Age, lifestyle and self-perceptions of hair: Is there an association with hair diameter and tensile properties?

OBJECTIVE: To determine the association of age, lifestyle habits and the self-perception of hair condition with the objectively measured physical properties of hair in Caucasian females with brown hair. METHODS: Hair biophysical properties, lifestyle habits data and self-perceptions of hair condition were collected on 110 Caucasian females with brown hair ranging in age from 17 to 78. Hair diameter (cross-sectional area) and tensile properties (elastic modulus, break strength and break extension) were measured at the root end of individual fibres (n = 100/subject) from the crown and frontal regions using objective instrumental methods. Other measures included body mass index (BMI) and Savin female pattern hair loss grades based on judging of standardized front, top and side view head images. Lifestyle habits and practices and self-perceived hair condition were obtained via a standardized self-assessment questionnaire. RESULTS: Hair fibre diameter and break extension decreased significantly with age. Hair fibre elastic modulus and Savin hair loss scores increased significantly with age. No age-related change in hair fibre break stress was observed. A history of smoking or being overweight was significantly associated with having lower hair fibre cross-sectional area but was not associated with any of the measured tensile properties. Subjects who perceived their hair as fine, thinning or weak had significantly lower cross-sectional areas than subjects who did not. Subjects who perceived their hair to be healthy or strong had significantly higher cross-sectional areas than subjects who did not. CONCLUSION: The biophysical properties of hair change significantly with age. A history of smoking or being overweight was significantly associated with having smaller hair cross-sectional area but was not associated with differences in hair tensile properties. The self-perception of having strong or healthy hair seems more associated with having a larger cross-sectional area than any real differences in hair strength.Abstrait.

OBJECTIF: Déterminer l'association entre l'âge, les habitudes de vie et la perception de l'état des cheveux avec les propriétés physiques mesurées de manière objective chez les femmes de race blanche à cheveux bruns. MÉTHODES: Les propriétés biophysiques des cheveux, les données sur les habitudes de vie et la perception de leur état de santé ont été recueillies chez 110 femmes de race blanche aux cheveux bruns âgés de 17 à 78 ans. Le diamètre des cheveux (surface transversale), résistance à la rupture et extension à la rupture) ont été mesurés à la racine des fibres individuelles (n = 100 / sujet) à partir des régions de la couronne et de la partie frontale en utilisant des méthodes instrumentales objectives. Parmi les autres mesures, citons l'indice de masse corporelle (IMC) et les degrés de perte de cheveux selon le modèle féminin de Savin, fondés sur l'évaluation d'images de tête normalisées de face, de dessus et de côté. Les habitudes et pratiques de mode de vie et l'état de poil auto-perçu ont été obtenues à l'aide d'un questionnaire d'autoévaluation standardisé. RÉSULTATS: Le diamètre de la fibre capillaire et l'extension de la rupture ont diminué de manière significative avec l'âge. Le module d'élasticité de la fibre capillaire et les scores de perte de cheveux de Savin augmentaient considérablement avec l'âge. Aucun changement lié au vieillissement du stress lié à la rupture de la fibre capillaire n'a été observé. Des antécédents de tabagisme ou d'embonpoint étaient significativement associés à une section inférieure de la fibre capillaire mais n'étaient associés à aucune des propriétés de traction mesurées. Les sujets qui percevaient leurs cheveux fins, fins ou clairsemés avaient une section transversale significativement plus basse que les autres. Les sujets qui percevaient que leurs cheveux étaient en bonne santé ou forts avaient des zones transversales significativement plus élevées que les sujets qui n'en avaient pas. CONCLUSION: Les propriétés biophysiques des cheveux changent de manière significative avec l'âge. Les antécédents de tabagisme ou d'embonpoint étaient significativement associés à une plus petite section transversale des cheveux mais n'étaient pas associés à des différences de propriétés de tension des cheveux. La perception de soi d'avoir des cheveux forts ou en bonne santé semble plus associée à une plus grande surface transversale que toute différence réelle dans la résistance des cheveux.

Comparison of the epidemiology of acne vulgaris among Caucasian, Asian, Continental Indian and African American women.

BACKGROUND: Acne vulgaris is a common skin disease with a large quality of life impact, characterized by comedones, inflammatory lesions, secondary dyspigmentation and scarring. There are few large objective studies comparing acne epidemiology between racial and ethnic groups. OBJECTIVE: This study aimed to define the prevalence and subtypes of acne in women of different racial groups from four ethnicities. METHODS: The sample consisted of 2895 (384 African American, 520 Asian, 1295 Caucasian, 258 Hispanic and 438 Continental Indian) women ranging in age from 10 to 70 years. Photographs of subjects were graded for acne lesions, scars, dyspigmentation, and measurements taken of sebum excretion and pore size. RESULTS: Clinical acne was more prevalent in African American and Hispanic women (37%, 32% respectively) than in Continental Indian, Caucasian and Asian (23%, 24%, 30% respectively) women. All racial groups displayed equal prevalence of both subtypes of acne with the exception of Asians, for whom inflammatory acne was more prevalent than comedonal (20% vs. 10%) acne, and in Caucasians, for whom comedonal acne was more prevalent than inflammatory (14% vs. 10%) acne. Hyperpigmentation was more prevalent in African American and Hispanic (65%, 48% respectively) than in Asian, Continental Indian and Caucasian (18%, 10%, 25% respectively) women. Dyspigmentation and atrophic scarring were more common in African American and Hispanic women than in all other ethnicities. There was a negative correlation between pore size and skin lightness for all ethnicities. Sebum production was positively correlated with acne severity in African American, Asian and Hispanic women, and pore size was positively correlated with acne in African American, Asian and Continental Indian women, (for all above results, P<0.05). LIMITATIONS: Only female participants were recruited. Data collection was restricted to four cities, with some ethnicities from single cities. Acne was evaluated only on the left side of the face and the two-dimensional nature of photography may not capture all skin surface changes. CONCLUSION: Acne prevalence and sequelae were more common in those with darker skin types, suggesting that acne is a more heterogeneous condition than previously described and highlight the importance of skin-colour tailored treatment.

A randomized, controlled comparative study of the wrinkle reduction benefits of a cosmetic niacinamide/peptide/retinyl propionate product regimen vs. a prescription 0.02% tretinoin product regimen.

BACKGROUND: Tretinoin is considered the benchmark prescription topical therapy for improving fine facial wrinkles, but skin tolerance issues can affect patient compliance. In contrast, cosmetic antiwrinkle products are well tolerated but are generally presumed to be less efficacious than tretinoin. OBJECTIVES: To compare the efficacy of a cosmetic moisturizer regimen vs. a prescription regimen with 0.02% tretinoin for improving the appearance of facial wrinkles. METHODS: An 8-week, randomized, parallel-group study was conducted in 196 women with moderate to moderately severe periorbital wrinkles. Following 2 weeks washout, subjects on the cosmetic regimen (n = 99) used a sun protection factor (SPF) 30 moisturizing lotion containing 5% niacinamide, peptides and antioxidants, a moisturizing cream containing niacinamide and peptides, and a targeted wrinkle product containing niacinamide, peptides and 0.3% retinyl propionate. Subjects on the prescription regimen (n = 97) used 0.02% tretinoin plus moisturizing SPF 30 sunscreen. Subject cohorts (n = 25) continued treatment for an additional 16 weeks. Changes in facial wrinkling were assessed by both expert grading and image analysis of digital images of subjects' faces and by self-assessment questionnaire. Product tolerance was assessed via clinical erythema and dryness grading, subject self-assessment, and determinations of skin barrier integrity (transepidermal water loss) and stratum corneum protein changes. RESULTS: The cosmetic regimen significantly improved wrinkle appearance after 8 weeks relative to tretinoin, with comparable benefits after 24 weeks. The cosmetic regimen was significantly better tolerated than tretinoin through 8 weeks by all measures. CONCLUSIONS: An appropriately designed cosmetic regimen can improve facial wrinkle appearance comparably with the benchmark prescription treatment, with improved tolerability.

New wrinkles on wrinkling: an 8-year longitudinal study on the progression of expression lines into persistent wrinkles.

BACKGROUND: While cumulative lifetime sun exposure is well recognized as having an important role in the progression of facial wrinkling, the role of facial expression has largely been overlooked, in part due to the lack of comprehensive longitudinal data on the change in both expression lines and persistent wrinkles with age. OBJECTIVES: To track the detailed pattern of facial wrinkling in the same group of people over several years and to verify that expression lines evolve into persistent wrinkles. In addition, to identify factors predictive of a faster or slower rate of wrinkling. METHODS: Standardized images were captured at baseline and at 8 years of 122 women (ages 10-72 years, skin types I-VI) with and without a smiling expression. The wrinkle pattern with expression at baseline was compared with the pattern without expression at 8 years. Severity of facial wrinkling was quantified using computer-based image analysis. Skin colour, hydration, sebum and pH were measured at baseline. A structured questionnaire captured demographic and lifestyle data at baseline and at 8 years. RESULTS: Each subject's unique pattern of persistent facial wrinkling observed without expression at year 8 was predicted by the pattern of lines observed with a smiling expression at baseline. Having a drier, more alkaline stratum corneum, a lighter complexion, being middle-aged (40s) or becoming menopausal were associated with faster persistent wrinkling. CONCLUSIONS: Repeated skin flexure during facial expression causes persistent wrinkles. The pattern of expression lines predicts the pattern of future persistent wrinkles. Certain intrinsic and extrinsic factors are not causative, but influence the rate, of facial wrinkling.

The effect of niacinamide on reducing cutaneous pigmentation and suppression of melanosome transfer.

BACKGROUND: Cutaneous hyperpigmentation occurs in multiple conditions. In addition, many Asian women desire a lighter skin colour. Thus, there is a need for the development of skin lightening agents. Niacinamide is a possible candidate. OBJECTIVES: To investigate the effects of niacinamide on melanogenesis in vitro and on facial hyperpigmentation and skin colour in vivo in Japanese women. METHODS: Melanin production was measured in a purified mushroom tyrosinase assay, cultured melanocytes, a keratinocyte/melanocyte coculture model, and a pigmented reconstructed epidermis (PREP) model. The clinical trials included 18 subjects with hyperpigmentation who used 5% niacinamide moisturizer and vehicle moisturizer in a paired design, and 120 subjects with facial tanning who were assigned to two of three treatments: vehicle, sunscreen and 2% niacinamide + sunscreen. Changes in facial hyperpigmentation and skin colour were objectively quantified by computer analysis and visual grading of high-resolution digital images of the face. RESULTS: Niacinamide had no effect on the catalytic activity of mushroom tyrosinase or on melanogenesis in cultured melanocytes. However, niacinamide gave 35-68% inhibition of melanosome transfer in the coculture model and reduced cutaneous pigmentation in the PREP model. In the clinical studies, niacinamide significantly decreased hyperpigmentation and increased skin lightness compared with vehicle alone after 4 weeks of use. CONCLUSIONS: The data suggest niacinamide is an effective skin lightening compound that works by inhibiting melanosome transfer from melanocytes to keratinocytes.

Quantitative evaluation of skin condition in an epidemiological survey of females living in northern versus southern Japan.

Image analysis and biophysical methods were used to compare the skin condition of a group of females ranging in age from 5 to 65 years who had lived all of their lives in either Kagoshima (n=300), located in southern Japan, or Akita (n=302), located in northern Japan. Kagoshima annually receives approximately 1.5 times more solar UVB radiation than Akita. The methods used and corresponding skin parameters reported in this survey were: high resolution digital imaging followed by computer analysis of facial images for facial skin wrinkling and hyperpigmentation; silicone skin replicas followed by Moiré interferometry for facial skin surface roughness (texture); the Minolta Chromameter for skin color (L*a*b*) on sun-exposed (forehead) and sun-protected (upper inner arm) skin sites; the Corneometer for skin capacitance (hydration) on the cheek and ventral forearm; the Sebumeter for sebum excretion rate on the forehead; and the Minolta Spot Thermometer for skin temperature on the upper cheek. Compared with Japanese women living in Akita, Japanese women living in Kagoshima had significantly longer facial wrinkles, higher number of wrinkles, larger hyperpigmented spots, higher number of spots, rougher facial skin texture, more yellow foreheads and upper inner arms, darker foreheads, and less stratum corneum hydration in the cheeks and arms. When compared on an age-for-age basis, the average 40-year-old Kagoshima women has the same level of facial wrinkling as a 48-year-old Akita women, a delay of 8 years for living in the northern latitude. For facial hyperpigmentation, the delay is 16 years; the average 40-year-old Kagoshima women has the same level of facial hyperpigmentation as a 56-year-old Akita women. The results further testify to the skin damaging effects of sun exposure and may be useful in public health education to promote everyday sun protection.

The efficacy of glycolic acid for treating wrinkles: analysis using newly developed facial imaging systems equipped with fluorescent illumination.

The clinical characteristics of photodamaged skin, such as coarse and fine wrinkling, can not be quantitatively evaluated from ordinary photographic records. The purpose of this study was to assess the efficacy of glycolic acid (GA) peeling on facial wrinkling, using computer assisted image analysis. This was accomplished with reproducible imaging techniques, which allowed precise repositioning of the subject's face in front of the camera. Two parameters, the change in wrinkle number and the change in wrinkle length were assessed. Although the clinical improvement of wrinkles correlated with both parameters, wrinkle length more precisely reflected the degree of clinical wrinkles, because the wrinkle number appeared to increase as some shallow wrinkles divided into multiple smaller wrinkles during their improvement. Comparison of responses by different age groups showed that the reduction of total wrinkle length was observed in the order of: 50s>30s and 40s>60s>over 70>under 30. The lack of response by subjects over 70 might be due to the nature of their wrinkles being mainly coarse wrinkles rather than fine ones. We next compared the effect of GA by concentration (35, 50 or 70%), but found no significant differences. As the concentration of GA used for treatment was determined by each subject's erythema reaction, our present result suggests that erythema elicited by GA correlates with improvement of wrinkles and that these two phenomena can be induced by a common pathway of GA treatment. This quantitative analysis clearly shows the efficacy and limitation of GA treatment of wrinkles, and might help to disclose the precise mechanisms of GA effects on the skin structure and function.

Acute and chronic ultraviolet radiation induction of epidermal ornithine decarboxylase activity in hairless mice.

The effects of acute, multiple, and chronic exposure of hairless mice to ultraviolet radiation (UVR) on induction of epidermal ornithine decarboxylase (ODC) (EC 4.1.1.17) activity were investigated. Acute UVR exposure results in a biphasic time course of induction of epidermal ODC activity. Enzyme activity maxima occur at 3 and 24 h postirradiation. The biphasic time course is observed in two different strains of hairless mice (Skh:HR-1 and Jackson HRS/J) when the UVR source is either UBV fluorescent tubes or a solar simulator. The ratio of 24-h/3-h postirradiation ODC activity increases with increasing UVR dose. UVR induction of ODC activity was not significant below the mouse minimum erythemal dose (MED). The 3- and 24-h ODC activities have similar apparent Kms for ornithine (34 and 50 microM, respectively), and thermal stabilities at 52 degrees C (t1/2 = 23 and 18 min, respectively), and exhibit similar half-lives in vivo (t1/2 = 15 and 18 min, respectively). Multiple UVR exposure experiments showed 24-h ODC activity is sensitive to the preexposure history of the mouse, while 3-h ODC is not. Preexposure of hairless mice to several sub-MED levels of simulated solar radiation (SSR) specifically suppresses induction of 24-h ODC by a follow-up 2 x MED of SSR. Preexposure to a single 2 x MED of SSR specifically enhances induction of 24-h ODC induced by a second 2 x MED of SSR administered 48 h after the first. The 3-h ODC was not significantly affected by either preexposure regimen. Preexposure to a single high or low dose of UVA radiation did not affect epidermal ODC activity nor had an effect on ODC induction by UVB radiation. Several weeks of chronic exposure to UVB radiation elevated basal levels of epidermal ODC substantially (up to 350-fold). In these chronically irradiated mice, exposure to 2 x MED SSR resulted in a further 3.5-fold increase in ODC activity over the elevated basal level. These data reveal novel properties of epidermal cell expression of ODC activity in response to acute and chronic UVR insult. The results provide additional insight into the use of ODC as a marker for skin photodamage.

Influence of template primary and secondary structure on the rate and fidelity of DNA synthesis.

High resolution gel electrophoresis was used to monitor the successive addition of dNMP residues onto the 3'-OH ends of discrete 5'-32P-primers, during DNA synthesis on natural templates. Resulting autoradiographic banding patterns revealed considerable variation in the relative rates of incorporation at different positions along the template. The pattern of "pause sites" along the template was unique for each of three different DNA polymerases (polymerase I (the "large fragment" form of Escherichia coli), T4 polymerase (encoded by bacteriophage T4), and AMV polymerase (DNA polymerase of avian myeloblastosis virus]. Most pause sites were not caused by attenuation of polymerization at regions of local secondary structure in the template. Assays of the accuracy of incorporation at different positions along the template (in which elongation was monitored in the presence of only 3 of the 4 2'-deoxynucleoside 5'-triphosphates) strongly suggested that the relative fidelity of DNA synthesis catalyzed by different polymerases depends on the position on the template at which the comparison is made. Primer-templates were constructed that permitted comparison of elongation during synthesis on a single-stranded template with that during polymerization through a double-stranded region (wherein elongation required concomitant displacement of a strand annealed adjacent to the 5'-32P-primer). Although strand displacement DNA synthesis catalyzed by polymerase I occurred approximately ten times more slowly than synthesis in the same region of a single-stranded viral template, most of the pause sites were the same in the presence or absence of "tandem" primer. Electrophoretic assays of the fidelity of DNA synthesis suggested that an increased tendency toward misincorporational "hotspots" occurred when elongation required concomitant strand displacement.

High-performance liquid chromatographic purification of deoxynucleoside 5'-triphosphates and their use in a sensitive electrophoretic assay of misincorporation during DNA synthesis.

This paper describes techniques and strategies for semi-preparative high-performance liquid chromatographic (HPLC) purification of 2'-deoxynucleoside 5'-triphosphates (dNTPs). The procedure yields dNTPs that are sufficiently pure for use in a sensitive electrophoretic assay of misincorporation during DNA synthesis. Anion-exchange HPLC was used to purify the four normal dNTPs (dATP, dGTP, dCTP and dTTP), plus the chemically modified analogues, 5-BrdUTP, 5-IodUTP and 1,N6-etheno-dATP (epsilon dATP). Baseline separations were achieved by isocratic elution of dNTPs with potassium dihydrogen phosphate mobile phase. In general, the resolution of dNTPs was highly dependent on pH, although the influence of mobile phase composition on separation of dNTPs was not the same for all three HPLC packing materials used. A Hewlett-Packard diode array detector was extremely valuable in the identification of contaminating peaks and in the development of optimal mobile phase conditions for dNTP purification. The pure dNTPs were used in the electrophoretic assay of misincorporation, yielding information about the mispairing potential of the modified dNTPs. BrdUMP and IodUMP were misincorporated in place of dCMP during chain elongation catalyzed by purified DNA polymerase I of Escherichia coli. epsilon dAMP was incorporated into DNA in place of dAMP, although at much lower efficiency than dAMP.

Misincorporation during DNA synthesis, analyzed by gel electrophoresis.

A method has been developed for simultaneous comparison of the propensity of a DNA polymerase to misincorporate at different points on a natural template-primer. In this method elongation of a [5'-32P] primer, annealed to a bacteriophage template strand, is carried out in the presence of only three dNTPs (highly purified by HPLC). Under these conditions the rate of primer elongation (monitored by gel electrophoresis/autoradiography) is limited by the rate of misincorporation at template positions complementary to the missing dNTP. Variations in the rate of elongation (revealed by autoradiographic banding patterns) reflect variations in the propensity for misincorporation at different positions along the template. The effect on primer elongation produced by addition of a chemically modified dNTP to 'minus' reactions reveals the mispairing potential of the modified nucleotide during DNA synthesis. By use of this electrophoretic assay of misincorporation we have demonstrated that the fidelity of E. coli DNA polymerase I varies greatly at different positions along a natural template, and that BrdUTP and IodUTP can be incorporated in place of dCTP during chain elongation catalyzed by this enzyme.

Template-dependent variation in the relative fidelity of DNA polymerase I of Escherichia coli in the presence of Mg2+ versus Mn2+.

The fidelity of E. coli DNA polymerase I in the presence of Mg2+ vs Mn2+ was examined at many positions along natural DNA templates, by use of an electrophoretic assay of misincorporation. Although there was an overall greater tendency for misincorporation to occur in Mn2+-activated chain elongation, some specific sites on the template were more prone to misincorporation with Mg2+ and others with Mn2+. This sequence-dependent effect was seen in spite of the finding that the relative rate of incorporation of the correct nucleotide at different positions on the template was essentially the same with Mg2+ and Mn2+. In agreement with previous studies, the fidelity of E. coli pol I was higher at activating, than at inhibiting, concentrations of Mg2+. The results reveal new complexities regarding the role of divalent cation in the control of fidelity in DNA synthesis and attest to the dynamic nature of interactions between DNA polymerase, its substrates and divalent metal activator during the course of polymerization on natural templates.