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Wang M, Hoekstra S, van Bergen S, Lamers GE, Oppedijk BJ, van der Heijden MW, de Priester W, Schilperoort RA. Apoptosis in developing anthers and the role of ABA in this process during androgenesis in Hordeum vulgare L. PLANT MOLECULAR BIOLOGY 1999; 39:489-501. [PMID: 10092177 DOI: 10.1023/a:1006198431596] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Intra-nucleosomal cleavage of DNA into fragments of about 200 bp was demonstrated to occur in developing anthers, in which microspores had developed into the mid-late to late uni-nucleate stage in situ, i.e. at the verge of mitosis. The same was observed, but to a much larger extent, if these anthers were pre-treated by a hyper-osmotic shock. Pretreatment of anthers before the actual culture of microspores was required for optimal androgenesis of microspores. The use of the TUNEL reaction, which specifically labels 3' ends of DNA breaks, after intra-nucleosomal cleavage of DNA, revealed that DNA fragmentation mainly occurred in the loculus wall cells, tapetum cells and filament cells. TUNEL staining was absent or infrequently observed in the microspores of developing anthers in situ. Electron microscopy studies showed condensed chromatin in nuclei of loculus wall cells in the developing anthers. These observations at the chromatin and DNA level are known characteristics of programmed cell death, also known as apoptosis. Features of apoptosis were infrequently found in microspores from freshly isolated mature anthers. However, most tapetum cells had disappeared in these anthers and the remaining cell structures showed loss of cellular content. The viability of microspores in pre-treated anthers was comparable to those in freshly isolated anthers and almost four times higher than in anthers from control experiments. This observation was correlated with three to four times less microspores showing TUNEL staining and a two times higher level of ABA in the anther plus medium samples than in controls. Addition of ABA to the controls enhanced the viability and lowered the occurrence of apoptosis linked characteristics in the microspores. These data suggest that pre-treatment is effective in stimulating androgenesis because it leads to an increase in ABA levels which protects microspores from dying by apoptosis.
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Hoekstra S, van Zijderveld MH, Heidekamp F, van der Mark F. Microspore culture of Hordeum vulgare L.: the influence of density and osmolality. PLANT CELL REPORTS 1993; 12:661-5. [PMID: 24201960 DOI: 10.1007/bf00233415] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/1993] [Revised: 06/01/1993] [Indexed: 05/21/2023]
Abstract
Donor plants of Hordeum vulgare L. cv. Igri were grown in a conditioned environment to minimise fluctuations in the composition of the microspore population. After isolation different types of microspores were identified within each population, amongst others an embryogenic subpopulation. It was shown that the optimum plating density is achieved by adjusting the density to 2×10(4) embryogenic microspores per ml, with a lower threshold at 5×10(3) per ml. By increasing the osmolality of the pretreatment solution to 440 mOs.kg(-1) and that of the culture medium to 350 mOs.kg(-1), up to 15% of the population developed into embryo-like structures. When microspores of cv. Igri were cultured under the optimized conditions, the ratio of green/albino plants increased from 1∶1 to 34∶1, and 50 green plants per anther were formed.
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Wijmstra T, Hoekstra S, De Vries B, Van Der Hammen T. A PRELIMINARY STUDY OF PERIODICITIES IN PERCENTAGE CURVES DATED BY POLLEN DENSITY. ACTA ACUST UNITED AC 2015. [DOI: 10.1111/j.1438-8677.1984.tb01845.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Molnar J, Hoekstra S, Ku CS, Van Alten P. Evidence for the recycling nature of the fibronectin receptor of macrophages. J Cell Physiol 1987; 131:374-83. [PMID: 2954989 DOI: 10.1002/jcp.1041310309] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Plasma fibronectin (pFN) has been shown to mediate phagocytosis of several types of artificial particles and tissue debris by macrophages. In the present investigation some of the dynamic aspects of this receptor-mediated cellular process have been studied. Plasma fibronectin did not bind specifically to fibronectin (FN)-receptors of rat peritoneal macrophages at either 4 degrees C or 37 degrees C. On the other hand, pFN aggregated on the surface of gelatin-coated latex beads (gLtx) and 125I-labeled pFN covalently coupled to latex beads (pFN-Ltx) bound strongly to macrophages at both temperatures. Both of these particles were also internalized at 37 degrees C. Treatment of macrophages by chymotrypsin, thermolysin, or trypsin in a protein-free tissue culture medium did not affect either of the above reactions; however, pronase treatment strongly reduced both the binding and internalization of the pFN-coated particles. The pronase-treated macrophage monolayers in time regained their ability to bind and internalize pFN-gLtx when incubated in fresh tissue culture medium. Such recovery, however, did not take place when the medium contained cycloheximide. On the other hand, phagocytosis of pFN-gLtx was not affected directly by cycloheximide with untreated macrophages; this suggests that the FN-receptor recycles during sustained phagocytosis. This assumption was substantiated by the observations that some of the established lysosomotropic amines--i.e., chloroquine, dansylcadaverine, and dimethyldansylcadaverine--caused total inhibition of internalization without affecting the binding of particles to macrophages. Furthermore, chloroquine protected the FN-receptors against destruction by pronase. Together these results suggest that macrophage receptors for FN are protein, present both on the cell surface and intracellularly, and recycle between the plasma membrane and intracellular sites during phagocytosis.
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Hoekstra S, Slakhorst J, Huber J. The development of recrystallization textures in (1̄10) [001] and (1̄10)[112̄] Ag single crystals after a plane-strain deformation of 80.9%. ACTA ACUST UNITED AC 1977. [DOI: 10.1016/0001-6160(77)90231-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Müller SE, Dijck EA, Bekker H, van den Berg JE, Böll O, Hoekstra S, Jungmann K, Meinema C, Noordmans JP, Nuñez Portela M, Onderwater CJG, Pijpker C, van der Poel APP, Santra B, Sytema A, Timmermans RGE, Versolato OO, Willmann L, Wilschut HW, Yai K. First test of Lorentz invariance in the weak decay of polarized nuclei. Int J Clin Exp Med 2013. [DOI: 10.1103/physrevd.88.071901] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Faltynek CR, Wang S, Miller D, Mauvais P, Gauvin B, Reid J, Xie W, Hoekstra S, Juniewicz P, Sarup J. Inhibition of T lymphocyte activation by a novel p56lck tyrosine kinase inhibitor. JOURNAL OF ENZYME INHIBITION 1995; 9:111-22. [PMID: 8583249 DOI: 10.3109/14756369509042811] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A new p56lck tyrosine kinase inhibitor WIN 61651 [1,4-dihydro-7-(4-methyl-1-piperizinyl)-1-(4-(4-methyl-1-piperi zinyl))phenyl- 4-oxo-3-quinolinecarboxamide) is described. WIN 61651, which is competitive with ATP, demonstrates selectivity for the lymphoid restricted tyrosine kinase p56lck over serine/threonine kinases, such as protein kinase C and protein kinase A, and over some other tyrosine kinases, including erbB2, epidermal growth factor receptor, and insulin receptor; however, it is equipotent for inhibition of p56lck and the platelet derived growth factor receptor tyrosine kinases. WIN 61651 inhibits p56lck activity in cell-free assays, tyrosine kinase activity in a T lymphocytic cell line, and T cell activation, as measured by IL-2 production by purified CD4 positive peripheral blood T lymphocytes and the mixed lymphocyte reaction. WIN 61651 constitutes a new tool for studies on the role for tyrosine kinases in lymphocyte function.
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Hoekstra S, Van Der Lelie H, Verbraak C. A general method of habit plane determination in bainitic steels—II. Habit plane determination of the bainite. ACTA ACUST UNITED AC 1978. [DOI: 10.1016/0001-6160(78)90062-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Reitsma G, Boschman L, Deuzeman MJ, González-Magaña O, Hoekstra S, Cazaux S, Hoekstra R, Schlathölter T. Deexcitation dynamics of superhydrogenated polycyclic aromatic hydrocarbon cations after soft-x-ray absorption. PHYSICAL REVIEW LETTERS 2014; 113:053002. [PMID: 25126915 DOI: 10.1103/physrevlett.113.053002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Indexed: 06/03/2023]
Abstract
We have investigated the response of superhydrogenated gas-phase coronene cations upon soft x-ray absorption. Carbon (1s)⟶π^{⋆} transitions were resonantly excited at hν=285 eV. The resulting core hole is then filled in an Auger decay process, with the excess energy being released in the form of an Auger electron. Predominantly highly excited dications are thus formed, which cool down by hydrogen emission. In superhydrogenated systems, the additional H atoms act as a buffer, quenching loss of native H atoms and molecular fragmentation. Dissociation and transition state energies for several H loss channels were computed by means of density functional theory. Using these energies as input into an Arrhenius-type cascade model, very good agreement with the experimental data is found. The results have important implications for the survival of polyaromatic hydrocarbons in the interstellar medium and reflect key aspects of graphene hydrogenation.
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Reitsma G, Boschman L, Deuzeman MJ, Hoekstra S, Hoekstra R, Schlathölter T. Near edge X-ray absorption mass spectrometry on coronene. J Chem Phys 2015; 142:024308. [DOI: 10.1063/1.4905471] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Groot S, Hoekstra S, Comtesse P, Kouwijzer I, Valent L. Relationships between internal and external handcycle training load in people with spinal cord injury training for the handbikebattle. J Rehabil Med 2018; 50:261-268. [DOI: 10.2340/16501977-2316] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Karhu J, Nauta J, Vainio M, Metsälä M, Hoekstra S, Halonen L. Double resonant absorption measurement of acetylene symmetric vibrational states probed with cavity ring down spectroscopy. J Chem Phys 2016; 144:244201. [DOI: 10.1063/1.4954159] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Hoekstra S, Ohm R, Verbraak C. A general method of the habit plane determination in bainitic steels—I. Orientation determination of the austenite. ACTA ACUST UNITED AC 1978. [DOI: 10.1016/0001-6160(78)90061-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Aggarwal P, Yin Y, Esajas K, Bethlem HL, Boeschoten A, Borschevsky A, Hoekstra S, Jungmann K, Marshall VR, Meijknecht TB, Mooij MC, Timmermans RGE, Touwen A, Ubachs W, Willmann L. Deceleration and Trapping of SrF Molecules. PHYSICAL REVIEW LETTERS 2021; 127:173201. [PMID: 34739281 DOI: 10.1103/physrevlett.127.173201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
We report on the electrostatic trapping of neutral SrF molecules. The molecules are captured from a cryogenic buffer-gas beam source into the moving traps of a 4.5-m-long traveling-wave Stark decelerator. The SrF molecules in X^{2}Σ^{+}(v=0,N=1) state are brought to rest as the velocity of the moving traps is gradually reduced from 190 m/s to zero. The molecules are held for up to 50 ms in multiple electric traps of the decelerator. The trapped packets have a volume (FWHM) of 1 mm^{3} and a velocity spread of 5(1) m/s, which corresponds to a temperature of 60(20) mK. Our result demonstrates a factor 3 increase in the molecular mass that has been Stark decelerated and trapped. Heavy molecules (mass>100 amu) offer a highly increased sensitivity to probe physics beyond the standard model. This work significantly extends the species of neutral molecules of which slow beams can be created for collision studies, precision measurement, and trapping experiments.
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Goodman AD, Hoekstra S, Busch RS, Meyer GS, Abend SS. Effects of prolactin and growth hormone on tissue and serum carnitine in the rat. Endocrinology 1988; 123:1955-61. [PMID: 3416821 DOI: 10.1210/endo-123-4-1955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Previous experimental observations have suggested to us that PRL and GH may be involved in regulating the metabolism of carnitine, a factor that plays a critically important role in fatty acid oxidation and ketogenesis. In the present study we administered bovine PRL (bPRL) or bovine GH (bGH) at a physiologic rate to hypophysectomized female rats for 2-3 days, and observed that bPRL caused a small (16%) increase (P less than 0.01), and bGH a 36% increase (P less than 0.01), in hepatic carnitine, bPRL decreased serum carnitine by 24% (P less than 0.05), and bPRL and bGH each increased the liver/serum carnitine ratio by 58% (P less than 0.01), suggesting that these hormones enhance the active uptake of carnitine from plasma. bPRL and bGH, alone or in combination, did not affect the carnitine content of cardiac or skeletal muscle, but in combination they increased the heart/serum and muscle/serum carnitine ratios by 45-76% (P less than 0.01), thus allowing maintenance of normal cardiac and skeletal muscle carnitine despite a decreased plasma level. In hypophysectomized male rats, bPRL did not affect liver or epididymal carnitine. We hypothesize that PRL and GH may play a role in the regulation of the carnitine concentration of female liver by enhancing hepatic uptake of carnitine from plasma, and through this mechanism may affect hepatic fatty acid oxidation and ketogenesis. The effect of lactogenic and somatogenic hormones on hepatic carnitine and ketogenesis could be of particular physiological importance in late pregnancy and during lactation.
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Goodman AD, Hoekstra S, Monahan JW. Suppressive effect of inflammation and other forms of stress on the binding of prolactin by rat liver. Endocrinology 1985; 116:835-42. [PMID: 4038484 DOI: 10.1210/endo-116-2-835] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We have found that in female rats a variety of stressful stimuli, including sc inflammation, skin incision, endotoxin injection, and cold exposure, cause a significant decrease (30-86%) in the capacity of the hepatic cell membranes to specifically bind [125I]ovine PRL. Stress-induced decrease in food intake was not a factor in these studies, as nourishment was given only by tube feeding. Neither sc inflammation nor cold exposure affected hepatic binding of [125I]insulin. Further, the induction of inflammation in lactating rats and rats bearing 7,12-dimethylbenz[a]anthracene-induced mammary carcinomas did not affect the binding of PRL by the lactating or malignant mammary tissue. The suppressive effect of inflammation on hepatic binding of PRL was demonstrable in adrenalectomized-ovariectomized rats, in hypophysectomized rats receiving hormone replacement, and in adrenalectomized rats that had undergone partial chemical sympathectomy. We conclude that sc inflammation, as well as other forms of stress, decreases hepatic binding of PRL, but does not affect hepatic binding of insulin or mammary binding of PRL. The decrease in hepatic PRL binding is not mediated by a hormone secreted by the adrenals, ovaries, or pituitary, or by catecholamines, but could be mediated by another plasma factor or by peripheral dopaminergic neurons. Stress-induced decrease in hepatic PRL binding, or a related decrease in the binding of other polypeptide hormones, could play a role in the physiological response to stress.
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Hoekstra S, Stoller D, Raef H. Does Gross Margin Examination Reduce Re-excision Rate in Breast Conservation for Invasive Carcinoma? CALLER Review. Eur J Breast Health 2020; 16:198-200. [PMID: 32656520 DOI: 10.5152/ejbh.2020.5180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/09/2020] [Indexed: 11/22/2022]
Abstract
Objective Determine if Gross Margin Examination reduces margin re-excision rate. Our institutional practice is to perform Gross Margin Examination (GME) with Real-time re-excision (RRE) for all breast conservation specimens with Invasive Carcinoma. Materials and Methods Chart review was done to determine if this practice is helpful. 51 CALLER charts were reviewed from December 2016 to December 2017. Results Thirty-three underwent margin RRE based on the GME. 11 had cancer in the re-resected margin, 6 of which were cleared with the RRE. The other 5 were reoperated on to clear the margin because on final pathology a margin other than the re-resected margin was positive for malignancy. GME was helpful in preventing reoperation in 55%. None of the remaining 22 patients receiving were found to have a positive margin on final pathology, with 1.6 margins on average re-resected. 13/18 patients did not have RRE and had a final clear margin, but of the other 5, final margin was positive for DCIS in 2 and Invasive Cancer in 3. GME missed invasive disease at the margin in 3 of these 18 patients. Conclusion GME was helpful in preventing reoperation in 6 of 11 patients who would have had a positive margin. However, this resulted in the unnecessary removal of additional normal breast tissue in 22 patients. 3 patients' positive margins were missed with GME and required reoperation. 13 patients were able to avoid re-excision and 11 were able to clear their margin in real-time, improving outcomes 24/51 patients. GME therefore does appear useful.
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Aggarwal P, Bethlem HL, Boeschoten A, Borschevsky A, Esajas K, Hao Y, Hoekstra S, Jungmann K, Marshall VR, Meijknecht TB, Mooij MC, Timmermans RGE, Touwen A, Ubachs W, Willmann L, Yin Y, Zapara A. A supersonic laser ablation beam source with narrow velocity spreads. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:033202. [PMID: 33819994 DOI: 10.1063/5.0035568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 02/06/2021] [Indexed: 06/12/2023]
Abstract
A supersonic beam source for SrF and BaF molecules is constructed by combining the expansion of carrier gas (a mixture of 2% SF6 and 98% argon) from an Even-Lavie valve with laser ablation of a barium/strontium metal target at a repetition rate of 10 Hz. Molecular beams with a narrow translational velocity spread are produced at relative values of Δv/v = 0.053(11) and 0.054(9) for SrF and BaF, respectively. The relative velocity spread of the beams produced in our source is lower in comparison with the results from other metal fluoride beams produced in supersonic laser ablation sources. The rotational temperature of BaF is measured to be 3.5 K. The source produces 6 × 108 and 107 molecules per steradian per pulse in the X2Σ+ (ν = 0, N = 1) state of BaF and SrF molecules, respectively, a state amenable to Stark deceleration and laser cooling.
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Roberts AE, Ritz MA, Hoekstra S, Descotes G, Hincks JR. Induction of liver cytochrome P-450 (CYP) 3A in male and female rats by a steroidal androgen receptor antagonist, zanoterone. JOURNAL OF BIOCHEMICAL TOXICOLOGY 1996; 11:101-10. [PMID: 9029268 DOI: 10.1002/(sici)1522-7146(1996)11:3<101::aid-jbt1>3.0.co;2-o] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The cytochrome P-450 (CYP) mediated hydroxylation of testosterone to 6 beta-, 7 alpha-, and 16 alpha-hydroxytestosterone (b beta-, 7 alpha-, and 16 alpha-OHT) and the dealkylation of ethoxycoumarin to 7-hydroxycoumarin (ECOD) and ethoxyresorufin to resorufin (EROD) were used to probe changes in CYP monooxygenase activities in liver microsomes from rats treated with the androgen receptor antagonist, zanoterone (Z). Phenobarbital (PB) and beta-naphthoflavone (beta-NF) were used as comparators. There were sex-related differences in the constitutive CYP activities and in the responses of CYP activities to Z. The greatest effect of Z administration was on 6 beta-OHT activity: It was increased up to 5.2-fold in males and 13.9-fold in females (Z high dose). The effect was larger than the produced by PB or beta-NF (< or = threefold increases). Z (high dose), PB, and beta-NF increased ECOD to a similar extent, e.g., about 1.3-fold in males and 1.2-2.9-fold in females. beta-NF increased EROD (11.2-fold males, 6.2-fold females) more than PB (3.4- to 4.6-fold) or Z (1.3- to 1.7-fold). Since hydroxylation of testosterone at the 6 beta position in rats and humans is catalyzed primarily by CYP isoforms from the 3A subfamily, the increase in 6 beta-OHT suggests that Z induced CYP 3A activity. These findings were confirmed with Western immunoblots with probes for rat CYP 1A1, 2B1/2, 2E1, 3A, and 4A. Z produced a three-to fourfold increase in the 3A isoform for both male and female rats. Results from this study suggest that in a clinical setting, Z therapy has the potential to induce CYPs of the 3A subfamily and in so doing alter the metabolism and clearance of drugs that are substrates for the 3A subfamily.
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Goodman AD, Hoekstra S, Monahan JW, Danis EH. Suppressive effect of glucose administration on the binding of prolactin by rat liver. Metabolism 1990; 39:568-76. [PMID: 2191185 DOI: 10.1016/0026-0495(90)90020-d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In an attempt to elucidate the physiologic role of the hepatic receptors for prolactin (PRL), we studied the effect of changes in diet on the specific binding of 125I-ovine prolactin (oPRL) by membranes from female rat liver. Specific binding of PRL (SBP) was decreased by over 50% in rats fed 15% glucose ad lib for 2 days, as compared with fasted rats (P less than .01), while serum PRL was similar in both groups. Feeding 20% glucose by tube decreased SBP significantly, but tube-feeding equicaloric amounts of fat or protein-amino acid solution did not. Glucose feeding did not decrease the specific binding of 125I-bovine growth hormone (bGH) to liver, or decrease SBP to membranes of nitrosomethylurea (NMU)-induced mammary carcinomas, indicating that the effect of glucose on hepatic SBP is selective. Administration of glucose decreased SBP significantly in adrenalectomized-ovariectomized rats, in adrenalectomized-chemically sympathectomized rats, and in hypophysectomized rats receiving replacement therapy, including bovine prolactin (bPRL), bGH, hydrocortisone, estrogen, and thyroid hormones. Thus, the effect of glucose is not mediated by a factor from the adrenals, ovaries, or pituitary, and probably not by catecholamines. Administration of insulin to fasted diabetic rats did not alter SBP. Infusion of glucagon for 1 day, at a rate that did not alter serum glucose, increased hepatic SBP 29% (P less than .01). Since glucose administration decreases plasma glucagon, we hypothesize that glucagon may contribute to the maintenance of the hepatic PRL receptors, and that the suppressive effect of glucose on hepatic SBP may be mediated at least in part by suppression of plasma glucagon.(ABSTRACT TRUNCATED AT 250 WORDS)
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Rusman T, Nurmohamed MT, Hoekstra S, van Denderen CJ, van Vollenhoven RF, Boers M, Ter Wee MM, van der Horst-Bruinsma IE. Disease activity in women with ankylosing spondylitis remains higher under Tumour Necrosis Factor inhibitor treatment than in men: a five-year observational study. Scand J Rheumatol 2021; 51:506-512. [PMID: 34726125 DOI: 10.1080/03009742.2021.1967046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVE To assess sex differences in response, level of disease activity, and drug survival in tumour necrosis factor inhibitor (TNFi)-naïve ankylosing spondylitis (AS) patients. METHOD Consecutive AS patients, fulfilling the modified New York criteria, were included in a prospective cohort study at initiation of the first TNFi and followed until this medication was stopped (drug survival). Disease activity scores [AS Disease Activity Score using C-reactive protein (ASDAS-CRP), Bath AS Disease Activity Index (BASDAI), and CRP] were measured at 3, 6, and 12 months, and every subsequent year, up to 5 years. The response was defined by the ASDAS-CRP response criteria (clinically important improvement: ASDAS-CRP decrease ≥ 1.1). Analyses included regression methods for repeated measurements and survival analyses. RESULTS Overall, 356 patients were included (34% women, mean ± sd age 46 ± 12 years), with a median disease duration of 12 (interquartile range 6;20) years. Women were less likely than men to achieve a clinically important response after 6 months of TNFi treatment (47% vs 64%; relative risk 1.4, 95% confidence interval (CI) 1.1;1.9, p = 0.02], despite a lack of sex differences in mean ASDAS-CRP levels over 5 year follow-up. Adjusted models for BASDAI over 5 years showed that women had a 0.6 point higher BASDAI score than men (β = 0.6 0.1;1.1 <0.02). Numerically, more women than men discontinued treatment over a period of 5 years (hazard ratio = 1.5, 95% CI 0.9;2.5, p = 0.15). CONCLUSION Female AS patients show a lower response to TNFi and a higher disease activity compared to men.
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Hoekstra S, Aarts J. A coherent approach to health informatics education: results of the Dutch curriculum project. Stud Health Technol Inform 2000; 57:66-70. [PMID: 10947672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
From the beginning a coherent approach to health informatics education has been aimed for in our project to develop learning materials. The features are the thematic approach of the contents, the interrelationship of the modules and the didactical approach embedded in the learning materials. Following results have been achieved. Learning materials have been developed for the following themes: healthcare policy and management, delivery of professional care (specific for nursing and allied health), more generic themes such as electronic patient record, clinical decision making, classification and coding of healthcare data and knowledge based systems. Software made available by private companies has been selected for use in the learning modules. In specific cases the available software products did not match the criteria to support the learning materials. In these cases model applications have been developed that can be considered as forerunners for systems in practical use. Already some companies have expressed interest to adapt our home grown products for use in clinical practice. The modules are based on a model curriculum that has been developed by Aarts et al in 1995. New developments in healthcare have prompted modification of the contents of a few modules. For example, a module has been redefined to cover the important issue of logistics in healthcare. The module on patient education has been adapted to take into account the resources available on the Internet. Also, new insights in the effectiveness of computer-based patient education have been taken into account. The module on informatics for disabled persons has been focussed on computer-based aids and is being linked to the EU-project "Impact" aimed at increasing knowledge about assistive technology. However, the model curriculum has proved to be reasonable robust as a base for our project to develop learning materials for health informatics.
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Oostendorp A, Hoekstra S, Aarts J. Exploring factors required for successful implementation of healthcare informatics. Stud Health Technol Inform 1997; 51:146-51. [PMID: 10179611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
This paper examines factors that are essential for a successful implementation of healthcare informatics in professional curricula. These factors are related to the design framework of the learning materials that have been developed as a part of a Dutch model curriculum of healthcare informatics. Next some ideas and suggestions for a successful implementation are presented.
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Hoekstra S, Mathijsen AJ. [Computer and nursing education]. TIJDSCHRIFT VOOR ZIEKENVERPLEGING 1985; 38:503-7. [PMID: 3901397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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