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Results for “Hair Color”

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At least 1,009 records · Page 56Linked to original sources
PubMed1997

Sooty foot, a novel mouse mutation that affects the pigmentation of exposed skin, but not hair, maps to chromosome 2.

We have characterized a novel recessive mouse mutation, named sooty foot, that increases the pigmentation of the exposed skin on the foot pads, the genital region, around the snout and muzzle, the ears, and the tail. By contrast, the pigmentation of the hair is unaffected. We have localized the mutation to Chromosome 2 by polymerase chain reaction (PCR) amplification of simple sequence repeats from pooled DNA from backcross progeny. In an extended backcross we have generated a detailed map of the region around sooty foot.

Agouti Signaling Protein↗
PubMed1997

A comparison of 3H-cocaine binding on melanin granules and human hair in vitro.

The in vitro experiments on the interaction of 3H-cocaine and melanin from Sepia officinalis confirmed the existence of drug binding sites on melanin granules. The results suggested that the binding of 3H-cocaine to melanin could be analyzed by assuming that the binding to the surface of pigment granules is analogous to the adsorption of a drug on a solid and follows Langmuir adsorption isotherm type I. Scatchard analysis indicated heterogeneity of binding sites. Structural and chemical alterations caused by isolation of the melanoproteins, which are heterogeneous in nature and show different physico-chemical properties, are considered to be most crucial. The studies on hair samples confirmed that melanin-drug interaction occur on the surface of melanin granules. These seem to be of minor importance compared to the drug-melanoprotein loading during melanogenesis for the observed influence of pigmentation on the drug content of hair fibers. From the results it was concluded that in vitro studies on melanin provide limited information and even drug-soaked hair must be regarded as inappropriate for the study of melanin-drug-binding in hair.

Animals↗
PubMed2003

Hermansky-Pudlak syndrome type 4 (HPS-4): clinical and molecular characteristics.

Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disorder of oculocutaneous albinism and bleeding attributable to storage-pool-deficient platelets. Although at least 14 mouse models of HPS exist, the human disorders that comprise HPS, i.e., HPS-1, HPS-2, HPS-3, and HPS-4, are recognized to result from mutations in four genes, viz., HPS1, ADTB3A, HPS3, and HPS4, respectively. To characterize further the recently identified HPS-4 disease on molecular and clinical grounds, we first identified the genomic organization of HPS4, located on chromosome 22q11.2-q12.2, including its intron/exon boundaries. We found that HPS4 produces at least two alternatively spliced mRNA transcripts that differ at their 5'-ends. Next, we performed an extensive analysis of 22 unassigned HPS patients (i.e., not having HPS-1, HPS-2, or HPS-3 disease). Using single-strand conformation polymorphism, we determined that seven of the 22 patients had HPS-4. In these seven individuals, we identified five different HPS4 mutations, including one frameshift insertion, one missense, and three nonsense mutations. Three alleles in two patients contained the previously reported Q698insAAGCA frameshift. Three HPS4 mutations were newly described. Four alleles in three patients contained R217X, and two siblings were compound heterozygotes for E138X and E222X. Clinically, our HPS-4 patients exhibited iris transillumination, variable hair and skin pigmentation, absent platelet dense bodies, and occasional pulmonary fibrosis and granulomatous colitis, a severe phenotype similar to that of patients with HPS-1.

Adolescent↗
PubMed2006

Identification of novel functional variants of the melanocortin 1 receptor gene originated from Asians.

Human melanocortin 1 receptor (MC1R) is a seven transmembrane G-coupled protein receptor that upregulates the cAMP pathway. Several functional variants of MC1R that show an impaired ability to activate the cAMP pathway are strongly associated with fair skin and red hair in Europeans and European descendants. The sequence variations of the MC1R gene were repeatedly investigated against worldwide populations; however, there was no evidence that functional variant of MC1R exists in non-European descendants. We report the presence of novel functional variants of MC1R with Asian origins. Three novel variants of MC1R, Phe147Delta, Thr157Ile, and Pro159Thr, were identified in our screening for the sequence variations of the MC1R gene against 995 individuals from 30 Asian and Oceanian populations; there was a single case for the Pro159Thr variant allele and two instances of Phe147Delta and Thr157Ile variant alleles. Our pharmacological assay revealed that Phe147Delta, Thr157Ile, and Pro159Thr variant showed similar or more dramatically impaired activities in comparison with Arg151Cys, which is a major functional variant of MC1R in Europeans. These functional variant alleles were geographically localized in relatively high latitudes, which suggest that the adaptation to ambient UV light intensity may play an important role in shaping the geographical distribution of MC1R alleles in Asia and Oceania.

Animals↗
PubMed2005

Treatment of pilonidal sinus by phenol application and factors affecting the recurrence.

BACKGROUND: Phenol injection, a less invasive method, has become more popular for the treatment of sinus pilonidalis. Recurrence rates after the use of phenol have been reported to be less than those after other surgical methods. METHODS: In this study, we applied 80% phenol to 143 patients with sinus pilonidalis. Patients were reevaluated at 1, 3, 6, 12 and 24 months after the phenolization procedure to search for any recurrences. Age, sex, skin color, occupation, hair distribution, complaints, macroscopic characteristics of the lesion, pouch volume, microbiological yield, complications of phenol injection, healing time, and recurrences were determined. RESULTS: The mean follow-up period was 24 months and the recurrence rate was 8.3% (12 of 143 patients). Volume of the sinus tract and number of sinus orifices were determined to be the factors significantly affecting recurrences (p<0.05). CONCLUSIONS: Injection of 80% phenol is an ideal approach for the conservative treatment of sinus pilonidalis. This study confirms that this is an effective and costless method with low recurrence rates.

Adolescent↗
PubMed2002

Genetic analyses of the mouse deafness mutations varitint-waddler (Va) and jerker (Espnje).

Genetic studies on spontaneous mouse mutants with hearing defects have provided important insights into the function of genes expressed in inner ear hair cells. Here we report on our genetic analyses of the deaf mutants varitint-waddler (Va) and jerker (Espnje). A high-resolution genetic map localizes VaJ to a 0.14 +/- 0.08 cM region between D3Mit85 and D3Mit259 on distal chromosome 3. By comparative mapping, the human ortholog resides at 1p22.3 between markers D1S3449 and D1S2252. To study the effect of different genetic backgrounds on the hearing phenotype, Espnje and VaJ were crossed to various inbred strains. Auditory-evoked brainstem response tests on F2 progeny demonstrate that expression, inheritance, and penetrance of the hearing phenotype are solely controlled by the mutant allele. To test for a genetic interaction between Espnje and Cdh23v, auditory function was analyzed in double heterozygotes; no significant increases of thresholds of sound pressure levels were observed. The results establish the framework for cloning the Va gene and provide valuable insights into the genetics of deafness mutations in the mouse.

Animals↗
PubMed1995

Gray hair, baldness, and wrinkles in relation to myocardial infarction: the Copenhagen City Heart Study.

To investigate a possible relation between aging signs such as graying of the hair, baldness, and facial wrinkling and myocardial infarction (MI), we analyzed data from The Copenhagen City Heart Study. During the 12-year follow-up, 750 cases of first-time MI were observed. After statistical adjustment for possible confounders, we found a correlation between graying of the hair, facial wrinkling, and frontoparietal baldness and crown-top baldness and MI in men. For example, the relative risk was 1.4 (95% CI, 0.9 to 2.0) for men with moderately gray hair compared with men with no gray hair and 1.9 (1.2 to 2.8) for men with completely gray hair (p < 0.001). With regard to gray hair, a similar although weaker and not statistically significant trend was seen in women. We conclude that, in addition to established coronary risk factors, aging signs like graying of the hair, male baldness, and facial wrinkling indicate an additional risk of MI.

Adult↗
PubMed1983

Auditory brainstem anomalies in albino cats. I. Evoked potential studies.

The amount of melanin pigmentation in the inner ear is positively correlated with the general pigmentation of the body and specifically with the amount of pigment in the eye. The misrouting of retinofugal projections which accompanies ocular and oculocutaneous albinism has been thought to be a defect in decussation unique to the visual system. Evidence suggests that functional abnormalities may also exist in the auditory systems of albino humans and animals. To evaluate this possibility, evoked potential techniques were used to examine the functional anatomy of decussating brainstem auditory pathways in albino and pigmented cats. Auditory brainstem responses (ABRs) were recorded from albino, pigmented, and Siamese cats using monaural stimulation. ABRs were recorded ipsilateral and contralateral to the stimulated ear. The albinos were complete tyrosinase-negative (cc), not the dominant white (W) variety associated with deafness. In pigmented cats, the amplitudes of ABRs recorded with the reference electrode ipsilateral to the stimulated ear and the ABRs recorded using the reference contralateral to the stimulated ear did not differ by more than 40% for individual components appearing between 2 and 4 ms after stimulus onset. In albino cats the components at these latencies were obliterated or greatly attenuated in the ABR recorded using the reference contralateral to the stimulated ear. These data indicate that anomalies may exist in the brainstem at the level of the acoustic striae, superior olivary nuclei and/or trapezoid body in tyrosinase-negative albino cats.

Animals↗
PubMed1980

The albino locus produces abnormal responses to opiates in the mouse.

Pedigreed inbred lines of pigmented mice were compared with albino lines differing at either a single locus or by a chromosomal segment of interest, for their responses to morphine. In either of two tests, behavioral activation or reduction in core temperature, albino mice were aberrant in their responses, demonstrating reliably less sensitivity to morphine than closely related pigmented lines. These findings suggest the need for caution in the use of albino lines in opiate research.

Animals↗
PubMed1988

Differential effects of short day pretreatment on melatonin-induced adjustments in Djungarian hamsters.

Djungarian hamsters which did not respond physiologically to short day conditions were injected daily with melatonin. Hamsters responded to this treatment with typical body weight alterations and molt. Therefore, we concluded that the lack of short day adjustments is not based on insensitivity to melatonin in this species. Pretreatment with short days affected the timing of melatonin-induced body weight loss and molt. Hamsters became refractory to melatonin injections earlier for both traits if pretreated with short days. Low body weight level was maintained for a shorter period of time, whereas duration of molt was not affected. These results might indicate differences in the control of melatonin-induced body weight adjustments and molt.

Animals↗