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PubMed2001

Assessment of mechanisms of thyroid hormone action in mouse Leydig cells: regulation of the steroidogenic acute regulatory protein, steroidogenesis, and luteinizing hormone receptor function.

Recently, we demonstrated that triiodothyronine (T(3)) stimulated steroid hormone biosynthesis and steroidogenic acute regulatory (StAR) protein expression in mLTC-1 mouse Leydig tumor cells through the mediation of steroidogenic factor 1 (SF-1). We now report a dual response mechanism of T(3) on steroidogenesis and StAR expression, and on LH receptor (LHR) expression and binding in mLTC-1 cells. T(3) acutely (8 h), induced a 260% increase in StAR messenger RNA (mRNA) expression over the basal level which was coincident with an increase in progesterone (P) production. In contrast, chronic stimulation with T(3) (beyond 8 h), resulted in an attenuation of StAR expression and P production. This attenuation was most likely caused by a decrease in cholesterol delivery to the inner mitochondrial membrane as demonstrated by incubations with the hydrophilic steroid precursors, 22R hydroxycholesterol and pregnenolone, which restored P synthesis. In similar studies, chronic treatment with T(3) increased the levels of cytochrome P450scc mRNA by 83%, whereas those of cytochrome P450 17alpha-hydroxylase and 3ss-hydroxysteroid dehydrogenase decreased. The diminished response in steroidogenesis following chronic T(3) exposure was not a result of alterations in StAR mRNA stability, but rather was due to inhibition of transcription of the StAR gene. Similar acute stimulatory and chronic inhibitory responses to T(3) were found when LHR mRNA expression and LHR ligand binding were examined. Transfections with an LHR or StAR promoter/luciferase reporter construct demonstrated that a 173-bp fragment of the LHR promoter containing an SF-1 binding motif was involved in T(3) response, as was the SF-1 recognition site at -135 bp in the StAR promoter. Furthermore, the importance of SF-1 in T(3) function was also verified employing mutation in the bases of SF-1 sequences using electrophoretic mobility shift assays. The potential physiological relevance of these findings was demonstrated when similar responses were obtained in mice rendered hypo and hyperthyroid. Collectively, these observations further characterize the thyroid-gonadal connection and provide insights into the mechanisms for a dual regulatory role of thyroid hormone in Leydig cell functions.

3-Hydroxysteroid Dehydrogenases↗
PubMed1990

Identification and characterization of two upstream elements that regulate adrenocortical expression of steroid 11 beta-hydroxylase.

We have studied the mechanisms that regulate the expression of the mouse gene encoding steroid 11 beta-hydroxylase (11 beta-OHase), a steroidogenic cytochrome P450 enzyme that is expressed only in the adrenal cortex. DNase I footprinting and gel-mobility shift analyses revealed potential regulatory elements at -370 and -310 in the 11 beta-OHase promoter region. To determine the contributions of these elements to expression, we altered their sequences by site-selected mutagenesis and studied promoter activity after transfection into Y1 mouse adrenocortical tumor cells. Mutation of either element markedly decreased basal promoter activity but did not affect the response to treatment with 8-bromo cAMP. These experiments thus document the functional roles of these elements, within the context of the intact promoter, in constitutive expression of 11 beta-OHase. Moreover, addition of either of these elements to p-40GH, a 5'-deletion plasmid containing 11 beta-OHase sequences from -40 to +8 upstream of a growth hormone reporter gene, significantly increased promoter activity but did not confer cAMP responsiveness. Finally, increased expression was seen after transfection of Y1 derivatives deficient in cAMP-dependent protein kinase, indicating that neither element required cAMP-dependent protein kinase activity. These studies thus define two regulatory elements that play important roles in 11 beta-OHase expression.

Adrenal Cortex Neoplasms↗
PubMed2004

High performance liquid chromatography with an electrochemical detector in the cathodic mode as a tool for the determination of p-nitrophenol and assay of acid phosphatase in urine samples.

Utilizing a commercially available helium-purging device and PEEK tubes for all tubing, especially for connection between the mobile phase and pump, high performance liquid chromatography with an electrochemical detector (ECD/HPLC) at the cathodic mode is a simple and precise method for the determination of p-nitrophenol (NP). Studies with cyclic and hydrodynamic voltammetry indicated that 25% aqueous MeOH containing 0.1% (v/v) CF(3)CO(2)H and -0.8 V vs. Ag/AgCl are the best mobile phase and detection potential for cathodic ECD/HPLC. With the present system, the limits of detection and determination were 0.2 and 0.25 microM, respectively, and up to 50 microM, a linear calibration curve was afforded. Within-day precisions for the analysis of 5 and 50 microM NP were 0.8 and 0.7% (n=6), respectively, and between-day precisions (n=6) for these samples were 3.5 and 2.2%, respectively. Compared with the commonly used Bessey-Lowry-Brock method, cathodic ECD/HPLC was useful for the assay of acid phosphatase in urine samples with p-nitrophenyl phosphate disodium salt as a substrate.

Acid Phosphatase↗
PubMed2004

Red blood cell-derived ATP as a regulator of skeletal muscle perfusion.

Blood flow to skeletal muscle is a complex process designed to provide adequate, yet not excessive, amounts of oxygen to meet the ever-changing metabolic needs of the tissue. To accomplish this goal, a mechanism must exist that couples the oxygen needs of the tissue with the oxygen delivery system. A number of mechanisms have been investigated that have focused primarily on the vessel or tissue supplied. However, because none of these was able to adequately explain the precision inherent in oxygen supply, we began to investigate the potential role of the mobile oxygen carrier itself, the red blood cell. This review will provide evidence in support of the idea that the red blood cell is able to both sense oxygen need and evoke changes in blood flow to meet that need. In this scheme, as a red blood cell enters a region of increased metabolic demand relative to supply, the fall in hemoglobin oxygen saturation evokes the release of ATP, found within the red blood cell in mM amounts. The released ATP binds to purinergic receptors located on the vascular endothelium and induces a vasodilation that is conducted upstream increasing oxygen supply to the region of tissue supplied by the vessel. Although this mechanism is likely only one component of a complex system, which precisely regulates blood flow, we suggest that it plays a vital role in the regulation of perfusion distribution within tissue.

Adenosine Triphosphate↗
PubMed2006

U.S. elementary and secondary schools: equalizing opportunity or replicating the status quo?

Although education pays off handsomely in the United States, children from low-income families attain less education than children from more advantaged families. In this article, Cecilia Elena Rouse and Lisa Barrow investigate why family background is so strongly linked to education. The authors show that family socioeconomic status affects such educational outcomes as test scores, grade retention, and high school graduation, and that educational attainment strongly affects adult earnings. They then go on to ask why children from more advantaged families get more or better schooling than those from less advantaged families. For low-income students, greater psychological costs, the cost of forgone income (continuing in school instead of getting a job), and borrowing costs all help to explain why these students attain less education than more privileged children. And these income-related differences in costs may themselves be driven by differences in access to quality schools. As a result, U.S. public schools tend to reinforce the transmission of low socioeconomic status from parents to children. Policy interventions aimed at improving school quality for children from disadvantaged families thus have the potential to increase social mobility. Despite the considerable political attention paid to increasing school accountability, as in the No Child Left Behind Act, along with charter schools and vouchers to help the children of poor families attend private school, to date the best evidence suggests that such programs will improve student achievement only modestly. Based on the best research evidence, smaller class sizes seem to be one promising avenue for improving school quality for disadvantaged students. High teacher quality is also likely to be important. However, advantaged families, by spending more money on education outside school, can and will partly undo policy attempts to equalize school quality for poor and nonpoor children.

Achievement↗
PubMed2005

Blind and sighted pedestrians' judgments of gaps in traffic at roundabouts.

This paper reports two experiments about street crossing under conditions of free flowing traffic, with a focus on modem roundabout intersections. Experiment 1 was conducted at three roundabouts varying in size and traffic volume. Six totally blind and six sighted adults judged whether gaps in traffic were long enough to permit crossing to the median (splitter) island before the next vehicle arrived. Gap distributions and measures of judgment quality are reported. Overall, blind participants were about 2.5 times less likely to make correct judgments than sighted participants, took longer to detect crossable gaps, and were more likely to miss crossable gaps altogether. However, the differences were significant only at the two higher volume roundabouts. In Experiment 2, we evaluated the response of drivers to pedestrians with and without mobility devices (i.e., long canes, dog guides). The experiment was conducted at a single-lane roundabout, a midblock crossing, and a two-way-stop-controlled intersection. Site-specific characteristics appeared to have a greater impact on drivers' yielding than did a mobility device. Actual or potential applications of this research include the development of methods for assessing pedestrian safety and driver behavior as well as identifying intersections that may require modification in order to be accessible to blind pedestrians.

Accidents, Traffic↗
PubMed2002

Passion in group: thinking about loving, hating, and knowing.

In his early work, Bion (1961) established the goal of learning about and getting beyond the basic assumptions to become a work group. Later, in his structural theory of affect, passion became a key concept. Passion describes the necessary and sufficient condition for a psychotherapy group to be a work group. Passion is an intersubjective process of bearing and utilizing one's most basic affects to reach self-conscious emotional awareness. Bion postulated three primary affects: loving, hating, and knowing (LHK). A clinical example illustrates how the therapist may represent, mentally organize, and mobilize the group's potential for passion by attending to the evolution of his or her own affects. Passion transcends transference-countertransference in that an optimal level of personal meaning from LHK is achieved and utilized in emotional participation.

Adult↗
PubMed2006

Expression and targeting of CX3CL1 (fractalkine) in renal tubular epithelial cells.

The chemokine CX3CL1 plays a key role in glomerulonephritis and can act as both chemoattractant and adhesion molecule. CX3CL1 also is upregulated in tubulointerstitial injury, but little is known about the subcellular distribution and function of CX3CL1 in renal tubular epithelial cells (RTEC). Unexpectedly, it was found that CX3CL1 is expressed predominantly on the apical surface of tubular epithelium in human renal transplant biopsy specimens with acute rejection or acute tubular necrosis. For studying the targeting of CX3CL1 in polarized RTEC, MDCK cells that expressed untagged or green fluorescent protein-tagged CX3CL1 were generated. The chemokine was present on the apical membrane and in subapical vesicles. Apical targeting of CX3CL1 was not due to signals that were conferred by its intracellular domain, to associations with lipid rafts, or to O-glycosylation but, rather, depended on N-linked glycosylation of the protein. With the use of fluorescence recovery after photobleaching, it was found that CX3CL1 is immobile in the apical membrane. However, CX3CL1 partitioned with the triton-soluble rather than -insoluble cellular fraction, indicating that it is not associated directly with the actin cytoskeleton or with lipid rafts. Accordingly, disruption of rafts through cholesterol depletion did not render CX3CL1 mobile. For exploration of potential functions of apical CX3CL1, binding of CX3CR1-expressing leukocytes to polarized RTEC was examined. Leukocyte adhesion to the luminal surface was enhanced significantly when CX3CL1 was present. These data demonstrate that CX3CL1 is expressed preferentially on the apical membrane of RTEC and suggest a novel function for the chemokine in recruitment and retention of leukocytes in tubulointerstitial inflammation.

Animals↗
PubMedDate not supplied

Wet chemical and phosphorus-31 nuclear magnetic resonance analysis of phosphorus speciation in a sandy soil receiving long-term fertilizer or animal manure applications.

In areas under intensive livestock farming and with high application rates of animal manure, inorganic and organic phosphorus (P) may be leached from soils. Since the contribution of these P compounds to P leaching may differ, it is important to determine the speciation of P in these soils. We determined the effect of various fertilization regimes on the P speciation in NaOH-Na2EDTA (ethylenediaminetetraacetic acid) and water extracts of acidic sandy soil samples from the top 5 cm of grassland with wet chemical analysis and 31P nuclear magnetic resonance (NMR) spectroscopy. These soils had been treated for a period of 11 years with no fertilizer (control), N (no P application), N-P-K, or different animal manures. Inorganic P was highly elevated in the NaOH-Na2EDTA extracts of the soils amended with N-P-K or animal manures, while organic P increased only in the soil treated with pig slurry. Water-extractable P showed a similar trend. As indicated by 31P NMR, orthophosphate monoesters were the main organic P compounds in all soils. Our results suggest that long-term applications of large amounts of P fertilizer and animal manures caused an accumulation of inorganic P, resulting in an increase of the potential risk related to mobilization of inorganic P in the top 5 cm of these soils.

Animals↗
PubMed2002

Benefit-risk considerations in the treatment of dementia with Lewy bodies.

Dementia with Lewy bodies (DLB) is a relatively recently characterised syndrome with clinical and pathological features that distinguish it from classical Alzheimer's disease. These characteristics include more rapid decline, spontaneous features of parkinsonism, visual hallucinations and fluctuating cognition. This article reviews the clinical syndrome of DLB and the agents used to treat its cognitive, motor and behavioural manifestations. Benefit-risk issues regarding the treatment of DLB are discussed based upon limited randomised, controlled clinical trials with some speculative conclusions being drawn from case reports and case series. We conclude that patients with DLB may respond better to cholinesterase inhibitors than patients with Alzheimer's disease on both cognitive and behavioural measures. Cholinesterase inhibitor therapy may result in reduced caregiver burden and less time institutionalised. These agents are well tolerated with the majority of adverse effects being gastrointestinal in nature. Although neuropsychiatric manifestations are numerous in patients with DLB, antipsychotics should be used infrequently and with caution, although atypical antipsychotics are better tolerated than conventional antipsychotics. Physicians should exhibit caution when prescribing these agents because of the increased risk of extrapyramidal adverse effects. Limited data suggest that the use of levodopa or other dopaminergic agents may be of benefit for the treatment of the parkinsonism that is associated with DLB. However, the increased risk of hallucinations and neuropsychiatric symptoms may negate the potential benefits of increased mobility. There is insufficient evidence to draw conclusions about the use of antidepressants; however, selective serotonin reuptake inhibitors may be of benefit.

Antidepressive Agents↗
PubMed2001

Investigation of brain potentials in sleeping humans exposed to the electromagnetic field of mobile phones.

An investigation was made of 8-hour EEG tracings of sleeping humans exposed to the electromagnetic field of a GSM-standard mobile phone. To analyze the EEG-patterns, manual scoring, nonlinear dynamics, and spectral analysis were employed. It was found that, when human beings were exposed to the electromagnetic field of a cellular phone, their cerebral cortex biopotentials revealed an increase in the alpha-range power density as compared to the placebo experiment. It was also found that the dimension of EEG correlation dynamics and the relation of sleep stages changed under the influence of the electromagnetic field of a mobile phone.

Adult↗
PubMedDate not supplied

Speciation analysis of heavy metals in natural waters: a review.

Metal speciation in natural waters is of increasing interest and importance because toxicity, bioavailability, environmental mobility, biogeochemical behavior, and potential risk in general are strongly dependent on the chemical species of metals. This paper provides an overview of the need for speciation of heavy metals in natural waters, the chemical and toxicological aspects of speciation, and the analytical procedures for separation and the different techniques for final determination that are used today. The trends and developments of speciation are also discussed. Finally, the case of chromium (Cr) was selected for a detailed presentation because the speciation of this metal has attracted a great deal of interest in view of the toxic properties of Cr(VI).

Chromatography, Liquid↗
PubMed2002

Identification of model newborn care practices through a positive deviance inquiry to guide behavior-change interventions in Haripur, Pakistan.

A positive deviance (PD) inquiry identifies uncommon, model practices that a follow-on program can spread. PD has been used to rehabilitate malnourished children, but not for improving newborn health. Save the Children Federation/US (SC) conducted newborn PD cycles in communities (total population about 5,000 each) in two project areas in Haripur District, Pakistan among Afghan refugees and among local Pakistanis. Each PD cycle included planning, community orientation, situation analysis, PD inquiries, and community feedback with action planning. PD inquiries were in-depth interviews to identify uncommon behaviors among surviving asphyxiated newborns, thriving low birthweight babies, surviving newborns who had danger signs, and normal newborns. The Afghan caregivers showed better use of services and some household practices than their Pakistani counterparts, consistent with duration of SC presence (15 years vs. 18 months, respectively). The practices of both groups for clean delivery, thermal control, immediate and exclusive breastfeeding, and fathers' involvement were weak. But PD individuals, families, and/or birth attendants modeled good maternal care and immediate, routine and special newborn care. Communities enthusiastically committed to change behavior and form neighborhood support groups for better newborn care, including a demand for hygienic delivery. The PD approach for the newborn is more complex than for child nutrition. Yet this pilot-test proposed a conceptual framework for household newborn care, suggested tools and methods for information gathering, identified PDs in two settings of different risk, galvanized SC staff to the potential of the approach, mobilized communities for better newborn health, and drafted a newborn PD training curricula.

Adult↗
PubMed2000

Examination of microgravity effects on spontaneous Ca2+ oscillations in AtT20 pituitary cells using heavy water.

Effects of heavy water (D2O) on various organisms have been extensively studied and a majority of D2O actions were generally ascribed to the viscosity (1.23 times of H2O) and a larger inter-molecule force of D2O that may eventually alternate molecular structure of various enzymes and ion channels. It is reported that chronic application of D2O induces toxic effects and the 35% substitution of whole body water with D2O induced fatal effects in the mouse. Mitosis of a fertile egg of sea urchin was completely inhibited by 75% D2O but the paused segmentation was recovered after rinse of D2O. In addition, we also observed that neuronal development of the Lymnaea stagnalis was reversibly inhibited by D2O (M. Sakakibara, unpublished data). However, mechanism of the toxicity of D2O and the effects of D2O on cellular events have not been fully understood. The spontaneous oscillation in cytosolic free Ca2+ concentration is one of the typical physiological events in living secretory cells. We previously demonstrated that the Ca2+ oscillations are regulated by voltage-sensitive Ca2+ channels (VSCC), Ca2+ ATPases, and Ca(2+)-induced Ca2+ release from intracellular stores. To analyze the site(s) of action of D2O in the living cellular systems, the present study examined effects of D2O on the Ca2+ mobilization and resting membrane potentials in AtT20 mouse pituitary cells.

Animals↗
PubMed2003

Maximum tolerable dose and low-dose metronomic chemotherapy have opposite effects on the mobilization and viability of circulating endothelial progenitor cells.

There is growing evidence that vasculogenesis (progenitor cell-derived generation of new blood vessels) is required for the growth of some neoplastic diseases. Here we show that the administration of cyclophosphamide (CTX) at the maximum tolerable dose with 21-day breaks or at more frequent low-dose (metronomic) schedules have opposite effects on the mobilization and viability of circulating endothelial progenitors (CEPs) in immunodeficient mice bearing human lymphoma cells. Animals treated with the maximum tolerable dose CTX experienced a robust CEP mobilization a few days after the end of a cycle of drug administration, and tumors rapidly became drug resistant. Conversely, the administration of metronomic CTX was associated with a consistent decrease in CEP numbers and viability and with more durable inhibition of tumor growth. Our findings suggest that metronomic low-dose chemotherapy regimens are particularly promising for avoiding CEP mobilization and, hence, to potentially reduce vasculogenesis-dependent mechanisms of tumor growth.

Animals↗
PubMed2004

Risk factors for entry into residential care after a support-needs assessment.

AIMS: To establish the influence of risk factors derived from the national 'Support Needs Assessment Form' for entry into residential care in New Zealand. METHODS: Using a retrospective cohort design, data was obtained for assessments of people aged over 65 years over a 12-month interval (August 2001 to August 2002) from an administrative database developed by the Needs Assessment and Service Co-ordination Service for Wellington, New Zealand. The risk factors for entry into residential care were examined by logistic regression. RESULTS: 2060 assessments were carried out over this period for people were aged over 65 years; 67.9% were female. The median age was 83 years, inter-quartile range 78 to 88 years. For 33.4% of people, residential care was recommended. For those aged 80 years or older, the relative risk of residential care was 2.95 (95% CI: 2.27 to 3.82) if continence problems were present, and 3.75 (95% CI: 2.99 to 4.73) for those aged 80 years or younger if continence problems were present. For those with mobility problems who had cognitive impairment the relative risk of residential care was 2.95 (95% CI: 2.25 to 3.87), and 1.77 (95% CI: 1.35 to 2.33) if there were no mobility problems. CONCLUSIONS: All of older age, continence problems, mobility problems and dementia predicted residential care after assessment. The effect of continence was more prominent for those aged under 80 years of age. The effect of dementia was more prominent for those with mobility problems. Intervention for continence problems and mobility problems has the potential to reduce the use of residential care.

Activities of Daily Living↗
PubMed1992

Hormonal responses to ingesting water or a carbohydrate beverage during a 2 h run.

Ingestion of fluids providing carbohydrate and electrolytes extends endurance times during prolonged exercise. To understand the contribution of these factors, we examined hormonal, physiologic, and metabolic responses to ingesting water (W) or a 7% glucose polymer/fructose/electrolyte solution (GPFE) in 10 men (age: 30 +/- 2 yr, VO2max: 57.4 +/- 3.2 ml.kg-1.min-1) who ran on a treadmill for 2 h at 60-65% of their VO2max. Subjects drank 200 ml of W or GPFE at 0-time and every 30 min while running (30,60, and 90 min). Changes in serum sodium, potassium, and osmolality; heart rate; plasma lactate and glucose; and serum insulin and plasma norepinephrine were similar for both fluid treatments. In contrast, changes in serum free fatty acids (FFA), plasma cortisol, and arginine vasopressin (AVP) differed across fluid treatments: with GPFE, exercise abolished the rise in plasma cortisol, and attenuated the rise in both AVP and FFA. The observed suppression of cortisol and AVP was not related to changes in any of the parameters examined, but were strongly correlated with each other. These findings suggest that adding carbohydrate and electrolytes to fluids ingested during prolonged exercise decreases activation of the hypothalamic-pituitary-adrenal axis, a potentially beneficial change. However, mobilization of FFA was also decreased. The mechanism by which they occur remains elusive.

Adult↗
PubMed2005

Cloning and characterization of the 5' flanking region of the HGFIN gene indicate a cooperative role among p53 and cytokine-mediated transcription factors: relevance to cell cycle regulation.

HGFIN, previously identified as nmb, and its homologs, osteoactivin are single transmembrane protein that is expressed in differentiated immune cells, and are linked to tumor progression. These dichotomous roles suggest that HGFIN could be linked to cell cycle regulation. We hypothesize that HGFIN is linked to different phases of cell cycle regulation via specific transcription factors. This study cloned and analyzed two fragments in the 5' flanking region of HGFIN: HGFIN-RM/2.0: 2.0 kb upstream of Exon 1; HGFIN-RM/1.5: 5' deletion (500 bp) of HGFIN-RM/2.0. Computer analyses indicated that HGFIN has unique upstream sequence with eight potential p53 sites. Electrophoretic mobility shift assay with Cy3-labeled PCR fragments indicated that p53 could interact with fragments encompassing p53 consensus regions. Reporter gene activities with HGFIN-RM/2.0 and HGFIN-RM/1.5 in cells with different p53 levels showed that p53 is relevant to HGFIN activities. Studies with modified T47D in which cytokine production was downregulated, but with p53 level similar to parental line showed synergism between p53 and mediators of cytokine in the regulation of HGFIN. In summary, p53 cooperate with cytokine-mediated transcription factors to regulate the expression of HGFIN.

5' Flanking Region↗