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Biomedical subjects

I Cohen

Publications and source records attributed to I Cohen.

At least 199 records · Page 11Linked to original sources
PubMed1994

Ovarian endometrioid carcinoma and endometriosis developing in a postmenopausal breast cancer patient during tamoxifen therapy: a case report and review of the literature.

We present the first case of ovarian endometrioid carcinoma and endometriosis in a postmenopausal patient who was treated with tamoxifen for breast cancer. The association with prolonged unopposed estrogen-like stimulation with tamoxifen as a possible factor in the development of ovarian endometrioid carcinoma is discussed.

Aged↗
PubMed1994

Altered proteoglycan gene expression and the tumor stroma.

Tumor stroma is a specialized form of tissue that is associated with epithelial neoplasms. Recent evidence indicates that significant changes in proteoglycan content occur in the tumor stroma and that these alterations could support tumor progression and invasion as well as tumor growth. Our main hypothesis is that the generation of tumor stroma is under direct control of the neoplastic cells and that, via a feedback loop, altered proteoglycan gene expression would influence the behavior of tumor cells. In this review, we will focus primarily on the work from our laboratory related to the altered expression of chondroitin sulfate proteoglycan and its role in tumor development and progression. The connective tissue stroma of human colon cancer is enriched in chondroitin sulfate and the stromal cell elements, primarily colon fibroblasts and smooth muscle cells, are responsible for this biosynthetic increase. These changes can be reproduced in vitro by using either tumor metabolites or co-cultures of human colon carcinoma cells and colon mesenchymal cells. The levels of decorin, a leucine-rich proteoglycan involved in the regulation of matrix assembly and cell proliferation, are markedly elevated in the stroma of colon carcinoma. These changes correlate with a marked increase in decorin mRNA levels and a concurrent hypomethylation of decorin gene, a DNA alteration associated with enhanced gene expression. Elucidation of decorin gene structure has revealed an unexpected degree of complexity in the 5' untranslated region of the gene with two leader exons that are alternatively spliced to the second coding exon. Furthermore, a transforming growth factor beta (TGF-beta)-negative element is present in the promotor region of decorin gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Alternative Splicing↗
PubMed1994

Laparoscopic Resection of a Cornual Pregnancy: A First Case Report

Laparoscopic surgery is currently the preferred diagnostic and treatment modality for ectopic pregnancy (EP). Cornual pregnancy, a rare and dangerous form of EP, is usually treated by cornual resection or hysterectomy. We report the first case to be treated by laparoscopic surgery. A 27 year old, gravida 3 para 2, was diagnosed with a nine week right cornual pregnancy. Laparoscopy revealed a 3 x 4 cm bulge into the right cornual area. Both fallopian tubes were otherwise normal. The uterus was fixed by a grasping forceps and the right tube and ovarian ligament were coagulated to reduce the blood supply. The gestational area was entered via a 1 cm incision using unipolar scissors and electrocoagulation. The pregnancy contents were suctioned; cavity margins and placental bed were coagulated until hemostasis was secured. The uterus contracted. The posterior leaf of the broad ligament was flapped over the incision site and attached by coagulation points. Postoperative course was uneventful. A hysterosalpingogram performed 4 months post surgery revealed a normal uterine cavity and blocked right tube.

Journal Article↗
PubMed1994

Ovarian cyst formation in two pre-menopausal patients treated with tamoxifen for breast cancer.

Pre-menopausal tamoxifen treatment causes hyperoestrogen production and ovarian cyst formation. Two pre-menopausal breast cancer patients who were treated with tamoxifen developed both permanent supraphysiological oestrogen concentration and ovarian cysts. Serum oestrogen decreased to post-menopausal concentrations and ovarian cysts completely resolved during and following simultaneous treatment with tamoxifen and gonadotrophin-releasing hormone agonist (GnRHa). In pre-menopausal breast cancer patients, GnRHa may prevent possible side-effects of tamoxifen, such as ovarian cysts and supraphysiological oestrogen production.

Adult↗
PubMed1994

Postmenopausal tamoxifen treatment and endometrial pathology.

Tamoxifen is widely used as adjuvant therapy for postmenopausal breast cancer patients with positive estrogen receptors. Data on a possible association of endometrial pathologies with tamoxifen treatment have been accumulating. In this review, we examine the current literature and include our own experience with this occurrence. We recommend close supervision of these patients.

Breast↗
PubMed1994

Histochemical studies of progressive p53 mutations during colonic carcinogenesis in Sprague-Dawley rats induced by N-methyl-N-nitro-nitrosoguanidine or azoxymethane.

We studied the increasing expression of the p53 tumor suppressor gene in Sprague-Dawley rats, chemically induced to develop colon cancer. p53 expression was evaluated histochemically at various stages of tumor progression (during a period of 40 weeks) that can be followed by colonic hyperproliferation labeled by 3H-thymidine incorporation. We found that high level nuclear expression of p53 protein correlates with progression of malignancy in carcinogen-induced animals, whereas cytoplasmic staining is related to the onset and early development of malignancy.

Adenocarcinoma↗
PubMed1994

Estrogen replacement in postmenopausal women: are we currently overdosing our patients?

As there are no proven optimal serum estradiol levels, we sought to evaluate the pharmacokinetic profiles of serum estradiol levels following a single oral dose of 2 mg estradiol and 1 mg of estriol (Trisequens) among 26 surgically induced, postmenopausal patients. Their serum estradiol levels were periodically measured over 24 h following oral administration of the drug. They were divided into two groups according to the computed hourly mean estradiol values: group A, < 250 pg/ml/h ( < 918 pmol/l/h) and group B, > 250 pg/ml/h ( > 918 pmol/l/h). The mean peak estradiol concentrations were noted 2 h after drug administration and amounted to 595 +/- 190 pg/ml (2,184 +/- 697 pmol/l) in the entire cohort; 435 +/- 117 pg/ml (1,597 +/- 430 pmol/l) in group A and 712 +/- 142 pg/ml (2,614 +/- 521 pmol/l) in group B (p < 0.001). The mean total area under the curve in group A was 4,887 pg/ml (17,940 pmol/l), which was significantly lower than that of 7,995 +/- 652 pg/ml/24 h (29,350 +/- 2,393 pmol/l/24 h) found for group B (p < 0.001). The mean body mass index showed a significant difference (p < 0.003) between group A and group B (29.4 +/- 0.56 vs. 24.3 +/- 0.24). We found that 57% of our patients were exposed to excessively high levels of estradiol during the 24-hour period following drug ingestion. We advise monitoring estradiol levels and individualizing estrogen replacement therapy, to avoid the long-term exposure of postmenopausal patients to superphysiological estradiol levels.

Adult↗
PubMed1994

Estrogen and progesterone receptor expression of decidual endometrium in a postmenopausal woman treated with tamoxifen and megestrol acetate.

To the best of our knowledge, this is the first report of in vivo endometrial estrogen and progesterone receptor induction as a result of tamoxifen exposure in a postmenopausal breast cancer patient. The following observations, that the postmenopausal endometrium is sensitive to tamoxifen, that this agent can act as an estrogen-like substance, and that it may cause proliferation of the endometrium in the absence of progestin, may explain the endometrial decidual changes described herein as a protective mechanism against possible neoplastic endometrial changes.

Breast Neoplasms↗
PubMed1994

Doppler flow evaluation of pathologic endometrial conditions in postmenopausal breast cancer patients treated with tamoxifen.

A prospective pilot study was conducted to evaluate the usefulness of uterine artery blood flow in the detection of various pathologic endometrial conditions in 39 asymptomatic postmenopausal breast cancer patients who were treated with tamoxifen. No specific pattern was seen for the uterine artery pulsatility index values in the tamoxifen-treated patients that could be related to any specific endometrial lesions, nor were any specific changes observed in the pulsatility index value with increasing severity of the pathologic endometrial conditions. Similarly, no correlation was found between ultrasonographically measured endometrial widths and uterine artery pulsatility index values. Thus, although pulsed Doppler flow ultrasonography has been shown previously to be effective in the detection of uterine cancer in non-tamoxifen-treated post-menopausal patients, it probably does not contribute to the assessment of endometrial lesions in post-menopausal breast cancer patients treated with tamoxifen.

Arteries↗
PubMed1994

Osteoid osteoma of the acetabulum. A case report.

The acetabulum is a very rare location for osteoid osteoma. Reported herein is the case of a 21-year-old man who had nonspecific hip pain. Preoperative diagnosis was made 2 months after the first visit. Excisional biopsy was performed through the inner wall of the acetabulum. The patient reported complete relief from pain and there has been no evidence of recurrence in 8 years of followup.

Acetabulum↗
PubMed1993

Cloning and characteristics of fish glial fibrillary acidic protein: implications for optic nerve regeneration.

Mammalian central nervous system neurons do not regenerate after axonal injury, unlike their counterparts in fish and amphibians. After axonal injury, glial cells in mammals do not support regrowth of axons, while in fish they support the regeneration process. Controversy exists as to whether or not the intact fish optic nerve expresses glial fibrillary acidic protein, a well-known marker for mature astrocytes, and thus whether its astrocytes differ in this respect from those of the brain and spinal cord, as well as from optic nerve astrocytes of other species. In an attempt to resolve this question we cloned fish glial fibrillary acidic protein. Two different complementary DNA clones were isolated from a carp brain complementary DNA library, each encoding a different form of glial fibrillary acidic protein apparently originating from different genes. Monospecific polyclonal antibodies were raised against a peptide synthesized according to the predicted amino acid sequence, and used to identify and localize the fish glial fibrillary acidic protein. Two glial fibrillary acidic proteins (of 49 kDa and 51 kDa) were identified by the antibodies in all tested fish central nervous system tissues. The antibodies were then used to examine glial fibrillary acidic protein immunoreactivity in sections taken from uninjured and injured optic nerves of goldfish. Injury was followed by an elevation in glial fibrillary acidic protein immunoreactivity along the whole length of the nerve, except at the site of the injury, where--as in the case of vimentin--no immunoreactivity was detectable. However, in contrast to vimentin-positive glial cells, which repopulate the site of the injury soon after the optic nerve is injured, glial fibrillary acidic protein-positive glial cells remained outside the injury site for as long as 6 weeks after the injury. Despite the injury-induced changes in glial fibrillary acidic protein immunoreactivity, no change was observed in the level of transcript encoding glial fibrillary acidic protein after injury, while there was an increase in the amount of glial fibrillary acidic protein associated with the cytoskeleton and a reduction in the soluble form. These results suggest that the injury-induced changes in immunoreactivity on sections involve changes not in transcription or translation of glial fibrillary acidic protein, but in glial fibrillary acidic protein compartmentalization.

Animals↗
PubMed1993

Altered proteoglycan gene expression and the tumor stroma.

Tumor stroma is a specialized form of tissue that is associated with epithelial neoplasms. Recent evidence indicates that significant changes in proteoglycan content occur in the tumor stroma and that these alterations could support tumor progression and invasion as well as tumor growth. Our main hypothesis is that the generation of tumor stroma is under direct control of the neoplastic cells and that, via a feedback loop, altered proteoglycan gene expression would influence the behavior of tumor cells. In this review, we will focus primarily on the work from our laboratory related to the altered expression of chondroitin sulfate proteoglycan and its role in tumor development and progression. The connective tissue stroma of human colon cancer is enriched in chondroitin sulfate and the stromal cell elements, primarily colon fibroblasts and smooth muscle cells, are responsible for this biosynthetic increase. These changes can be reproduced in vitro by using either tumor metabolites or co-cultures of human colon carcinoma cells and colon mesenchymal cells. The levels of decorin, a leucine-rich proteoglycan involved in the regulation of matrix assembly and cell proliferation, are markedly elevated in the stroma of colon carcinoma. These changes correlate with a marked increase in decorin mRNA levels and a concurrent hypomethylation of decorin gene, a DNA alteration associated with enhanced gene expression. Elucidation of decorin gene structure has revealed an unexpected degree of complexity in the 5' untranslated region of the gene with two leader exons that are alternatively spliced to the second coding exon.(ABSTRACT TRUNCATED AT 250 WORDS)

Alternative Splicing↗