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C Monteagudo

Publications and source records attributed to C Monteagudo.

42 records · Page 3Linked to original sources
PubMed1990

Immunohistochemical distribution of type IV collagenase in normal, benign, and malignant breast tissue.

Production of type IV collagenase by tumor cells has been linked to their metastatic potential in several experimental models. A possible role for this enzyme in basement membrane type IV collagen turnover has also been suggested. Two recently developed affinity-purified, monospecific antibodies directed against the amino terminus (H1), or an internal active site domain (metal binding region [MBR]) of human type IV collagenase, were employed in the avidin-biotin-immunoperoxidase technique in formalin-fixed, paraffin-embedded breast tissue samples from 55 patients. Intense cytoplasmic immunostaining of myoepithelial cells was found in normal and hyperplastic tissue, and discontinuous staining was noted in intraductal carcinomas. Luminal epithelial cells were negative or weakly positive in large- or medium-sized ducts but reacted frequently in normal terminal ducts and hyperplastic lesions. Epithelial cells in intraductal carcinomas exhibited immunoreactivity in 20 of 23 cases. Invasive carcinomas were positive in 36 of 40 cases, and metastatic cells in lymph nodes stained in 10 of 12 cases. These results support a role for type IV collagenase in the basement membrane remodeling of normal breast. Our findings suggest that myoepithelial cells play a pivotal role in this enzymatic activity. The high percentage of positive cells in invasive carcinomas and the strong immunoreactivity of lymph node metastases support the role of the enzyme in tumor invasion and metastasis and suggest that tumor cells are the essential source of the enzyme in these processes.

Antibodies↗
PubMed1984

Relative cellular distribution of particulate androgen binding between Sertoli and germ cells in rat testis.

An androgen binding activity with characteristics similar to ABP is present in a particulate fraction (105,000 g pellet) obtained by differential centrifugation of seminiferous tubules, impure Sertoli cells and impure germ cells homogenates. Purification of germ cells through albumin gradients, results in almost a complete loss of androgen binding activity in the purified germ cell suspensions. Furthermore, Sertoli cell enriched testes from 22-, 32- and 40-day old rats showed increases in particulate androgen binding, when compared to matched controls, parallel to increments in the activity of a Sertoli cell marker enzyme (beta-glucuronidase). These results suggest that particulate androgen binding activity is only present in Sertoli cells and this protein may play a role in the compartmentalization of androgens in the testis.

Androgen-Binding Protein↗
PubMed1982

Androgen binding to subcellular particles of rat testis.

Androgen binding activity was evaluated in different subcellular particulate fractions obtained by differential centrifugation of 32-day-old rat seminiferous tubules homogenates. After eliminating heavy particles by centrifugation at 4300 g during 4 min in 0.25 M sucrose buffer, a 27,000 g pellet was obtained and layered on 1.05 M sucrose buffer. The relatively light particulate interface (LPF) formed during centrifugation at 27,000 g 60 min, showed the highest androgen binding activity among particulate fractions. This binding was associated with the plasma membrane marker 5'-nucleotidase and it did not follow any of six other subcellular structure markers: DNA for nuclei, succinate dehydrogenase for mitochondria, acid phosphatase for lysosomes, NADPH-cytochrome C reductase for smooth endoplasmic reticulum, RNA for rough endoplasmic reticulum and lactate dehydrogenase for cytosol. In LPF, concentrations of sites were estimated to be 328 +/- 54 fmol per mg proteins and affinity constant 0.78 +/- 0.23 10(9) M-1. Heat stability, steroid specificity, affinity constant and rate of dissociation were similar to the well known androgen binding protein, ABP. Presence of ABP or a similar protein in subcellular particles might play a role in the mechanism of action of androgens in seminiferous tubules of maturing rats.

Androgens↗
PubMed1979

Testicular function in post pubertal male pseudohermaphroditism.

Testicular endocrine function was studied in twelve post pubertal patients with male pseudohermaphroditism and 46 XY chromosomal constitution. Patients were divided into three groups, four subjects who became feminized during puberty, five who became masculinized during puberty and three who were castrated before puberty. Serum dehydroepiandrosterone, progesterone, 17-hydroxyprogesterone, androstendione, testosterone, dihydrotestosterone, LH and FSH were determined by radioimmunoassay. Patients of the first group had the clinical characteristics of testicular feminization secondary to absence of the androgen receptor. One of the five patients of the second group had deficient testosterone secretion but no enzymatic defect could be demonstrated. One of the subjects castrated before puberty had a deficiency in 17,20-desmolase. Therefore, evidence of a failure of the fetal testes could be found in only two of the twelve patients studied.

Adolescent↗
PubMedDate not supplied

Mucinous eccrine nevus: an unusual lesion in a child.

Mucinous eccrine nevus has been described as a variant of eccrine nevus. Only one instance of this variant, diagnosed in a 47-year-old woman, has been reported. We report a 2-year-old girl who had two 1 cm, asymptomatic, brownish nodules. Histologic analysis revealed a dermal lobulated proliferation of eccrine structures surrounded by a prominent mucinous stroma. This is thus, to the best of our knowledge, the first case of this extremely rare entity in a child.

Biopsy, Needle↗