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An Electron Microscopic Study of Melanin in the Hair and Hair Follicles

Richard S. Snell
1972 Journal of Investigative Dermatology  
In the lower part of the sheath t he majority of the cells con ta in ed onl y a s ma ll amo un t of melanin p igment.  ...  In the upper part of the outer root sheath the distribution of melanin closely resemb led t hat found in t he epider mi s .  ...  T he majori ty of cells at thi s level contained onl y a few melanosomes. However, a n occas iona l ce ll s howed a large group of me lanosomes (Fig. 5) .  ... 
doi:10.1111/1523-1747.ep12625934 pmid:5050344 fatcat:etav5n7hkrb6pgj3mna7uw7mva

Effect of the Alpha Melanocyte Stimulating Hormone of the Pituitary on Mammalian Epidermal Melanocytes

Richard S. Snell
1964 Journal of Investigative Dermatology  
Snell (8) showed in the guinea pig that beta M.S.ll. caused an increase in the length, width and complexity of the dendritic processes of the epidermal melanocytes and this was due to an increase in the  ...  S. A. and supplied by Dr. R. Guillemin and Dr. A. V.Schally.  ...  (19) ) and the presence of estrogen and small doses of progesterone stimulates melanin production (Bischitz and Snell (19) ; Snell and Bischitz (18) findings.  ... 
doi:10.1038/jid.1964.74 fatcat:jl5lywh7tvh4lm2gq7d42wjtp4

Effect of Melatonin on Mammalian Epidermal Melanocytes**From the Section of Dermatology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut

Richard S. Snell
1965 Journal of Investigative Dermatology  
The skin specimens were then processed under identical conditions and treated with the dopa reagent as described previously (Snell (5) ).  ...  The skin specimens were then processed under identical conditions and treated with the dopa reagent as described previously (Snell (5) ).  ... 
doi:10.1038/jid.1965.49 fatcat:ivixwmgg5vepddxfcpiw6hhh4u

An Electron Microscopic Study of Melanin in the Hair and Hair Follicles

Richard S. Snell
1972 Journal of Investigative Dermatology  
In t hi s study an R.  ...  Note that at seve ra l s ites (arrowed) the d ense material is attached to t he inner s urface of t he t hi cke ned plasma memb ranes. x 16,700.  ... 
doi:10.1111/1523-1747.ep12539924 pmid:4336521 fatcat:zwwumzwbfjgt5jvinx5tfsbv2y

The Pigmentary Changes Occurring in the Breast Skin During Pregnancy and Following Estrogen Treatment**From the Section of Dermatology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut

Richard S. Snell
1964 Journal of Investigative Dermatology  
All the skin specimens were processed and treated with the Dopa reagent as described previously (Snell 1). Skin sheets and vertical skin n fi® (cL A FIG. 1.  ...  Sncll (13 and 14) has shown that both alpha-and beta-melanocyte stimulating hormones are capable of strongly stimulating melanogenesis in mammalian skin ;S C / '// - / //S Cf •--, - / /#•• a V but the  ...  Bisehitz and Snell (2) and Snell and Bischitz (7) showed that different doses of estrogen were capable of greatly stimulating melanogenesis as seen by the increased production of melanin both inside  ... 
doi:10.1038/jid.1964.140 fatcat:dan6wvarm5d7nbxn3zrxlxcbtq

Effect of Size of Dose and Prolonged Administration of Alpha Msh on the Melanophores of the Frog**From the Department of Medicine, Yale University and The Department of Anatomy, New Jersey College of Medicine and Dentistry

Richard S. Snell, Stanko Kulovich
1969 Journal of Investigative Dermatology  
OF ALPHA MSH ON THE MELANOPHORES OF THE FROG* RICHARD S.  ...  B.Lerner and S. Lande. ment cells are situated in the basal layer of the epidermis and donate melanin to adjacent epidermal cells.  ... 
doi:10.1038/jid.1969.52 pmid:5823218 fatcat:nggelzm43ff2za7m2f6rx67gae

Skin Pigmentation in Relation to the Menstrual Cycle*

Richard S. Snell, Raymond Turner
1966 Journal of Investigative Dermatology  
The skin biopsy specimens were processed using the Dopa reaction as described previously (Snell and Bisehitz (2) ).  ...  SKIN PIGMENTATION IN RELATION TO THE MENSTRUAL CYCLE* RICHARD S. SNELL, M.D., Pn.D. AND RAYMOND TURNER, M.D.  ...  The skin biopsy specimens were processed using the Dopa reaction as described previously (Snell and Bisehitz (2) ).  ... 
doi:10.1038/jid.1966.119 fatcat:rg5jipcjqjdnbof7ohbynsoscm

The Response of Mammalian Epidermal Melanocytes in Culture to Hormones**From the Departments of Medicine and Anatomy, Yale University School of Medicine, New Haven, Connecticut

Sidney N. Klaus, Richard S. Snell
1967 Journal of Investigative Dermatology  
Changes in the skin color of mammals, ineluding man, have been brought about by the administration of certain hormones (1, 2, 3). The manner in which the hormones act at the cellular level is not yet clear. In this report, the effects of four hormones on normal adult guinea pig melanocytes in tissue culture are described. The hormones are alpha melanocyte-stimulating hormone (a-MSH), acetylcholine, norepinephrine, and melatonin. MATERIAL5 AND METHODs Epidermal cells were cultivated from adult
more » ... ivated from adult red and brown guinea pig skin according to the method of Cruickshank (4). Small pinch grafts were taken from the ears after they had been shaved and cleansed with 70 per cent alcohol. The grafts were floated, dermal surface downwards, on a solution of 0.15 per cent trypsin (Difco 1:250) diluted in calcium-and magnesium-free Tyrode's solution, for 15-20 minutes at 37° C. The dermis was peeled from the grafts with forceps and the intact epidermis was transferred to a watch glass that contained a small amount of Eagle's Minimal Essential Medium with 10 per cent calf serum. The cells were dispersed with paired needles. Sufficient medium then was added to produce a suspension of approximately 200,000 cells/ml. Twotenths milliliters of the suspension was injected into each Cruickshank chamber, the aperture sealed with beeswax, and the chamber incubated at 37° C., coverglass side downwards, for 24 hours. The chambers then were turned over and incubation continued with the coverglass uppermost. In this investigation, the ages of the cultures ranged from 2 days to 29 days. The cells were observed by phase contrast microscopy. A melanocyte was selected for observation, and its behavior was recorded with a time lapse movie unit on Kodak Plus-X Reversal film. Frames were exposed every eight seconds. During the first hour of observation, the normal range of movement of the melanin granules and cell membranes in a hormone-free medium was established. The medium then was aspirated from the culture chamber and replaced with medium conand AM 5264-06. taming hormone. The melanocytes were observed and photographed for periods varying from 2 to more than 6 hours. Eight different cultures were used for each hormone. The concentrations of the various hormones ia the media are listed in Table I . Once a culture had been exposed to a hormone, it was not used again. The melanin granule dispersion or aggregation effect of each of the hormone-culture medium solutions was tested by the in vitro frog skin technic (5). RESULTS Appeoronees of Cultures During the Control Period After incubation for 24 hours, the cultures of epidermal cells seemed fairly uniform. Many cells had become attached to the coerglass and appeared flattened. The medium usually was renewed at this stage. During the changeover, cells that had not survived were washed out with the old medium. At 36-48 hours, the keratinocytes underwent further flattening and their cytoplasm contained a number of highly refractile bodies. The keratinocytes, at this stage, tended to be triangular and the cell membranes undulated continuously (Fig. 1) . During the next 3-4 Weeks the kcratinocytes enlarged and multiplied. As cell division continued, the small islands of cells enlarged gradually and finally met to form a continuous sheet of cells (Fig. 2) . The melanocytes at 24-48 hours often had a quadrilateral or fusiform shape (Fig. 3) . Towards the end of this period they began to send out multiple branching processes. Melanin granules were distributed throughout the cytoplasm of the cell body of most of the melanocytes examined. Sometimes the granules were more heavily concentrated around the periphery of the cytoplasm; at times, small areas of cytoplasm near the nucleus practically were devoid of granules. Time-lapse sequences indicated that the granules oscillated and cytoplasmic flow carried them along as the dendritic processes were extended or retracted. After only one or two days of cultivation, the melanocytes, With their pigment granules and multiple branching 352
doi:10.1038/jid.1967.57 fatcat:7fvlh3uktjahvmbunrvvj6y3xm

Prototypical Networks for Few-shot Learning [article]

Jake Snell, Kevin Swersky, Richard S. Zemel
2017 arXiv   pre-print
k in {1, . . . , N C } do S k ← RANDOMSAMPLE(D V k , N S ) Select support examples Q k ← RANDOMSAMPLE(D V k \ S k , N Q ) Select query examples c k ← 1 N C (xi,yi)∈S k f φ (x i ) Compute prototype from  ...  RANDOMSAMPLE(S, N ) denotes a set of N elements chosen uniformly at random from set S, without replacement.  ... 
arXiv:1703.05175v2 fatcat:uhozztpvfvcgjaj7arv5mgtgna

The Effect of Laser Radiation on the Mammalian Epidermal Melanocyte*

Charles J McDonald, Richard S Snell, Aaron B Lerner
1965 Journal of Investigative Dermatology  
All specimens were processed under identical histochemical conditions as described by Snell (6). Half of each specimen was subjected to the DOPA reaction and the other half to the tyrosine reaction.  ...  All specimens were processed under identical histochemical conditions as described by Snell (6) .  ... 
doi:10.1038/jid.1965.102 fatcat:iuzqrqzbababdkempi2ffso6gq

The Effect of Chlorpromazine on Oculocutaneous Pigmentation in the Guinea Pig**From the Section of Dermatology, Department of Medicine and Department of Anatomy, Yale University School of Medicine, New Haven, Connecticut

Charles J. McDonald, Richard S. Snell, Aaron B. Lerner
1967 Journal of Investigative Dermatology  
Group IV S' labeled chiorpromazine was not detected in any of the autoradiographic sections examined.DiscussioNChlorpromazine has been used (1) to alleviate the multiplicity of symptoms wInch arc manifestations  ... 
doi:10.1038/jid.1967.102 fatcat:kxuzrffy75b3relt7rm2mv7vdi

Guide to presenting clinical prediction models for use in clinical settings

Laura J Bonnett, Kym I E Snell, Gary S Collins, Richard D Riley
2019 BMJ (Clinical Research Edition)  
(t) = S 0 (t) exp (β 1 X 1 + β 2 X 2 + β 3 X 3 + ... ) 1 -S (t) = 1 -S 0 (t) Box 1: Typical format of prediction models developed using regression to enable risk predictions in new individuals (adapted  ...  Estimates of baseline survival at one year (S 0 (1)) and three years (S 0 (3)) are also provided, based on a Nelson-Aalen type estimator.  ... 
doi:10.1136/bmj.l737 pmid:30995987 fatcat:lulcgrujq5h5lpl7yd32nygh2y

Learning to Generate Images with Perceptual Similarity Metrics [article]

Jake Snell, Karl Ridgeway, Renjie Liao, Brett D. Roads, Michael C. Mozer, Richard S. Zemel
2017 arXiv   pre-print
The contrast C(x, y) and structure S(x, y) components are applied at all scales. The luminance component is applied only at the coarsest scale, denoted M .  ...  The single-scale SSIM metric [32] compares corresponding pixels and their neighborhoods in two images, denoted x and y, with three comparison functions-luminance (I), contrast (C), and structure (S):  ... 
arXiv:1511.06409v3 fatcat:ig2kqqvucjcihbogroo5djy3bi

Learning to generate images with perceptual similarity metrics

Jake Snell, Karl Ridgeway, Renjie Liao, Brett D. Roads, Michael C. Mozer, Richard S. Zemel
2017 2017 IEEE International Conference on Image Processing (ICIP)  
The contrast C(x, y) and structure S(x, y) components are applied at all scales. The luminance component is applied only at the coarsest scale, denoted M .  ...  The single-scale SSIM metric [29] compares corresponding pixels and their neighborhoods in two images, denoted x and y, with three comparison functions-luminance (I), contrast (C), and structure (S):  ... 
doi:10.1109/icip.2017.8297089 dblp:conf/icip/SnellRLRMZ17 fatcat:ykczprlhjbhzbax5btzs7vnjai

Flexible Few-Shot Learning with Contextual Similarity [article]

Mengye Ren, Eleni Triantafillou, Kuan-Chieh Wang, James Lucas, Jake Snell, Xaq Pitkow, Andreas S. Tolias, Richard Zemel
2020 arXiv   pre-print
., 2016) , and Prototypical Network (Snell et al., 2017) .  ...  Further, the prototypical network likelihood is given by, c j = 1 k x i ∈S j g(x i ) = 1 k x i ∈S j d l=1 z il W a l , for j ∈ {0, 1}, (A) p(y = 0|x) = exp − W x − c 0 2 2 exp − W x − c 0 2 2 + exp − W  ... 
arXiv:2012.05895v1 fatcat:soy4cb65szcvrjoxypwesf3ryy
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