Biomedical subjects

E Berensztein

Publications and source records attributed to E Berensztein.

10 recordsLinked to original sources

PubMed2006

Dose dependency of the serum bio/immuno GH ratio in children during pharmacological secretion tests.

Dissociation between GH bioactivity (bio-GH) and GH immunoactivity (immuno-GH) is due to the heterogeneity of the molecule: the measurements do not always provide reliable information on the bio-GH. We studied the ratio of bio-GH and immuno-GH during pharmacological secretion tests in 211 sera to study the concentration-response curve of the assay (C1), 16 samples of normally growing subjects with idiopathic short stature (C2), 13 samples from patients with GH deficiency (GHD1) and 6 samples of 3 patients with GHD and normal provocative tests (GHD2). GH bioactivity was determined by the Nb2 cell proliferation assay (bio-GH) and immuno-GH by a time-resolved immunofluorometric assay (IFMA) (immuno-GH). A non-linear negative relationship between the serum bio-GH/immuno-GH ratio and serum immuno-GH was observed in C1. In log-log plotting representation, two cut-off lines were drawn: a vertical cut-off line separating above-below cut-off serum peak immuno-GH values in provocative tests, and a diagonal cut-off line separating normal-abnormal serum bio-GH/immunoGH ratio; four areas were defined. GHD1 had normal ratios, but below cut-off peak immuno-GH responses. P2 and P3 of Group GHD2 had abnormal ratios in samples with low serum immuno-GH but only P2 had autosomal dominant mutation. P1 had the same autosomal dominant isolated GHD as P2 but a low normal ratio. Our data underline the importance of relatively low serum GH concentrations in mediating GH biological actions. An abnormal serum bio-GH/immuno-GH ratio might explain certain cases of GHD and might be useful in detecting abnormal circulating isoforms of GH in patients with growth failure.

Adolescent↗

PubMed2000

Expression of the aromatase gene in the human prepubertal testis.

It has been proposed that estrogens might play a negative feedback role in the local regulation of androgen biosynthesis in the testis. Although aromatase has been reported to be present in human adult Leydig cells, CYP19 gene expression in the human prepubertal testis has not been studied. Human prepubertal testicular tissue was obtained from 12 testes collected at necropsy. Ages ranged from 0.07 to 7 years, but 7 of the 12 subjects were younger than 3 months old. Tissue mRNA was subjected to RT-PCR analysis by two methods. Cytochrome P450arom mRNA was detected by non-radioactive RT-PCR in five of the 12 prepubertal testes collected from 0.05-7 year-old subjects, and in one testis collected from a 15 year-old pubertal control. Four of these five prepubertal samples belonged to the youngest infant group. Using a more sensitive, radioactive RT-PCR, aromatase mRNA was detected in all prepubertal testes. This study shows that the CYP19 gene is expressed in the prepubertal human testis including the period of early postnatal activation. It is possible that estrogens may have a role in prepubertal males during this period.

Adolescent↗

PubMed2000

Secretion of inhibin B by human prepubertal testicular cells in culture.

OBJECTIVE: Inhibin B is a secretory product of Sertoli cells of the human testis. It has been reported that serum levels of inhibin B in infant boys, peaking at 3 months of age, exceed levels in adult men. The aim of this study was to evaluate inhibin B secretion in primary prepubertal mixed testicular cell cultures, prepared from testes collected at necropsy. DESIGN AND METHODS: Cell cultures were divided into three age groups on the basis of differences in testicular histology: group 1 (n = 7), 1- to 10-day-old newborns, group 2 (n = 7), 1- to 9-month-old infants, and group 3 (n = 8), 12- to 84-month-old children. Cells were maintained in culture for 6 days, harvested and counted. In some samples, during the last 4 days, cells were stimulated with 10ng/ml highly purified human (h) LH (n = 9), 2 ng/ml recombinant human (rh) FSH (n = 9) or 50 ng/ml rhGH (n = 4). On day 6, the secretion of inhibin B and testosterone into the medium was estimated in triplicate. Inhibin B was determined by ELISA and testosterone by RIA. RESULTS: Median (range) inhibin B secretion was 465 (225-1007), 275 (107-298), and 58 (15-184) pg/million cells.24h in groups 1, 2 and 3 respectively. A logarithmic transformation of these values was performed to normalize data. Mean+/-s.d. of transformed inhibin B secretion in group 1 was significantly higher than in group 2 or 3 (P<0.005) and the values for groups 1 and 2 were significantly higher than that for group 3 (P< 0.005). No significant correlation between testosterone and inhibin B secretion into the medium was found when the 22 culture samples were analyzed as a whole. Inhibin B secretion was significantly increased after stimulation with highly purified hLH, rhFSH and rhGH (P < 0.05) and a significant positive correlation between inhibin B and testosterone was found under both hLH and rhFSH stimulation. CONCLUSIONS: It is concluded that cells collected from newborns have the highest capacity to secrete inhibin B in vitro, and that this capacity decreases with age during the first years of life. Since no data are available on serum inhibin levels in newborns, it is possible that concentrations at 3 months of age do not represent a post-natal peak but a declining level of high newborn values. As expected, FSH stimulated inhibin B secretion in culture. LH stimulation was probably mediated by paracrine factors secreted by interstitial cells. Finally, our results add new evidence of the involvement of GH in testicular maturation.

Cells, Cultured↗

PubMed1999

Smith-Lemli-Opitz syndrome: in vivo and in vitro study of testicular function in a prepubertal patient with ambiguous genitalia.

The pathogenesis of the development of ambiguous genitalia reported in some 46,XY patients with Smith-Lemli-Opitz syndrome is not understood. Presumably, it is related to the 7-dehydrocholesterol reductase deficiency present in these patients. In this study we have evaluated testicular function, both in vivo and in vitro, in a 46,XY patient with ambiguous genitalia, reared as a girl. The diagnosis was based on clinical features, low serum cholesterol and high serum 7-dehydrocholesterol levels. Serum hormone values, determined during the first month of age, showed normal basal testosterone (1.95 ng/ml), LH (0.91 U/l) and FSH (2.51 U/l). However, serum testosterone did not increase after hCG administration (1.98 ng/ml). On the other hand, the patient had a positive biological response to exogenous testosterone (decrease in sex hormone-binding globulin serum levels). She was orchidectomized at the age of 33 mo. Testicular cells were dispersed and maintained in culture for 6 d. These cells showed a very good capacity to secrete testosterone into the culture medium (X +/- SD, 26.1 +/- 11.7 vs. 4.36 +/- 1.70 pmol/10(6) cells/24 h in a control group of testicular cells prepared from testes collected at necropsy). The patient's cells failed to respond to LH stimulation (18.6 +/- 4.0 pmol/10(6) cells/24 h), although they did respond to other stimuli. It is concluded that the severe cholesterol deficiency of this patient did not impair the capacity of the testes to synthesize testosterone. However, the LH/hCG receptor or its subsequent message was activated neither in vivo nor in vitro. This finding suggests that the foetal testes might have failed to respond to placental hCG at the time of male external genital differentiation. This failure could have been responsible for the ambiguous genitalia present in this patient.

Cells, Cultured↗

PubMed1999

[Role of 3 beta hydroxysteroid dehydrogenase (3 beta HSD) in human adrenal androgen synthesis].

Adrenarche is the maturational increase of adrenal androgens that takes place in 6-8 year old children. In order to study the role of 3 beta HSD in the regulation of the synthesis of human adrenal androgens, the abundance of 3 beta HSD mRNA (Dot Blot and semiquantitative RT-PCR) was measured in 11 human prepubertal and early pubertal adrenal tissues. Subjects were divided in 2 age groups (Gr): Gr1, < 8 years (y) old (n = 6, range 0.1-2.5) and Gr2, > or = 8 y old (n = 5, range 8.0-13.0). Tissue from one adrenal tumor with Cushing's syndrome (TSC) and 2 virilizing adrenal tumors (TV), as well as adrenal cells prepared from the TSC and from 1 TV were also studied. They were maintained in culture for 3 days in basal conditions (BC) and under ACTH and IGF-1 stimulation. mRNA in Gr1 was higher than in Gr2 (Dot blot: 4.65 +/- 2.70 and 0.28 +/- 0.27 AU, p = 0.006; RT-PCR: 21.5 +/- 12.5 and 6.77 +/- 3.78 AU, p = 0.039, respectively). 3 beta HSD mRNA in TSC (8.74 +/- 1.74) was higher than in the 2 TVs (0.47 +/- 0.02 and 0.87 +/- 0.08) p = 0.001. In TSC cells, basal mRNA (0.82 +/- 0.10) decreased under ACTH (0.55 +/- 0.06), p = 0.005, and increased under IGF-1 (2.36 +/- 0.07), p = 0.006. No changes were observed in TV cells. On day 3, TV cells in BC secreted 1170.0 +/- 210.0 and 335.0 +/- 29.0 pmol/10(6) cells in 24 hs of DHEAS and androstenedione, while TSC cells secreted 17.1 +/- 3.5 and 73.7 +/- 11.7, respectively. Values increased under ACTH in TV cells (2006.0 +/- 360.0 and 525.0 +/- 76.0) and in TSC cells (29.8 +/- 5.4 and 366.8 +/- 129) p < 0.05, but they decreased under IGF-1 only in TSC cells (7.9 +/- 2.4 and 43.7 +/- 6.1) p < 0.05. These data support the hypothesis that human adrenarche could be secondary to a decrease of 3 beta HSD mRNA. Our finding that when 3 beta HSD mRNA decreases androgen secretion increases (ACTH) and when 3 beta HSD mRNA increases androgen secretion decreases (IGF-1), strongly suggests that 3 beta HSD has a modulatory role in adrenal androgen steroidogenesis.

3-Hydroxysteroid Dehydrogenases↗

PubMed1995

Testicular steroid biosynthesis in a boy with a large cell calcifying Sertoli cell tumor producing prepubertal gynecomastia.

A study of a large cell calcifying Sertoli cell tumor of the testis associated with bilateral gynecomastia in an 8-year-old boy is presented. Macroscopically, the two testes showed multiple, large, and hard calcified nodules. Histology revealed clusters or cords of tumor cells with foci of calcifications as well as evidences, in the adjacent testicular parenchyma, of initiation of gonadal development, such as early signs of spermatogenesis and sparse Leydig cell differentiation. In vivo, serum hormone studies showed gonadotropin-independent gonadal activity. After orchidectomy two macroscopically distinct fractions of the removed testes, tumoral and extratumoral, were processed separately for cell isolation and culture. The secretion of testosterone, androstenedione, and 17-hydroxyprogesterone to the medium on day 6 of culture showed that steroidogenesis in cells of the extratumoral fraction was more active than in the tumoral fraction. On the other hand, tumoral fraction cells showed much higher aromatase activity than extratumoral cells. Furthermore, conditioned medium of tumoral fraction cells was able to stimulate testosterone secretion when it was added to subcultures of testicular cells isolated from a control subject. It is postulated that tumoral cells might have stimulated neighboring interstitial cells to differentiate into Leydig cells and to secrete androgens, which in turn might have been aromatized to estrogens by tumoral cells.

Adult↗

PubMed1995

Human prepubertal testicular cells in culture: steroidogenic capacity, paracrine and hormone control.

The neonatal human Leydig cell undergoes a transient period of activation during the first months of life. The biological significance of this activation is unknown. Furthermore, little is known about the hormonal regulation of this biological process, even though it coincides with an elevation of LH levels in serum. In order to study the function of human prepubertal testicular culture cells, obtained during the neonatal period, a method for maintaining primary culture cells (isolated from testes collected at necropsy) in culture was developed. Within 24 h after death, testes were collected from 1-36-month-old subjects. Subjects were divided into two age groups, based on the presence or absence of fetal Leydig cells: 1-7-month-old infants (group 1) and 12-36-month-old children (group 2). Testes were digested with collagenase, and cells were seeded in multi-well dishes. Cells were grown in serum-free conditioned media supplemented with 5 mg/l vitamin C, 0.2 IU/l vitamin E and 10% fetal bovine serum for 2 days. Cells were then grown for an additional 4 days in serum-free media in the presence or absence of hLH (40 IU/l), hCG (135 IU/l), rh FSH (1.5 IU/l), rhGH (0.12 IU/l) or insulin (0.9 mumol/l). Concentrations of steroids in media were determined by RIA on day 6 of culture. In basal conditions cells of group 1 (n = 11) secreted more testosterone, androstendione, 17-hydroxyprogesterone, progesterone and dehydroepiandrosterone (mean +/- SE: 6.76 +/- 1.86, 7.37 +/- 1.82, 61.9 +/- 1.86, 5.75 +/- 1.74 and 8.51 +/- 3.23 pmol/10(6) cells/24 h, respectively) than cells of group 2 (n = 5) (2.95 +/- 1.15, 1.50 +/- 2.75, 1.44 +/- 2.75, 0.78 +/- 1.74 and 3.23 +/- 1.32, respectively). Under hLH stimulation, cells of group 1 increased testosterone, androstendione and 17-hydroxyprogesterone secretions (to 38.2 +/- 0.89, 13.5 +/- 1.17 and 51.7 +/- 3.23), while progesterone secretion remained unchanged (2.82 +/- 1.20). Cell response to rhFSH and rhGH was similar to that of hLH. On the other hand, medium collected from cultures of cells isolated from a Sertoli cell tumor was able to stimulate testosterone secretion in subcultures of control testicular cells in a way similar to that of hCG. In conclusion, (1) these prepubertal human testicular cells can be maintained in primary culture for several days keeping their in vivo steroidogenic potential; (2) cells isolated from young infants can respond to hLH in culture; (3) response to rhFSH is probably mediated by a paracrine factor; (4) response to rhGH is observed in the absence of gonadotropins.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗

PubMed1995

Basal testosterone secretion and response to human luteinizing, follicle-stimulating, and growth hormones in culture of cells isolated from testes of infants and children.

Little is known on the hormonal regulation of the early postnatal phase of Leydig cell activation in the human. Testosterone secretion by prepubertal testicular cells in culture was studied in two different age groups, 0-7-mo-old (group 1) and 16-36-mo-old (group 2) boys. A mixed cell preparation was isolated from testes collected at necropsy and maintained in culture for 6 d. Cells were cultured in serum-free medium in basal conditions and under the stimulation of human (h)LH, hFSH, or recombinant hGH, and the secretion of testosterone was determined on d 6 by RIA. In basal conditions, cells of group 1 secreted more testosterone (median 5.83 pmol/10(6) cells.d, n = 7) than cells of group 2 (median 1.73, n = 5), p < 0.05, reflecting the steroidogenic potential of the testes in vivo. Under hLH stimulation, cells of group 1 responded by increasing testosterone secretion significantly. Surprisingly, hFSH stimulation elicited a similar response in cells of group 1. Because FSH receptors are presumably located in Sertoli cells, it is concluded that these cells secreted a paracrine factor that stimulated testosterone secretion by Leydig cells. On the other hand, recombinant hGH also stimulated the secretion of testosterone by cells of group 1. Recombinant hGH could have interacted with either GH or prolactin receptors of testicular cells. Cells of group 2 did not respond to any stimulus. Because serum levels of LH, FSH, GH, and prolactin are higher during the first months of life than later in childhood, it is possible that the early postnatal activation of the testis is under multiple pituitary hormone influence.

Age Factors↗

PubMed1989

[Experimental autoimmune orchitis].

Experimental autoimmune orchitis (EAO) has been extensively studied in spite of which its pathogenic mechanisms are still poorly understood. It has been mostly induced in guinea pigs using spermatozoa or a testicular homogenate plus adjuvants. Initially, the aim of our work was to establish if non-spermatic antigens, such as extracellular components of the walls of seminiferous tubules, were able to induce an autoimmune orchitis. For this purpose, we obtained from rat testes: a) a preparation rich in basement membranes of seminiferous tubules (STBM) and b) a soluble fraction of STBM, non-related to collagen (D-STBM), presenting common antigenic determinants with laminin, the main non-collagen glycoprotein of basement membranes. Fifty per cent of rats immunized with STBM, D-STBM or a murine laminin, developed a multifocal and moderate damage of the testes characterized by mild interstitial cell infiltrates, alterations of the basement membranes of seminiferous tubules and Sertoli cells, sloughing of the germinal epithelium and tubular atrophy. Circulating antibodies and a specific cellular immune response were also detected. Moreover, rats passively injected with an heterologous anti-D-STBM serum developed a similar testicular lesion and showed Ig deposits on the basement membranes of seminiferous tubules. In relation to the pathogenic mechanisms of EAO, we studied the variations of T and B cell populations, at the immunization draining lymph nodes, during the development of orchitis. A severe EAO was induced in Wistar rats by immunization with an homologous testes homogenate plus adjuvants.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Testis lesions and cellular and humoral immune responses induced in rats by immunization with laminin.

Sixty-six percent of rats immunized with laminin isolated from a mouse Engelbreth-Holm-Swarm (EHS) sarcoma developed moderate lesions in the testis characterized by multiple foci of seminiferous tubules with different degrees of sloughing of the germinal epithelium or atrophy intermingled with normal histological areas. Interstitial mononuclear cell infiltrates were seen in the epididymis. By electron microscopy, pathological changes in the basement membranes of the seminiferous tubules, such as splitting and focal thickenings of knob-like projections toward the epithelium, were observed. Moreover, Sertoli cell cytoplasm showed dilated smooth endoplasmic reticulum and large vacuoles. By electron microscopy with the immunoperoxidase technique, staining for in vivo-bound rat IgG was detected along the walls of the seminiferous tubules as a bright linear immunofluorescence and as a dense reaction product on the basal lamina. High titers of circulating antilaminin antibodies were detected by ELISA in all the rats immunized with laminin. As revealed by the skin test, a delayed type hypersensitivity reaction to laminin was observed in these rats.

Animals↗