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R V Lloyd

Publications and source records attributed to R V Lloyd.

At least 91 records · Page 5Linked to original sources
PubMed1998

Retinoic acid-dependent stimulation of 2,2'-azobis(2-amidinopropane)-initiated autoxidation of linoleic acid in sodium dodecyl sulfate micelles: a novel prooxidant effect of retinoic acid.

(E)-Retinoic acid (RA) was shown to stimulate the rate of 2,2'-azobis(2-amidinopropane) (AAPH)-initiated autoxidation of linoleic acid (18:2) in sodium dodecyl sulfate (SDS) micelles. RA-dependent stimulation of 18:2 autoxidation was characterized by enhanced rates of dioxygen uptake which were linear with retinoid concentration. In contrast, 5,6-epoxy-RA, a major oxidation product of RA, failed to affect the rate of dioxygen consumption at all concentrations tested. RA was also shown to stimulate peroxyl radical-dependent oxidation of styrene to the corresponding oxirane when styrene was included in the micellar system as a molecular probe. Furthermore, unequivocal evidence of RA-dependent stimulation of 18:2 autoxidation was obtained by relative quantitation of 13-hydroxy-(9Z, 11E)-octadecadienoic acid (13-HODE) plus 9-hydroxy-(10E,12Z)-octadecadienoic acid (9-HODE) production. In addition, enhanced carbon-centered radical formation was demonstrated in the presence of RA by EPR spectroscopy using alpha-(4-pyridyl 1-oxide)-N-tert-butylnitrone (4-POBN) as a spin trap. Analysis and quantitation of RA oxidation products indicated that RA was oxidized to one primary product, 5,6-epoxy-RA, which was identified on the basis of cochromatography with synthetic standard (in a reverse-phase HPLC system), electronic absorption spectroscopy, and positive chemical ionization mass spectrometry of the corresponding methyl ester. Other minor oxidation products were also detected but not characterized. In contrast, reaction mixtures devoid of 18:2 failed to demonstrate significant retinoid oxidation. Mechanisms are proposed to account for the prooxidant effects of RA in this system.

Amidines↗
PubMed1998

Development of ganglioneuroma following successful treatment for orbital rhabdomyosarcoma.

A female infant presented with a left orbital embryonal rhabdomyosarcoma at the age of 3 months. She was successfully treated for this tumour with chemo- and radiotherapy. Eight years later she developed a ganglioneuroma in the same area which was treated surgically, but recurred at the age of 19. Re-examination of all of the specimens using immunohistochemistry confirmed that the initial and successive diagnoses had been correct. Two further explanations for this rare sequence of events are considered: whether the initial biopsy had been unrepresentative of the whole tumour, or whether there had indeed been two separate tumours arising in the same area. The theories of this previously undocumented occurrence are discussed further.

Adult↗
PubMed1998

In situ hybridization detection of low copy nucleic acid sequences using catalyzed reporter deposition and its usefulness in clinical human papillomavirus typing.

In situ hybridization (ISH) detection of low copy DNA and RNA sequences using nonisotopic probes has been difficult in the past because of a lack of sensitivity. Several techniques, such as ISH with radioisotopic-labeled probes, in situ polymerase chain reaction, in situ reverse transcription polymerase chain reaction, self-sustained sequence replication, and chemiluminescence, have allowed increased sensitivity but have required specialized and often expensive equipment, lengthy protocols, and in the case of radioactive probes, there has been an associated increased health risk. Catalyzed reporter deposition (CARD) combined with ISH (CARD-ISH) increases the signal-generating potential of labeled hybridized probes and allows the detection of low copy sequences of nucleic acids in formalin-fixed, paraffin-embedded tissue sections. To determine the sensitivity of CARD-ISH to detect nucleic acids in routinely processed specimens, we analyzed the detection of HPV 16 and 18 infection in formalin-fixed, paraffin-embedded sections of cultured cell lines, including CaSki cells with 400-600 copies of HPV 16, HeLa 229 cells with 10-50 copies of HPV 18, and SiHa cells with 1-2 copies of HPV 16 using a conventional ISH method and by CARD-ISH. In addition, 20 cases of clinical specimens previously analyzed for HPV 6, 11, 16, 18, 31, 33, and 51 with the Enzo PathoGene kit (Enzo Diagnostics, Inc., Farmingdale, NY, U.S.A.) were reexamined with the CARD-ISH method. The CARD-ISH system detected one to two copies of HPV 16 in the SiHa cells whereas the conventional ISH method did not. Both methods detected HPV 16 and 18 in CaSki and HeLa 229 cells, respectively. Three clinical cases that were previously negative and two weakly positive cases of HPV infection were all strongly positive with the CARD-ISH system, a 25% increase in the detection of positive cases by CARD-ISH. We also showed for the first time that a cocktail of six biotinylated oligonucleotide probes was capable of detecting one to two copies of HPV 16 in SiHa cells. These results show that the CARD-ISH method increases the sensitivity of nonisotopic ISH to the level of detecting one to two copies of HPV DNA in formalin-fixed, paraffin-embedded tissue sections using biotinylated cDNA or oligonucleotide probes.

3,3'-Diaminobenzidine↗
PubMed1998

Expression of D-type cyclins in normal and neoplastic rat pituitary.

The D-type cyclins (D1, D2, and D3) are involved in progression through the G1 phase of the cell cycle and are induced as part of the delayed early response to growth factor stimulation. To better understand the role of D-type cyclins in pituitary cell function and the regulatory role of growth factors in the cell cycle, we analyzed the expression and regulation of D-type cyclins in normal and neoplastic rat pituitary cells. Immunocytochemical and RT-PCR analyses showed expression of all three D-type cyclins in the normal pituitary, with higher percentages of positive cells by immunocytochemistry in the nuclei of normal pituitaries (D1, 20-30%; D2, 50-60%; D3, 70-80%), compared with GH3 cells. In the normal pituitary, there were significantly higher levels of cyclins D2 and D3 in PRL, GH, LH, and TSH cells, compared with ACTH cells. Cyclin D1 protein was not detected in GH3 cells, while D2 was present in less than 1 percent and D3 in 10-15 percent of GH3 cells. There were low levels of cyclin D1 and D2 messenger RNA expression in GH3 cells, by RT-PCR. When dissociated rat pituitary cells were cultured in the presence of basic fibroblast growth factor (5.6 nM) for 3 days, cyclin D2 was up-regulated 2-fold in normal PRL cells (control, 33 +/- 1%; treated, 68 +/- 2%). Similarly, bFGF treatment stimulated cyclin D3 expression 3-fold in GH3 cells (control, 15 +/- 1%; treated, 44 +/- 1%). Treatment of GH3 cells with 5-aza-2'-deoxycytidine, which induces gene demethylation, produced marked increases in cyclin D2 and D3 expression. Transfection of mouse cyclin D1 complementary DNA, driven by a cytomegalovirus promoter into GH3 cells, led to ectopic cyclin D1 expression; and there was a slight stimulation of cell proliferation and increased apoptosis in GH3 cells. These results indicate that there is a differential expression of various D-type cyclins in different types of normal pituitary cells and between normal pituitary and GH3 cells. Growth factors, such as bFGF and demethylation increased D-type cyclin expression, whereas ectopic overexpression of cyclin D1 stimulates cell proliferation and increases apoptosis in GH3 pituitary tumor cells.

Animals↗
PubMed1998

Prolactinomas in male and female patients: a comparative clinicopathologic study.

OBJECTIVE: To explore the basis of the gender-based differences in endocrine and surgical findings in patients with prolactinoma (prolactin cell adenoma) as well as in their clinical outcome. MATERIAL AND METHODS: In young or reproductive-age female patients, older women (beyond 40 years of age), and male patients, we systematically studied the following factors: operative and endocrine features (tumor size, invasiveness, preoperative serum prolactin level, and biochemical outcome), specific biologic variables (mitotic index, MIB-1 labeling index, and p27 immunoreactivity), and hormone receptor status (estrogen and progesterone receptor proteins as well as dopamine D2 receptor messenger RNA). RESULTS: Of the various factors assessed, the preoperative prolactin level and MIB-1 labeling index were lower in young female patients in comparison with older female and particularly male patients. Hormone levels were also positively associated with mitotic activity as well as the MIB-1 labeling index. Although invasion was infrequent in microadenomas of young female patients, no statistically significant differences in tumor size or invasiveness were noted among the three patient groups. Absence of differences in invasiveness may, in part, be explained by artifacts of case selection. CONCLUSION: The basis for the observed differences in proliferative activities in tumors of the three study groups is not readily apparent but may reflect differences in the endocrine milieu or the effect of sex steroid hormone receptors, tumoral vascularity, or specific growth factors.

Adult↗
PubMed1998

Expression of p27kip1 and Ki-67 in benign and malignant thyroid tumors.

Thyroid neoplasms represent a broad spectrum of tumors with different biologic behaviors. The majority of these tumors can be readily diagnosed by characteristic histopathologic features, but the distinction between follicular adenomas and follicular carcinomas can be difficult. Recent studies with cell cycle proteins such as p27kip1 (p27), a cell cycle inhibitory protein, and Ki-67, a proliferation marker, suggest that these markers might be useful in predicting the behavior of various neoplasms. We analyzed 95 thyroid lesions (16 follicular adenomas, 23 follicular carcinomas, 22 papillary carcinomas, 27 anaplastic carcinomas, plus 7 non-neoplastic thyroids [NNTs], used as a control group) for expression of p27 and Ki-67 by immunostaining. The distribution of immunoreactivity was analyzed by quantifying nuclear staining in each case without knowledge of the diagnosis or outcome. Clinical history and follow-up information were obtained by chart review. There were significant differences in the expression of p27 between follicular adenomas (labeling index [LI] = 47.9+/-5.6) and follicular carcinomas (LI = 15.7+/-2.0). Papillary carcinomas (LI = 11.6+/-3.0) and anaplastic carcinomas (LI = 9.4+/-1.7) had p27 LIs similar to that of follicular carcinomas; the NNT group had the highest p27 LI (74.1+/-4.9). The Ki-67 LI of anaplastic carcinomas (57.6+/-3.8) was more than threefold greater than that of any other group. Logistic regression showed that p27 was effective in distinguishing follicular adenomas from follicular carcinomas (P = .0056) and that Ki-67 could also distinguish follicular adenomas from follicular carcinomas (P = .0060). Analysis of follicular carcinomas with and without metastases showed significantly higher expression of Ki-67 in patients with metastases (P = .0019). These results indicate that antibodies to p27 and Ki-67 might be useful in distinguishing between thyroid neoplasms that are difficult to diagnose by the usual histopathologic criteria.

Adenocarcinoma, Follicular↗
PubMed1998

Expression of p27kip1 in prostatic adenocarcinoma.

p27kip1 (p27) protein is an inhibitor of cyclin and cyclin-dependent kinase complexes and prevents progression of cells from G1 to the S phase of the cell cycle. p27 might have tumor suppressor activity, and decreased p27 expression is associated with aggressive tumor behavior in several human malignancies. The object of this study was to evaluate p27 expression in prostatic adenocarcinoma treated by radical prostatectomy and to assess its association with numerous morphologic and clinical features. One hundred thirty-eight prostatic adenocarcinomas were evaluated for p27 expression by quantifying nuclear immunohistochemical staining. p27 expression was tested for association with patient age, family history of prostate cancer, preoperative serum prostate-specific antigen level, Gleason score, extraprostatic extension, seminal vesicle involvement, lymph node metastases, tumor-node-metastasis stage, DNA ploidy by flow cytometric analysis, and subclinical biochemical failure. p27 expression was analyzed as a continuous variable, and we also classified the tumors as low expressors (< 50% of cells p27 positive) or high expressors (> 50% of cells p27 positive) for comparison. Patients with adenocarcinomas that exhibited low p27 expression had higher mean Gleason scores than did high expressors (7 vs. 6.2, respectively; P = .002). Low p27 expression correlated with positive surgical margins (P = .05), seminal vesicle involvement (P = .007), lymph node metastasis (P = .03), and aneuploid cancers (P = .003), but it did not correlate with subclinical biochemical failure. p27 expression correlated with a number of prognostic morphologic features in prostatic adenocarcinoma, and the evaluation of p27 expression might provide additional prognostic information.

Adenocarcinoma↗
PubMed1998

Pulmonary lymphomatoid granulomatosis in acquired immunodeficiency syndrome: lesions with Epstein-Barr virus infection.

We report the clinicopathologic characteristics of pulmonary lymphomatoid granulomatosis (LYG) in 11 patients (identified from a series of 330 consecutive patients who underwent autopsy between 1984 and 1995 at the University of Texas Medical Branch at Galveston, Texas) with a diagnosis of acquired immunodeficiency syndrome (AIDS). We used immunohistochemical stains, RNA in situ hybridization (ISH), and gene rearrangement studies to identify the immunophenotype and the presence or absence of Epstein-Barr virus (EBV) infection. All of the patients were men ranging in age from 27 to 65 years (mean age, 38.6 yr). Autopsy lungs of 21 age-matched controls were examined for EBV using ISH; these included 9 patients with AIDS who did not have pulmonary lesions and 12 HIV-negative individuals who died accidentally (mean age, 38.6 yr). All of the 11 pulmonary lesions showed the gross and microscopic characteristics of LYG, with zonal necrosis and prominent angioinvasion. The tumor nodules consisted of a mixture of atypical large lymphocytes, with vesicular nuclei and prominent nucleoli and with a background of small and intermediate-size lymphocytes, histiocytes, and plasma cells. The large lymphocytes were CD20 positive, consistent with a B-cell phenotype. Ten of the 11 cases demonstrated EBV1-encoded RNA and CD20 positivity in the large, atypical lymphocytes by double labeling. One patient showed EBV positivity in CD20-negative, CD45RO-positive large cells, but these cells were CD3 negative and showed a monoclonal heavy chain gene rearrangement by polymerase chain reaction, indicating that these were of B-cell origin. Aberrant CD43 coexpression was identified in four cases. EBV latent membrane protein was demonstrated in 9 of 11 cases by immunohistochemical stains. The lungs of all of the 21 control patients were negative for EBV by ISH. We conclude that, in our series, AIDS-associated LYG is a B-cell neoplasm and that it has a strong association with EBV infection.

Adult↗
PubMed1997

Transcription factors in normal and neoplastic pituitary tissues.

Transcription factors are proteins that bind to regulatory elements in DNA and have critical roles in gene regulation during development, in cellular growth and differentiation. The four major groups of transcription factors have been classified according to the motif in the DNA-binding domains and include: (1) the helix-turn-helix group, which includes the Pit-1/GHF-1 (Pit-1) transcription factor; (2) the zing finger group, which includes estrogen and other steroid hormone receptors; (3) the leucine zipper group, which includes c-fos protooncogene, and (4) the helix-loop-helix group, which includes the c-myc oncogene. Members of all four groups have been described in normal and neoplastic anterior pituitary gland tissues. Pit-1 has been shown to regulate prolactin (PRL), growth hormone (GH), and thyroid-stimulating hormone (TSH) cells during development and differentiation. Genetic defects in this transcription factor have led to specific diseases in rodents and humans such as dwarfism and cretinism. Estrogen receptor (ER) protein plays a critical role in the regulation of gene expression in some anterior pituitary cells. There is a differential distribution of ER in anterior pituitary cells and tumors; PRL, gonadotroph, and null cell tumors are the principal adenomas expressing ER. The protooncogene c-fos is regulated by estrogen in various tissues, linking the regulation of one transcription factor by another transcription factor with a different motif. The c-myc oncogene has been detected in the pituitary gland and in some pituitary tumors, although the exact role of this oncogene in pituitary tumor development is uncertain. Because of the critical role that transcription factors play in pituitary cell development and differentiation, we can anticipate many more studies to elucidate their many functions in normal and neoplastic pituitary tissues.

Animals↗
PubMed1997

Extrapulmonary small cell carcinoma.

BACKGROUND: Extrapulmonary small cell carcinoma (EPSCCA) is often an underrecognized clinicopathologic entity, distinct from small cell lung carcinoma. The purpose of this study was to review the study institution's experience with EPSCCA with specific emphasis on the epidemiology and response to treatment of these uncommon neoplasms. METHODS: Using the tumor registry database of the study institution, the authors retrieved and reviewed the records of all patients with EPSCCA treated between 1974 and 1994. Study eligibility required that the patients had a normal chest radiograph, computed tomography scan of the chest, sputum cytology, and/or negative bronchoscopy. Patients with well differentiated neuroendocrine carcinomas and Merkel cell carcinomas of the skin were excluded. RESULTS: Primary sites of EPSCCA in the current series were: gastrointestinal system in 29 patients, ear, nose, and throat in 14, genitourinary system in 12, internal genitalia in 10, upper respiratory system in 5, unknown primary-lymph nodes in 5, unknown primary-other in 2, the thymus in 3, and the peritoneum in 1. After the initial evaluation and confirmation of histologic diagnosis, 10 of 81 patients had been lost to follow-up. Of the remaining 71 patients, 54 had limited disease. Forty of the 54 patients underwent surgical treatment of their malignancy; 10 patients (25%) remained alive and disease free at least 3 years after surgery, whereas 30 patients (75%) relapsed with a median disease free survival of 6 months. Six patients of 54 with limited disease were treated with chemotherapy and radiation. Five of these 6 (83%) relapsed at a median time of 11.5 months. Another 8 of the total of 54 patients received only radiation therapy and all had disease recurrence at a median time of 5 months. In the group of patients with extensive or recurrent disease, platinum-based chemotherapy was employed in 22 patients. There was a 72% response rate with a median duration of 8.5 months. Seven patients had doxorubicin-based chemotherapy. There was a 57% response rate with a median duration of 4.5 months. In the current study group of patients, the 3-year disease free and overall survival rates were 26% and 38%, respectively, whereas the 5-year disease free and overall survival rates were each 13%. CONCLUSIONS: EPSCCA is usually a fatal disease, with a 13% 5-year survival rate. In a small percentage of patients, surgery can be curative if the tumor is small and confined to the organ of origin. Because of the poor overall outcome, one needs to consider the possible use of adjuvant chemotherapy in appropriate circumstances if surgery is to be employed. In most patients with limited disease, the combination of chemotherapy and radiation as the primary treatment can be as effective as surgery. EPSCCA is responsive to commonly employed regimens for small cell lung carcinoma; however, the responses are short-lived. The extent of disease at diagnosis represents the most sensitive predictor of survival.

Adult↗
PubMed1997

Pituitary carcinoma: a clinicopathologic study of 15 cases.

BACKGROUND: Pituitary carcinomas are rare adenohypophysial neoplasms, the definition, diagnosis, therapy, and prognosis of which are controversial. METHODS: Pituitary carcinomas were defined as primary adenohypophysial neoplasms with documented craniospinal and/or systemic metastases. The authors report a clinicopathologic study of 15 examples examined by light microscopy, immunohistochemistry, and image analysis. Both proliferative activity and p53 tumor suppressor gene expression were studied. RESULTS: The study group consisted of 15 patients, including 8 males and 7 females ranging in age from 34-71 years (mean, 56 years). Of these patients, seven had adrenocorticotropic hormone (ACTH)-producing tumors (four in the context of Nelson's syndrome), seven had prolactin-producing tumors, and one had a nonfunctioning tumor. No evidence of diabetes insipidus was seen in any case. Fourteen tumors were initially considered macroadenomas. Of the ten cases for whom tumor extent was known, all had invasive tumors. The interval from the initial diagnosis of adenoma to that of carcinoma ranged from 0.3 to 18.0 years (mean, 6.6 years; median, 5.0 years); the longest mean interval (15.3 years) occurred for patients with Nelson's syndrome. The latency was twice as long for ACTH-producing tumors as for prolactin (PRL) cell tumors (9.5 vs. 4.7 years). All carcinomas showed a greater tendency toward systemic metastasis than craniospinal metastasis; the rate of systemic metastasis was 71% for PRL cell tumors and 57% for ACTH-producing tumors. Thirteen percent of tumors showed both patterns of metastasis. Fully 50% of primary tumors and the majority of metastases showed nuclear pleomorphism and/or hyperchromasia. The mean mitotic, MIB-1, and proliferating cell nuclear antigen indices for primary tumors and metastases were as follows: 2/10 high-power field (hpf), 2.6% and 11%, respectively; 6/10 hpf, 7.8% and 16%, respectively. Staining for p53 protein was noted in 57% of primary tumors and 88% of metastatic tumors; a relative increase in p53 expression in metastases was noted in 83%. All but one of the primary and metastatic tumors were aneuploid. The most common treatments were radiation therapy and, for PRL cell carcinomas, dopamine agonist administration. Both treatments provided only palliation. Eighty percent of the patients died of metastatic disease 7 days to 8 years after the diagnosis of carcinoma; of these, 66% died within 1 year. At last follow-up, 20% of patients were alive with metastases 9-18 months after diagnosis. CONCLUSIONS: Nearly all pituitary carcinomas present as functioning, microscopically atypical or mitotically active, invasive macroadenomas. By definition, after an interval related to their immunotype, all metastasize. The tumors show a greater tendency toward systemic metastasis than craniospinal metastasis and are associated with poor prognosis. Radiation and dopamine agonist therapy generally provide only palliation. Proliferation indices and p53 expression tend to be higher in metastases than in primary tumors. The current definition of pituitary carcinoma requires the demonstration of metastasis; however, high mitotic and MIB-1 labeling indices as well as p53 immunoreactivity suggest the diagnosis and appear to be of prognostic significance. A redefinition of aggressive pituitary tumors is proposed--one that facilitates the recognition of tumors prone to metastasis.

Adrenocorticotropic Hormone↗
PubMed1997

Hepatocellular carcinoma: needle biopsy findings in 74 cases.

Needle aspiration specimens from 74 cases of hepatocellular carcinoma (HCC) diagnosed between January 1986 and December 1992 were reviewed and compared with 57 other lesions. The most specific cytologic findings for HCC included capillaries separating tumor cells (34%), bile associated with malignant cells (19%), and endothelial cells lining clusters of neoplastic cells (18%). Less specific findings included polygonal cells with central nuclei resembling normal hepatocytes and intranuclear inclusions. Tissue core fragments available in 53 cases of HCC disclosed that a weak keratin (AE1/AE3) stain (75% of HCC), a canalicular pattern of polyclonal carcinoembryonic antigen (54%), and a positive alpha-fetoprotein stain (58%) are diagnostic of HCC. All HCCs were negative for monoclonal carcinoembryonic antigen. In situ hybridization for albumin mRNA was positive in 27 of 33 cases of HCC. The diagnosis of HCC by needle biopsy should include cytologic findings and the appropriate immunohistochemical profile, along with detection of albumin mRNA by in situ hybridization.

Adult↗
PubMed1997

Mixed medullary-follicular carcinoma of the thyroid. A morphological, immunohistochemical and in situ hybridization analysis of 11 cases.

Mixed medullary-follicular carcinomas (MMFC) of the thyroid are rare tumours showing the morphological and immunochemical properties of both parafollicular and follicular cell lineages. Their recognition is based on a classical WHO definition, although several other patterns have been described in recent years. We investigated 11 cases of MMFC by immunohistochemistry and in situ hybridization (ISH) to analyse the structural features, the immunophenotypic profile and the calcitonin (CT) and thyroglobulin (TG) gene expression of the neoplasm. Histologically, 10 cases had mixed parafollicular and follicular cell populations in the primary tumour and 1 only in the lymph node metastasis. All cases were immunoreactive for CT (in medullary areas) and TG (in follicular areas and also in the solid component of 8/11 cases). These findings were confirmed by ISH analysis. Combined ISH and immunostaining showed that most cases had separate CT and TG gene expression, although rare cells with concurrent CT and TG gene expression were identified in 2 tumours. We conclude that (a) MMFC display heterogeneous morphological patterns and are a special type of thyroid tumour undergoing divergent differentiation; (b) in MMFC, CT and TG genes are generally not simultaneously expressed by the same cell, although dual expression of CT and TG was present in rare neoplastic elements; and (c) the origin of MMFC, whether they are derived from the ultimo-branchial body or result from neoplastic transformation of different cell populations following common oncogenic stimuli, is unclear.

Adenocarcinoma, Follicular↗
PubMed1997

Antiproliferative effect of the somatostatin analogue octreotide on growth hormone-producing pituitary tumors: results of a multicenter randomized trial.

OBJECTIVE: To determine and quantify the in vivo effects of octreotide on the cell cycle kinetics of growth hormone-producing pituitary adenomas. DESIGN: A multicenter randomized trial had been conducted to assess the clinical efficacy of octreotide, and we studied tissue specimens from pituitary macroadenomas in 32 patients with acromegaly from that trial-16 of whom had received 4 months of octreotide therapy before surgical resection and 16 of whom had undergone surgical resection only. MATERIAL AND METHODS: All tumors had been fully characterized on the basis of their immunophenotypic profile and their ultrastructural morphologic features. Included were 16 densely and 16 sparsely granulated somatotroph adenomas. In each case, immunostaining for the cell cycle-specific nuclear antigen Ki-67 was performed with use of the MIB-1 antibody. The staining reaction was manually quantified, and a tumor growth fraction was derived in each case. RESULTS: The mean growth fraction of tumors exposed to octreotide was suppressed by 83% in comparison with untreated surgical controls (0.011+/-0.004% versus 0.065+/-0.016%, respectively; P = 0.0068). The association between octreotide treatment and lower tumor growth fractions was statistically independent of tumor subtype, being evident among both sparsely and densely granulated somatotroph adenomas. CONCLUSION: Octreotide exerts a significant antineoplastic effect on somatotroph adenomas, one readily reflected at the level of the cell cycle. This antiproliferative response provides insight into several clinicopathologic issues surrounding octreotide therapy for these neoplasms.

Acromegaly↗
PubMed1997

The origin of the hydroxyl radical oxygen in the Fenton reaction.

There is an ongoing discussion in the chemical literature regarding the nature of the highly reactive hydroxyl radical formed from the reaction between ferrous iron and hydrogen peroxide (the Fenton reaction). However, the fundamental experiment of directly determining the source of the hydroxyl radicals formed in the reaction has not yet been carried out. In this study, we have used both hydrogen peroxide and water labeled with 17O, together with ESR spin trapping, to detect the hydroxyl radicals formed in the reaction. ESR experiments were run in phosphate buffer with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap, and either H2O2 or H2O labeled with 17O. The hydroxyl radical was generated by addition of Fe2+ ion to H2O2, or as a control, by photolysis of H2O2 in the ESR cavity. Observed ESR spectra were the sum of DMPO/.16OH and DMPO/.17OH radical adduct spectra. Within experimental accuracy, the percentage of 17O-labeled hydroxyl radical trapped by the DMPO was the same as in the original hydrogen peroxide, for either method of hydroxyl radical generation, indicating that the trapped hydroxyl radical was derived exclusively from hydrogen peroxide and that there was no exchange of oxygen atoms between H2O2 and solvent water. Likewise, the complementary reaction with ordinary H2O2 and 17O-labeled water also showed that none of the hydroxyl radical was derived from water. Our results do not preclude the ferryl intermediate, [Fe = O]2+ reacting with DMPO to form DMPO/.OH if the ferryl oxygen is derived from H2O2 rather than from a water ligand.

Cyclic N-Oxides↗
PubMed1997

Estrogen receptor expression and growth-promoting function in human choriocarcinoma cells.

Tamoxifen (1.0 microM) was found to inhibit the expression of a thymidine kinase (TK) promoter-reporter gene, lacking an estrogen response element (ERE), in transiently transfected BeWo cells, suggesting that inhibition of TK promoter activity was linked to secondary estrogen-dependent effects on BeWo cell function. Estradiol (0.05-0.45 microM) stimulated BeWo cell proliferation and increased the percentage of S-phase cells. Tamoxifen (1.35-4.05 microM) inhibited BeWo cell growth and antagonized the stimulatory actions of 0.15 microM estradiol. Reverse transcription-polymerase chain reaction and Western analyses confirmed the presence of estrogen receptor (ER) transcripts and the 67-kD ER in BeWo cells. The BeWo cell ER binds to an ERE consensus sequence and the ER-ERE complex is supershifted by antibodies directed against the ER. We conclude that BeWo cells express a functional ER that is important for the control of BeWo cell proliferation, suggesting a potential role for estrogens in mediating placental trophoblast growth and development.

Animals↗
PubMed1997

Detection of albumin messenger RNA in hepatic and extrahepatic neoplasms. A marker of hepatocellular differentiation.

Albumin is a ubiquitous protein synthesized only by hepatocytes. Detection of albumin messenger RNA (mRNA) in neoplastic and non-neoplastic tissues using in situ hybridization may be useful in demonstrating hepatocellular differentiation. We investigated the presence of albumin mRNA by in situ hybridization in 69 hepatic and 29 extrahepatic tumors to determine its sensitivity and specificity for hepatocellular differentiation. Albumin mRNA was detected in 22 of 23 hepatocellular carcinomas (96%); all hepatoblastomas, hepatocellular adenomas, and focal nodular hyperplasias; and within the hepatoid areas of an extrahepatic malignant mixed germ cell tumor. All other hepatic and extrahepatic tumors were negative for albumin mRNA. The staining was intense in focal nodular hyperplasias, weak in hepatocellular adenomas, and variable in hepatocellular carcinomas and hepatoblastomas. Non-neoplastic, noncirrhotic liver was present in 50 cases; all were positive for albumin mRNA with variable staining, which was usually more intense than in the neoplasms. A zonal pattern of staining was present in 49 (98%) of these, with more intense staining within acinar zone 1 and least in zone 3. This study shows that albumin mRNA is a specific marker of hepatocellular differentiation but may be present in extrahepatic germ cell tumors with hepatoid features. For primary hepatocellular carcinomas, in situ hybridization for albumin mRNA is a useful adjunct diagnostic method.

Adenoma, Liver Cell↗