Hair Wave Research Articles

Countermeasure Analysis of The Status Quo of Digital Communication Among the Elderly under the Background of COVID-19 Epidemic

The aging of the population is an important trend of social development, a manifestation of the progress of human civilization, and a basic national condition of China for a long time to come. In the digital age, with the “silver hair wave” and the impact of the epidemic, the “cloud dilemma” situation appears. To overcome this impasse and develop a “digital” pattern that favors the old, we must go further into the path of wisdom to assist the elderly and create a social environment that prioritizes providing for the elderly, filial piety, and respect for the elderly.

Potassium bromate – inhalable fraction. Documentation of proposed values of occupational exposure limits (OELs)

Potassium bromate (V), (KBrO3) exists as white crystals, crystalline powder or granules. It is highly soluble in water, tasteless and odourless. Potassium bromate is a strong oxidizing agent. In the past it has been used as food additive in flour milling, as an ingredient in fish-paste in Japan, in cheese making, in beer malting, as a component of cold hair wave liquid and an oxidizing compound. Moreover, bromate is formed as a by-product of water disinfection by ozonation and is frequently detected in tap and bottled water. In fact bromate is one of the most prevalent disinfection by-product of surface water. Occupational exposure to potassium bromate occurs mainly in production plants during packaging processes. In Poland, about 1 160 persons were exposed to this compound in 2016. Bromate caused many acute poisonings by accidental ingestion, mainly among children, and more often ingested for tentative suicide by young women, especially hairdressers. In the acute phase of poisoning, gastrointestinal disturbances, irreversible hearing loss, and acute renal failure were observed. Acute renal failure was associated with hemolytic uremic syndrome. There are no data on chronic intoxication of humans by potassium bromate and epidemiological studies on this subject. On the basis of the value of median lethal dose (LD50) per os in rat, potassium bromate has been classified as a compound belonging to the category „Toxic”. Major toxic signs and symptoms in animals after a single intragastric administration of potassium bromate were tachypnea, hypothermia, diarrhea, lacrimation, suppression of locomotor movement, ataxic gait, and animals lying in a prone position. At autopsy the major findings were strong hyperemia of glandular stomach mucosa and congestion of lungs. Microscopically, necrosis and degenerative changes of the proximal tubular epithelium and hearing cells of internal ear were found. It was stated that the compound is not irritating, corrosive or sensitizing. In subchronic and chronic exposure of rodents, potassium bromate led to liver and kidney dysfunction and tubular epithelial damage. Potassium bromate had mutagenic and clastogenic effects. It induced point mutations, structural chromosome aberrations, micronuclei in polychromatic erythrocytes in male mice, DNA oxidative damage by modification of deoxyguanosine to 8-hydroxydeoxyguanosine, and DNA double-strand breakage. Potassium bromate induced neoplasms in rodents and exerted promotion effect in comparison with well-known carcinogens. Besides from preneoplastic changes, expressed by high incidences of renal cell tumors and dysplastic foci, bromate induced solid neoplasms, such as adenomas and adenocarcinomas in a rat kidney and thyroid, and mesotheliomas of peritoneum and tunica vaginalis testis. The European Union classified potassium bromate as a substance that can cause cancer (Group 1.B), whereas IARC classified it as a presumably carcinogenic agent for human (Group 2.B). In principle, effects of bromate on reproduction and ontogenetic development of offspring were not observed. Animal studies suggest that a kidney is a critical organ in the exposure to potassium bromate. The results of subchronic exposure of male rats to potassium bromate administered with drinking water were used to calculate the value of MAC-NDS. The critical effects in kidney were: an increase of organ weight and dose-dependent histopathological alterations defined as epithelium urinary tract hypertrophy. The NOAEL value is 1.5 mg/kg b.w./day. For the calculation of the maximum allowable concentration (MAC) value, 5 uncertainty factors with total value of 24 were used. Based on this estimation it is proposed to accept the MAC-TWA value for potassium bromate at 0.44 mg/m3. The risks of kidney and thyroid cancer in condition of occupational exposure are 2.2 · 10-3 and 0.6 · 10-3, respectively. There is no reason to determine the value of short-term exposure limit (STEL) and the biological exposure index (BEI). „Carc.1.B” notation (carcinogenic substance) was proposed

Factors Associated with Internal Phthalate Exposure among Pregnant Women

Objective: To analyze the potential factors related to phthalic acid ester (PAE) exposure in pregnant women using multivariate statistical methods. Methods: The study was conducted from April to June 2013 in Xiamen, China. A total of 1020 pregnant women (gestational age ≤16 weeks) met the criteria for inclusion in the cohort. We selected 100 participants by systematic random sampling. Participant information was collected by questionnaires, and urine samples were collected, detect five PAEs (MEP; MBzP; MBP; MEHP; and MMP) levels in urine samples. Single-factor and multi-factor logistic analysis were used to analyze the association between PAE exposure levels and potential associated factors. Results: After creatinine adjustment, medians of the five PAEs in the 100 urine samples were 54.64 μg/g, 29.25 μg/g, 17.56 μg/g, 3.91 μg/g, and 53.79 μg/g, respectively. Multivariate analysis results indicated that MMP was associated with education level and the use of hair permanents, hair dyes, and hair dryers; ORs were 0.560 and 2.056, respectively. MEP was associated with education level and makeup use during pregnancy; ORs were 0.548 and 1.968, respectively. MBP was associated with education level, the use of makeup, hair permanents, dyes, and dryers; ORs were 0.559, 1.876, and 2.812, respectively. MBZP was associated with level of education; OR was 0.482. Finally, MEHP was associated with education level, drinking water type, and medication use during pregnancy; ORs were 0.560, 1.972, and 2.100, respectively. Conclusion: PAE exposure levels in pregnant women were associated with level of education, type of drinking water, and use of medication, permanent hair waves, hair dyes, hair dryers or makeup during pregnancy.

217 The adenosine-generating ecto-enzyme CD73 regulates human hair growth

217 The adenosine-generating ecto-enzyme CD73 regulates human hair growth

Regenerative Hair Waves in Aging Mice and Extra-Follicular Modulators Follistatin, Dkk1, and Sfrp4

Hair cycling is modulated by factors both intrinsic and extrinsic to hair follicles. Cycling defects lead to conditions such as aging associated alopecia. Recently we demonstrated that mouse skin exhibits regenerative hair waves, reflecting a coordinated regenerative behavior in follicle populations. Here, we use this model to explore the regenerative behavior of aging mouse skin. Old mice (>18 months) tracked over several months show that with progressing age hair waves slow down, wave propagation becomes restricted, and hair cycle domains fragment into smaller domains. Transplanting aged donor mouse skin to a young host can restore donor cycling within a 3mm range of the interface, suggesting that changes are due to extra-cellular factors. Therefore, hair stem cells in aged skin can be re-activated. Molecular studies show that extra-follicular modulators Bmp2, Dkk1, and Sfrp4 increase in early anagen. Further, we identify follistatin as an extra-follicular modulator which is highly expressed in late telogen and early anagen. Indeed follistatin induces hair wave propagation and its level decreases in aging mice. We present an excitable medium model to simulate the cycling behavior in aging mice and illustrate how the inter-organ macro-environment can regulate the aging process by integrating both “activator” and “inhibitor” signals.

Many Paths to Alopecia via Compromised Regeneration of Hair Follicle Stem Cells

Alopecia can be caused by defective formation, defective regeneration, or increased destruction of hair follicles. Much work has elucidated the roles of diffusible morphogens in modulating hair follicle stem cell activities. Recent studies have revealed novel molecular events within the nucleus, which are required for the activation and progression of hair stem cells. These studies will provide new clues and targets for designing therapeutic strategies for hair loss.

Outback Elvis: Riding with the King in Parkes, Australia

Outback Elvis:Riding with the King in Parkes, Australia Gretchen Wood (bio) Click for larger view View full resolution Aboard the CountryLink Elvis Express, Australia's Channel Nine News interviews Ross Mancini, an Elvis tribute artist from Sydney. [End Page 98] For the past twenty years, Australian fans have gathered in Parkes, New South Wales, to celebrate Elvis Presley's birthday. Since the initial gathering of two hundred, hosted by Bob and Anne Steel at their Gracelands banquet hall, the CountryLink Parkes Elvis Festival has turned into a community-wide effort, and attendance has mushroomed to 18,000, nearly double the town's population. But why Elvis? He never traveled to Australia; nonetheless, this agricultural and mining town approximately 200 miles west of Sydney stakes a sizeable chunk of its annual economy on celebrating the Mississippi-born icon of American rock and roll. Free of the gravitas involved in a memorial festival like Elvis Week in Memphis, the scheduling around Presley's birthday induces a celebratory atmosphere and encourages men to don the Elvis jumpsuit. After all, as festival founder Anne Steel says, "Elvis was a bloke." The Parkes festival also tends to encourage a more conservative or wholesome image of Elvis, and yet the various depictions create the festival's gonzo feel that is rich with an uncalculated, homespun hospitality. Most of all, the event creates a place for Elvis fans in Australia to celebrate the birth of the King of Rock and Roll without having to leave the continent. The festival's growth is a sure sign that Elvis's popularity continues to reverberate globally. Last year, after the Friday, January 13th, arrival of the Country-Link Elvis Express from Sydney, Elvis tribute artists performed onstage for a crowd in Cooke Park through the weekend. Elvis buskers lined Clarinda Street, which also served as the route for the Elvis parade. Shops featured Elvis window displays; couples renewed their marriage vows before an Elvis wedding celebrant; and even the statue of Sir Henry Parkes, the town's namesake, sported Elvis's seventies-era sunglasses. [End Page 99] Click for larger view View full resolution [End Page 100] Click for larger view View full resolution Elias (opposite, top), Australia's representative at the 2011 Ultimate Elvis Tribute Artist contest, performs in Sydney Central Railway Station before passengers board the CountryLink Elvis Express train to Parkes, New South Wales. On-board the Express, things heat up for a rapturous fan (opposite, bottom), and later another adoring fan poses with Elvis tribute artist Paul French (above). [End Page 101] Click for larger view View full resolution [End Page 102] Click for larger view View full resolution Opposite: Elvii greet the Elvis Express in Parkes and stroll past Elvis Central, an outlet for costumes and festival souvenirs. Above: The Confederate battle flag was a common sight in Parkes and included this one, customized with the pop icon's face. A statue of town founder Sir Henry Parkes even donned Elvis shades. [End Page 103] Click for larger view View full resolution [End Page 104] Click for larger view View full resolution Opposite: Pricillas pose for photographs on their parade float, and an Elvis with mad hair waves to crowds during the Elvis parade. Above: The Elvis parade rolls past Dimmeys, Australia's iconic variety chain store. [End Page 105] Click for larger view View full resolution [End Page 106] Click for larger view View full resolution Opposite: Celebrant Andrew "Elvis" Appleby (top) conducts the annual renewal of marriage vows for about thirty couples. Brides (bottom) line up before an Elvis wedding celebrant. Above: Elvii—and Elvettes—are everywhere. [End Page 107] Click for larger view View full resolution Married thirty years, Allison and Dick Howlett of Parkes share a kiss after renewing their vows. [End Page 108] Click for larger view View full resolution Above: Gnarnayarrahe Waitairie (left), an Elvis tribute artist of Aboriginal descent, greets fans before the karaoke competition, and, in Cooke Park, Elias (right) strikes a pose for the crowds. Click for larger view View full resolution Below: CountryLink representative Cameron Nichols (left) poses with fans, and the winner of the junior division in busking, Bailey Sutcliffe (right), performs...

Module-based complexity formation: periodic patterning in feathers and hairs.

Patterns describe order which emerges from homogeneity. Complex patterns on the integument are striking because of their visibility throughout an organism’s lifespan. Periodic patterning is an effective design because the ensemble of hair or feather follicles (modules) allows the generation of complexity, including regional variations and cyclic regeneration, giving the skin appendages a new lease on life. Spatial patterns include the arrangements of feathers and hairs in specific number, size, and spacing.We explorehowa field of equivalent progenitor cells can generate periodically arranged modules based on genetic information, physical–chemical rules and developmental timing. Reconstitution experiments suggest a competitive equilibrium regulated by activators/inhibitors involving Turing reaction-diffusion. Temporal patterns result from oscillating stem cell activities within each module (microenvironment regulation), reflected as growth (anagen) and resting (telogen) phases during the cycling of feather and hair follicles. Stimulating modules with activators initiates the spread of regenerative hair waves, while global inhibitors outside each module (macroenvironment) prevent this. Different wave patterns can be simulated by cellular automata principles. Hormonal status and seasonal changes can modulate appendage phenotypes, leading to ‘organ metamorphosis’, with multiple ectodermal organ phenotypes generated from the same precursors. We discuss potential novel evolutionary steps using this module-based complexity in several amniote integument organs, exemplified by the spectacular peacock feather pattern. We thus explore the application of the acquired knowledge of patterning in tissue engineering. New hair follicles can be generated after wounding. Hairs and feathers can be reconstituted through self-organization of dissociated progenitor cells.

In search of the Golden Fleece: unraveling principles of morphogenesis by studying the integrative biology of skin appendages.

The mythological story of the Golden Fleece symbolizes the magical regenerative power of skin appendages. Similar to the adventurous pursuit of the Golden Fleece by the multi-talented Argonauts, today we also need an integrated multi-disciplined approach to understand the cellular and molecular processes during development, regeneration and evolution of skin appendages. To this end, we have explored several aspects of skin appendage biology that contribute to the Turing activator/inhibitor model in feather pattern formation, the topo-biological arrangement of stem cells in organ shape determination, the macro-environmental regulation of stem cells in regenerative hair waves, and potential novel molecular pathways in the morphological evolution of feathers. Here we show our current integrative biology efforts to unravel the complex cellular behavior in patterning stem cells and the control of regional specificity in skin appendages. We use feather/scale tissue recombination to demonstrate the timing control of competence and inducibility. Feathers from different body regions are used to study skin regional specificity. Bioinformatic analyses of transcriptome microarrays show the potential involvement of candidate molecular pathways. We further show Hox genes exhibit some region specific expression patterns. To visualize real time events, we applied time-lapse movies, confocal microscopy and multiphoton microscopy to analyze the morphogenesis of cultured embryonic chicken skin explants. These modern imaging technologies reveal unexpectedly complex cellular flow and organization of extracellular matrix molecules in three dimensions. While these approaches are in preliminary stages, this perspective highlights the challenges we face and new integrative tools we will use. Future work will follow these leads to develop a systems biology view and understanding in the morphogenetic principles that govern the development and regeneration of ectodermal organs.

Buddhists, Existentialists, and Situationists: Waking up in Waking Life

Buddhists, Existentialists, and Situationists:Waking up in Waking Life Douglas Mann1 (bio) Introduction: What If Life Were Just a Dream? Richard Linklater's 2001 film Waking Life is all about dreaming and how we can sometimes lucidly control our dreams. Yet it is also about some broad philosophical issues, including one of the oldest philosophical conundrums, the distinction between appearance and reality. When René Descartes sat at his stove and meditated on the world and on whether an evil demon controlled everything he perceived, he wondered, what's more real, dreams or waking life? The diverse collection of characters in Linklater's film asks the same question. Yet they ask it not just in a literal sense, but also as a metaphor for the nature of modern culture and for the human condition as a whole—in what ways do we fall asleep even while awake? How can we lead a life that is more awake, more aware of people and things, more authentic? The film provides the outlines of three wake-up calls to three more-or-less separate ways in which we sleep too easily. This issue is not new. It goes all the way back to Plato's Allegory of the Cave: what if you were chained in a dimly lit cave your whole life, where you saw only the shadows of real things passing by the entrance to your cave reflected on its back wall? Suddenly you are free and come into the sunlight. Would you recognize this new world as more real than your cave world? And would you be able to convince those still enchained in the cave that there was a greater world outside their dwelling? Would you be able, in Plato's terms, to wake up to reality? This whole idea of "waking up" is a key idea in a number of philosophies explored in the film. In ancient Eastern philosophy—the Indian Vedanta philosophy of the Upanishads, Taoism, and Buddhism—the key to waking up is enlightenment and a correct understanding of the relation of the self to the external world. In existentialism, we have to wake up to our personal freedom and our responsibility for creating our own selves and lives. And in the situationism of Guy Debord and others, we have to wake up from the sugar-coated spell of consumer society. The film was made by first filming live action with a digital video camera and then transferring the video to computers and rotoscoping (coloring over) the images to turn them into animation. Thirty different artists were involved in the process, all with different styles. Rotoscoping has been used before—as early as Disney's 1937 Snow White and several decades later in Ralph Bakshi's The Lord of the Rings and American Pop. It gives a flowing, surreal, dreamlike quality to much of the film, surely Linklater's intention. And although the film is divided into thirty-four more or less distinct shorts, they are linked together by the constant presence of the "dreamer," Wiley Wiggins, who also acted in Linklater's Dazed and Confused. In addition, the shorts are linked by most of them taking place in Linklater's hometown of Austin, [End Page 15] Texas, and by thematic links between the ideas presented in adjacent scenes. If one were to describe the visual style in a single word, that word would be instability. In some scenes, we see a fairly stable human figure, often Wiley, surrounded by a fluid, undulating background of objects, buildings, and other characters. In others, the very components of human bodies and faces are out of sync with each other: a head remains stationary as its eyes and mouth move back and forth; elements of clothing change their shape or substance; a character's hair waves up and down without any evidence of windy weather elsewhere in the scene. The style of animation also changes significantly from scene to scene, sometimes reflecting the topic being discussed (e.g., angry political rants tend to feature sharp colors and solid black lines), and in other cases merely to provide a contrast with preceding and succeeding scenes. A good example of this can...

Giant molecules: From nylon to nanotubes

Walter Gratzer, Oxford University Press, Oxford, England, 2009, 254 pp., ISBN 978-0-19-955002-9 (Hard Cover), $24.95 Laura Lowe Furge*, * 1200 Academy Street, Kalamazoo, Michigan 49080. Did you know that the word “ion” came from the Greek word for “a wanderer”? Or that the expression “racemic mixture” was derived from Louis Pasteur's seminal experiments with racemic acid—a by-product of the fermentation process with Latin root in racemus, a grape? Or that the first permanent hair waves were produced using bovine urine or NaOH and heat? Walter Gratzer's new book is full of such interesting historical insights into the fields of organic and polymer chemistry. True to the author's claim in the foreword, “Giant Molecules: From Nylon to Nanotubes” is written for a lay audience. However, the brief descriptions of personalities, seminal experiments and debates in the field of polymer chemistry over roughly the past two centuries would make this book a great source of added insights for those teaching organic chemistry or biochemistry. Though the subtitle leads the reader to believe the book is going to focus on synthetic polymers, this is misleading as over half of the book is dedicated to protein, carbohydrate, and nucleic acid polymers. Indeed, the chapter on proteins gives overviews of protein secondary structure (from the story of Linus Pauling cutting out paper models and rolling them together) to structural motifs to discussion of prions and everything in between with helpful figures and diagrams (there are over 40 figures in the text). The same is true in the chapters on carbohydrates and nucleic acids. Pages are narrow, so though it is 254 pages in length, the pages read quickly and flow well. Mixed in with presentation of the naturally occurring polymers are chapters on synthetic polymers—plastics, coatings, superconductors, to microarrays and nanotubes. Throughout these sections again the author includes the personal stories or often forgotten histories of the nomenclature in polymer chemistry. For instance, there is a brief introduction to the creator of nylon, Wallace Carothers, who was both genius and depressive and ultimately took his own life with cyanide poisoning. Or the folklore of the plastics industry beginning when a laboratory cat knocked formaldehyde into its milk bowl. Each year the Chemistry Department at my institution gives a prize to the top few first year chemistry students. A book such as “Giant Molecules” would make an excellent choice for such a prize—or for any student about to begin the study of carbon chemistry or for one that simply enjoys the history of great scientific discoveries.

Analyses of regenerative wave patterns in adult hair follicle populations reveal macro-environmental regulation of stem cell activity

The control of hair growth in the adult mammalian coat is a fascinating topic which has just begun to be explored with molecular genetic tools. Complex hair cycle domains and regenerative hair waves are present in normal adult (> 2 month) mice, but more apparent in mutants with cyclic alopecia phenotypes. Each hair cycle domain consists of initiation site(s), a propagating wave and boundaries. By analyzing the dynamics of hair growth, time required for regeneration after plucking, in situ hybridization and reporter activity, we showed that there is oscillation of intra-follicular Wnt signaling which is synchronous with hair cycling, and there is oscillation of dermal bone morphogenetic protein (BMP) signaling which is asynchronous with hair cycling. The interactions of these two rhythms lead to the recognition of refractory and competent phases in the telogen, and autonomous and propagating phases in the anagen. Boundaries form when propagating anagen waves reach follicles which are in refractory telogen. Experiments showed that Krt14-Nog mice have shortened refractory telogen and simplified wave dynamics. Krt14-Nog skin grafts exhibit non-autonomous interactions with surrounding host skin. Implantation of BMP coated beads into competent telogen skin prevents hair wave propagation around the bead. Thus, we have developed a new molecular understanding of the classic early concepts of inhibitory "chalone", suggesting that stem cells within the hair follicle micro-environment, or other organs, are subject to a higher level of macro-environmental regulation. Such a novel understanding has important implications in the field of regenerative medicine. The unexpected links with Bmp2 expression in subcutaneous adipocytes has implications for systems biology and Evo-Devo.

Complex Hair Cycle Domain Patterns and Regenerative Hair Waves in Living Rodents

Single hair follicles go through regeneration and involution cycles. In a population, hair follicles may affect each other during anagen re-entry, thus forming propagating regenerative hair waves. We review these regenerative hair waves and complex hair cycle domains, which were recently reported in transgenic mice. Two non-invasive methods to track the propagating hair wave in large populations of hair follicles in vivo are described. We also reviewed early accounts of "hair growth patterns" from classical literature. We decipher the "behavior rules" that dictate how dynamic hair waves lead to complex hair cycle domains. In general, a single domain expands when a regenerative hair wave reaches a responsive region and boundaries form when the wave reaches a non-responsive region. As mice age, multiple hair cycle domains form, each with its own regeneration rhythm. Domain patterns can be reset by physiological events such as pregnancy and lactation. Longitudinal sections across domains show arrays of follicles in a continuum of hair cycle stages. Hair cycle domains are different from regional specificity domains. Regenerative hair waves are different from the developmental wave of newly forming hair follicles. The study provides insights into the dynamic states of adult skin and physiological regulation of organ regeneration.

Effects of Olfactory Bulb Resection Upon the Hair Waves in Mice

Bilateral and unilateral resection of the olfactory bulbs was performed in groups of male C3H/Ep mice while the controls were sham-operated. All the animals were clipped along the back from the neck to the base of the tail. The advance of the hair waves was observed at weekly intervals and the denuded area covered by hair measured for 48 days. The animals were clipped again and observed in the same way during a 77 day period, at the end of which a complete autopsy was performed and the endocrine organs were weighed. The rate of advance of the hair waves was slower in the animals with bilateral resection of the olfactory bulbs, intermediate in those with unilateral resection and faster in the sham-operated controls in both experimental periods. There was atrophy of the adrenals, testicles, pituitary, thyroid and thymus in the animals with olfactory bulb removal.

Effects of the Pineal Gland Upon the Hair Cycles in Mice

Hair growth in rats and mice is cyclic, each hair follicle having alternate periods of growth and rest. Also, the hair follicles develop in waves of hair growth which cover gradually the skin with a new coat of hair (1, 2, 3, 4, 5). Diverse endocrine factors may be stimulants or inhibitors, modifying the initiation, advance and characteristics of the hair wave (6, 7, 8, 9, 10). The inhibitory honnonal factors appear to be of pituitary origin, and its effect on the adrenals and gonads (6, 9, 10, 11). The stimulating hormonal factors are in part hypophyseal and in part extrahypophyseal (10, 11). Part of the stimulating action of the pituitary is produced by means of the thyroid (7, 8, 12, 13). The nervous system also intervenes in the regulation of the hair cycle. Slow hair waves were found in hemiarquidecortieated rats. This inhibitory effect is that of gonad stimulation, as shown by its suppression through castration (14). Lesions of the olfactory cortex, especially the anterior and internal part of the tuberculum olfactoriurn, resulted in slower pace of advance of hair waves both in normal and in castrated mice (15). These data suggested the hypothesis of the neurohormonal control of the hair growth waves in rats and mice. Thus, mechanisms probably located in the nervous system, would regularly alter the balance between the stimulating and inhibitory factors (15). The pineal gland is considered to be a neuroendocrine transducer and to regulate ovarian function in mammals (16). Melatonin, active principle of the pineal gland, lightens the amphibian skin through its effect upon melanocytes

Effect of a Sympathomimetic Agent (Methoxamine Hydrochloride) on Growth of Hair in the House Mouse (Mus musculus)

THE association of an intense capillary network with regions of active hair growth in the rat1 suggests that blood supply plays an important part in the mechanism of the hair cycle in rodents. It was therefore of interest to test the effects of a vasoconstrictor sympathomimetic drug, methoxamine hydro-chloride β-hydroxy-β(2,5-dimethoxyphenyl) isopropylamine) on the time taken for the spread of the hair wave and on the amount of hair grown during the cycle.

Quantitative studies of hair growth in the albino rat. II. The effect of sex hormones.

SUMMARY 1. Spaying of female rats aged 7 weeks accelerated the passage of the second wave of hair growth. Longer hairs were produced as a result of faster growth, and the rate of loss of dead or 'club' hairs [cf. Johnson, 1958] was increased. 2. Oestradiol implanted into spayed females delayed the initiation and passage of the wave. Shorter hairs were produced by a reduced rate of growth, and loss of club hairs was inhibited. 3. Castration of male rats aged 7 weeks accelerated the passage of the second wave of growth, and implantation of testosterone slowed it down. Testosterone had no effect on the definitive length of hair produced or on the rate at which club hairs were lost. 4. Oestradiol implanted into castrated males produced the same effects as in spayed females except that it had no effect on the time of initiation of the wave. 5. Combined implantation of testosterone with oestradiol into castrated males did not off-set the inhibitory effects of the oestradiol on hair length or rate of loss of club hairs, but may have slightly speeded the hair wave.

DERMATITIS OF THE EYELIDS DUE TO PHILODENDRON (SCANDENS CARDATUM) PLANTS

Dermatoses of the eyelids are frequently seen, especially in women. They are usually associated with involvement of other parts of the body, as in seborrheic dermatitis, psoriasis, neurodermatitis or lupus erythematosus. When a dermatitis involves only the eyelids it is usually considered to be of the contact type (due to an external irritant). The commonest irritants which cause such a dermatitis are mascara, eye shadow, perfume, various types of cosmetic creams and nail polish. A review of the literature disclosed numerous allergens which may cause a dermatitis of the eyelids. Greenbaum1reported a case of a severe edematous vesicular dermatitis involving the eyelids from an eyelash dye. Rattner2described 4 cases in which dermatitis of the eyelids was due to hair tonic, wave lotion, fur collar and cold cream respectively. Hollander3observed a case in which hair tonic was the causative agent. In this case the hair