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Biomedical subjects

S R Bornstein

Publications and source records attributed to S R Bornstein.

At least 55 records · Page 3Linked to original sources
PubMed2002

A novel approach using transcomplementing adenoviral vectors for gene therapy of adrenocortical cancer.

Current therapies for adrenocortical carcinomas do not improve the life expectancy of patients. In this study, we tested whether a gene-transfer therapy based upon a suicide gene/prodrug system would be effective in an animal model of the disease. We employed E4- and E1A/B-depleted, herpes simplex virus-thymidine kinase-expressing adenoviral mutants that transcomplement each other within tumor cells, hereby improving transgene delivery and efficacy by viral replication in situ. Transcomplementation of vectors increased the fraction of transduced of tumor cells. This increase was accompanied by greater tumor volume reduction compared to non-transcomplementing approaches. Survival time improved with non-replicating vectors plus GCV compared to controls. However, transcomplementation/replication of vectors led to a further significant increment in anti-tumor activity and survival time (p < 0.02). In treated animals, we observed a high number of apoptotic nuclei both adjacent to and distant from injection sites and sites of viral oncolysis. Ultrastructural analyses exhibited nuclear inclusion bodies characteristic of virus production in situ, and provided further evidence that this therapy induced apoptotic cell death within tumor cells. We conclude that the efficacy of suicide gene therapy is significantly amplified by viral replication and, in combination with GCV, significantly reduces tumor burden and increases survival time.

Adenoviridae↗
PubMed2002

The adrenal hormone metabolism in the immune/inflammatory reaction.

The interactions between the immune system and HPA axis may be characterized by a circuit which includes; (i) activation of the HPA axis and initiation of the stress response which, in term, has immunomodulating properties; (ii) a feedback mechanism derived from the immune system which regulates the HPA axis. Over the past few years, it has become evident that the adrenal gland, itself, as the main effector organ of the HPA axis, is a major site for both the synthesis and action of numerous cytokines. In addition to the cytokine mediated activation of adrenal regulation there are cytokine independent cell-cell mediated immune-adrenal interactions. The nature of this immune-endocrine crosstalk is implicated in adrenal dysfunction and disease. During inflammatory and autoimmune disorders including sepsis, inflammatory bowel disease and rheumatoid arthritis, the immune-adrenal crosstalk becomes more critical in maintaining an adequate adrenal stress response.

Adaptation, Physiological↗
PubMed2002

The short synacthen test in the evaluation of adrenal masses in patients with malignancies.

Adrenal computed tomography with determination of Hounsfield units has proved to be sensitive and specific in the differential diagnosis of benign vs. malign adrenal lesions. On the other hand, computed tomography may fail in patients with small adrenal masses of less than 1.0 cm. However, especially in patients with diagnosed malignancies and small adrenal masses which were discovered during the diagnostic staging procedure it is important to determine the origin of the adrenal lesion. An augmented increase in 17alpha-hydroxyprogesterone (17-OHP) levels following corticotropin (1-24) stimulation has been noted in incidentally discovered adrenal masses by several groups. Therefore, we tested the hypothesis that elevated ACTH-stimulated 17-OHP (delta > 2.6 ng/mL) can predict primary adrenal lesions. We evaluated the use of the ACTH test in 85 patients with adrenocortical tumors and in 16 patients who underwent abdominal imaging for staging of a carcinoma other than of adrenal origin. We found an augmented 17-OHP response in 70 (>82%) of patients with known adrenocortical tumors and in 10 (>62%) of patients with adrenal masses and diagnosed malignancies. Results in the latter group have been confirmed in histological studies after operation or puncture. In the group of patients who suffered from a solid malignant tumor and had an adrenal mass, it was thus possible to separate primary from secondary adrenal lesions in 100%. In the group of patients with known adrenocortical tumors, it failed to differentiate between benign and malignant adrenocortical lesion in one case. We therefore think that the ACTH test is a valuable biochemical tool to distinguish primary adrenal tumors from adrenal metastasis derived from other malignancies.

17-alpha-Hydroxyprogesterone↗
PubMed2001

Expression of corticotropin releasing hormone receptors type I and type II mRNA in suicide victims and controls.

Corticotropin-releasing hormone (CRH) is a key neuroendocrine factor implementing endocrine, immune and behavioral responses to stress. CRH exerts its action through two major receptors, CRH-R1 and CRH-R2. Recently novel non-peptidic antagonists directed against CRH-R1 or CRH-R2 have been proposed as promising agents in the treatment of depression, anxiety and eating disorder. However, so far the CRH-receptor system has not been widely studied in humans. Therefore, we employed quantitative TaqMan PCR to analyze the expression and distribution of both CRH-R1 and CRH-R2 in human brain tissue and peripheral organs. Furthermore the expression of CRH receptors was analyzed for the first time in pituitaries of suicide victims by in situ hybridization and quantitative PCR. Our data demonstrated a different expression pattern in humans as compared to rodents. Both CRH-R1 and CRH-R2 were expressed in high amounts in the brain with the strongest expression in the pituitary. As described in rodents, however the CRH-R1 in human was the predominant receptor in the brain (82.7 +/- 11.0%), whilst CRH-R2 was the predominant receptor in peripheral organs (77.0 +/- 15.8%). There was a shift in the ratio of CRH-R1/R2 in the pituitaries of suicide victims. In conclusion, both CRH-R1 and CRH-R2 are widely expressed in human tissues with a distribution substantially different from rodents. Strong expression of both CRH-R1 and CRH-R2 in human pituitaries suggests that particularly under stress, activation of the HPA axis can be maintained through both receptors.

Adolescent↗
PubMed2001

Leptin mediates a proliferative response in human gastric mucosa cells with functional receptor.

BACKGROUND: Recently, the rat stomach was reported as a source of leptin, a hormone mainly secreted by adipocytes. Also Helicobacter pylori-induced gastritis in humans was associated with locally elevated leptin levels. In addition, it was suggested that gastric leptin adjusts the function of the intestinal tract in parallel to the function of hypothalamic satiety centers. AIMS: Here we examined the synthesis and potential physiologic role of leptin in the human stomach. METHODS: RT-PCR was employed to detect leptin mRNA in the human stomach and the human gastric carcinoma cell line AGS while immunogold staining and electron microscopy were used to detect leptin protein. The in vitro effects of leptin on cell proliferation were examined in the AGS cell line. RESULTS: No leptin mRNA could be detected by RT-PCR, yet immunogold labeling and electron microscopy allowed visualization of leptin protein in the human gastric mucosa. At concentrations of 100 nM, leptin led to a significantly increased BrdU-uptake in AGS cells (+27%, p < 0.017). The MAP-kinase-1-specific inhibitor U0126 blocked the leptin-induced cell proliferation in a dose-dependent fashion. CONCLUSIONS: Leptin protein may not be produced but rather stored in human gastric cells. Leptin-induced increases in the proliferation of gastric mucosa cells suggests that leptin might contribute to mucosal integrity and gastroprotection.

Carrier Proteins↗
PubMed2001

Intraadrenal mechanisms of DHEA regulation: a hypothesis for adrenopause.

Dehydroepiandrosterone (DHEA) and its sulfate metabolite DHEAS are the major androgens secreted by the human adrenal gland. The specific control of these hormones remains unclear. While ACTH is a potent stimulator of DHEA secretion, other factors both systemic and local have been involved in adrenal androgen control. Here we review the extra and intraadrenal regulation of DHEA and propose a hypothetical model for adrenal senescence.

Adrenal Glands↗
PubMed2001

Expression and distribution of the prolactin receptor in normal rat liver and in experimental liver cirrhosis.

Recent results have suggested a role for prolactin (PRL) as a regeneration factor in the liver. In order to investigate the involvement of prolactin in the pathogenesis of liver cirrhosis, we studied the expression of the prolactin receptor (PRLR) and PRL during the development of cirrhosis in an animal model. 30 male rats were exposed to CCl4 by inhalation. Phenobarbitone was added to the drinking water to accelerate the formation of toxic metabolites by enzyme induction. Two control groups of 30 animals each were treated with phenobarbitone only or received no treatment. 10 animals of each group were sacrificed 35, 55, and 70 days after initiation of treatment. Liver tissue was subjected to histological examination, which demonstrated fibrosis of different grades and cirrhosis in the CCl4-treated rats. Expression of PRLR mRNA was investigated by mRNA extraction, RT-PCR and computer-supported densitometric evaluation. Compared to control liver, PRLR mRNA was expressed at a higher level in fibrotic and cirrhotic liver specimens. In normal tissue, immunohistochemical staining showed a high concentration of PRLR around the central vein and in the epithelium of the bile ducts. This pattern of distribution was lost in fibrosis and cirrhosis. An accumulation of PRLR was demonstrated within the damaged cells. Neither PRL nor PRL mRNA was detectable in normal, fibrotic, or cirrhotic liver. We conclude that PRLR is distributed in normal rat liver in a typical pattern which is lost with increasing fibrosis. PRL is not produced by rat liver, indicating that PRL does not act through autocrine or paracrine mechanisms.

Animals↗
PubMed2001

Differential gene expression profile of glucocorticoids, testosterone, and dehydroepiandrosterone in human cells.

Glucocorticoids are the major immunomodulating hormones in the human body. Recently, increasing interest in androgens as immunomodulators has emerged. In particular, Dehydroepiandrosterone (DHEA) has been suggested as beneficial in the treatment of some autoimmune disorders. However, the action and role of testicular and adrenal androgens on human immune cells remains unclear. This is the first study to provide large-scale gene expression data on the action of different steroids (DHEA, glucocorticoids, and testosterone) on human peripheral blood mononuclear cells using the recently developed genomic-scale technology of microarrays. Novel computational tools and techniques such as Principal Component Analysis (PCA) were used for analysis, clustering and visualization. We have demonstrated that each steroid has its distinct gene expression profile, although DHEA and testosterone co-regulated most genes in a similar direction while glucocorticoids frequently regulated the same genes in an opposite direction. Our data suggest an important and a complex regulatory role for androgens on human immune cells that should be considered in androgen replacement or treatment strategies.

Dehydroepiandrosterone↗
PubMed2001

Human breast adipocytes express interleukin-6 (IL-6) and its receptor system: increased IL-6 production by beta-adrenergic activation and effects of IL-6 on adipocyte function.

Adipocytes produce the inflammatory cytokine interleukin-6 (IL-6); however, it is not known whether these cells express the IL-6 receptor system, how the secretion of this cytokine is regulated, and whether it has a function within adipose tissue. Using cultured human breast adipocytes, we investigated the expression of IL-6 and its receptor system, the effects of IL-6 on main adipocyte functions, and the regulation of IL-6 secretion by catecholamines and glucocorticoids. In the culture system, immunohistochemistry demonstrated expression of IL-6 and its receptor system, consisting of the ligand-binding IL-6 receptor and the signal-transducing protein gp130, in mature adipocytes, but not in undifferentiated adipocyte precursor cells. In freshly isolated adipocytes, RT-PCR detected messenger ribonucleic acids encoding the above proteins. Chronic incubation of adipocytes with 1 nmol/L IL-6 during adipose differentiation reduced glycero-3-phosphate dehydrogenase (GPDH) activity, a marker of adipocyte differentiation, and triglyceride synthesis to 67 +/- 9% of the basal level (mean +/- SEM; P < 0.05) only on day 21. Incubation of differentiated adipocytes with 10 nmol/L IL-6 for 24 h also resulted in a reduction of GPDH activity to 81 +/- 5% (P < 0.05). On the other hand, 24-h exposure to 10 nmol/L IL-6 increased basal glycerol release by 42 +/- 12% (P < 0.01) and isoproterenol-induced glycerol release by 21 +/- 6% (P < 0.05). The same concentration of IL-6, however, did not alter basal or insulin-stimulated glucose transport. IL-6 secretion was acutely and chronically stimulated by 1 micromol/L isoproterenol (peak of 6.2-fold after 3 h; P < 0.001) and only moderately suppressed by 100 nmol/L cortisol (-36 +/- 10%; P < 0.001). In conclusion, human breast adipocytes release substantial amounts of IL-6 and express IL-6 receptor and gp130. The secretion of IL-6 by adipocytes is strongly stimulated by beta-adrenergic activation and is modestly suppressed by glucocorticoids. IL-6 reduces GPDH activity and stimulates lipolysis, suggesting an autocrine/paracrine role of this cytokine in human adipose breast tissue.

Adipocytes↗
PubMed2001

Pheochromocytomas in von Hippel-Lindau syndrome and multiple endocrine neoplasia type 2 display distinct biochemical and clinical phenotypes.

This study examined the mechanisms linking different biochemical and clinical phenotypes of pheochromocytoma in multiple endocrine neoplasia type 2 (MEN 2) and von Hippel-Lindau (VHL) syndrome to underlying differences in the expression of tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine synthesis, and of phenylethanolamine N-methyltransferase (PNMT), the enzyme that converts norepinephrine to epinephrine. Signs and symptoms of pheochromocytoma, plasma catecholamines and metanephrines, and tumor cell neurochemistry and expression of TH and PNMT were examined in 19 MEN 2 patients and 30 VHL patients with adrenal pheochromocytomas. MEN 2 patients were more symptomatic and had a higher incidence of hypertension (mainly paroxysmal) and higher plasma concentrations of metanephrines, but paradoxically lower total plasma concentrations of catecholamines, than VHL patients. MEN 2 patients all had elevated plasma concentrations of the epinephrine metabolite, metanephrine, whereas VHL patients showed specific increases in the norepinephrine metabolite, normetanephrine. The above differences in clinical presentation were largely explained by lower total tissue contents of catecholamines and expression of TH and negligible stores of epinephrine and expression of PNMT in pheochromocytomas from VHL than from MEN 2 patients. Thus, mutation-dependent differences in the expression of genes controlling catecholamine synthesis represent molecular mechanisms linking the underlying mutation to differences in clinical presentation of pheochromocytoma in patients with MEN 2 and the VHL syndrome.

Adolescent↗
PubMed2001

Adrenocortical-pituitary hybrid tumor causing Cushing's syndrome.

We describe the first case of an adrenocortical-pituitary hybrid tumor causing Cushing's syndrome in a 17-yr-old boy. Adrenal vein sampling confirmed elevated secretion of both cortisol and ACTH precursors from a right adrenal mass, whereas pituitary ACTH levels, as determined by bilateral inferior petrosal sinus samples (IPSS), were unresponsive to CRH and equal to peripheral levels. There was no biochemical or histological evidence for a pheochromocytoma, but, rather, the tumor demonstrated lipid-rich clear cells characteristic of an adrenocortical adenoma. Immunohistochemical analysis revealed ACTH immunoreactivity and synaptophysin proteins in the tumor. Isolation of tumor cells by the novel technique of laser capture microdissection and subsequent RT-PCR showed expression of POMC messenger ribonucleic acid and cytochrome p450 enzyme messenger ribonucleic acid within the same cells. Finally, ultrastructural analysis provided ultimate proof for adrenocortical-pituitary hybrid cells exhibiting the characteristic vesicular mitochondria and abundant smooth endoplasmic reticulum of steroid cells and the typical secretory granules of corticotrophs within the cytoplasm of the same cells. The adrenocortical tumor expressed the pituitary transcription factor pituitary homeobox factor 1 and the steroidogenic factor 1. The intermingling of the centrally located ectodermally derived pituitary tissue with the mesodermally derived adrenocortical tissue in this adenoma suggests a hitherto unrecognized genetic and phenotypic plasticity within the hypothalamic-pituitary-adrenal axis.

Adenoma↗
PubMed2001

Mutational analysis of the PRL receptor gene in human breast tumors with differential PRL receptor protein expression.

PRL is a major growth and differentiating hormone in the human breast, with activation of the PRL-PRL receptor complex increasingly recognized as an important mechanism in the induction and progression of mammary tumors. Although constitutive activation of various hormone and growth factor receptors is newly recognized as a common cause of tumor development, the PRL receptor gene has not been analyzed for similar aberrations in breast and other tumors. Therefore, using bacterial artificial chromosomes containing the PRL receptor gene and intron-spanning PCR, we determined the exon-surrounding intron sequences providing primers for the first analysis of the entire coding region of the human PRL receptor gene. We examined the presence of PRL receptor in 41 breast tumors by immunohistochemistry and attempted a correlation of its expression to pathological grading of the disease. Then tumor cells were isolated by laser capture microdissection to examine DNA from 30 patients for PRL receptor mutations. The PRL receptor immunoreactive score did not correlate to the tumor size, histopathological grading, age, or family history of patients. PRL receptor immunoreactivity was predominantly found in steroid hormone receptor-positive tumors, but without overall correlation of immunoreactive score. In both PRL receptor-positive and PRL receptor- negative breast cancer cells, direct sequencing of the coding sequence of the PRL receptor gene did not detect any somatic or hereditary gene aberrations. In conclusion, PRL receptor mutations do not appear to be common in human breast cancer, suggesting that constitutive activation of the PRL receptor can be excluded as a major cause of mammary tumor genesis. The molecular structure of the PRL receptor seems to remain intact in tumor tissue, and systemic and local production of PRL may participate in tumor cell growth and proliferation through functional receptors.

Adult↗
PubMed2001

Adrenal androgens regulation and adrenopause.

Adrenal androgens (AA) are mainly produced by the human adrenal cortex. ACTH is the major regulator of their secretion. However, other factors, such as gonadal sex steroids, insulin, growth hormone, prolactin, hypothalamic peptides and growth factors have been involved in AA regulation. More recently, it has become well accepted that, besides systemic factors, AA secretion is under the control of the "sympathoadrenal system" and "immunoadrenal system". Here we review the extraadrenal and intraadrenal mechanisms of AA regulation and how they may relate to endocrinoimmunosenescence.

Adrenal Glands↗
PubMed2000

Haploinsufficiency of steroidogenic factor-1 in mice disrupts adrenal development leading to an impaired stress response.

Adrenal steroids are essential for homeostasis and survival during severe physiological stress. Analysis of a patient heterozygous for the steroidogenic factor-1 (SF-1) gene suggested that reduced expression of this nuclear receptor leads to adrenal failure. We therefore examined SF-1 heterozygous (+/-) mice as a potential model for delineating mechanisms underlying this disease. Here we show that SF-1 +/- mice exhibit adrenal insufficiency resulting from profound defects in adrenal development and organization. However, compensatory mechanisms, such as cellular hypertrophy and increased expression of the rate-limiting steroidogenic protein StAR, help to maintain adrenal function at near normal capacity under basal conditions. In contrast, adrenal deficits in SF-1 heterozygotes are revealed under stressful conditions, demonstrating that normal gene dosage of SF-1 is required for mounting an adequate stress response. Our findings predict that natural variations leading to reduced SF-1 function may underlie some forms of subclinical adrenal insufficiency, which become life threatening during traumatic stress.

Adrenal Glands↗
PubMed2000

Deletion of tyrosine hydroxylase gene reveals functional interdependence of adrenocortical and chromaffin cell system in vivo.

Catecholamines are produced in the medulla of the adrenal gland and may participate in the intraglandular regulation of its cortex. We analyzed the adrenal structure and function of albino tyrosine hydroxylase-null (TH-null) mice that are deficient in adrenal catecholamine production. Adrenal catecholamines were markedly reduced, and catecholamine histofluorescence was abrogated in 15-day-old TH-null mice. Chromaffin cell structure was strikingly altered at the ultrastructural level with a depletion of chromaffin vesicles and an increase in rough endoplasmic reticulum compared with wild-type mice. Remaining chromaffin vesicles lined up proximally to the cell membrane in preparation for exocytosis providing a "string-of-pearls" appearance. There was a 5-fold increase in the expression of proenkephalin mRNA (502.8 +/- 142% vs. 100 +/- 17.5%, P = 0.016) and a 2-fold increase in the expression of neuropeptide Y (213.4 +/- 41.2% vs. 100 +/- 59.9%, P = 0.014) in the TH-null animals as determined by quantitative TaqMan (Perkin-Elmer) PCR. Accordingly, immunofluorescence for met-enkephalin and neuropeptide tyrosine in these animals was strongly enhanced. The expression of phenylethanolamine N-methyl transferase and chromogranin B mRNA was similar in TH-null and wild-type mice. In TH-null mice, adrenocortical cells were characterized by an increase in liposomes and by tubular mitochondria with reduced internal membranes, suggesting a hypofunctional state of these steroid-producing cells. In accordance with these findings, plasma corticosterone levels were decreased. Plasma ACTH levels were not significantly different in TH-null mice. In conclusion, both the adrenomedullary and adrenocortical systems demonstrate structural and functional changes in catecholamine-deficient TH-null mice, underscoring the great importance of the functional interdependence of these systems in vivo.

Adrenal Glands↗
PubMed2000

Adrenomedullary dysplasia and hypofunction in patients with classic 21-hydroxylase deficiency.

BACKGROUND: Glucocorticoids are essential for the normal development and functioning of the adrenal medulla. Whether adrenomedullary structure and function are normal in patients with congenital adrenal hyperplasia is not known. METHODS: We measured plasma and urinary catecholamines and plasma metanephrines in 38 children with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (25 children with the salt-wasting form and 13 with the simple virilizing form), 39 age-matched normal subjects, and 20 patients who had undergone bilateral adrenalectomy. Adrenal specimens obtained from three other patients with 21-hydroxylase deficiency who had undergone bilateral adrenalectomy and specimens obtained at autopsy from eight other patients were examined histologically. RESULTS: Plasma epinephrine and metanephrine concentrations and urinary epinephrine excretion were 40 to 80 percent lower in the patients with congenital adrenal hyperplasia than in the normal subjects (P<0.05), and the values were lowest in the patients with the most severe deficits in cortisol production. Urinary epinephrine excretion and plasma epinephrine concentrations were at or below the limit of detection of the assay in 8 (21 percent) of the patients with congenital adrenal hyperplasia and in 19 (95 percent) of the patients who had undergone adrenalectomy. In the group of patients with congenital adrenal hyperplasia, plasma epinephrine and metanephrine concentrations and urinary epinephrine excretion were approximately 50 percent lower in those who had been hospitalized for adrenal crises than in those who had not. In three patients with congenital adrenal hyperplasia who had undergone bilateral adrenalectomy, the formation of the adrenal medulla was incomplete, and electron-microscopical studies revealed a depletion of secretory vesicles in chromaffin cells. CONCLUSIONS: Congenital adrenal hyperplasia compromises both the development and the functioning of the adrenomedullary system.

Adolescent↗