Histologic and cell kinetic studies of hair loss and subsequent recovery process of human scalp hair follicles grafted onto severe combined immunodeficient mice.
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To establish a model for studying human scalp hair, individually isolated hair follicles were grafted onto back skin of severe combined immunodeficient mice. Histologic changes and cell kinetics in the hair loss and subsequent recovery process were investigated. In the dystrophic stage (from day 7 to 30), all the hair shafts became dystrophic and were shed. Thickening and corrugation of vitreous membrane, apoptosis, and regression of the lower part were observed in the grafted hair follicles. 5-bromo-2'-deoxy-uridine-labeled cells were not detected in the lower end of the follicles, and keratin 19-positive cells appeared there. At the end of this stage their lower part was maximally retracted, secondary germ remained beneath the bulge, and the vitreous membrane disappeared. In the regeneration stage (from day 30 to 50), the same histologic findings as those at the end of the dystrophic stage were observed. The keratin 19-positive cells in the secondary germ, however, were replaced with keratin 19-negative and 5-bromo-2'-deoxy-uridine-labeled cells. Then, differentiation into an inner root sheath and a hair shaft began, and apoptosis was terminated. In the stable growth stage (from day 40 to at least 150), the grafted follicles were immunohistochemically and light microscopically identical with the normal anagen hair follicles except for the presence of melanin incontinence. These findings suggest that the grafted hair follicles entered into dystrophic catagen, subsequently dystrophic telogen, then returned to normal anagen follicles, and that stem cells or their close progeny in the secondary germ play an important part in the recovery process. (+info)
Inter-ocular interference and circadian regulation of the chick electroretinogram.
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Illumination of a chick's eye allows light to pass through to the retina of the contralateral eye. Electroretinographic (ERG) recording employing the scalp or comb as a reference results in shorter implicit time, higher amplitude and lower sensitivity during the day than during the night in a light:dark (LD) cycle and in constant darkness (DD). ERG recordings employing the contralateral eye as reference abolishes rhythmicity or reverses the phase angle (higher amplitudes at night). This is probably due to light transmission through the eyes to elicit visual responses in the reference. The contralateral eye is a poor choice for reference in birds and obscures physiological analyses of clock control of vision. (+info)
An autopsy case of Adams-Oliver syndrome.
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We report an autopsy case of a male fetus with Adams-Oliver syndrome. His mother was a healthy, 31-year-old woman and her family and past histories were unremarkable. Therapeutic termination was done at 28(+6) weeks gestational age due to oligohydramnios detected by antenatal ultrasonography. Chromosomal study revealed normal karyotype. On autopsy, characteristic transverse terminal defect of four extremities was found. Both feet were short and broad. All toes were rudimentary with no nails and fingers were irregularly short. On infantogram, all toe-bones were stubby and rudimentary. The middle and terminal phalanges of 2nd, 3rd & 5th fingers and the terminal phalange of 4th finger on the right hand were absent. The middle and terminal phalanges of 2nd & 5th fingers and terminal phalange of 3rd finger were defected on the left hand. His abnormalities were consistent with features of Adams-Oliver syndrome, which has not been reported in Korea. (+info)
Neutrophil-rich anaplastic large cell lymphoma of T-cell lineage. A report of two cases arising in HIV-positive patients.
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Neutrophil-rich anaplastic large cell lymphoma (ALCL) is an uncommon morphologic variant of ALCL. We report 2 cases of neutrophil-rich T-cell ALCL that presented as scalp masses in HIV-positive men. Histologically, the neoplastic cells extensively infiltrated the dermis and subcutaneous tissue. The neoplastic cells strongly expressed CD30 and were of T-cell lineage, positive for CD3 and CD45RO, and negative for CD20. The neoplastic cells were negative for anaplastic lymphoma kinase-1. Numerous admixed neutrophils also were present, representing up to 70% of all cells in some microscopic fields. Neither patient had peripheral blood leukocytosis. One patient had relative neutrophilia, 79% (0.79; reference range, 50%-70% [0.50-0.70]). The absolute CD4 counts were 160 cells/microL (160 x 10(6)/L) and 150 cells/microL (150 x 10(6)/L), respectively (reference range, 431-1,623/microL [431-1,623 x 10(6)/L]). Both patients were treated with multiagent chemotherapy but died of Pneumocystis carinii pneumonia within 6 months of diagnosis. In our review of the literature, we identified 5 similar T-cell cases, including 1 in an HIV-positive patient. Neutrophil-rich T-cell ALCL is a rare morphologic variant of ALCL that should be considered in the histologic evaluation of neutrophil-rich biopsy specimens. (+info)
Prevention of chemotherapy-induced alopecia in rats by CDK inhibitors.
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Most traditional cytotoxic anticancer agents ablate the rapidly dividing epithelium of the hair follicle and induce alopecia (hair loss). Inhibition of cyclin-dependent kinase 2 (CDK2), a positive regulator of eukaryotic cell cycle progression, may represent a therapeutic strategy for prevention of chemotherapy-induced alopecia (CIA) by arresting the cell cycle and reducing the sensitivity of the epithelium to many cell cycle-active antitumor agents. Potent small-molecule inhibitors of CDK2 were developed using structure-based methods. Topical application of these compounds in a neonatal rat model of CIA reduced hair loss at the site of application in 33 to 50% of the animals. Thus, inhibition of CDK2 represents a potentially useful approach for the prevention of CIA in cancer patients. (+info)
A unique type I keratin intermediate filament gene family is abundantly expressed in the inner root sheaths of sheep and human hair follicles.
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A unique type I keratin intermediate filament group, comprising three highly related proteins and expressed in the inner root sheath of hair follicles, has been identified in both sheep and human. The first members from these species are named oIRSa1 and hIRSa1 and each encodes a protein of 450 amino acids, with compositional characteristics intermediate between those of previously described hair keratin and epidermal cytokeratin type I intermediate filaments. Detection of abundant mRNA transcripts derived from the sheep and human genes by cRNA in situ hybridization only in the inner root sheath and not in the medulla concurs with the findings of earlier ultrastructural analyses that have reported intermediate filaments only in the inner root sheath. Clustering of the IRSa keratin genes is apparent in the genomes of both species. The three hIRSa genes, known to reside on human chromosome 17, are closely linked to three further type I keratin intermediate filament genes of unknown function. This new gene complex, contained almost entirely within a 156 kb BAC (hRPK.142_H_19), is likely to lie near the type I intermediate filament cytokeratin and hair keratin gene loci at 17q12-q21. A phylogenetic analysis including all known human type I intermediate filament cytokeratins, hHa keratins, hIRSa, and hIRSa-linked keratins suggests that origin of the IRSa keratin intermediate filament linkage group preceded origin of most of the epidermal cytokeratins and all hair keratins during emergence of the keratin intermediate filament genes. (+info)
Characterization of a cluster of human high/ultrahigh sulfur keratin-associated protein genes embedded in the type I keratin gene domain on chromosome 17q12-21.
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Low stringency screening of a human P1 artificial chromosome library using a human hair keratin-associated protein (hKAP1.1A) gene probe resulted in the isolation of six P1 artificial chromosome clones. End sequencing and EMBO/GenBank(TM) data base analysis showed these clones to be contained in four previously sequenced human bacterial artificial chromosome clones present on chromosome 17q12-21 and arrayed into two large contigs of 290 and 225 kilobase pairs (kb) in size. A fifth, partially sequenced human bacterial artificial chromosome clone data base sequence overlapped and closed both of these contigs. One end of this 600-kb cluster harbored six gene loci for previously described human type I hair keratin genes. The other end of this cluster contained the human type I cytokeratin K20 and K12 gene loci. The center of the cluster, starting 35 kb downstream of the hHa3-I hair keratin gene, contained 37 genes for high/ultrahigh sulfur hair keratin-associated proteins (KAPs), which could be divided into a total of 7 KAP multigene families based on amino acid homology comparisons with previously identified sheep, mouse, and rabbit KAPs. To date, 26 human KAP cDNA clones have been isolated through screening of an arrayed human scalp cDNA library by means of specific 3'-noncoding region polymerase chain reaction probes derived from the identified KAP gene sequences. This screening also yielded four additional cDNA sequences whose genes were not present on this gene cluster but belonged to specific KAP gene families present on this contig. Hair follicle in situ hybridization data for single members of five different KAP multigene families all showed localization of the respective mRNAs to the upper cortex of the hair shaft. (+info)
Dermatofibrosarcoma protuberans of scalp : a case report.
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A case of dermatofibrosarcoma protuberans of scalp involving the underlying bone, operated after recurrence by taking safety margin of 3 cm and skin deficit covered by transposition flap, is being reported. Modality of treatment has been discussed. (+info)