Melanocyte-stimulating hormone, tyrosinase activity and the regulation of eumelanogenesis and phaeomelanogenesis in the hair follicular melanocytes of the mouse

ABSTRACT Skin tyrosinase levels and the eumelanin and phaeomelanin contents of the hair were measured in pubertal and adult C3H–HeA*vy mice that grow dark and golden yellow hair respectively. Hair growth was initiated by plucking and the skin tyrosinase levels, which increased during the growth of new hair and peaked at around 9 days after plucking, were higher during the growth of dark hair in the pubertal mice than during the growth of yellow hair in the adult mice. Although there was only a twofold difference in the phaeomelanin contents of these two types of hair, the dark hair of the pubertal mice contained over 20 times more eumelanin than the golden-yellow hair of the adult mice. These results suggest that the changes in coat colour in C3H–HeA*vy mice are due mainly to changes in eumelanin synthesis by the hair follicular melanocytes and that the production of this pigment requires higher levels of the enzyme tyrosinase than does the production of phaeomelanin. These changes did not appear to be related to plasma α-MSH levels. Nevertheless, administration of α-MSH increased skin tyrosinase activity in the pubertal mice that were growing dark hair and produced a twofold increase in the eumelanin content of the hair. However, it had no such effects in adult mice and also failed to affect the phaeomelanin content of the hair in both groups of mice. In contrast to α-MSH, bromocriptine decreased skin tyrosinase levels and the eumelanin content and increased the phaeomelanin content of the hair in pubertal mice. These effects of bromocriptine were unrelated to plasma immunoreactive α-MSH levels and were not restored when α-MSH was administered together with the dopamine agonist. Although the present results support the idea that α-MSH increases coat darkening in the C3H–HeA*vy mouse through its actions on tyrosinase activity and eumelanin synthesis, it seems that these actions are more dependent on changes at the melanocyte level than changes in circulating α-MSH. The present results further suggest that dopaminergic mechanisms may also play a direct regulatory role in the control of coat colour in this mouse. J. Endocr. (1986) 109, 15–21

The Martyrdom of General George Armstrong Custer, U.S.A

Dime novelist Frederick Whittaker first met George Armstrong Custer in the New York offices of Galaxy magazine, for whom the general was writing a series of articles (later collected as My Life on the Plains). Whittaker had served honorably and well in the Civil War himself; yet despite a serious chest wound received in the Wilderness, his zest for martial glory and his admiration for the glorious had not diminished. He immediately became “The Boy General's” ardent admirer and, after the battle of the Little Big Horn in 1876, was his fallen hero's most ardent apologist. Within two weeks of the first news of the battle, Whittaker had published eighty lines of creditable doggerel in the Army and Navy Journal—“Custer's Last Charge”; a eulogy in Galaxy appeared shortly afterward (in which he compared “The Yellow Hair,” favorably, to Don John of Austria, the Black Prince, Alexander the Great; Custer was as much the beau sabreur as Murat, as brilliant as Seidlitz; he charged like Murat and died like Leonidas); and then the Grand Finale, a six-hundred-plus page biography, The Life of General George A. Custer, written and put into print within six months of Custer's death. As a writer for Beadle and Adams, Whittaker had learned how to roll out his prose with steam press rapidity; but the tone, the fullness of the narrative, and the ardor which blushes every page show that these various works were de amore.

Cnephia abdita, a New Black Fly (Diptera: Simuliidae) from Eastern North America

Female: General body color dark brown to blackish-brown; legs lighter brown. Length: body, 2.0-2.7 mm.; wing, 2.1-2.3 mm.Head dark, posterior and undersurface densely covered with long, pale yellow hair; a row of stout, erect, dark hairs along posterior and lateral margins of eye. Frons tinged with gray; moderately broad, diverging above; covered with moderately long, decumbent, pale yellow hair. Clypeus lighter than frons, tinged with gray; longer than wide; densely covered with fine, pale yellow hair. Antenna short, eleven-segmented; uniformly dark brown, covered with short, pale yellow hair; flagellun about 2.5 times as long as scape and pedicel; pedicel considerabIy larger than other segments. Palpus yellowish-brown, covered with fine, pale ykllow hair and some coarser, dark hair; third segment slightly longer than fourth and slightly shorter than fifth; sensory vesicle of third segment globular, small, about one-fifth as long as the segment and is proximally situated; the tube leading from the sensory vesicle to the exterior is short, arises dorsally on the distal portion of the vesicle, extends nearly vertical and is nearly of uniform width (Figs. 4, 5). Edges of mandible with about 32 fine serrations; galea of maxilla with about 32 large, retrorse teeth. Median space of buccopharyngeal apparatus broad and shallow; dorsolateral arms broad, outwardly curved and directed posteriorly, a sclerotized ridge occurs on inner margin (Fig. 6).

Charles Bolton 1870-1947

Bolton was a Yorkshireman, born 24 September 1870, at Whitby, and his forebears may have been long in that neighbourhood. In many ways he recalled the old stock of Danish invaders who had grasped for settlement that pleasant part of England. Big and strongly made, with fair skin and reddish yellow hair that in his younger days was accompanied by a great drooping moustache, he had no small share of the Viking characteristics. An outspoken cheerfulness, whatever the troubles looming around, a genial accessibility to all, and a strong loyalty to his fellows, these were qualities of his manly nature, and they at once gained for him the affection of every student and colleague at the medical school where his life was spent. Resoluteness, not dogged and determined but just inborn, kept him easily on his chosen path of work, and enabled him straightforwardly, and therefore with little jealousy from others, to take to himself good opportunities for all he desired to do. Such thoughts as spring from artistic sensitiveness or troubling human sympathy did not arise to give complexity to his mind. But that mind was very strong and clear, with powers of accurate judgment and the uncommon breadth of outlook which is, perhaps wishfully, so often spoken of as common sense. His parentage held no note of distinction, and his father having died relatively young the mother, Jane, daughter of Joseph Shaw of Huddersfield, was left to bring up her two sons on small resources. Both of them had the gift of intellect and they may have received it from their mother, for her personality always stayed in their memories as a guiding influence upon ambition. Both resolved to become doctors, not an easy achievement half a century ago for youngsters without means; and both had to wait and earn some reserves of money before they could seek entry to a London medical school.

A NEW HELIOLONCHE FROM SOUTHERN CALIFORNIA (LEPID., NOCTUIDAE)

Head, palpi and thorax clothed with rough olive-ochreous hair, the palpi with a considerable admixture of black hairs apically. Pectus and legs with similarly colored, rough vestiture. Abdomen dorsally with sparse ochreous hairs over a black ground and with the posterior margins of segments ringed narrowly with ochreous scales ; laterally and ventrally with strong vestiture of rather bright yellow hair. Primaries deep pink with a broad, subterminal curved band of oliveochreous from below apex of wing to near base of wing above vein I, narrowing considerably at this point; a streak of the same color in the cell.