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At least 433 records · Page 24Linked to original sources
PubMed2004

Purkinje cell loss in the cerebellum of ataxic mutant mouse, dilute-lethal: a fractionator study.

This study estimated total number of Purkinje cells in the cerebellum of an ataxic mutant mouse, dilute-lethal (DL), with reference to severe ataxic symptoms of this mutant. On postnatal day (PD) 21, the cerebellar weight is significantly lower in DL than in non-ataxic littermates (control mice). Total number of Purkinje cells is also significantly lower in DL than in the controls; approximately 25% less in DL than in the controls. Furthermore, we performed in situ nick end labeling (TUNEL) -staining in the cerebellum of DL during prenatal and postnatal periods in order to examine the cause of the reduced Purkinje cell number. For analyzes of the mutant fetuses, it is necessary to identify the homozygous mutant. We succeeded in identifying the homozygous DL fetuses from the control fetuses (wild-type or heterozygous fetuses) by the hair color of the grafted skin pieces on nude mice. The histological features of the cerebellar primordium did not differ between the DL and controls on embryonic and postnatal ages examined. In DL, a significantly greater number of TUNEL-positive Purkinje cells was detected on embryonic day (ED) 12, but not throughout ED 14 to PD 21. The results suggest that the Purkinje cell loss in the DL cerebellum is attributed to increased apoptotic cell death of the progenitors. This may be involved in the development of severe ataxic symptoms of DL.

Animals↗
PubMed2004

Mechanisms of hair graying: incomplete melanocyte stem cell maintenance in the niche.

Hair graying is the most obvious sign of aging in humans, yet its mechanism is largely unknown. Here, we used melanocyte-tagged transgenic mice and aging human hair follicles to demonstrate that hair graying is caused by defective self-maintenance of melanocyte stem cells. This process is accelerated dramatically with Bcl2 deficiency, which causes selective apoptosis of melanocyte stem cells, but not of differentiated melanocytes, within the niche at their entry into the dormant state. Furthermore, physiologic aging of melanocyte stem cells was associated with ectopic pigmentation or differentiation within the niche, a process accelerated by mutation of the melanocyte master transcriptional regulator Mitf.

Adult↗
PubMed2005

Checkpoints of melanocyte stem cell development.

The bulge region of the adult hair follicle contains the niches for both epithelial and melanocyte stem cells. Recent evidence suggests that the development of melanocyte stem cells is controlled by a complex network of transcription factors, including Pax3, Sox10, and Mitf, and of regulatory extracellular cues such as Wnt. However, additional players are likely to be involved. It will be intriguing to identify these signals and to elucidate whether and how neighboring epithelial stem cells influence the balance between melanocyte stem cell maintenance and differentiation.

Animals↗
PubMed2005

Risk factors for melanoma by body site.

It has been hypothesized that cutaneous melanoma at different anatomic sites develops through divergent pathways. We examined this hypothesis prospectively. We followed 152,949 women and 25,204 men free of cancer at baseline for up to 14 years in three large prospective studies. We examined risk factors for melanoma by anatomic location (head or neck, trunk, upper extremity, and lower extremity). Polytomous logistic regression was used to test the difference among risk factors by location of melanoma. A total of 511 incident cases of invasive melanoma (49 head or neck, 188 trunk, 98 upper extremity, and 176 lower extremity) were included in the analysis. Compared with females, males had a higher risk of developing melanoma on the head or neck and trunk. History of severe and painful sunburn was most strongly related to melanoma of upper extremity; individuals with >10 burns had a 6.86-fold (95% confidence interval, 2.62-18.00) higher risk of melanoma of upper extremity compared with those with no burns (P for trend < 0.0001; P for difference by body site = 0.04). Number of moles was most strongly related to melanoma of the trunk; the multivariate relative risk for having >10 moles was 4.67 (95% confidence interval, 3.07-7.11) compared with having no moles (P for trend < 0.0001; P for difference by body site = 0.04). Age, family history of melanoma, and hair color did not statistically differ by anatomic site of the cancer. These data support divergent etiologic pathways of melanoma development by anatomic sites.

Abdomen↗
PubMedDate not supplied

Inhibition of irritation and contact hypersensitivity by phenoxyacetic acid methyl ester in mice.

New anti-irritant treatments are required to prevent irritation and sensitization reactions to consumer medicines and dermatological drugs. We report here that phenoxyacetic acid methyl ester (PAME) is an effective agent to prevent and treat irritant and allergic contact dermatitis. Balb/c mice skin-treated with 1% PAME do not lose weight relative to vehicle-treated mice, nor is it irritating to mouse skin. Topical PAME prevents skin irritation to a wide variety of irritants including: arachidonic acid, capsaicin, sodium lauryl sulfate (SLS), disodium laureth sulfosuccinate and tetradecanoylphorbol-13-acetate. Histological studies showed that 1% PAME greatly diminished dermal neutrophilic infiltration and dermal capillary vessel dilation, and prevented epidermal hyperproliferation and hyperkeratosis that accompanies detergent (SLS)-induced skin irritation. Topical PAME inhibited ear swelling following ear challenge during the elicitation phase of contact hypersensitivity in mice sensitized with 1-chloro-2, 4-dinitrochlorobenzene (DNCB), oxazolone and the hair coloring dye rho-phenylenediamine (PPD). Finally, topical administration of 1% PAME prior to PPD or DNCB sensitization prevented the induction phase of contact hypersensitivity. These results indicate that PAME represents a potential new category of potent topical anti-inflammatory agents.

Administration, Topical↗
PubMed1992

Riyadh chromosome breakage syndrome: mental retardation with depigmentation of the skin and hair.

A 20-month-old infant with "silvery-blond" hair color, widespread confettilike depigmentation of the skin, and mental retardation was found to have, in lymphocytes and fibroblast cultures, increased spontaneous chromosome breaks and breaks induced by both mitomycin and gamma-irradiation. The sister chromatid exchange frequency was normal. This child probably represents a new chromosome breakage syndrome.

Albinism↗
PubMed2026

Transcranial Photobiomodulation Variables Assessment Battery: Development and Validation.

Transcranial photobiomodulation (tPBM) response variability is partly driven by biophysical characteristics such as skin tone and hair properties that attenuate photon penetration, and by lifestyle factors including sleep quality, alcohol use, and nicotine consumption that disrupt the mitochondrial and vascular pathways on which tPBM acts. To date, no validated self-report tool exists to capture these moderators systematically. To address this gap, the tPBM Variables Assessment Battery was developed and psychometrically evaluated. It integrates adapted versions of established measures (Brief Pittsburgh Sleep Quality Index, E-cigarette Dependence Scale, Hair Scale Assessment PRO, Monk Skin Tone Scale, and Heaviness of Smoking Index), validated wellbeing evaluators (Ryff's Psychological Wellbeing), and custom measures (Hairstyle Classification, Hair Color Classification). Face and content validity met recommended expert thresholds, internal consistency was acceptable across adapted subscales, and criterion validity analyses confirmed meaningful associations between the lifestyle components and PROMIS-10 global health outcomes. The battery is low-burden, digitally deployable, and psychometrically defensible, offering a practical tool for characterizing the variables most likely to moderate tPBM response in home-use studies.

Humans↗
PubMed2026

Aerobic Fitness and Health-Related Phenotypes: A Two-Stage Phenome-Wide Mendelian Randomization Study.

PURPOSE: We investigated potentially causal associations between genetically predicted aerobic fitness and multiple health phenotypes using a two-stage phenome-wide Mendelian randomization (MR) study. METHODS: Genetically determined aerobic fitness, as operationalized by Cai et al., served as the exposure instrument. We screened 712 health-related phenotypes as outcomes using publicly available European-ancestry genome-wide association studies (GWAS) summary statistics from OpenGWAS (Discovery GWAS n > 5000), prioritizing non-UK Biobank/non-FinnGen datasets for Discovery when available and selecting an independent GWAS for validation. Associations were estimated using the MR-Robust Adjusted Profile Score method, controlled for multiple testing (5% false discovery rate) and unaffected by violations of MR assumptions (directional concordance between discovery and validation; no evidence of horizontal pleiotropy across inverse-variance weighted, MR-Egger, weighted-median, and weighted-mode methods; negative control analysis on hair color). RESULTS: We identified 108 discovery associations, of which 34 remained valid and statistically significant after validation. Higher genetically determined aerobic fitness was associated with lower lacunar stroke risk, lower arterial stiffness, higher heart rate variability, lower diastolic blood pressure, more favorable anthropometric measures, lower use of antidiabetic drugs, lower asthma risk, lower C-reactive protein, higher bone mineral density, favorable liver function biomarkers, favorable platelet-related traits, multiple blood count-derived hematological cell indices and counts, as well as higher years of schooling. Adverse associations were confined to atrial fibrillation, valvular heart disease, and systolic blood pressure. CONCLUSIONS: Genetically determined aerobic fitness is linked to a broad pattern of favorable cardiometabolic, inflammatory, musculoskeletal, respiratory, hepatic, and hematological phenotypes, alongside a narrow set of potential cardiovascular hazards.

Humans↗
PubMed1995

High cell density cultivation and high recombinant protein production of Escherichia coli strain expressing uricase.

Uricase from Cellulomonas flavigena SK-4 is an industrially useful enzyme for commercial formulations of hair coloring. The uricase production by recombinant Escherichia coli strain with a high cell density cultivation technique was described. Of three kinds of media, synthetic media with the feeding of a high concentration of glucose solution were suitable for high cell density cultivation. As for feeding, both biomass concentration and uricase productivity were increased by about two (61.2 g dry cell weight (DCW)/liter) and three times (1037 U/ml broth), respectively, in 24 h by continuous supply. In the case of feeding by a DO-stat method, however, cell concentration was comparable to continuous glucose supply but uricase activity was reduced. By supplying pure oxygen to compensate for oxygen limitation during cultivation, the highest values of 77.4g DCW/liter and 1113 U/ml broth of the uricase activity were achieved with the total cultivation time of 15 h.

Actinomycetales↗
PubMed1997

TM rats: a model for platelet storage pool deficiency.

TM rats have a light brown hooded coat pattern resembling that of Fawn hooded (FH) rats which are a model of platelet storage pool deficiency (SPD). We examined whether the TM strain has the same platelet SPD as the FH strain. TM rats had a prolonged bleeding time and a low blood serotonin level, although their blood coagulation time and platelet counts were normal. The light coat color of the TM strain was judged to be associated with the red-eyed dilution gene as in the FH strain, but not pink eye dilution as in the RCS rat strain. Platelet SPD seen in TM rats may be a pleiotropic effect of the red-eyed dilution gene proposed in FH rats. Despite these similarities, the genetic background of the TM strain was obviously different from that of the FH strain. The TM strain, developed independently of the FH strain, will therefore be used as a model of platelet SPD.

Animals↗
PubMedDate not supplied

Copper in green hair: a quantitative investigation by electron probe x-ray microanalysis.

Eleven cases of green hair were collected and hair tips were analyzed in the electron microscope by energy-dispersive x-ray microanalysis. In all cases, remarkable copper concentrations could be demonstrated (0.2-1.8% w/w). In normal hair the concentration of copper was below the detection limit (0.02% w/w). Analyses of hair cross sections showed a concentration gradient from the periphery toward the center, the periphery having higher values. This observation is in agreement with suspected contamination of the hair with copper from extraneous sources: analysis of the tapwater in patients' homes showed elevated copper concentrations. In addition, the water showed aggressive properties (pH outside the recommended range, high nitrate concentrations, heavily chlorinated). Investigations by transmission electron microscopy showed damage in the endocuticula. Experimental studies of normal unaffected hair fibers showed that treatment with a copper salt alone could result in binding of copper to the hair but that the extent of copper binding could be greatly increased by damaging the cuticula with chlorinated water. It is suggested that aggressive water attacks copper tubings leading to increased copper concentrations in tapwater and causes cuticular damage, which facilitates entry of copper into the hair.

Adolescent↗
PubMed1993

Factors associated with appendicular bone mass in older women. The Study of Osteoporotic Fractures Research Group.

OBJECTIVE: To determine the factors associated with appendicular bone mass in older women. DESIGN: Cross-sectional analysis of baseline data collected for a multicenter, prospective study of osteoporotic fractures. SETTING: Four clinical centers in Baltimore, Maryland; Minneapolis, Minnesota; Portland, Oregon; and the Monongahela valley, Pennsylvania. PATIENTS: A total of 9704 ambulatory, nonblack women, ages 65 years or older, recruited from population-based listings. MEASUREMENTS: Demographic and historical information and anthropometric measurements were obtained from a baseline questionnaire, interview, and examination. Single-photon absorptiometry scans were obtained at three sites: the distal radius, midradius, and calcaneus. Multivariate associations with bone mass were first examined in a randomly selected half of the cohort (training group) and were then tested on the other half of the cohort (validation group). RESULTS: In order of decreasing strength of association, estrogen use, non-insulin-dependent diabetes, thiazide use, increased weight, greater muscle strength, later age at menopause, and greater height were independently associated with higher bone mass. Gastric surgery, age, history of maternal fracture, smoking, and caffeine intake were associated with lower bone mass (all P < 0.05). For example, we found that 2 or more years of estrogen use was associated with a 7.2% increase in distal radius bone mass, whereas gastrectomy was associated with an 8.2% decrease in bone mass. The associations between bone mass and dietary calcium intake and rheumatoid arthritis were inconsistent. Alcohol use, physical activity, use of calcium supplements, pregnancy, breast-feeding, parental nationality, and hair color were among the many variables not associated with bone mass. Multivariate models accounted for 20% to 35% of the total variance of bone mass. CONCLUSIONS: A large number of factors influence the bone mass of elderly women; however, age, weight, muscle strength, and estrogen use are the most important factors.

Aged↗