Keratogenous Zone Research Articles

The distribution of coated vesicles in keratinizing cells of the wool follicle.

The presence and distribution of coated vesicles in the cells of the lower third of the Romney wool follicle are described, with special reference to cortical cells. Coated vesicles were typically found free in the cytoplasm and associated with plasma membranes and Golgi complexes. They were most prevalent in the bulb and in the elongation and lower keratogenous zones of the cortex. However, the numbers of coated vesicles decreased markedly in the remainder of the keratogenous zone, especially of those associated with plasma membranes. A similar decrease in the numbers and sizes of Golgi complexes in this zone was also noted. The possible role of coated vesicles in the lower wool follicle is discussed.

Alpha-Naphthyl Acid Phosphatase Activity in Normal Human Skin and Keloids

The activity of α-naphthyl acid phosphatase was measured fluorometrically in μg samples of normal human skin and its appendages and in keloids. The preponderant distribution of this enzyme was in the keratogenous zones of the epidermis and hair follicles and in the disintegrating central portion of sebaceous glands. Enzyme activity was higher in the papillary than in the reticular layer of the dermis. Acid phosphatase activity in both the epidermis and dermis was higher in keloids than in normal skin: keloid nodules in the reticular layer exhibited a ten fold increase.

MECHANISMS OF PARAKERATOSIS

SUMMARY. The removal of the horny layer of the guinea-pig ear by tape stripping causes rapid development of a parakeratotic scale during the first 12 hr. Some epidermal cells, which were labelled with 3H-Thymidine when stripping was performed, could be detected autoradiographically in the parakeratotic stratum corneum a few hours later. Since the proliferative response of the epidermis is retarded after vigorous stripping, these cells have become parakeratotic due to exposure and subsequent cell death. Topical application of Vitamin A-acid produces morphological alterations of the keratogenous zone together with increased DNA-synthesis in the lower portion of the epidermis, leading to the persistence of nuclei in the stratum corneum. Prolonged treatment with Vitamin A-acid and Hexadecane increases the epidermal thickness to values such as are found in psoriasis. The turnover time of this hyperplastic epidermis is reduced to about 3 days, yet no parakeratosis can be found. These observations lead to the conclusion that maximally stimulated epidermopoiesis does not result in parakeratosis unless there is a defect in cell differentiation.

Hot, Acidified Rhodamine B and Methylene Blue; A Differential Stain Dichromatic for Hair Follicular Keratins, Achromatic for Epidermal Keratin

Procedure:Cut paraffin sections and float on a 45–50 C water bath; spread silicone-rubber adhesive (Clear Seal-General Electric) thinly and evenly over 2/3 of the slide; pick up the sections from the floatation water with the coated slide; dry for 1.5 hr at 25 C and at 60 C for 0.5 hr; deparaffinize, and hydrate to water. Place 150 mg of rhodamine B and 150 mg of methylene blue each in separate 100 ml beakers and add 80 ml of 10% HCl to each beaker. Bring both solutions to a boil on a hot plate in a fume hood; immerse tissue sections in the boiling rhodamine B exactly 2 min; rinse in a beaker of 10% HCl 5 sec; immerse in the boiling methylene blue exactly 0.5 min; rinse in distilled water; blot dry; and mount in a silicone-rubber medium (Glass and Ceramic Adhesive—Dow Corning Corp.). Hair shaft keratin stains red; inner root sheath keratin and keratogenous zone of the hair shaft, blue green; epidermal keratin remains unstained. Pilomatrixornas show foci of both red and blue green keratin; epidermal and ha...

Sodium rhodizonate staining of the keratogenous zone of the hair follicle and lingual papilla.

Exposure of frozen sections of guinea pig skin to a saturated aqueous solution of sodium rhodizonate buffered to pH 6.2 selectively induces a band of black granules in the keratogenous zone of hair follicles. The major staining is in the cortex, but to a lesser extent granules develop in the medulla and inner root sheath in the same zonal pattern. A similar granular staining is seen in the lingual papillae and naisl. Other structures in the skin and other organs do not show this. At pH 9.0 the sodium rhodizonate selectively stains the hair follicles a reddish brown. Although the affinity of the keratogenous zone of the hair follicle for sodium rhodizonate remains unexplained, one might postulate the stain is dependent upon the presence of an unusually high sulfhydryl content. In favor of this is the fact that the highest level of protein-bound sulfhydryl activity is in the exact site of the rhodizonate staining, and the fact that rhodizonic acid can oxidize sulfhydryl compounds to dark end products.

The Keratinised Teeth of Myxine glutinosa. A Histological, Histochemical, Ultrastructural and Experimental Study1

AbstractThe structure and function of the keratinised teeth of Myxine glutinosa have been studied. Following a detailed histological examination, histochemical, ultrastructural and experimental techniques have been used to study some aspects in more detail. A modification of the standard glutaraldehyde fixative for electron microscopy has been developed for Myxine tissues.The development of the horn cap (HC) and the pokal cell cone (PCC) have been traced. The HC is seen to increase in thickness with increasing length of the animal but there are irregularities in the development of the PCC which suggest that this cone may act as a replacement tooth for the HC. Experiments, in which the HCs were removed and the changes in the PCC observed, were performed to test this hypothesis. As a result of these and other observations it is suggested that it is possible for tooth replacement to occur.The structure and formation of the keratin in the HC and PCC cells has been followed using electron microscopy and histochemistry. The accumulation of keratin fibres in the early stages of PCC development has been traced, and keratinisation, which is probably associated with an increase in height of the cusps has been followed across a keratogenous zone at the bases of well developed HCs and PCCs.It has been established that the HC pigment granules are lipofuscin and that they can originate from lipid droplets.A detailed investigation has been made of the pokal cells. It is suggested that the beaded fibres, observed in electron micrographs of the apical band of these cells, are synthesised from lipid droplets in basal portions of the pokal cells, in a synthetic cycle, during which the nucleus descends through the length of the cell.

Epilating effect of cystaselenonine on induced hair growth in mice.

SummaryCystaselenonine, the selenium analog of cystathionine, causes a hair loss in mice that is limited to the older growing hairs which have aged 16 days after mechanical epilation. The hair does not regrow for 20 days if the mice are treated with cystaselenonine for 12 days. The mice lose weight during treatment, but eventually recover. Cystaselenonine may act by interfering with sulfhydryl metabolism in the keratogenous zone of the hair follicle and not by interfering with mitosis.

The pathogenesis of alopecia areata.

SUMMARY.— The pathogenesis of alopecia areata was studied by plucking hairs from each of a series of concentric zones, using felt patterns placed over lesions. It was possible to group lesions according to the zone with the greatest proportion of club hairs. The results are logically interpreted to mean that a wave of hair follicle damage or arrest moves centrifugally from a focal point beyond the area of alopecia. It is suggested that follicles may react in I of 3 ways. Firstly, severe damage may weaken the hair in the keratogenous zone, this being followed by breakage when the weak zone reaches the plane of the scalp; at the same time the follicle is precipitated into catagen and the hair is extruded as an exclamation mark. Secondly, the follicle may be precipitated into catagen with loss of the club in a normal manner, followed by replacement with a dystrophic anagen hair. Thirdly, the follicle may become dystrophic without a catagen phase.

A histochemical study of keratinization in the domestic fowl (Gallus gallus)

The microanatomy of the epidermis of the domestic fowl is described and related to the distribution of various histochemical constituents involved in keratinization.The avian horny layer over the back is composed of a loose network of structurally solid horny cells. This is in contrast to most mammalian epidermal horny cells in which structural keratin is found only in the peripheral cytoplasm, and the interior of the keratinocyte contains soluble products of cytolysis with possibly some free keratin filaments dispersed in the fluid material.The avian tarsal epidermal horny scales show similarities to both the scales of lizards and snakes and to mammalian tail scales which appear to be homologous structures.It is suggested that a thin layer of cells containing no detectable disulphide bonds, found in the tarsal scale region of the young chick, is probably mechanically weak and may function as a fission plane for sloughing of the horny layer. A specialized epidermis and thickened horny layer is developed in the fowl on the plantar underside of the toes, but this is quite different in structure from the mammalian plantar epidermis.The overlapping of zones rich in ribonucleic acid (RNA) and bound cysteine (SH) in the growing feather suggests that protein synthesis and the preparatory stages to keratin disulphide bonding normally occur concurrently in feather formation. This is in contrast to the growing hair which has a region rich in RNA followed immediately before it becomes keratinized by a discrete keratogenous zone weak in RNA but rich in bound cysteine.

Calcifying Epithelioma of Malherbe: Histochemical and Electron Microscopic Studies

Calcifying epithelioma is a rare, solitary tumor which often occurs in young individuals (1), most frequently on the face and the arms (1, 2). Since Malherbe and Chenantais (3) described “calcified epithelioma of sebaceous glands” in 1880, the histogenesis of this tumor has been attributed to various skin appendages such as sebaceous glands (3, 4) and hair (2, 5, 6, 7). Lever and Griesemer (7) regarded the basophilic cells in calcifying epithelioma as primary epithelial germ cells with a tendency to differentiate into keratotic hair cells. Forbis and Helwig (1), in their recent study on 240 specimens, agreed with the opinion of Lever (2) and Lever and Griesemer (7) that calcifying epithelioma arises from primitive cells of the hair matrix. They pointed out that the broad dense transitional zone from basophilic to shadow cells of this tumor, where sulfhydryl groups are abundant, is analogous to the kera-togenous zone of the hair. They also demonstrated that hyalinized shadow cells in some instances show a brilliant birefringence, as does the keratogenous zone of the hair.

THE INCORPORATION AND FATE OF H3-TYROSINE IN THE HAIR CORTEX OF RATS OBSERVED BY RADIOAUTOGRAPHY.

The incorporation of H(3)-tyrosine into the protein of the cells in the cortex of rat hair has been investigated by radioautography. In growing hairs, radioactivity is found in the matrix, the upper bulb, and the whole of the keratogenous zone up to the fully keratinized part of the shaft, 10 and 30 minutes after an injection of labelled tyrosine. This is unequivocal evidence of protein synthesis at these sites. There is a very precise relationship between the end of protein synthesis and the hardening of the cortical cells at the top of the keratogenous zone. The way in which the silver grains of the radioautographs are clustered indicates that at 30 minutes after the injection the isotope is distributed more evenly in the matrix and upper bulb than in the top of the keratogenous zone. Possibly this reflects a difference, at these sites, in the cell components engaged in protein synthesis, or in the proteins being synthesized. The fully keratinized and hardened part of the hair was not radioactive at 10 and 30 minutes after the injection of H(3)-tyrosine. The rate at which the radioactivity moves into this region shows that the hair of rats grows 0.9 mm/24 hours. Comparison of the degree of radioactivity along the growing hair in the 30-minute, 12-hour, and 36-hour materials shows conclusively that protein accumulates in the cortical cells during their keratinization. An injection of a labelled amino acid does not behave as an ideal pulse dose; consequently, the grain density over the hair cortex at 36 hours is 100 per cent larger than would be expected if an ideal pulse dose situation existed.

A STUDY OF THE ULTRASTRUCTURAL LOCALIZATION OF HAIR KERATIN SYNTHESIS UTILIZING ELECTRON MICROSCOPIC AUTORADIOGRAPHY IN A MAGNETIC FIELD.

The sites of the incorporation of labeled cystine into keratinizing structures were studied in electron microscopic autoradiographs. The tracer used was cystine labeled with S(35) emitting long-range ionizing particles. During exposure for 1 to 2 months, according to our method of electron microscopic autoradiography, emulsion-coated specimens were exposed to a static magnetic field which appeared to result in a marked increase in the number of reacted silver grains. In young Swiss mice receiving intraperitoneal injections at 1, 3, and 6 hours before biopsy, conventional autoradiography demonstrated that S(35)-cystine was intensely localized in the keratogenous zone of anagen hair follicles, and that the radioactivity there increased in intensity progressively with time while the radioactivity in the hair bulb always remained very low. Our observations with electron microscopic autoradiography in a magnetic field appeared to indicate that at 3 and 6 hours after injection the S(35)-cystine was directly and specifically incorporated into tonofibrils in the hair cortex and into amorphous keratin granules of the hair cuticle layer, possibly without any particular concentration of this substance in the other cellular components. There seemed to be an appreciable concentration of cystine in tonofibrils of the cuticle of the inner root sheath. However, trichohyalin granules in the hair medulla and inner root sheath failed to show any evidence of cystine concentration. The improved sensitivity of the electron microscopic autoradiography with S(35)-cystine appeared to be partly due to the application of a static magnetic field. However, the reason for this could not be explained theoretically.

THE INFLUENCE OF ALLOXAN DIABETES, METHYLTHIOURACIL, CORTISONE AND ADRENALINE ON THE UTILIZATION OF GLUCOSE 14C AND L-CYSTINE 35S AND MITOTIC ACTIVITY BY HAIR FOLLICLES IN WHITE MICE

ABSTRACT Autoradiographs of hair follicles 1, 3, 5 and 8 days after the induction of growth by plucking were prepared from mice injected with 15 μc glucose 14C 5.5 hours before autopsy. It was demonstrated that radioactivity increased principally in the »active« regions of the follicle, namely, the regions engaged in cell proliferation or keratin synthesis. The level of radioactivity in these regions of the follicle increased with maturation. Alloxan diabetes and cortisone induced a conspicuous depression of glucose 14C absorption during anagen (day-1, 3, 5 follicles) but these effects were markedly reduced in metagen (day-8 follicles). Adrenaline and methylthiouracil (MTU) had no effect on the absorption of glucose 14C at any of the stages of follicle activity observed. Mitotic counts in follicles from the same animals in which glucose 14C utilization was studied revealed that these endocrine states exerted similar effects on cell proliferation. Alloxan diabetes and cortisone strongly depressed mitotic activity during anagen, but had a relatively weak effect during metagen, in fact cortisone appeared slightly stimulative. Whilst adrenaline and MTU had no apparent influence. The radioactivity present in follicles representing 2, 4, 6 and 9-day stages of development was assessed by autoradiographic means from mice injected with 1 μc L-cystine 35S 24 hours before autopsy. L-cyst(e)ine 35S was absorbed in large quantities only in day-9 follicles, in which it accumulated mainly in the keratogenous zone. Absorption of L-cyst(e)ine 35S by metagen (day-9) follicles was unaffected by alloxan diabetes, cortisone, adrenaline and MTU.

Activity of the acetabular secretory apparatus of cercariae of Schistosoma mansoni under experimental conditions

A combination of experimental and histologic techniques was employed to demonstrate the two pairs of preacetabular glands and ducts and the three pairs of postacetabular glands and ducts of cercariae of Puerto Rican Schistosoma mansoni. By these techniques secretion from the preacetabular secretory apparatus, either unstained or stained intravitally with purpurin, was induced into skin, on a surface of human sebum rubbed on a substratum, and into a vaseline wall rimming a coverglass sealing a mount of cercarial suspension. These glands were emptied during the initial stages of skin penetration during which schistosomules migrated along the keratogenous zone of skin and across the cellular epidermis. It was observed that cercariae deposited mucoid (PAS-positive) secretion from the postacetabular secretory apparatus as they looped over skin during exploration, at the site of penetration, and into the horny layers and keratogenous zone. Both types of glands were unstained, and therefore considered exhausted of their contents, shortly after the beginning of penetration in single penetrants, when maximum effort appeared to have been required for entry. Occasional schistosomules which penetrated in groups or which entered areas already invaded retained remnants of glandular contents which showed specific stain. It is suggested that the mucoid postacetabular secretion serves adhesive, lubricative, protective and enzyme-directive functions, while the preacetabular secretion is primarily enzymatic. The possibility remains, however, that secretions from both pre- and postacetabular glands may be active enzymatically.

Non-enzymatic Reduction of Tetrazolium Salts by Sulfhydryl Groups

1. The non-enzymatic reduction of tetrazolium salts by SH groups was studied mainly in the keratogenous zone of the hair.2. The effect of non-enzymatic reduction of tetrazolium salts by SH groups is pH-dependent, beginning at about pH4.4, gradually increasing up to pH7.0 and continuing to increase rapidly thereafter until pH13 which is the highest alkaline pH tested. Addition of diphosphopyridine nucleotide (DPN) intensifies the reaction.3. It was shown that several inorganic as well as organic substance having SH groups can reduce tetrazolium salts in vitro.4. It is concluded that the hydrogen of SH groups can be transferred directly to tetrazolium salts in addition to the pathway via specific diaphorases as described by ZIMMERMAN and PEARSE (1959). The main implication of this fact is that the precise histochemical localization of not only coenzyme-linked dehydrogenases but also cytochrome-linked dehydrogenases may be difficult without proper controls for tissue-SH.5. Since it was found that sodium cyanide higher than 0.01M in the final concentration of the incubation medium can also reduce tetrazolium salts, which may result in the false positive localization of enzymes, the concentration of the sodium cyanide should be kept lower than 0.01M in the incubation medium in the histochemical demonstration of coenzyme-linked dehydrogenases.

Histology and cytochemistry of human skin. XI. The distribution of beta-glucuronidase.

1. Various amounts of beta-glucuronidase activity may be found in all of the cutaneous appendages. 2. In the epidermis, the basal layer and the Malpighian layer contain a moderate amount of it, but a band of cells, including the stratum granulosum and the cells immediately above it, is rich in beta-glucuronidase. 3. The cells of the duct of eccrine sweat glands have moderately strong enzyme activity, but those in the secretory coil are strongly reactive; small and large reactive granules are crowded in the reactive cytoplasm. 4. The cells of the secretory coil of the apocrine glands contain more beta-glucuronidase than any other cutaneous appendage. 5. In the sebaceous glands, a very strong concentration of enzyme activity is found in the undifferentiated peripheral cells, a smaller amount of it is found in the differentiating cells. 6. In active hair follicles, the largest amount of beta-glucuronidase is found in the outer root sheath and in the bulb. In the outer sheath, the strongest concentration is found around the level of the keratogenous zone of the cortex. The dermal papilla is strongly reactive. In quiescent hair follicles, the outer root sheath has a moderate amount of enzyme concentration, but the dermal papilla is unreactive. 7. In the dermis, the fibroblasts in the papillary layer, the smooth muscle cells of the arrectores pilorum and the tunica media of arteries, and the fat cells all exhibit enzyme activity. Mast cells show a great concentration of beta-glucuronidase.

The entry of Ca45 into the skin and other soft tissues of the rat; an autoradiographic and spodographic study.

The uptake of radiocalcium by specific regions of the skin, eye, cartilage and mucous glands has been demonstrated with the help of integrated autoradiographs. Most of the calcium that enters the hair follicle is found in the keratogenous zone. In the skin and eye, it appears that Ca45 has entered by bio-synthesis while in the cartilage and mucous glands, that uptake of labelled Ca might represent cation adsorption by the sulfopolysaccharides. The autoradiographic record of Ca45 follows the distribution of the blue/white dust in the spodograms of skin, cartilage and mucous glands.