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Long Jin

Publications and source records attributed to Long Jin.

At least 37 records · Page 2Linked to original sources
PubMed2004

Analysis of parathyroid neoplasms by interphase fluorescence in situ hybridization.

Recent studies have indicated that numerical chromosomal abnormalities, including changes in cyclin D1 and p53, may be involved in parathyroid tumorigenesis. We analyzed a series of parathyroid neoplasms with DNA fluorescent probes to evaluate the diagnostic and prognostic utility of numerical abnormalities of chromosomes 1, 6, 9, 11, 13, 15, 17, and 22 and cyclin D1 and p53 gene loci. Interphase fluorescence in situ hybridization (FISH) analysis was performed on paraffin-embedded tissue sections from 15 parathyroid adenomas and 18 parathyroid carcinomas. Directly labeled fluorescent DNA probes for the centromere region of chromosomes 1, 6, 9, 11, 15, and 17, and locus-specific probes for chromosome 22 and chromosome 13 and for cyclin D1 and p53 gene loci were used for dual-probe hybridization. Sixty-seven percent (10 of 15) parathyroid adenomas and 78% (14 of 18) of parathyroid carcinomas showed chromosome gains. Seventy-three percent (11 of 15) of parathyroid adenomas and 33% (6 of 18) of parathyroid carcinomas showed chromosome losses. Normal parathyroid tissues used as controls showed no chromosomal abnormalities. Parathyroid hyperplasias averaged 1.8 gains and 0.2 losses per case. Parathyroid adenomas averaged 2.8 gains and 0.8 losses per case, and parathyroid carcinomas averaged 3.6 gains and 0.6 losses per case. In summary, chromosome abnormalities, both gains and losses, are common in parathyroid adenomas and carcinomas. Parathyroid carcinomas tend to show gains of more chromosome than adenomas. Chromosome 11 was the most frequent chromosome loss identified in parathyroid adenomas and a frequent chromosomal gain in parathyroid carcinomas. These results indicate that gain of chromosome 11 is associated with more aggressive biologic behavior in parathyroid neoplasms.

Adenoma↗
PubMed2004

Induction of RANTES by TWEAK/Fn14 interaction in human keratinocytes.

TNF-like weak inducer of apoptosis (TWEAK), a member of the tumor necrosis factor (TNF) family, is a multifunctional cytokine that regulate cellular proliferation, angiogenesis, inflammation, and apoptosis. In this study, we investigated the effect of TWEAK on human keratinocytes. Primary cultured normal human keratinocytes constitutively expressed a TWEAK receptor, fibroblast growth factor-inducible 14 (Fn14), and produced regulated on activation, normal T expressed and secreted (RANTES) upon TWEAK stimulation in a concentration-dependent manner. The TWEAK-induced RANTES production was abrogated by anti-Fn14 antibody, and synergistically augmented by simultaneous stimulation with transforming growth factor-beta. In addition, human keratinocytes differentiated in vitro with high Ca(2+)-containing medium showed enhanced production of RANTES upon TWEAK stimulation. Furthermore, TWEAK induced rapid phosphorylation of IkappaB-alpha in human keratinocytes. Collectively, TWEAK acts on human keratinocytes as an inducer of RANTES via Fn14. Because RANTES has been implicated in inflammation, TWEAK/Fn14 interaction in human keratinocytes may be involved in the pathophysiology of inflammatory skin disorders.

Apoptosis Regulatory Proteins↗
PubMed2004

Regulation of VEGF-A, VEGFR-I, thrombospondin-1, -2, and -3 expression in a human pituitary cell line (HP75) by TGFbeta1, bFGF, and EGF.

Pituitary tumors are highly vascular neoplasms, which suggest an important role of angiogenesis in pituitary tumor growth. We used the human pituitary cell line (HP75) to examine the effects of the growth factors TGFbeta1, bFGF, and EGF on cell growth, and on the regulation of the pro-angiogenic growth factor VEGF-A and the VEGFR-I and the anti-angiogenic molecules thrombospondin (TSP) TSP-1 and TSP-2 along with TSP-3. Real-time RT-PCR was used to measure mRNA levels, and Western blot was used to analyze TSP-1 and TSP-2 protein levels. TGFbeta1 treatment (1 x 10(-9) M) increased VEGF-A mRNA levels significantly (p < 0.05) after 4 and 24 h of treatment. TGF beta1 treatment decreased VEGF-R mRNA levels after 96 h of treatment (p < 0.05). After 96 h of treatment, TSP-1 and TSP-2 mRNA levels were significantly increased (p < 0.05) by TGFbeta1 treatment, which also inhibited HP75 cell growth. Basic FGF also increased TSP-1 mRNA levels after 96 h of treatment, but did not regulate growth of the pituitary tumor cells. Basic FGF and EGF did not modulate changes in VEGF-A mRNA levels after 4 and 24 h of treatment, but EGF increased VEGF-A significantly (p < 0.05) after 96 h of treatment. These results indicate that TGFbeta1 treatment may regulate angiogenesis in pituitary cells by initially increasing levels of pro-angiogenic VEGF-A and then stimulating the anti-angiogenic molecules TSP-1 and TSP-2 levels.

Blotting, Western↗
PubMed2004

Analysis of Cox-2 and thromboxane synthase expression in pituitary adenomas and carcinomas.

Recent studies have examined the role of cyclooxygenase-2 (Cox-2) expression in normal pituitaries and pituitary adenomas and have suggested a role for Cox-2 in the regulation of angiogenesis in the pituitary. Thromboxane synthase (TBXAS), which catalyzes the synthesis of thromboxane A2, is one of the downstream enzymes in Cox metabolism and appears to play a role in the regulation of invasiveness and angiogenesis in some neoplasms. To analyze the role of Cox-2 and TBXAS in pituitary tumor progression, we examined normal pituitaries (n = 8), pituitary adenomas (n = 174), and pituitary carcinomas (n = 7) for expression of Cox-2 and TBXAS by immunohistochemistry. Weak Cox-2 and moderate TBXAS expression was present in normal pituitary cells. Most pituitary adenomas showed increased expression of both Cox-2 and TBXAS. Pituitary tumors as a whole, but particularly carcinomas, showed greater Cox-2 expression than did normal pituitaries. Pituitary adenomas and carcinomas also showed greater staining for TBXAS when compared to normal pituitary. Nonfunctional adenomas had significantly higher levels of TBXAS expression compared to functional adenomas (p = 0.017). Adenomas and carcinomas showed similar degrees of staining for TBXAS. In summary, TBXAS appears to be one of the up-regulated downstream enzymes of Cox metabolism in pituitary tumors. Both Cox-2 and TBXAS may play an important role in pituitary tumor development and progression.

Biomarkers, Tumor↗
PubMed2004

Expression of cyclooxygenase-2 and thromboxane synthase in non-neoplastic and neoplastic thyroid lesions.

Cyclooxygenase-2 (COX-2) and thromboxane synthase (TBXAS) are important enzymes involved in the arachidonic acid pathway and synthesis of prostaglandins. We examined COX-2 and TBXAS immunoreactivity in 150 surgically resected thyroid specimens using immunohistochemistry to determine expression in benign and malignant thyroid lesions and to examine their roles in thyroid tumor progression. Papillary thyroid carcinomas and follicular carcinomas expressed higher levels of COX-2 compared to follicular adenomas and adenomatous nodules. We showed for the first time that TBXAS was expressed in thyroid tissues, with higher levels in papillary carcinomas compared to non-neoplastic and benign thyroid tissues. Western blot was performed on seven thyroid samples. These results indicate that both COX-2 and TBXAS are expressed in benign and malignant thyroid tissues. Although some malignant thyroid tumors showed higher levels of COX-2 expression, COX-2 and TBXAS are probably not useful in the immunohistochemical diagnosis of thyroid malignancies. However, the expression of both COX-2 and TBXAS by thyroid tissue may provide insight into the role of these enzymes in progression from benign to malignant thyroid tumors.

Adenoma↗
PubMed2003

Differential expression of galectin-3 in pituitary tumors.

Galectin-3 (Gal-3), a beta-galactoside-binding protein, has been implicated in a variety of biological functions, including cell proliferation and differentiation, tumor cell adhesion, angiogenesis, apoptosis, tumor progression, and metastasis. We investigated the role of Gal-3 in the development and progression of pituitary tumors. Immunohistochemical and Western blot analysis of normal and neoplastic human pituitaries showed that only lactotroph (PRL) and corticotroph (ACTH) hormone-producing cells and tumors expressed Gal-3. Gal-3 was present in 24 of 38 (63.2%) PRL adenomas, 5 of 6 (83.3%) PRL carcinomas, 19 of 41 (46.3) ACTH adenomas, and 7 of 8 (87.5%) ACTH carcinomas, but not in 112 other pituitary adenomas and carcinomas. Pituitary folliculo-stellate cells, which have macrophage-type functions in the anterior pituitary, also expressed Gal-3. Hyperplastic and neoplastic pituitaries from p27(Kip1) (p27)-null mice, which produce mainly ACTH, showed increased Gal-3 expression levels compared with control mice. Treatment with transforming growth factor beta1, which regulates pituitary cell proliferation, reduced Gal-3 as well as p27 expression levels in cultured HP75 pituitary cells and Gal-3 in cultured pituitary cells from p27-null mice, suggesting that p27 is not necessary for the inhibitory effects of transforming growth factor beta1 on the cell cycle in the pituitary. The role of Gal-3 in pituitary cell function was examined by RNA interference experiments. Inhibition of Gal-3 gene expression by RNA interference decreased HP75 cell proliferation and increased apoptosis. These results indicate that Gal-3 has an important role in pituitary cell proliferation and tumor progression.

Adenoma↗
PubMed2003

Merkel cell carcinomas: expression of S-phase kinase-associated protein 2 (Skp2), p27, and proliferation markers.

Merkel cell carcinomas are rare and aggressive tumors about which the expression of cell cycle regulatory proteins are not well known. We evaluated the clinicopathologic features of Merkel cell carcinomas and examined the expression of the cell cycle regulatory markers p27 and S-phase kinase-associated protein 2 (Skp2) and the proliferation markers Ki-67 and DNA topoisomerase II alpha (topo II alpha) in a group of these tumors. Thirty-nine cases of Merkel cell carcinoma were studied, 19 from the Mayo Clinic, Rochester, MN, and 20 from the University of Torino, Torino, Italy. Although the University of Torino patients tended to be slightly older at time of surgery compared to the Mayo Clinic patients, no clinical, pathologic, or immunohistochemical feature was statistically significantly different between the two groups. Of the 39 patients, 20 were male and 19 were female. The age at surgery averaged 72 yr. Formalin-fixed paraffin-embedded archival tissues from the 39 Merkel cell carcinomas were analyzed by immunohistochemistry for p27, Skp2, Ki-67, and topo II alpha with the avidin-biotin peroxidase system. The distribution of immunoreactivity was analyzed by quantifying the percentage of positive nuclei, which was expressed as the labeling index. There was a statistically significant inverse relationship between p27 and Skp2 (p = 0.005). Most tumors with increased levels of Skp2 were associated with reduced p27, and tumors with high levels of p27 expression were associated with reduced levels of Skp2. These results suggest that Skp2 regulates p27 expression in Merkel cell carcinomas. Tumors showing increased Skp2 expression were not always correlated with increased proliferation as evaluated by Ki-67 and topo II alpha, suggesting that Skp2 may be involved in Merkel cell tumorigenesis, but that other factors may also influence cell proliferation in these tumors.

Aged↗
PubMed2003

Regulation of cell growth and expression of 7B2, PC2, and PC1/3 by TGFbeta 1 and sodium butyrate in a human pituitary cell line (HP75).

Recent studies have shown that 7B2 and the neuroendocrine- specific proconvertase PC2 have important roles in pituitary cell proliferation and hormone secretion. Studies from our laboratory have also shown that TGFb1 regulates anterior pituitary cell proliferation and hormone secretion. To study the regulation of 7B2 in human pituitary tumors, we used a cell line derived from a human pituitary adenoma (HP75) that has been shown to express 7B2, PC1, PC2, and TGFbeta receptors to analyze the effects of TGFbeta1 and the histone deacetylase inhibitor (HDACI) sodium butyrate (NaB) treatment on 7B2 mRNA expression along with the neuroendocrine-specific proconvertases 1/3 (PC1) and PC2 mRNA and protein expression. RNA was quantified by real-time PCR and proteins were detected by immunohistochemistry and Western blotting. Treatment of cells with 1 mM NaB or 1 nM TGF 1 for 4 d decreased cell proliferation with a concomitant increase in the cell cycle protein p21. Real-time PCR analysis showed a significant increase in 7B2 mRNA after NaB and TGFbeta1 treatment. PC2 mRNA was down regulated by NaB while PC1 mRNA was unchanged. TGFbeta1 stimulated PC1, but not PC2 mRNA levels. Changes in PC1 and PC2 protein were similar to changes in the mRNAs, but the differences were not significant. These results indicated that NaB and TGFbeta1 inhibit pituitary cell proliferation and regulate the expression of 7B2, PC1, and PC2 in a cell culture model of pituitary tumors. Our results also indicate that inhibition of pituitary cell proliferation is associated with increased expression of 7B2 mRNA.

Blotting, Western↗
PubMed2003

Chromogranin a processing in human pituitary adenomas and carcinomas: analysis with region-specific antibodies.

The expression of various chromogranin A (CgA) peptide fragments was examined with region-specific antisera in benign and malignant pituitary tumors. Analysis of the proconvertases responsible for proteolytic processing of CgA, prohormone convertase 1/3 (PC1/3), and PC2 was also performed. Adenomas were studied using tissue microarrays, and a larger tissue section of a subset of the prolactin (PRL) adenomas was used to compare to the tissue microarray analysis. Carcinomas were analyzed using larger tissue sections. There were differences in CgA proteolytic products detected between the functional (PRL, adrenocorticotropic hormone [ACTH], and growth hormone tumors and the nonfunctional (gonadotroph and null cell) tumors, with the former group expressing lower levels of many peptides. These differences were most notable in the PRL adenomas and carcinomas in which the region-specific antisera against vasostatin I and vasostatin II detected these fragments in the lowest percentage of tumors and/or had the weakest immunoreactivity. The CgA peptide fragment detected by CgA 176-195 (chromacin) antiserum was expressed by the highest percentage of most functional and nonfunctional benign and malignant pituitary tumors. ACTH carcinomas (n = 3) were more strongly immunoreactive compared to the ACTH adenomas. These results show that there is differential expression of CgA peptide fragments and PC1/3 among different types of pituitary tumors and that ACTH pituitary carcinomas have higher levels of immunoreactive CgA peptide fragments compared to ACTH adenomas. This study also shows the utility of tissue microarrays in the analysis of a large group of tumors with regionspecific antisera.

Adenoma↗
PubMed2002

Pituitary hyperplasia in glycoprotein hormone alpha subunit-, p18(INK4C)-, and p27(kip-1)-null mice: analysis of proteins influencing p27(kip-1) ubiquitin degradation.

Most spontaneously developing hyperplastic and neoplastic lesions of the pituitary occur in the anterior pituitary. Targeted disruption of various cell-cycle proteins, including Rb, p27(kip1) (p27), and p18(INK4c) (p18), is associated with intermediate lobe pituitary hyperplasia. To develop a model of anterior pituitary proliferation to study the pathogenesis of pituitary tumors, we crossed the glycoprotein hormone alpha-subunit (alphaSU)-null mice that develop thyroid-stimulating hormone (TSH) cell hyperplasia with p18-null mice. The resulting offsprings developed accelerated enlargement of the anterior lobe with predominantly TSH cell hyperplasia. Immunohistochemical and histological analyses of these mice along with p27/p18 double-null mice, p18-null mice, and p27-null mice showed evidence of TSH, adrenocorticotropic hormone, prolactin, and luteinizing hormone hyperplasia. To determine whether there were alterations of p27 and the target proteins implicated in the ubiquitin degradation of p27 and other cyclin-dependent kinase inhibitors, we examined expression of SKP 2, Grb 2, and Jab 1 in the pituitaries of null mice. In the alphaSU-null mice there were decreased levels of SKP 2 and elevated levels of Grb 2 expression by Western blot analysis. Immunohistochemical analysis of the pituitary showed elevated Grb 2 in alphaSU-null and p18/alphaSU double-null mice. Jab 1 levels were not different from controls in the pituitary. These results show that 1) the p18/alphaSU double-null mice represent a good model to study the rapid development of anterior pituitary hyperplasia, and 2) various proteins important in p27 and other cyclin-dependent kinase inhibitor protein degradation are altered in the pituitary of alphaSU-null and p18/alphaSU double-null mouse models.

Animals↗
PubMed2002

Preexposure of murine macrophages to CpG-containing oligonucleotides results in nuclear factor kappaB p50 homodimer-associated hyporesponsiveness.

BACKGROUND: DNA containing the CpG motif is associated with immunomodulation of the innate immune response. Preexposure of macrophages to CpG DNA elicits a hyporesponsiveness to subsequent lipopolysaccharide (LPS) stimulation. We tested the hypothesis that this effect is due to decreased nuclear translocation of nuclear factor kappaB (NF-kappaB). METHODS: Murine macrophage-like RAW 264.7 cells were incubated with 1.5 microg/mL CpG-containing oligonucleotides (CpG ODN) for 0.5 to 9 hours followed by restimulation with 1 microg/mL LPS for 20 minutes. Some cells were cotransfected with an NF-kappaB sensitive luciferase reporter construct and a control beta-gal plasmid. Cytoplasmic and nuclear extracts were assayed for NF-kappaB by electrophoretic mobility shift assay and supershift assays, for NF-kappaB, IkappaB and phospho-IkappaB by Western blot, for luciferase activity, and for p38, c-Jun NH(2)-terminal kinase, and extracellular signal-related kinase activity assay. RESULTS: NF-kappaB functional activity was decreased as demonstrated by luciferase activity assay in the prolonged CpG ODN pretreatment groups. Unlike endotoxin tolerance, CpG ODN preexposure increased cytoplasmic phospho-IkappaB-alpha and did not abrogate mitogen-activated protein kinase activity. CONCLUSIONS: In macrophages, exposure to CpG DNA increases expression of the inhibitory p50 NF-kappaB homodimer and decreases NF-kappaB activity without inhibition of IkappaB kinases. Mitogen-activated protein kinase activity remains intact. Understanding these interactions between different toll receptor ligands may provide insight into novel therapeutic modalities.

Adjuvants, Immunologic↗
PubMed2002

Oxyphil parathyroid carcinomas: a clinicopathologic and immunohistochemical study of 10 cases.

Oxyphil parathyroid carcinomas are uncommon neoplasms, and the clinicopathologic features of these tumors are largely unknown. We evaluated the clinicopathologic features of oxyphil parathyroid carcinomas and the expression of cytokeratin 14 (CK14), the high-affinity glucose transporter-4 (Glut-4), as well as the cell cycle proteins p27 and Ki67 and compared these with oxyphil parathyroid adenomas and chief cell parathyroid adenomas and carcinomas. Formalin-fixed, paraffin-embedded archival tissues from primary (n = 6) and recurrent (n = 4) oxyphil carcinomas were analyzed and compared with chief cell parathyroid carcinomas (n = 12), oxyphil parathyroid adenomas (n = 38), and chief cell parathyroid adenomas (n = 17) by immunohistochemistry for CK14, Glut-4, p27, and Ki67 using the avidin-biotin peroxidase system. Patients with primary oxyphil and chief cell carcinoma presented with high levels of serum calcium (n = 15.5 and 13.7 mg/dL, respectively). Approximately half the patients in each group died of disease. The Ki67 labeling index was higher (4.9 vs 1.9) and the p27 index lower (23 vs 66) in primary oxyphil carcinoma compared with primary oxyphil adenomas. CK14 was expressed in most oxyphil adenomas (35 of 38 cases) but not in oxyphil carcinomas (0 of 10 cases). Glut-4 was more commonly expressed in both groups of adenomas compared with carcinomas. These results show that oxyphil parathyroid carcinomas are functional malignancies similar to chief cell carcinomas and are associated with hypercalcemia, recurrence, and death. Expression of CK14 is very different in oxyphil adenomas compared with carcinomas. Although distinction between parathyroid adenomas and carcinomas can only be made by histopathologic and clinical findings, these results suggest that immunostaining for CK14, p27, and Ki67 may provide additional information to help distinguish between difficult cases of parathyroid adenomas and carcinomas. These findings also indicate that the same histopathologic features should be used to diagnose oxyphil and chief cell parathyroid carcinomas.

Adenoma↗
PubMed2002

Desmoplastic small round cell tumor: a clinicopathologic, immunohistochemical, and molecular study of 32 tumors.

Desmoplastic small round cell tumor is a rare, aggressive neoplasm that mainly affects young male patients and is characterized by a reciprocal translocation t(11;22)(p13;q12) associated with the EWS-WT1 gene fusion transcript. Clinical, histopathologic, immunohistochemical, and molecular genetics features were reviewed for 32 tumors. There were 29 male and three female patients, with ages from 6 to 54 years (mean, 25 years). The main clinical signs and symptoms included abdominal pain (eight patients), weight loss (five patients), and presence of umbilical hernia (four patients). Two tumors primarily involved the ethmoid sinus and the soft tissues of the scalp; the other tumors (mean size, 10 cm) involved the abdominal cavity (88%). One patient presented initially with an axillary lymph node metastasis. Generally, all tumors showed the typical histologic findings of variably sized clusters of small, round, or spindled cells lying in a desmoplastic stroma. The neoplastic cells in formalin-fixed, paraffin-embedded tissue sections were positive for desmin (dot pattern) (81% of the cases), WT1 (91%), keratin (87%), neuron-specific enolase (84%), CD99 (23%), and actin (3%). The EWS-WT1 gene fusion transcript was detected in 29 of 30 tumors. One tumor with typical clinicopathologic and immunohistochemical features did not show the gene fusion. Follow-up for 27 patients showed that 19 patients (70%) died of uncontrolled, local, or widespread metastatic disease 3-46 months (mean, 20 months) after diagnosis, and eight patients were alive with known evidence of disease. Occasionally, desmoplastic small round cell tumor lacks the classic clinical, histologic, and immunohistochemical features. This study emphasizes the utility of analysis of the EWS-WT1 gene fusion transcript, which was performed on paraffin-embedded tissues, to confirm the diagnosis.

Abdominal Neoplasms↗
PubMed2002

The expression of a variant prostate-specific antigen in human prostate.

Although a splicing variant of prostate specific antigen (PSA-v) mRNA has been described previously, whether its protein (PSA-v or PSA-related protein 1, i.e., PSA-RP1) is actually expressed in human prostate cells remains elusive. We report that PSA-v protein is expressed in prostatic epithelia of both cancerous and benign tissues. Also, secreted PSA-v can be detected in the medium of a prostate cancer (PCa) cell line. Consistently, PSA-v mRNA is exclusively expressed in benign luminal epithelia and cancer cells of the prostate by in situ hybridization. Northern analysis of a cohort of 51 pairs of RNA samples from microdissected tissues showed that PSA-v mRNA levels remained constant in both benign and cancerous tissues, whereas PSA levels declined in cancerous areas. Our result suggests that it would be feasible to develop proper immunoassays for PSA-v to test whether PSA-v could have some clinical utility.

Aged↗
PubMed2000

Insulin and Glucagon mRNA Expression and Prohormone Convertase Immunoreactivity in Normal and Neoplastic Pancreatic Endocrine Tissue.

Prohormone convertase (PC) 1/3 and PC2 are neuroendocrine-specific enzymes that convert prohormones to active hormones. To learn more about the role of these PCs in normal and neoplastic islet cells, we analyzed a series of pancreatic endocrine tumors to determine the role of PC1/3 and PC2 in islet cell hormone processing. In situ hybridization with insulin and glucagon probes and immunostaining with antibodies to PC1/3 and PC2 were done with 6 normal pancreases, 33 insulinomas, and 7 glucagonomas. The intensity of the reactions was graded from 0 to 3+. Normal islets stained strongly for both proinsulin and proglucagon mRNAs. Insulinomas and glucagonomas had readily detected hormone mRNAs for proinsulin and proglucagon, respectively. Normal pancreatic insulin cells stained weakly for PC1/3 (1+) and PC2 (1-2+), and glucagon cells stained weakly for PC1/3 (1-2+) and strongly for PC2 (2-3+). Both insulinomas and glucagonomas stained strongly for PC2 (2-3+) with less intense staining for PC1 (1-2+). These results indicate that PC2 is more highly expressed in insulin- and glucagon-producing pancreatic islet cell tumors and that there is increased expression of PC2 in insulinomas compared to normal insulin-producing cells.

Journal Article↗
PubMed1998

Percoll Density Gradient-Enriched Populations of Rat Pituitary Cells: Interleukin 6 Secretion, Proliferative Activity, and Nitric Oxide Synthase Expression.

We used a discontinuous Percoll density gradient centrifugation to prepare enriched populations of prolactin (PRL), growth hormone (GH), and folliculo-stellate (FS) cells from rat anterior pituitaries in order to characterize these various cell populations. After cell dissociation and centrifugation, enriched PRL cells (55% of total cells as determined by immunocytochemistry [ICC] were present in Fraction 1 (Fr1) (density ([d]) = 1.059). Fr2 (d=1.071) had enriched S100-positive FS cells (31% of total cells), but enriched GH cell (60% of total cells) were present in Fr3 (d=1.094). Interleukin 6 (IL-6) was secreted mainly by enriched PRL cells in Fr1 (350 pg/mL/106 cells) and Fr2 (194 pg/mL/106 cells), and much less by the enriched GH cells inFr3 (16 pg/mL/106). Proliferation studies with combined 3H-thymidine and ICC for pituitary hormones showed that only the PRL cell had significant prolifereative activity. Immunostaining showed that immediately after separation, all three isoforms of nitric oxide synthase (NOS) were expressed anterior pituitary cells. After 3 d of culture, there was a marked increase in nuclear staining for neuronal NOS (nNOS) in all three fractions, whereas inducible NOS (iNOS) and endothelial NOS (eNOS) rexpression did not change significantly. These results indicate that: 1. Enriched populations of PRL, FS, and GH pituitary cells can be readily obtained with a rapid discontinuous percoll density separation procedure. 2. PRL cells from different fractions of the gradient show differenet proliferation rates and IL-6 secretion varied in different enriched cell populations. 3. Although all three isoforms of NOS were expressed in rat pituitary cells, nNOS is the prindipal isoform in anterior pituitary cells, and its expression was icreased after 3 d of culture of anterior pitutuitary cells.

Journal Article↗
PubMed1998

Prevalence and Prognostic Significance of Neuroendocrine Differentiation in Colorectal Carcinomas.

The prognostic significance of neuroendocrine differentiation in colorectal carcinoma is uncertain. We analyzed 289 moderately differentiated (grades II and Ill) colorectal carcinomas for neuroendocrine differentiation by immunohistochemistry and in situ hybridization. The tumors were divided into three groups based on the presence of and the numbers of neuroendocrine cells, with group I having no neuroendocrine cells, group II having <1 positive cell/mm(2), and group Ill with >1 positive cell/mm(2). In situ hybridization with probes for chromogranin A and B detected almost twice as many neuroendocrine cells as did immunostaining with an antibody for chromogranin A. There was no prognostic difference associated with the presence or absence of neuroendocrine differentiation in this group of moderately differentiated carcinomas. These results indicate that the presence of neuroendocrine cells detected by expression of chromogranin protein or mRNA does not influence prognosis in moderately differentiated colorectal carcinomas.

Journal Article↗