viewpoint #2mentioning

confidence: 99%

What are melanocytesreallydoing all day long…?

Płonka

Passeron

Brenner

et al. 2009

Experimental Dermatology

264

242

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Everyone knows and seems to agree that melanocytes are there to generate melanin -an intriguing, but underestimated multipurpose molecule that is capable of doing far more than providing pigment and UV protection to skin (1). What about the cell that generates melanin, then? Is this dendritic, neural crestderived cell still serving useful (or even important) functions when no-one looks at the pigmentation of our skin and its appendages and when there is essentially no UV exposure? In other words, what do epidermal and hair follicle melanocytes do in their spare time -at night, under your bedcover? How much of the full portfolio of physiological melanocyte functions in mammalian skin has really been elucidated already? Does the presence or absence of melanoctyes matter for normal epidermal and ⁄ or hair follicle functions (beyond pigmentation and UV protection), and for skin immune responses? Do melanocytes even deserve as much credit for UV protection as conventional wisdom attributes to them? In which interactions do these promiscuous cells engage with their immediate epithelial environment and who is controlling whom? What lessons might be distilled from looking at lower vertebrate melanophores and at extracutaneous melanocytes in the endeavour to reveal the 'secret identity' of melanocytes? The current Controversies feature explores these far too infrequently posed, biologically and clinically important questions. Complementing a companion viewpoint essay on malignant melanocytes (2), this critical re-examination of melanocyte biology provides a cornucopia of old, but underappreciated concepts and novel ideas on the slowly emerging complexity of physiological melanocyte functions, and delineates important, thought-provoking questions that remain to be definitively answered by future research. Praeludium pigmentosumFor those uninformed, the skin is an inert plastic wrap nature provides to keep us in and everything else out. How mistaken they are! The skin, in particular the epidermis, is one of the most active of all tissues ⁄ organs.Nature wisely placed the capillary circulation in the dermis. The epidermis has no vascular circulation thereby minimizing the probability that toxic chemicals, bacteria or fungi that penetrate through the stratum corneum can diffuse into the blood stream. That does not leave the epidermis defenseless. The epidermis has proteins called defensins that have anti-microbial properties. There are Toll-like receptors that recognize invading organisms and incite a host response. Even more interesting, it is well known that keratinocytes are avidly phagocytic. They have the capacity to phagocytize the wandering, invasive fungi or bacteria and digest them. It is both interesting and important that a-MSH stimulates the ingestion of candida by keratinocytes. a-MSH has a wide array of activities, only one of which is to stimulate the synthesis of melanin. There are receptors for a-MSH on Langerhans cells and keratinocytes as well as melanocytes. It has the ability to suppress infla...

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Spleen pigmentation in young C57BL mice is caused by accumulation of melanin

Cited by 15 publications

References 3 publications

Preparation and Biologic Evaluation of a Novel Radioiodinated Benzylpiperazine, 123I-MEL037, for Malignant Melanoma

Preparation and Biologic Evaluation of a Novel Radioiodinated Benzylpiperazine, 123I-MEL037, for Malignant Melanoma

Effects of dietary Ca/P ratio, P level and microbial phytase supplementation on nutrient digestibilities in growing pigs: precaecal, post‐ileal and total tract disappearances of OM,

What are melanocytesreallydoing all day long…?

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