A histopathological and immunological profile of a single lesion lepromatous leprosy (LLs).
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Aged↗
Biomedical subjects
B Iyengar
Publications and source records attributed to B Iyengar.
Proliferating trichilemmal cysts over the vulva.
A sixty-year-old woman with multiple proliferating trichilemmal cysts over the vulva is described. The appearance of the eruptions suggests a hamartomatous origin. The lesions in the later stages resembled basal cell carcinoma. The malignant potential of the cysts and their treatment are discussed.
Biopsy↗
Hypomelanosis of ito: histochemical and ultrastructural observations.
Skin biopsies were taken from an infant girl with Hypomelanosis of Ito (Incontinentia Pigmenti Achromians) for histopathological, histochemical and electron microscopic studies. Histological observations were similar to those reported previously. Electron microscopy revealed two groups of melanocytes, an effete group and another group with a highly dendritic appearance. The significance of these findings is discussed.
Female↗
Modulation of melanocytic activity by acetylcholine.
Acetylcholine esterase (AChE) activity is lowered in vitiliginous skin. The AChE activity in 52 cases of vitiligo during repigmentation and depigmentation has been observed in this study. The cases with marginal dendritic melanocytes show that AChE is negative in these cells during depigmentation but positive on repigmentation. There is little variation in activity in the cases showing nondendritic marginal melanocytes. Acetylcholine (ACh) has an inhibitory effect on dopa oxidase activity in both types of marginal melanocytes in vitiligo. ACh modulates pigment production by the melanocytes, its role being inhibitory. From the present results, it is evident that a fall in AChE activity in the melanocytes leads to greater inhibition by ACh aggravating the process of depigmentation in vitiligo.
Acetylcholine↗
Hair cycle and the histogenesis of pillar tumours.
In a study of 50 tumours of pilar origin, it was observed that tumours arise from each cell type depending upon the phase of the hair cycle. Thus nevoid lesions arise from the pluripotent cells of the early anagen phase; tumours from the hair matrix, outer root sheath and inner root sheath arise during the anagen phase, and the keratoacanthomas during the interphase between anagen and telogen. Basal cell epitheliomas can arise at any phase. It was observed that the tumours arising during the anagen phase from the fully differentiated follicles formed the bulk (88%) and the keratoacanthoma simulating the catagen/telogen phase was rare in consonance with the length of each phase. It is proposed that the inner root sheath tumours be named trichilemmomas and the outer root sheath tumours trichochlamydomas to distinguish them from one another.
Hair↗
Neural differentiation of melanocytes in vitiliginous skin.
Biopsies from 74 cases of vitiligo were examined to study the reactions of marginal melanocytes. In 35 cases, the melanocytes at the edge of the patch appeared highly dendritic and large with marked arborization of the dendrites between the surrounding epidermal cells. These cells showed low pigmentation but a high enzyme activity which extended along the dendrites. The enzymes include tyrosinase/dopa oxidase, dopamine oxidase and noradrenaline activity, indicating that these cells have a biphasic melanogenic/adrenergic differentiation. This similarity between the dendritic melanocytes and the amelanotic melanoma cell line HT-18 is of interest.
Cell Differentiation↗
Cupric ions and DOPA oxidase activity in melanocytes.
The inhibition of DOPA oxidase activity by cupric ions has been quantitated in cases of vitiligo showing dendritic and non-dendritic melanocytes at the margins. Cupric sulphate was added to the substrate solution, containing a reacting quantity of 12.12 micrograms of DOPA, to give 42.8 micrograms, 85.6 micrograms, 128.4 micrograms and 171.2 micrograms of cupric ions. Control slides were incubated with DOPA alone as substrate. On cytospectrophotometric analysis it was seen that the initial level of enzyme activity determines the type of inhibition curve. Thus, there is a gradual fall in activity with dendritic melanocytes which have a very high enzyme content, whereas the non-dendritic melanocytes show complete inhibition with one dose. It was observed that 15.75 micrograms of cupric ions were reduced by 12.12 micrograms of DOPA. The enzyme activation by cupreous ions is countered by the enzyme inhibition by cupric ions, the rate of inhibition being determined by the level of cupric ions.
Catechol Oxidase↗
The biphasic nature of a human amelanotic melanoma tumour line HT-18.
The morphological features of a human amelanotic melanoma tumour line, HT-18 was studied in vitro. Primary cultures show that the tumour cells are biphasic with respect to their differentiation as revealed by light microscopy, SEM and TEM. Most of the cells show numerous processes resembling neuronal dendrites. The cytoplasm contains stage I and II melanosomes, occasionally melanosomes showing irregular pigmentation. According to these observations it appears that the HT-18 cells are at an earlier phase of differentiation showing both melanogenic and neurogenic activity.
Animals↗
Reaction of dendritic melanocytes in vitiligo to the substrates of tyrosine metabolism.
Frozen sections of vitiliginous skin were treated with the substrates involved in melanogenesis and adrenergic activity to study the effect of changing chemical milieu on the biphasic dendritic melanocytes. The substrates used are tyrosine, DOPA, tyrosine + DOPA, dopamine, adrenalin and cupric ions. It was observed that tyrosine when used alone has a weak melanogenic reaction while DOPA and tyrosine + DOPA show a prominent activity. Adrenalin and dopamine inhibit the neural limb and enhance melanogenesis. Cupric ions on the other hand enhance the neural limb and inhibit melanogenesis. These changes are not evident in the non-dendritic melanocytes. Thus the highly dendritic melanocytes are at a lower state of differentiation. These biphasic cells are more sensitive to changes in the chemical milieu.
Copper↗
Unilateral expression of multiple glomus tumors. An unusual occurrence.
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Adult↗
Methylene blue and organised differentiation in the chick embryo.
The sub-blastodermal administration of methylene blue at 17 h of incubation gives rise to a mosaic of neuroectodermal differentiation with a disruption of the neural axis at 40 h of incubation. These features appear to be due to the rapid and direct movement of this dye into all the cells of the chick embryo blastoderm, and its binding and breakdown of the cytoplasmic ribose nucleotides, due to which neural tube formation is completely inhibited. The findings are confirmed by combined copper sulphate and methylene blue treatment, as copper is a powerful catalyst of methylene blue activity and binds with RNA.
Animals↗
Serum ferritin in diagnosis of anemia.
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Anemia, Hypochromic↗
The role of transcription in primary induction.
The present study shows that transcription is responsible for primary induction. Areas which have been already induced continue to differentiate and proliferate. From this it is evident that actinomycin D acts on Hensen's node and does not pass into the induced areas. On comparing the initial 17 hours differentiation and the 40 hours development it is evident that induction starts in the middle of the axis when Hensen's node matures, so that the anterior region of the axis. i.e., the brain, is induced both during elongation and regression of the primitive streak. The spinal region is induced only during the regression of the primitive streak.
Animals↗
12-0-Tetradecanoylphorbol-13-acetate-induced amplification of mesenchymal tumorigenesis in the mouse skin.
Skin tumors were induced in 6-week-old female Swiss albino mice by a single subcutaneous (SC) injection of 20-methylcholanthrene (MCA) in the right scapular region and the animals were then divided into four groups. Mice in group I did not receive further treatment. Six weeks after MCA injection, those in groups II and III received twice weekly applications of 0.1 ml acetone and 1.8 nmol 12-0-tetradecanoylphorbol-13-acetate (TPA) in 0.1 ml acetone, respectively, at the site of MCA injection until tumor development. Group IV animals were divided into four subsets and administered two, four, six, or eight TPA applications commencing 6 weeks after carcinogen injection. The effect of TPA pretreatment on MCA-induced tumorigenesis was studied in animals in group V. In mice treated with MCA alone, the most predominant mesenchymal tumor type is fibrosarcoma with induction of some rhabdomyosarcomas. Mixed mesenchymal tumors consisting of fibrosarcoma, rhabdomyosarcoma, or hibernoma were observed in only 12% of the animals. The number of animals bearing mixed mesenchymal tumors such as fibrosarcoma, rhabdomyosarcoma, hibernoma, and/or liposarcoma increased to 46% in mice receiving MCA + TPA until tumor development. Interestingly, liposarcomas were not found at all in animals treated with MCA alone. The data indicates that TPA application to precancerous mouse skin enhances mesenchymal tumorigenesis.
Animals↗
Movement of copper into a rapidly proliferating organised system of differentiating cells.
The early chick blastoderm has been used as a rapidly proliferating organised system of differentiating cells. From the present study, it is noted that copper is transported into the blastoderm through the periblastodermal yolk globules. Over a large dose range the changes are identical, indicating that the yolk monitors the movement. Mordanting of haematoxylin and histochemical staining indicate that copper is bound to nucleic acids during transport. The changes produced by this trace metal appear to be a reflection of this binding. The possible role of this finding in neoplasia has been discussed.
Animals↗
A new in situ organ culture technique using the early chick blastoderm.
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Animals↗
Use of Dacron velour in choledochoplasty. An experimental study.
Patch choledochoplasty for experimentally produced defect and annular stricture and replacement choledochoplasty with Dacron velour was carried out in 20 healthy mongrel dogs with a maximum follow-up of 485 days. There was no derangement of liver functions after patch choledochoplasty for defect and replacement choledochoplasty. Elevated levels of serum bilirubin and alkaline phosphatase observed after stricture production returned toward normal following choledochoplasty. Flat diameter of the common bile duct could be increased significantly after patch choledochoplasty for defect and annular stricture. There was no change in the flat diameter of the common bile duct at the anastomotic sites after replacement choledochoplasty. The graft became completely incorporated in the common bile duct. Neobiliary and glandular regeneration occurred over the graft, which persisted without shrinkage or fibrosis.
Alkaline Phosphatase↗