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At least 991 records · Page 55Linked to original sources
PubMed1993

Modulation of serotonin binding sites in the brain of the Djungarian hamster, Phodopus sungorus, during adaptation to a short photoperiod.

During the physiological adaptation of the Djungarian hamster, Phodopus sungorus, to a short photoperiod in autumn the modulation of specific serotonin (5-HT) binding sites of synaptic membranes was investigated in two brain regions, i.e. cerebral cortex and basal brain (CNS without cerebral cortex, cerebellum, pineal gland, and spinal cord). The radioligands [3H]5-HT and [3H]ketanserin were used to characterize total 5-HT1 and 5-HT2 binding sites, respectively. An increase of 5-HT1 and 5-HT2 binding sites was observed in both brain regions within 14 days after reduction of the photoperiod from a 14:10 h light/dark (l/d) cycle to an 8:16 h l/d cycle. The increase was still present after 56 days of the short photoperiod. Binding kinetics assayed after 4 days of the short photoperiod show that maximal specific binding of [3H]5-HT and [3H]ketanserin was increased, while dissociation constants (KD) were not changed. The membrane anisotropy of synaptic membranes, measured by fluorescence polarization, was reduced transiently during the early part of the adaptation. Neither the phospholipids nor the mole ratio of cholesterol to phospholipids were significantly affected by adaptation to short photoperiod. The results suggest an important role of the central nervous 5-HT system in the physiological adaptation of the Djungarian hamster to a short photoperiod.

Adaptation, Physiological↗
PubMed1990

A single gene controls resistance to Japanese encephalitis virus in mice.

The inheritance of resistance to Japanese encephalitis virus (JEV) was investigated using inbred strains of mice to study genetic resistance against JEV infection. C57BL/6 mice immunized intraperitoneally (i.p.) with an infective dose of JEV were resistant to intracerebral (i.c.) challenge with JEV, whereas most C3H/He mice treated in the same manner died. C57BL/6 mice developed this resistance 2 weeks earlier than C3H/He after intraperitoneal (i.p.) immunization. Passive transfer of spleen cells from immunized C57BL/6 protected the recipient mice from i.c. challenge, while transfer from immunized C3H/He was less effective. Since immunized athymic nude mice were not resistant to i.c. challenge with JEV, T lymphocytes were considered to be necessary for protection. When F1, F2 and backcross mice derived from C57BL/6 and C3H/He were challenged i.c. with JEV after i.p. immunizations, the number of resistant and susceptible mice were consistent with Mendelian ratios. Thus it can be concluded that resistance to JEV in mice was controlled by a single, dominant autosomal gene which was not linked to a (non agouti)-locus (chromosome 2).

Animals↗
PubMed1976

Phaeomelanic pigments from a human melanoma.

The pigments in melanomas from 2 patients were studied with regard to solubility and chemical composition. Melanoma pigment from a patient with red-blonde hair was alkali-soluble and contained 9 or 10% sulfur and was thus of phaeomelanic type. Melanoma pigment from a patient with red-brown hair was insoluble in 0.2 N NaOH. Its sulfur content was 6%. This pigment was eumelanic with regard to solubility characteristics but the sulfur content was higher than previously observed for eumelanin.

Adult↗
PubMed1980

Mutagenicity of melanin from human red hair.

The Salmonella typhimurium histidine reversion test of Ames et al. was used to demonstrate the pheomelanin, the red-brown polymeric pigment produced in human skin and hair, becomes mutagenic after exposure to long wave-length UV-light; a finding consistent with the UV-induced somatic mutation hypothesis for the origin of freckles and the high susceptibility of redheads and blonds to sunlight-induced skin cancers.

Hair↗
PubMed1990

Brittle cornea syndrome: an heritable connective tissue disorder distinct from Ehlers-Danlos syndrome type VI and fragilitas oculi, with spontaneous perforations of the eye, blue sclerae, red hair, and normal collagen lysyl hydroxylation.

We report a patient with the characteristic features of the brittle cornea syndrome, a rare, autosomal recessively inherited disorder, namely brittle corneae, blue sclerae, and red hair. The patient also showed joint hyperextensibility, a soft skin, and dysplastic auricles with unusually soft cartilage. Phenotypically, the disorder bears a certain resemblance to fragilitas oculi and the type VI (ocular) form of the Ehlers-Danlos syndrome, two conditions which are, themselves, not readily distinguishable. However, the hydroxylysine content of dermal collagen was normal, as was the activity of lysyl hydroxylase in cultured dermal fibroblasts, thus supporting the distinction of the brittle cornea syndrome as an independent entity. No abnormality was discernible in types I or III collagens synthesised by cultured fibroblasts, but electron microscopy revealed dramatic ultrastructural alterations in dermis in that distributed over its whole thickness were 20-60 microns wide "holes" or fibre-free spaces, filled with an amorphous material.

Child, Preschool↗
PubMed1979

Photoperiodic effects in the Djungarian hamster: one minute of light during darktime mimics influence of long photoperiods on testicular recrudescence, body weight and pelage colour.

In male Djungarian hamsters (Phodopus sungorus) short photoperiods (L/D 8/16) with additional 1- or 5-min light-pulses 8 h after light-off were as effective as long photoperiods (L/D 16/8) in stimulating testicular recrudescence, increase in body weight and moult into summer pelage. The results are discussed with regard to the hypothesis that the pattern of melatonin release from the pineal gland is important in mediating photoperiodic effects in mammals.

Animals↗
PubMed1995

B-cell maturation in chimaeric mice deficient for the heat stable antigen (HSA/mouse CD24).

The murine differentiation marker heat stable antigen (HSA) is a GPI-anchored surface glycoprotein showing strong expression on immature B- and T-lymphocytes and gradually reduced expression during maturation. Although HSA has been suggested to be involved in adhesion and/or signalling, its function has not been clearly demonstrated so far. In order to elucidate the function of HSA, we analysed chimaeric mice that were generated by targeted disruption of both HSA alleles in ES cells. These mice contain normal numbers of peripheral B-cells and normal serum IgM and IgG titres of ES cell-derived allotype, demonstrating that HSA expression on B-cells is not an absolute requirement for their maturation. However, a reduction in immature B-cells in the bone marrow and an altered degree of bone marrow and blood chimaerism suggest that HSA expression influences the maturation of B-cells.

Alleles↗
PubMed1991

Coinjection strategy for visual identification of transgenic mice.

Transgenic mice were generated by coinjection of a dominant marker gene that induces fur and eye pigmentation (a tyrosinase minigene) plus an unrelated DNA construction that has a gamma-glutamyl transferase (gamma GT) promoter linked to a ras oncogene. Mice transgenic for gamma GT-ras could be identified in the first and all subsequent generations by simple visual inspection for pigmentation. Furthermore, the gamma-glutamyl transferase promoter was active in kidney but not skin of the transgenic mice, indicating that the cointegrated DNA was active and independently expressed. These results confirm that the tyrosinase minigene can be used for coinjections to allow rapid visual identification of transgenic mice.

Animals↗
PubMedDate not supplied

Pigmentation and temporal effects on trace elements in hair.

Variations in trace element concentration in the head and facial hair of five individuals with ever-increasing amounts of white hair were examined. Hair was collected from the scalp, cheeks, and chin from one donor on a regular basis since 1984. Samples were separated into white and pigmented fractions, and analyzed at SLOWPOKE-Toronto by INAA for the short-lived, isotope-producing elements Br, Ca, Cl, Cu, I, Mg, Mn, Na, S, and Zn. Temporal concentration variations of these elements over time, and variations of the elemental concentrations in pigmented and white hair were established.

Adult↗
PubMed2004

Midazolam causes less sedation in volunteers with red hair.

PURPOSE: We studied sedation, cognition, and mood during midazolam infusion in volunteers with red and non-red (blond or brown) hair, to test the hypothesis that patients with red hair may require more drugs to attain desired levels of sedation. METHODS: Twenty red and 19 non-red hair subjects were studied in a randomized, placebo-controlled cross-over design. Subjects were studied during placebo and midazolam at 30 ng.mL(-1) target effect site concentration. Sedation was assessed using the observer's assessment of alertness/sedation (OAA/S) scale, the drowsiness visual analogue scale (VAS), and the bispectral index; cognition was assessed using the Repeatable Battery for Assessment of Neuropsychological Status; and mood was assessed using the bipolar form of the Profile of Mood States (POMS). RESULTS: Red hair volunteers showed significantly higher OAA/S (P < 0.01) and lower drowsiness VAS (P < 0.05) scores compared to non-red hair subjects during midazolam infusion. Visuospatial score was significantly higher in subjects with red compared to non-red hair during placebo and midazolam trials. Delayed memory score was significantly higher during midazolam infusion in subjects with red compared to non-red hair. There were no group differences in POMS during either trials. CONCLUSION: Midazolam appears to cause significantly less sedation and cognitive impairment in red haired subjects.

Adult↗
PubMedDate not supplied

Premature hair greying may predict reduced bone mineral density in Graves' disease.

BACKGROUND: Premature hair greying has been associated with low bone mineral density (BMD), and it may be more frequent in Graves' disease. AIMS: To determine whether premature greying is associated with reduced BMD in women with Graves' disease and in control women, and to examine whether premature greying is more common in Graves' disease. METHODS: Premature greying (> 50% grey by 40 years) and BMD were determined in 44 women with a history of Graves' disease and 133 female controls referred for routine BMD measurement. Exclusion criteria included diseases or drugs known to affect BMD. RESULTS: Mean Z and T scores at the lumbar spine were significantly lower (P < 0.04) in subjects with premature greying than in those not prematurely grey among women with Graves' disease, but not among control women. Multiple regression confirmed this difference between Graves' and control women (P = 0.041). There were no differences at other measurement sites. Of Graves' patients, 36% were prematurely grey compared with 25% of control women (P = 0.14). CONCLUSION: Premature greying may be a weak marker for reduced BMD in women with a history of Graves' disease, but it is not a marker in normal women.

Adult↗
PubMedDate not supplied

Accelerated phase in partial albinism with immunodeficiency (Griscelli syndrome): genetics and stem cell transplantation in a 2-month-old girl.

UNLABELLED: A 2-month-old girl presented with fever, hepatosplenomegaly, pancytopenia, hypertriglyceridaemia and silvery-greyish hair, suggesting the diagnosis of Griscelli syndrome (partial albinism with immunodeficiency). This diagnosis was confirmed by the characteristic agglomeration of melanin in the hair shaft and accumulation of melanosomes in melanocytes of the skin. The patient was homozygous for polymorphic markers around the myosin-Va gene on chromosome 15q21, which co-localize to the Griscelli disease locus. Natural-killer cells were in the lower range. The stimulation of lymphocytes with antigen and mitogen was normal. The patient's accelerated phase, characterized by haemophagocytosis was treated with prednisolone, rabbit anti-thymocyte globulins, and intrathecal methotrexate. Remission was maintained with cyclosporin A until HLA-compatible peripheral blood stem cell transplantation from her mother. CONCLUSION: The silvery-greyish hair associated with fever, pancytopenia and hypertriglyceridaemia is the clue to early diagnosis of Griscelli syndrome and important to prevent death before stem cell transplantation.

Chromosomes, Human, Pair 15↗
PubMed1997

[Green hair caused by frequent swimming pool use].

Three patients presented with an acquired green discoloration of their scalp hair. History revealed that all of them swam regularly in private swimming pools. Examination of the hair by atomic emission spectroscopy showed that the green discoloration was caused by an excessively high copper content of the hair. This exogeneous discoloration is characteristically related to the uptake of copper from private swimming pools.

Adolescent↗
PubMed1999

Premature greying of the hair is not associated with low bone mineral density.

In two recent case-control studies premature greying of the hair was associated with a lowering of bone mineral density (BMD) and osteopenia, suggesting that this might be a clinically useful risk marker for osteoporosis. We report a further re-examination of this proposal in 52 prematurely grey-haired women from East Yorkshire who responded to an advertisement inviting them for bone densitometry. Thirty-five had no clinical or drug history that could influence bone density. All were Caucasian with a mean age of 52.8 years. In the group as a whole the mean BMD values at the lumbar spine and femoral neck were no different from those of a young adult, but there was a trend toward a greater than average BMD than that of the local age-matched population (p = 0.097 and 0.218, respectively). Twenty women were premenopausal, with an average age of 45.3 years. Mean BMD values at the lumbar spine and femoral neck in this group were no different from those of young adults. There was, however, a trend toward a BMD greater than that of the local age-matched population at the femoral neck (p = 0.117). Fifteen women were postmenopausal with an average age of 62.9 years and an average age at menopause of 51.1 years. Mean BMD values at both the lumbar spine and femoral neck in this group were lower than those of young adults, but no different from those of the local age-matched population. In conclusion, our group of prematurely grey-haired women had average BMD for their age, and we are therefore unable to support the proposed clinical usefulness of premature greying as a risk marker for osteoporosis.

Absorptiometry, Photon↗
PubMed2006

Genetic characterization of a new set of recombinant inbred lines (LGXSM) formed from the inter-cross of SM/J and LG/J inbred mouse strains.

A new set of LGXSM recombinant inbred (RI) strains is presented. The RI strain panel consists of 18 remaining strains of the original 55 founding strains. Strain characterization is based on 506 polymorphic microsatellites and 4,289 single nucleotide polymorphisms (SNPs) distributed across the genome. Average microsatellite inter-marker distance is 4.80+/-4.84 Mb or 2.91+/-3.21 F(2) cM. SNPs are more densely spaced at 0.57+/-1.27 Mb. Ninety-five percent of all microsatellite inter-marker intervals are separated by less than 15.00 Mb or 8.50 F(2) cM, while 95% of the SNPs are less than 0.95 Mb apart. Strains show expected low levels of nonsyntenic association among loci and complete genomic independence. During inbreeding, the RI strains went through strong natural selection on the agouti locus on Chromosome 2, especially when the epistatically interacting tyrosinase locus on Chromosome 7 carried the wild-type allele. The LG/J and SM/J strains differ in a large number of biomedically important traits, and they and their inter-cross progeny have been used in multiple mapping studies. The LGxSM RI strain panel provides a powerful new resource for mapping the genetic bases of complex traits and should prove to be of great biomedical utility in modeling complex human diseases such as obesity and diabetes.

Animals↗
PubMed2005

Exon skipping in the KIT gene causes a Sabino spotting pattern in horses.

Sabino (SB) is a white spotting pattern in the horse characterized by white patches on the face, lower legs, or belly, and interspersed white hairs on the midsection. Based on comparable phenotypes in humans and pigs, the KIT gene was investigated as the origin of the Sabino phenotype. In this article we report the genetic basis of one type of Sabino spotting pattern in horses that we call Sabino 1, with the alleles represented by the symbols SB1 and sb1. Transcripts of KIT were characterized by reverse transcriptase polymerase chain reaction (RT-PCR) and sequencing cDNA from horses with the genotypes SB1/SB1, SB1/sb1, and sb1/sb1. Horses with the Sabino 1 trait produced a splice variant of KIT that did not possess exon 17. Genomic DNA sequencing of KIT revealed a single nucleotide polymorphism (SNP) caused by a base substitution for T with A in intron 16, 1037 bases following exon 16. The SNP associated with SB1 was designated KI16+1037A. This substitution eliminated a MnlI restriction site and allowed the use of PCR-RFLP to characterize individuals for this base change. Complete linkage was observed between this SNP and Sabino 1 in the Tennessee Walking Horse families (LOD = 9.02 for Theta = 0). Individual horses from other breeds were also tested. All five horses homozygous for this SNP were white, and all 68 horses with one copy of this SNP either exhibited the Sabino 1 phenotype or were multipatterned. Some multipatterned individuals appeared white due to the additive effect of white spotting patterns. However, 13 horses with other Sabino-type patterns did not have this SNP. Based on these results we propose the following: (1) this SNP, found within intron 16, is responsible for skipping of exon 17 and the SB1 phenotype, (2) the White and Sabino phenotypes are heterogeneous and this mechanism is not the only way to produce the pattern described as "Sabino" or "White," and (3) homozygosity for SB1 results in a complete or nearly completely white phenotype.

Animals↗