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Biomedical subjects

A Lupulescu

Publications and source records attributed to A Lupulescu.

At least 37 records · Page 2Linked to original sources
PubMed1980

Effects of prostaglandins on tumor transplantation.

Administration of prostaglandins F2 alpha (PGF2 alpha) and E2(PGE2) to syngeneic mice transplanted with chemically induced squamous cell carcinoma from the same species (allograft) markedly enhanced the transplantability and cellular atypicality of these tumors. Large and invasive tumors with an atypical cellular pattern, anaplastic squamous cell carcinoma, grade IV (or fibrosarcoma), occurred in approximately 87% of mice transplanted with squamous cell carcinoma, grade I, and treated with PGF2 alpha. Similar transplanted tumors in syngeneic nontreated mice grew to a much lesser extent and remained squamous cell carcinoma, grade I. Light microscopic autoradiography and radioactivity measurements revealed a significant increase of 3H-thymidine incorporation in tumor tissue of transplanted and PG-treated mice as compared to control epidermis or to that of tumor transplanted only. Electron microscopic examination revealed that the cellular evolution in transplanted tumors treated with PGF2 alpha is shifted towards atypical fibroblasts (fibrosarcomas) which originate from the squamous cells. These findings demonstrate that PGF2 alpha and PGE2 can play an important role in tumor transplantability and cellular evolution.

Animals↗
PubMed1979

The dermatopathology of Cowden's syndrome.

During the past 2 years we have studied eighty-nine biopsy specimens from nineteen patients with Cowden's syndrome. Among fifty-three facial lesions, twenty-nine were trichilemmomas. Twenty-three of the others were consistent with trichilemmoma, showed a non-specific benign verrucous acanthoma, or were not diagnostic; one was a blue naevus. All fourteen oral mucosal biopsy specimens were benign fibromas. Nineteen of twenty-two biopsy specimens from the hands and feet showed the pattern of benign keratosis. Multiple trichilemmomas were found in all patients with Cowden's syndrome, but at times several biopsy specimens were required before a diagnostic picture was uncovered. All patients with multiple facial trichilemmomas were found to have Cowden's syndrome. The combination of multiple facial trichilemmomas, oral fibromas, and benign acral keratoses enables one to diagnose Cowden's syndrome at a stage before serious internal complications develop.

Abnormalities, Multiple↗
PubMed1978

Effect of prostaglandins on skin tumorigenesis.

Concomitant administration of prostaglandins E2 (PGE2) and F2alpha (PGF2alpha) with a carcinogen, 3-methylcholanthrene (MCA) to mice for 2 months markedly enhanced the occurrence of squamous cell carcinomas. Only epidermal cell hyperplasia occurred in mice treated with MCA alone by that time. Radioactivity measurements and electron microscopic autoradiography revealed that prostaglandins stimulate DNA, RNA and protein synthesis in neoplastic cells. These findings indicate that PGE2 and PGF2alpha can act as cocarcinogens on skin tumorigenesis.

Animals↗
PubMed1978

Effects of calcitonin on epidermal regeneration and collagen synthesis in rabbits with experimental wounds.

The cellular and metabolic effects induced by calcitonin on regenerative epidermal cells, fibroblasts and collagen fibers during wound healing were studied in rabbits. Electron microscopy revealed marked changes at 2 and 5 days post-wounding in epidermal cells and fibroblasts in calcitonin-treated rabbits such as: an increase in keratohyaline granules, tonofilaments, polysomes and a hypertrophy of nuclei in the epidermal cells. Fibroblasts are hypertrophied and surrounded by large areas of mature collagen fibers, namely at 5 and 14 days. Electron microscopic autoradiography revealed an increase in the incorporation of 3H-thymidine mostly in the nuclear chromatin, 3H-uridine in the nucleoli, 3H-leucine in the endoplasmic reticulum, polysomes and newly formed keratin layers, and 3H-proline over fibroblasts and collagen fibers. Most of the cellular and metabolic effects are evident at 2.5 hours and gradually decline by 5 and 24 hours of hormone administration. Scanning electron microscopy showed changes in the keratin pattern and collagen fibers. At 5 days after wounding and calcitonin treatment, a typical scaly pattern of keratin can be noted while in controls it is smooth and homogeneous. At 14 days post-wounding the collagen fibers are hypertrophied, with an extensive network of fibrils in calcitonin-treated rabbits. These findings demonstrate that synthetic salmon calcitonin stimulates protein synthesis, keratinogenesis and collagen formation in epidermal cells and fibroblasts during wound healing.

Animals↗
PubMed1978

Colloid resorption in thyroid glands as revealed by scanning electron microscopy.

Colloid resorption from thyroid follicles in control and in calcitonin-treated rabbits was studied with the scanning electron microscope. Thus, an intense cell surface activity with several vesicles (exocytotic vesicles) and large pseudopods, sometimes cylindroids, is predominant on the thyroid follicular cells of calcitonin-treated rabbits. The pseudopods are irregular, mostly elongated, cup or dome-shaped and operate by phagocytosis or engulfment of colloid droplets (endocytosis). Only microvilli are visible on the cell surface of thyroid follicles in control rabbits. Comparative ultrastructural studies also revealed the occurrence of small exocytotic vesicles and large pseudopods in thyroid glands stimulated by calcitonin. The present findings demonstrate that the scanning electron microscopy better visualizes the colloid resorption and provides more details for the role of follicular cell surface in thyroid physiology.

Animals↗
PubMed1977

Venereal warts vs Bowen disease. A histologic and ultrastructural study of five cases.

Verrucous growths of the genitalia in young patients are usually condylomata acuminata. In five cases this type of genital lesion, viewed by light microscopy, showed dysplastic cellular changes of Bowen disease, a diagnosis that was further confirmed by electron microscopy. Bowen disease should be included in the differential diagnosis of verrucous lesions of genitalia in young people and should be ruled out by histologic examination.

Adult↗
PubMed1977

Bowen's disease of genital areas. An ultrastructural study.

Ultrastructural changes in specimens removed from Bowen's diseased genital areas of five patients are described, and a comparison is made with the tissue from the surrounding normal skin. Electron microscopic findings in Bowen's disease include an advanced dyskeratosis, acantholysis due to dissolution of desmosomal-tonofilament complexes, enlarged nuclei and nucleoli, increased polysome populations, mitochondrial alterations and nuclear inclusions. The basement membrane remains intact. Occasionally, atypical cells are undergoing cytolysis and are engulfed and phagocytized by the neighboring keratinocytes (apoptosis). The normal epithelium at the periphery of the lesion exhibits only a minimal degree of ultrastructural change.

Adult↗
PubMed1976

Electron microscopic observations on rat epidermis during experimental carcinogenesis.

Early ultrastructural changes and their progressive evolution were studied in rat epidermis following topical application of carcinogen (3-methylcholanthrene) and were compared to ultrastructural features of fully developed tumors (sebaceous epithelioma and basal cell epithelioma) in animals of the same group. Similar cytologic alterations were found, such as a marked increase in free ribosomes and polysomes, extensive endoplasmic reticulum, considerable increase of mitochondria, and dilated intercellular spaces, occupied by cytoplasmic projections. Predominance of dark cells, considered by us to be only phenotypically different from normal (light) cells, was also observed. A two-stage or multiple-stage of neoplastic evolution was suggested.

Animals↗
PubMed1976

Goiter formation following prostaglandin administration in rats.

Prostaglandins (PGE1 and PGE2) induced a hyperplastic microfollicular goiter with a high radioiodine (131I) thyroid uptake, increased endocytosis, a heavy autoradiographic (125I) reaction, and a moderate increase of thyroid hormones (T4, T3), thyroxine-binding globulin (TGB), and thyrotropin (TSH) concentrations in adult rats. Ultrastructurally, both prostaglandins (E1 and E2) markedly stimulated the thyroid cell activity and increased the number of pseudopodia, the size of colloid and dense granule populations, and the number of polysomes. Conversely, a hypofunction of thyroid glands with low radioiodine (131I) thyroid uptake, a decreased autoradiographic (125I) reaction, and a moderate decrease in T4, T3, TGB, and TSH concentrations were observed following prostaglandin F 2alpha. Ultrastructurally, a decrease in size of the colloid and dense granule population and the number of degenerative mitochondria occurred infollicular cells. An intense hyperplasia of parafollicular (C) cells, with abundant population of characteristic dense granules, could be seen in PGF 2alpha-treated rats. A marked decrease of radioiodine (131I) uptake, endocytosis, and autoradiographic (125I) reaction and a sharp decline in T4, T3, and TBG were observed in hypophysectomized and chronically prostaglandin-treated rats. Light and electron microscopy revealed signs of an advanced thyroid hypofunction with flat cuboidal cells, reduced microvilli, scarce endoplasmic reticulum, and few dense droplets. The present findings demonstrate that the chronic administration of prostaglandins exerts significant effects of thyroid gland and goiter formation (goitrogenesis), radioiodine metabolism, and hormone synthesis, and that these effects are mediated by TSH secretion.

Animals↗
PubMed1975

Effect of prostaglandins on protein, RNA, DNA and collagen synthesis in experimental wounds.

The effect of exogenous prostaglandins E1, E2 and F2alpha (PGE1, PGE2 and PGF2alpha) on 3H-leucine, 3H-uridine, 3H-thymidine and 3H-proline incorporation in experimental cutaneous wounds has been studied in rats. Prostaglandins E1 and E2 markedly stimulate the incorporation of these tritiated precursors, into protein, RNA, DNA and collagen synthesis, whereas F2 inhibits it. All tested prostaglandins exhibit their maximum effect within the first hours following administration. Most active is PGE1. These observations indicate that application of prostaglandins significantly stimulate incorporation with protein, RNA, DNA and collagen synthesis in the skin of wounded rats and thus, may play a role in epidermal cell growth and division as well as in scar-forming tissue.

Animals↗
PubMed1975

Effect of calcitonin on DNA synthesis in experimental wounds.

3H-thymidine incorporation and intracellular distribution in epidermal cells and fibroblasts of scar tissue from wounded rabbits were studied following synthetic salmon calcitonin administration. Both scintillation counting and electron microscopic autoradiography revealed a marked increase in 3H-thymidine incorporation within nuclear dense chromatin of epidermal and fibroblasts cells, mainly in 2-day wounded rabbits and at 2.5 hr. Then, 3H-thymidine uptake decreased moderately. These findings demonstrate an important role of calcitonin on DNA synthesis.

Animals↗