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Liu JZ, Dai TH, Elster TH, Sahgal V, Brown RW, Yue GH. Simultaneous measurement of human joint force, surface electromyograms, and functional MRI-measured brain activation. J Neurosci Methods 2000; 101:49-57. [PMID: 10967361 DOI: 10.1016/s0165-0270(00)00252-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Functional magnetic resonance imaging (fMRI) has been increasingly used in studying human brain function given its non-invasive feature and good spatial resolution. However, difficulties in acquiring data from peripheral (e.g. information from muscle) during fMRI studies of motor function hinder interpretation of fMRI data and designing more sophisticated investigations. Here we describe a system that was designed to concurrently measure handgrip force, surface electromyograms (EMG) of finger flexor and extensor muscles, and fMRI of human brain. The system included a pressure transducer built in a hydraulic environment, a heavily shielded EMG recording element, and a visual feedback structure for online monitoring of force and/or EMG signal, by the subject positioned in the scanner during an fMRI experiment. System evaluation and subsequent fMRI motor function studies have indicated that by using this system, high quality force and EMG signals can be recorded without sacrificing the quality of the fMRI data.
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MacDonald P, MacKenzie S, Ramage LE, Seckl JR, Brown RW. Corticosteroid regulation of amiloride-sensitive sodium-channel subunit mRNA expression in mouse kidney. J Endocrinol 2000; 165:25-37. [PMID: 10750033 DOI: 10.1677/joe.0.1650025] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Corticosteroid control of distal nephron sodium handling, particularly through the amiloride-sensitive sodium channel (ENaC), has a key role in blood pressure regulation. The mechanisms regulating ENaC activity remain unclear. Despite the generation of useful mouse models of disorders of electrolyte balance and blood pressure, there has been little study of distal nephron sodium handling in this species. To investigate how corticosteroids regulate ENaC activity we isolated cDNA for the three mouse ENaC subunits (alpha, beta and gamma), enabling their quantitation by competitive PCR and in situ hybridisation. Kidneys were analysed from mice 6 days after adrenalectomy or placement of osmotic mini-pumps delivering aldosterone (50 microg/kg per day), dexamethasone (100 microg/kg per day), spironolactone (20 mg/kg per day) or vehicle alone (controls). In controls, renal ENaCalpha mRNA exceeded beta or gamma by approximately 1.75- to 2.8-fold. All subunit mRNAs were expressed in renal cortex and outer medulla, where the pattern of expression was fully consistent with localisation in collecting duct, whereas the distribution in cortex suggested expression extended beyond the collecting duct into adjacent distal tubule. Subunit mRNA expression decreased from cortex to outer medulla, with a gradual reduction in beta and gamma, and ENaCalpha decreased sharply ( approximately 50%) across the outer medulla. Expression of ENaCbeta and gamma (but not alpha) extended into inner medulla, suggesting the potential for inner medulla collecting duct cation channels in which at least ENaCbetagamma participate. Aldosterone significantly increased ENaC subunit expression; the other treatments had little effect. Aldosterone caused a 1.9- to 3.5-fold increase in ENaCalpha (particularly marked in outer medullary collecting duct), but changes for beta and gamma were minor and limited to the cortex. The results raise the possibility that medullary ENaCalpha upregulation by aldosterone will create more favourable subunit stoichiometry leading to a more substantial increase in ENaC activity. In cortex, such a mechanism is unlikely to have a major role.
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Brown RW, Jewell RT, Rous JJ. Abortion decisions among Hispanic women along the Texas-Mexico border. SOCIAL SCIENCE QUARTERLY 2000; 81:237-52. [PMID: 16856268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
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Juarez D, Brown RW, Ostrowski M, Reardon MJ, Lechago J, Truong LD. Pheochromocytoma associated with neuroendocrine carcinoma. A new type of composite pheochromocytoma. Arch Pathol Lab Med 1999; 123:1274-9. [PMID: 10583935 DOI: 10.5858/1999-123-1274-pawnc] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The coexistence of pheochromocytoma and other tumor types in a single adrenal gland has been rarely documented. This type of pheochromocytoma is designated "composite" or "mixed," depending on whether the pheochromocytoma and the nonpheochromocytoma components show the same embryologic origin. The nonpheochromocytoma components reported in the composite pheochromocytoma include ganglioneuroma, ganglioneuroblastoma, neuroblastoma, and malignant schwannoma. The components found in the mixed pheochromocytoma include adrenal cortical neoplasms and spindle cell sarcoma. We report a unique case of composite pheochromocytoma in which the nonpheochromocytoma element is a neuroendocrine carcinoma. The histologic and the immunohistochemical profiles of the 2 distinct components of this tumor were typical for those of pheochromocytoma and neuroendocrine carcinoma. This dual differentiation was also supported by ultrastructural findings. This case not only broadens the morphologic spectrum of composite pheochromocytoma but also provides some additional insight into the histogenesis of this rare but fascinating type of tumor.
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80
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Nasr SZ, Hurwitz ME, Brown RW, Elghoroury M, Rosen D. Treatment of anorexia and weight loss with megestrol acetate in patients with cystic fibrosis. Pediatr Pulmonol 1999; 28:380-2. [PMID: 10536070 DOI: 10.1002/(sici)1099-0496(199911)28:5<380::aid-ppul11>3.0.co;2-a] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Four patients with severe cystic fibrosis lung disease, anorexia and weight loss, received Megestrol Acetate (MA), as an appetite stimulant. The initial dose was 400-800 mg daily and was continued for 6-15 months. Appetite was improved, with significant weight gain in all patients and an increase in their weight for age percentile from <5% at the start of the study to approximately the 25(th) percentile after 6 months of use and improvement in quality of life. One patient discontinued MA after 6 months, and subsequently appetite and weight were depressed.
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81
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Clark NM, Brown RW, Parker E, Robins TG, Remick DG, Philbert MA, Keeler GJ, Israel BA. Childhood asthma. ENVIRONMENTAL HEALTH PERSPECTIVES 1999; 107 Suppl 3:421-9. [PMID: 10423388 PMCID: PMC1566232 DOI: 10.1289/ehp.99107s3421] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Asthma prevalence in children has increased 58% since 1980. Mortality has increased by 78%. The burden of the disease is most acute in urban areas and racial/ethnic minority populations. Hospitalization and morbidity rates for nonwhites are more than twice those for whites. Asthma is characterized by recurrent wheezing, breathlessness, chest tightness, and coughing. Research in the past decade has revealed the importance of inflammation of the airways in asthma and clinical treatment to reduce chronic inflammation. Asthma is associated with production of IgE to common environmental allergens including house dust mite, animal dander, cockroach, fungal spores, and pollens. Some interventions to reduce symptoms through control of dust mite and animal dander have had positive results. Control of symptoms through interventions to reduce exposures to cockroach antigen has not been reported. Studies illustrating causal effects between outdoor air pollution and asthma prevalence are scant. Increases in asthma prevalence have occurred at the same time as general improvements in air quality. However, air quality appears to exacerbate symptoms in the child who already has the disease. Decreased pulmonary function has been associated with exposure to particulates and bronchial hyperresponsiveness to smoke, SO(2) and NO(2). Symptoms have been correlated with increased levels of respirable particulates, ozone, and SO(2). Interventions that reduce the negative outcomes in asthma associated with outdoor environmental factors have not been reported. Control of asthma in children will entail the collaborative efforts of patients, family, clinical professionals, and school personnel, as well as community-wide environmental control measures and conducive national and local policies based on sound research.
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Fujita H, Petropoulos LS, Morich MA, Shvartsman SM, Brown RW. A hybrid inverse approach applied to the design of lumped-element RF coils. IEEE Trans Biomed Eng 1999; 46:353-61. [PMID: 10097470 DOI: 10.1109/10.748988] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A combination of inverse procedures is employed in the design of radio-frequency (RF) coils with specific examples in, but not restricted to, magnetic resonance imaging. The first inverse procedure is the use of functional methods for the optimization of coil characteristics subject to restrictions on the field behavior. Continuous current distributions are derived from analysis of the fields they are required to produce. To make use of these distributions at a desired frequency, the method of moments is applied as a second inverse procedure to a discretized version of the current distribution. The advantage of this hybrid technique is that it provides a computational algorithm for optimization of feeding, tuning, impedance matching and other aspects of RF coil design. A prototype RF coil has been built using the engineering values predicted by the theory. Experimental results including images acquired from the prototype coil are presented.
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Kotelevtsev Y, Brown RW, Fleming S, Kenyon C, Edwards CR, Seckl JR, Mullins JJ. Hypertension in mice lacking 11beta-hydroxysteroid dehydrogenase type 2. J Clin Invest 1999; 103:683-9. [PMID: 10074485 PMCID: PMC408118 DOI: 10.1172/jci4445] [Citation(s) in RCA: 207] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Deficiency of 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) in humans leads to the syndrome of apparent mineralocorticoid excess (SAME), in which cortisol illicitly occupies mineralocorticoid receptors, causing sodium retention, hypokalemia, and hypertension. However, the disorder is usually incompletely corrected by suppression of cortisol, suggesting additional and irreversible changes, perhaps in the kidney. To examine this further, we produced mice with targeted disruption of the 11beta-HSD2 gene. Homozygous mutant mice (11beta-HSD2(-/-)) appear normal at birth, but approximately 50% show motor weakness and die within 48 hours. Both male and female survivors are fertile but exhibit hypokalemia, hypotonic polyuria, and apparent mineralocorticoid activity of corticosterone. Young adult 11beta-HSD2(-/-) mice are markedly hypertensive, with a mean arterial blood pressure of 146 +/- 2 mmHg, compared with 121 +/- 2 mmHg in wild-type controls and 114 +/- 4 mmHg in heterozygotes. The epithelium of the distal tubule of the nephron shows striking hypertrophy and hyperplasia. These histological changes do not readily reverse with mineralocorticoid receptor antagonism in adulthood. Thus, 11beta-HSD2(-/-) mice demonstrate the major features of SAME, providing a unique rodent model to study the molecular mechanisms of kidney resetting leading to hypertension.
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85
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Dhar A, Salamonsen LA, Doughton BW, Brown RW, Findlay JK. Effect of immunization against the amino-terminal peptide (alpha N) of the alpha 43-subunit of inhibin on follicular atresia and expression of tissue inhibitor of matrix metalloproteinase (TIMP-1) in ovarian follicles of sheep. JOURNAL OF REPRODUCTION AND FERTILITY 1998; 114:147-55. [PMID: 9875167 DOI: 10.1530/jrf.0.1140147] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ewes actively immunized against alpha N, the N-terminal peptide of inhibin alpha 43 precursor, have lowered fertility associated with ovulation failure, restricted tissue remodelling and reduced matrix metalloproteinase-2 activity in the follicular fluid at the time of expected ovulation. This could be due to altered ratios of matrix metalloproteinase-2 and tissue inhibitor of matrix metalloproteinase (TIMP-1), or to the onset of atresia in antral follicles destined to ovulate. The objectives of the present study were to investigate the effects of immunization against alpha N on the localization of TIMP-1 in ovine follicles, and on follicular growth and atresia in the follicular phase. Ewes were either immunized against alpha N or remained as controls and the ovaries were removed before (0, n = 4) and at 12 h (n = 4) and 24 h (n = 4) after hCG administration in a synchronized follicular phase, 48 h after removal of intravaginal pessaries. Observations were made on a single section taken through the largest follicle present in the ovaries of each ewe. There were no healthy antral follicles > 1 mm in immunized ovaries (0/29) compared with controls (16/31) (P < 0.001), whereas the proportion of healthy antral follicles < 1 mm was the same in each group (9/19 versus 5/12). TIMP-1 immunoactivity was localized in large luteal cells, smooth muscle and endothelial cells, and in all antral follicles, including oocytes. At the time of hCG administration, no TIMP-1 immunoreactivity was detected in the apical region of the follicular wall of large follicles (> 6 mm) compared with the rest of the follicle wall, but staining appeared in the apical granulosa layer 24 h later. In newly formed corpora lutea, TIMP-1 expression was found along the invaginating vascular layer. There was no effect of immunization on the patterns of TIMP-1 immunoreactivity, suggesting that changes in TIMP-1 are not involved in the effects of alpha N. These data are consistent with a paracrine role for alpha N in the selection and atresia of antral follicles, and for TIMP-1 in tissue reorganization and steroidogenesis at the time of ovulation.
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Marchevsky AM, Patel S, Wiley KJ, Stephenson MA, Gondo M, Brown RW, Yi ES, Benedict WF, Anton RC, Cagle PT. Artificial neural networks and logistic regression as tools for prediction of survival in patients with Stages I and II non-small cell lung cancer. Mod Pathol 1998; 11:618-25. [PMID: 9688182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The prognosis of patients with Stage I and II non-small cell lung cancer (NSCLC) can be estimated but cannot be definitively ascertained by use of current clinicopathologic criteria and tumor marker studies. The potential value of probabilistic neural networks (NNs) with genetic algorithms and multivariate logistic regression to predict the survival of NSCLC patients has not been previously evaluated. Multiple prognostic factors (age, sex, cell type, stage, tumor grade, smoking history, and immunoreactivity to c-erbB-3, bcl-2, Glut1, Glut3, retinoblastoma gene and p53 were correlated with 5-year survival in 63 patients with Stage I or II NSCLC, treated solely by surgical excision at Baylor Medical College, Houston, Texas. Several probabilistic NNs with genetic algorithm models were developed using the prognostic features as input neurons and survival at 5 years (free of disease/dead of disease) as output neurons. The probabilistic NN yielded excellent classification rates for dependent variable survival. The best model was trained with 52 cases and classified all 11 "unknown" test cases correctly. Several statistically significant logistic regression models were fitted using 50 cases to build the models and 13 cases as "hold-out" test cases. These multivariate statistical models provide various cutoff values that predict/classify the probability of survival at 5 years. In conclusion, probabilistic NNs and logistic regression models can be useful in estimating the prognosis of patients with Stage I and II NSCLC using multiple clinicopathologic and molecular variables. These multivariate predictive models need to be validated with much larger groups of patients to assess their potential clinical value.
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Truong LD, Williams R, Ngo T, Cawood C, Chevez-Barrios P, Awalt HL, Brown RW, Younes M, Ro JY. Adult mesoblastic nephroma: expansion of the morphologic spectrum and review of literature. Am J Surg Pathol 1998; 22:827-39. [PMID: 9669345 DOI: 10.1097/00000478-199807000-00005] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Mesoblastic nephroma (MN) is a distinctive tumor that is seen mostly in early infancy and that consists of classic and cellular (atypical) variants. Mesoblastic nephroma rarely occurs in adulthood, but MN in this age group still is poorly characterized because there are only 17 reported cases. We describe five additional cases of adult MN, including one case of the cellular variant, characterize the immunohistochemical profiles in detail, and critically review the previously reported cases. The collective data obtained from these 22 cases of adult MN showed that the patients predominantly were women (20 cases), ranging in age from 19 to 78 years, who were asymptomatic (5 cases) or had nonspecific signs and symptoms referable to a renal mass. Twenty tumors were classified as classic and 2 as cellular. The tumors were 2-24 cm, well circumscribed, and partially encapsulated and displayed a solid/ cystic cut surface, with a predominantly solid component in most tumors. One tumor, however, was almost purely cystic. Most tumors extended to the renal sinus. and some appeared entirely intrapelvic on imaging studies; however, gross and microscopic evaluation did not show destructive invasion of the pelvic wall. Extension of the tumor beyond the renal capsule has not been described. Each tumor was composed of epithelial and stromal components both. The epithelial component, which displayed no difference between the classic and cellular variants, was composed of isolated or clustered tubules and cysts lined by a benign epithelium with a wide range of cytologic differentiation. The stromal cells were composed of fibroblasts, myofibroblasts, and smooth muscle cells in various combinations. Stromal cellularity was low for the classic variant but high for the cellular variant. Hemorrhage, necrosis, and high mitotic index were noted in the stroma of the cellular, but not in the classic variant. Immunohistochemical study applied to the five current cases and seven normal control kidneys confirmed the presence of fibroblasts, myofibroblasts, smooth muscle cells, and prominent vessels in the stroma of each tumor. Most cysts and tubules within the tumors had a distinctive immunohistochemical profile, similar to that of collecting duct but different from those of other portions of the nephron in the normal control kidneys. After total or partial nephrectomy, without adjuvant chemotherapy or radiotherapy, 19 patients, including the 2 with cellular MN, were alive and well at 8-months to 48-years follow-up. Follow-up was not available in two patients. The remaining patient had recurrence at the surgical site 24 years after nephrectomy. Adult MN displays a distinctive morphologic spectrum that parallels that of its pediatric congener. It probably is a benign tumor that can be treated successfully by complete excision. The collecting duct differentiation expressed by most tubules and cysts of adult MN implies ureteric bud, which is the exclusive embryologic origin of collecting duct, as an important element in the histogenesis of this rare but fascinating type of tumor.
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Diaz R, Brown RW, Seckl JR. Distinct ontogeny of glucocorticoid and mineralocorticoid receptor and 11beta-hydroxysteroid dehydrogenase types I and II mRNAs in the fetal rat brain suggest a complex control of glucocorticoid actions. J Neurosci 1998; 18:2570-80. [PMID: 9502816 PMCID: PMC6793118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/1997] [Revised: 12/18/1997] [Accepted: 01/01/1998] [Indexed: 02/06/2023] Open
Abstract
Glucocorticoids (GCs) act via intracellular mineralocorticoid (MR) and glucocorticoid receptors (GR). However, it has recently been recognized that GC access to receptors is determined by the presence of tissue-specific 11beta-hydroxysteroid dehydrogenases (11beta-HSDs) that catalyze the interconversion of active corticosterone and inert 11-dehydrocorticosterone. 11beta-HSD type 1 (11beta-HSD1) is a bidirectional enzyme in vitro that acts predominantly as a reductase (regenerating corticosterone) in intact neurons. In contrast, 11beta-HSD type 2 (11beta-HSD2) is a higher affinity exclusive dehydrogenase that excludes GCs from MR in the kidney, producing aldosterone-selectivity in vivo. We have examined the ontogeny of 11beta-HSD mRNAs and enzyme activity during prenatal brain development and correlated this with GR and MR mRNA development. These data reveal that (1) 11beta-HSD2 mRNA is highly expressed in all CNS regions during midgestation, but expression is dramatically reduced during the third trimester except in the thalamus and cerebellum; (2) 11beta-HSD2-like activity parallels closely the pattern of mRNA expression; (3) 11beta-HSD1 mRNA is absent from the CNS until the the third trimester, and activity is low or undectectable; and (4) GR mRNA is highly expressed throughout the brain from midgestation, but MR gene expression is absent until the last few days of gestation. High 11beta-HSD2 at midgestation may protect the developing brain from activation of GR by GCs. Late in gestation, repression of 11beta-HSD2 gene expression may allow increasing GC activation of GR and MR, permitting key GC-dependent neuronal and glial maturational events.
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Waddell BJ, Benediktsson R, Brown RW, Seckl JR. Tissue-specific messenger ribonucleic acid expression of 11beta-hydroxysteroid dehydrogenase types 1 and 2 and the glucocorticoid receptor within rat placenta suggests exquisite local control of glucocorticoid action. Endocrinology 1998; 139:1517-23. [PMID: 9528929 DOI: 10.1210/endo.139.4.5900] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Placental 11beta-hydroxysteroid dehydrogenase (11beta-HSD) regulates transplacental passage of maternal glucocorticoids to the fetus and is thus a key determinant of fetal glucocorticoid levels. It has also been proposed that placental 11beta-HSD expression may influence local glucocorticoid actions by regulating access of corticosterone to the glucocorticoid receptor (GR) or mineralocorticoid receptor (MR). Therefore, the present study used a rat model to assess whether the GR or MR are coexpressed with the two forms of 11beta-HSD (types 1 and 2) in the placental labyrinth zone, the major site of maternal-fetal transfer, and in the basal zone, the primary site of placental hormone synthesis. In situ hybridization analysis was used to assess messenger RNA (mRNA) expression for the GR, MR, 11beta-HSD-1, and 11beta-HSD-2 in the two placental zones on days 16, 19 and 22 of pregnancy (term = day 23). Whereas expression of the GR appeared relatively unchanged in both zones at these three stages of pregnancy, that of 11beta-HSD-1 clearly increased in the labyrinth zone but fell in basal zone, whereas the opposite pattern of expression was observed for 11beta-HSD-2. MR expression was not detected at any stage. The pattern of placental 11beta-HSD-2 mRNA expression over days 16, 19, and 22 of pregnancy was paralleled by changes in 11beta-HSD-2-specific bioactivity, but despite clear expression of 11beta-HSD-1 mRNA, no bioactivity attributable to this enzyme was measurable in either placental zone. To assess the role of fetal adrenal maturation on these changes in 11beta-HSD, two experimental models, maternal adrenalectomy and fetectomy, were employed. Maternal adrenalectomy on day 13 advanced maturation of the fetal adrenal cortex but had no effect on 11beta-HSD-2 bioactivity in either of the placental zones at day 19. Placental 11beta-HSD-2 bioactivity on day 22 was also unaffected by fetectomy 3 or 6 days earlier. In conclusion, the consistent expression of the GR in the two placental zones late in pregnancy suggests that concomitant and marked changes in 11beta-HSD-1 and 11beta-HSD-2 expression could have a major influence on glucocorticoid action in the placenta at this time. Moreover, the changes in 11beta-HSD expression appear to be unrelated to development of the fetal adrenal cortex and are likely to reduce the placental glucocorticoid barrier near the end of pregnancy.
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Cheng YC, Brown RW, Chung YC, Duerk JL, Fujita H, Lewin JS, Schuele DE, Shvartsman S. Calculated RF electric field and temperature distributions in RF thermal ablation: comparison with gel experiments and liver imaging. J Magn Reson Imaging 1998; 8:70-6. [PMID: 9500263 DOI: 10.1002/jmri.1880080116] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The present paper is a study of theoretic modeling and experimental tests of that modeling for the local heating due to radiofrequency thermal ablation. A model is developed for the current and the associated electric field produced by a radiofrequency ablation probe. The temperature distributions resulting from the induced ohmic currents in the surrounding material are considered. A comparison is made between the theoretic temperature profiles and the shapes of thermal ablation 'lesions' produced in a controlled gelatin sample experiment. Comparison with the contours of human thermally induced liver lesions found in MRI studies also provides a validation of the success of the modeling. Successful modeling should lead to methods for optimization of the ablation procedure, especially as it is used in interventional MRI.
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Kraemer PJ, Randall CK, Dose JM, Brown RW. Impact of d-amphetamine on temporal estimation in pigeons tested with a production procedure. Pharmacol Biochem Behav 1997; 58:323-7. [PMID: 9300587 DOI: 10.1016/s0091-3057(97)00296-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The influence of d-amphetamine on timing in pigeons was examined with a production procedure. Birds were trained with a fixed time schedule in which food reinforcement was contingent on the first response made after a duration signal had appeared for 30 s. Probe tests involved trials in which the duration signal was extended to 90 s and reinforcement was omitted. In Experiment 1, 2.0 mg/kg d-amphetamine shifted peak responding to a duration shorter than that found with saline. In Experiment 2, the dose-response function for this drug effect was examined. A 0.3-mg/kg dose of d-amphetamine had no impact on performance, but a 1.0-mg/kg dose shifted the peak duration significantly relative to saline; a 2.0-mg/kg dose shifted the function even more. These results complement previous findings with rats tested with the peak procedure and pigeons tested with a discrimination procedure.
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Younes M, Brown RW, Stephenson M, Gondo M, Cagle PT. Overexpression of Glut1 and Glut3 in stage I nonsmall cell lung carcinoma is associated with poor survival. Cancer 1997; 80:1046-51. [PMID: 9305704 DOI: 10.1002/(sici)1097-0142(19970915)80:6<1046::aid-cncr6>3.0.co;2-7] [Citation(s) in RCA: 290] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Increased expression of Glut1 and Glut3 has been reported in many human cancers, including nonsmall cell lung carcinoma (NSCLC). The aim of this study was to determine the biologic significance of Glut1 and Glut3 overexpression in Stage I NSCLC. METHODS Using immunohistochemistry and polyclonal anti-Glut1 and anti-Glut3 antibodies, the authors immunostained sections of formalin fixed, paraffin embedded tissues from 289 Stage I NSCLCs. The Kaplan-Meier survival method, the log rank test, and Fisher's exact test were used for statistical analysis. RESULTS Of the 289 cases, 49 (17%) were negative for both Glut1 and Glut3, 239 (83%) were Glut1 positive, 61 (21%) were Glut3 positive, 179 (62%) were positive for Glut1 but negative for Glut3, 1 (0.3%) was positive for Glut3 but negative for Glut1, and 60 (21%) were positive for both Glut1 and Glut3. Only 1 of 50 Glut1 negative tumors (2%) was positive for Glut3, whereas 60 of 239 Glut1 positive tumors (25%) were positive for Glut3 (P < 0.0001). Glut1 or Glut3 were detected more often in poorly differentiated and undifferentiated tumors (P < 0.0001 and P = 0.0008, respectively). Overexpression of Glut1 and/or Glut3 was associated with poorer survival (P = 0.0133), especially in patients with well-differentiated and moderately differentiated tumors (P = 0.0017). CONCLUSIONS In Stage I NSCLC, Glut3 overexpression likely occurs after Glut1 overexpression. The appearance of Glut1 positive clones is associated with aggressive biologic behavior, which is worsened by the emergence of Glut3 positive clones. Glut1 and Glut3 are significant of poor prognosis indicators in cases of NSCLC.
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93
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Scheff SW, Baldwin SA, Brown RW, Kraemer PJ. Morris water maze deficits in rats following traumatic brain injury: lateral controlled cortical impact. J Neurotrauma 1997; 14:615-27. [PMID: 9337124 DOI: 10.1089/neu.1997.14.615] [Citation(s) in RCA: 185] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
This experiment utilized a laterally placed controlled cortical impact model of traumatic brain injury (TBI) to assess changes on spatial learning and memory in the Morris water maze (MWM). Adult rats were subjected to one of two different levels of cortical injury, mild (1 mm) or moderate (2 mm) deformation, and subsequently tested for their ability to learn (acquisition) or remember (retention) a spatial task, 7 or 14 days after injury. Results revealed an injury-dependent deficit for experimental animals compared to sham-operated controls. Not only did the TBI result in longer escape latencies, but also significant deficits in search time and relative target visits. Although the moderately injured animals demonstrated significant histopathology in the cortex and hippocampus, mildly injured subjects demonstrated no obvious tissue destruction, but did manifest significant behavioral change. These results demonstrate that a laterally placed controlled cortical impact is capable of producing significant cognitive deficits on both acquisition and retention paradigms utilizing the MWM.
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Anton RC, Brown RW, Younes M, Gondo MM, Stephenson MA, Cagle PT. Absence of prognostic significance of bcl-2 immunopositivity in non-small cell lung cancer: analysis of 427 cases. Hum Pathol 1997; 28:1079-82. [PMID: 9308733 DOI: 10.1016/s0046-8177(97)90062-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The bcl-2 gene product inhibits apoptosis and is thought to participate in oncogenesis. Association of bcl-2 immunopositivity with improved prognosis of non-small cell lung cancers (NSCLC) is controversial. Although two studies have reported better survival in bcl-2-immunopositive NSCLCs, a third series has contradicted this finding. The authors studied a relatively larger case series involving 427 patients for whom detailed information on long-term follow-up was available to determine the prognostic significance of bcl-2 expression. The study included 252 adenocarcinomas (AC), 111 squamous cell carcinomas (SCC), and 64 large cell carcinomas (LC). After antigen retrieval, sections were immunostained using a monoclonal anti-bcl-2 antibody (1:60, Clone 124, Dako) and the avidin-biotin complex technique. Staining was scored as positive or negative and also on a semiquantitative scale as 0, low (<10%), moderate (10% to 75%), or extensive (>75%). Bcl-2 immunoreactivity was correlated with survival using the actuarial survival method, Kaplan-Meier method, and log-rank test and was not associated with statistically significant differences in survival for NSCLCs (P = .5537). Differences in survival remained insignificant even after NSCLCs were stratified for cell type, stage, or grade, singly or in combination. Therefore, using this method, bcl-2 immunopositivity does not appear to act as an independent prognostic indicator in NSCLCs.
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MESH Headings
- Adenocarcinoma/chemistry
- Adenocarcinoma/diagnosis
- Adenocarcinoma/mortality
- Adult
- Aged
- Aged, 80 and over
- Carcinoma, Large Cell/chemistry
- Carcinoma, Large Cell/diagnosis
- Carcinoma, Large Cell/mortality
- Carcinoma, Non-Small-Cell Lung/chemistry
- Carcinoma, Non-Small-Cell Lung/diagnosis
- Carcinoma, Non-Small-Cell Lung/mortality
- Carcinoma, Squamous Cell/chemistry
- Carcinoma, Squamous Cell/diagnosis
- Carcinoma, Squamous Cell/mortality
- Humans
- Immunohistochemistry
- Lung Neoplasms/chemistry
- Lung Neoplasms/diagnosis
- Lung Neoplasms/mortality
- Middle Aged
- Prognosis
- Proto-Oncogene Proteins c-bcl-2/analysis
- Survival Rate
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95
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Abstract
Two experiments examined retention of spatial learning in rats using a Morris water maze. Retention was scored in terms of probe trial performance when the platform was removed. Latency to reach the platform location, percent of time in the quadrant that had contained the platform, and relative frequency of visits to the platform location were analyzed. Results of the first experiment showed that preweanlings and juveniles exhibited substantial forgetting at 3- and 7-day retention intervals. Forgetting in adults was much lower than that found in the younger animals, and no differences in amount of forgetting appeared between the 3- and 7-day retention intervals at any age. The second experiment showed that forgetting in juveniles was alleviated by a single training trial administered just prior to the probe trial. These results are discussed in terms of ontogenetic differences in memory processing and measurement issues pertinent to the Morris water maze test procedure.
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96
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Brown RW. Errors in medicine. JOURNAL OF QUALITY IN CLINICAL PRACTICE 1997; 17:21-5. [PMID: 9107601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The medical profession has been reminded of the problem of errors occurring in the practice of medicine by some recent local and overseas studies. These studies provide data on the incidence and demographics of these errors, and they provide a starting point for improving the situation. A body of research is developing on the subject of human error, and it is suggested that the medical profession take advantage of the knowledge derived from this research. In particular, attention should be directed towards developing an atmosphere of reporting errors without fear of blame, developing back-up systems, standardizing processes, monitoring processes extensively, and recertifying operators. Some of these suggestions are already being adopted in this country.
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97
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Kissinger P, Trim S, Williams E, Mielke E, Koporc K, Brown RW. An evaluation of initiatives to improve family planning use by African-American adolescents. J Natl Med Assoc 1997; 89:110-4. [PMID: 9046764 PMCID: PMC2608217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Teen pregnancies in the United States have reached epidemic proportions, and consequently, efforts to promote family planning among adolescents have increased. At the Orleans Parish Family Planning Clinic in New Orleans, Louisiana, adolescent-specific initiatives were implemented to improve understanding of family planning services and promote contraceptive use. Since 92% of the patients are African American, the study population was limited to this group. This study examines the efficacy of two initiatives (i.e., orientation sessions and 3-month booster visits conducted in adolescent-specific clinics) for improving initiation and continuation of family planning services among African-American adolescent women. Initiation of services was compared among those who attended the orientation session and those who did not attend. Continuation of services was determined by attendance of the annual visit for those who attended the 3-month follow-up visit and those who did not attend. Of 737 teens entering into the clinic, the mean age was 16 years, 95% were enrolled in school, 23% attended the orientation session, and 71% initiated services. Of the 507 who initiated services and who underwent follow-up for at least 12 months, 29% attended the 3-month follow-up visit and 32% attended an annual visit. Attendance of the orientation session was associated with initiation of services and attendance of the 3-month booster visits was associated with attendance of the annual visit in multivariate logistic regression. Simple and cost-effective techniques such as orientation sessions and follow-up visits conducted in adolescent clinics can improve initiation of family planning and compliance among adolescents.
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98
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Yi ES, Harclerode D, Gondo M, Stephenson M, Brown RW, Younes M, Cagle PT. High c-erbB-3 protein expression is associated with shorter survival in advanced non-small cell lung carcinomas. Mod Pathol 1997; 10:142-8. [PMID: 9127320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
c-erbB-3 is a new member of the Type I growth factor receptor family that includes epidermal growth-factor receptor (also called c-erbB-1) and HER-2/neu (also called c-erbB-2). Frequency and significance of c-erbB-3 overexpression in lung cancers have not been reported previously. A series of 549 cases of primary lung carcinomas were immunostained with a monoclonal anti-human c-erbB-3 antibody (Clone RTJ.1) using formalin-fixed, paraffin-embedded archival tissue. Sharp membranous staining or punctate cytoplasmic staining was interpreted as positive and scored 0 (< 5% of tumor cells), 1 (5-9%), 2 (10-49%), or 3 (> or = 50%). Medical records were reviewed for clinical data, including stage and survival. Actuarial cumulative survival analysis with the Mantel-Cox test was performed on 443 cases that had a single primary site in the lung of pure non-small cell carcinoma (adenocarcinoma, squamous cell carcinoma, large cell carcinoma) and that also had follow-up data for more than 3 months. In all stages, squamous cell carcinoma showed the greatest rate of high c-erbB-3 positivity (score, 3) (34/119; 28.6%), followed by adenocarcinoma (41/256; 15.9%) and large cell carcinoma (7/66; 10.6%). Patients with high c-erbB-3 expression (score, 3) survived for significantly shorter times than did patients with low c-erbB-3-expression (score, 0-2) in Stages III and IV (P = 0.002), but not in Stage I or II non-small cell lung carcinomas. In conclusion, high c-erbB-3 expression in advanced non-small cell lung carcinomas might be an adverse prognostic factor. This finding suggests that c-erbB-3 might be a potential target for molecular therapy in advanced non-small cell lung carcinomas.
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99
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Brown RW, Campagna LB, Dunn JK, Cagle PT. Immunohistochemical identification of tumor markers in metastatic adenocarcinoma. A diagnostic adjunct in the determination of primary site. Am J Clin Pathol 1997; 107:12-9. [PMID: 8980361 DOI: 10.1093/ajcp/107.1.12] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Adenocarcinoma that metastasizes from an unknown primary site is a significant oncologic problem. With the exception of prostate-specific antigen and thyroglobulin, no single immunohistochemical marker is entirely site-specific. A retrospective study was undertaken to determine whether a panel of markers could accurately predict the site of origin of common metastatic adenocarcinomas. On the basis of reports of their relatively restricted specificity for carcinomas of colon, breast, lung, ovary, and upper gastrointestinal tract (stomach, pancreas, and bile duct), eight markers were selected for simultaneous evaluation: gross cystic disease fluid protein-15, breast cancer antigen 225 (BCA225), B72.3, DF3 (CA15-3), carcinoembryonic antigen (CEA), CA19-9, CA125, and estrogen receptor. The study population consisted of 128 metastatic nonmucinous adenocarcinomas for which the primary site was known. Staining was performed on formalin-fixed, paraffin-embedded tissue using an enhanced-sensitivity avidin-biotin peroxidase complex detection system. The most informative markers were CEA, CA19-9, CA125, and BCA225. With this four-marker panel, the most predictive multiple-marker phenotypes, as determined by a combination of area under the receiver operating characteristic curve, specificity, and percent correct predictions, were CEA+, BCA225-, and CA125- for colon tumors; BCA225+, CEA-, and CA125- for breast tumors; BCA225+, CEA+, and CA19-9- for lung tumors; CA125+ and CEA- for ovarian tumors; and CEA+, CA19-9+, and CA125+ for upper gastrointestinal tract tumors. Overall, these phenotypes correctly predicted the known primary site in 66% of cases. Until single highly sensitive and specific markers are developed for adenocarcinomas other than prostate and thyroid tumors, the origin of a metastatic adenocarcinoma can best be suggested or excluded with clinicopathologic data combined with a panel of selected immunohistochemical markers.
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100
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Gilcrease MZ, Truong L, Brown RW. Correlation of very late activation integrin and CD44 expression with extrarenal invasion and metastasis of renal cell carcinomas. Hum Pathol 1996; 27:1355-60. [PMID: 8958311 DOI: 10.1016/s0046-8177(96)90350-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cell adhesion molecules mediate cell-cell and cell-matrix interactions, and they are thought to play an important role in tumor invasion and metastasis. Altered expression of integrins and CD44 in renal cell carcinoma has been recently demonstrated, but an association with invasive or metastatic behavior has not been reported. We examined very late activation (VLA) integrin and CD44 expression in 37 renal cell carcinomas and correlated adhesion molecule expression with multiple histological and clinical parameters. Most tumors exhibited positive staining for VLA3 (81%). Approximately one third of the tumors stained positively for VLA6 and CD44, and fewer (27%) were positive for VLA2. Only a few tumors were positive for VLA4 (8%) and VLA5 (14%). Most of the tumors exhibiting positive staining showed a combination of membranous and cytoplasmic staining patterns. Low-grade tumors positive for VLA6 showed a tendency for basilar staining of the tumor cells, whereas high-grade tumors exhibited diffuse cytoplasmic staining. All tumors exhibiting weak or strong positive staining for VLA4 or VLA5 showed extrarenal invasion or were known to have developed metastases at the time of nephrectomy. All tumors strongly positive for VLA2 or CD44 showed invasion beyond the renal capsule or metastases. In contrast to a previous study, no association was observed between positive staining and tumor grade. Nor were tumor size, architectural pattern, cell type, or DNA ploidy found to be associated with particular staining patterns. Although many of the invasive tumors showed no difference in VLA integrin or CD44 expression compared with tumors confined to the kidney, increased expression in some of them suggests that these cell adhesion molecules may contribute to the invasive or metastatic phenotype.
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