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Nederfors T, Isaksson R, Mörnstad H, Dahlöf C. Prevalence of perceived symptoms of dry mouth in an adult Swedish population--relation to age, sex and pharmacotherapy. Community Dent Oral Epidemiol 1997; 25:211-6. [PMID: 9192149 DOI: 10.1111/j.1600-0528.1997.tb00928.x] [Citation(s) in RCA: 195] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The aim of the study was to evaluate the prevalence of subjective perception of dry mouth in an adult population and to determine the prevalence of pharmacotherapy in this population. An additional aim was to assess a possible co-morbidity between symptoms of dry mouth and continuing pharmacotherapy. Four-thousand-two-hundred persons were selected at random from the national census register of the adult population of the southern part of the province of Halland, Sweden. The sample was stratified according to age and sex, and 300 men and an equal number of women aged 20, 30, 40, 50, 60, 70 and 80, were included. A newly developed questionnaire was mailed to each individual. In addition to questions about subjective perception of dry mouth, the subjects were asked to report on present diseases and continuing pharmacotherapy. Three-thousand-three-hundred and thirteen (80.5%) evaluable questionnaires were returned. The estimated prevalence of xerostomia in the population was 21.3% and 27.3% for men and women, respectively. This difference between the sexes was statistically significant. In non-medicated subjects, women tended to report a higher prevalence of xerostomia compared with men, 18.8% vs. 14.6%, and also among medicated subjects the estimated prevalence of dry mouth was higher for women than for men, 32.5% vs. 28.4%. There was a strong association between xerostomia and increasing age and also between xerostomia and continuing pharmacotherapy. The average prevalence of dry mouth among medicated and non-medicated subjects was 32.1% and 16.9%, respectively, the difference being statistically significant. There was also a strong association between xerostomia and the number of medications. In a logistic regression, the probability of reporting mouth dryness was significantly greater in older subjects and in women, and the probability increased with the number of medications taken. In conclusion, this epidemiological survey of an adult population has demonstrated that women, independent of age, do report a higher prevalence of xerostomia than men and that the symptom of dry mouth is strongly associated with age and pharmacotherapy. It is, however, not possible to discriminate between disease and pharmacotherapy as causal factors.
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Erlandsson P, Hansson L, Isaksson R. Direct analytical and preparative resolution of enantiomers using albumin adsorbed to silica as a stationary phase. J Chromatogr A 1986; 370:475-83. [PMID: 3029151 DOI: 10.1016/s0021-9673(00)94717-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A rapid and simple method for the preparation of high-performance liquid chromatography columns for chiral separations is described. The stationary phase is prepared by adsorbing bovine serum albumin on silica. Both analytical and preparative applications are described. A polarimeter was used as a detector to determine the enantiomer elution orders.
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Erlandsson P, Isaksson R, Lorentzon P, Lindberg P. Resolution of the enantiomers of omeprazole and some of its analogues by liquid chromatography on a trisphenylcarbamoylcellulose-based stationary phase. The effect of the enantiomers of omeprazole on gastric glands. JOURNAL OF CHROMATOGRAPHY 1990; 532:305-19. [PMID: 2084128 DOI: 10.1016/s0378-4347(00)83781-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The enantiomers of omeprazole and some of its analogues have been separated on a chiral stationary phase comprising trisphenylcarbamoylcellulose coated on 3-aminopropyl silica. The nature of the supporting silica has a crucial effect on the separations obtained. The racemisation half-life of omeprazole was estimated to be 1.3.10(2) h at 37 degrees C. In vitro tests on isolated gastric glands from rabbits showed that both enantiomers of omeprazole had an inhibitory effect on acid formation.
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Comparative Study |
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Ståhlberg J, Henriksson H, Divne C, Isaksson R, Pettersson G, Johansson G, Jones TA. Structural basis for enantiomer binding and separation of a common beta-blocker: crystal structure of cellobiohydrolase Cel7A with bound (S)-propranolol at 1.9 A resolution. J Mol Biol 2001; 305:79-93. [PMID: 11114249 DOI: 10.1006/jmbi.2000.4237] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cellobiohydrolase Cel7A (previously called CBH 1), the major cellulase produced by the mould fungus Trichoderma reesei, has been successfully exploited as a chiral selector for separation of stereo-isomers of some important pharmaceutical compounds, e.g. adrenergic beta-blockers. Previous investigations, including experiments with catalytically deficient mutants of Cel7A, point unanimously to the active site as being responsible for discrimination of enantiomers. In this work the structural basis for enantioselectivity of basic drugs by Cel7A has been studied by X-ray crystallography. The catalytic domain of Cel7A was co-crystallised with the (S)-enantiomer of a common beta-blocker, propranolol, at pH 7, and the structure of the complex was determined and refined at 1. 9 A resolution. Indeed, (S)-propranolol binds at the active site, in glucosyl-binding subsites -1/+1. The catalytic residues Glu212 and Glu217 make tight salt links with the secondary amino group of (S)-propranolol. The oxygen atom attached to the chiral centre of (S)-propranolol forms hydrogen bonds to the nucleophile Glu212 O(epsilon1) and to Gln175 N(epsilon2), whereas the aromatic naphthyl moiety stacks with the indole ring of Trp376 in site +1. The bidentate charge interaction with the catalytic glutamate residues is apparently crucial, since no enantioselectivity has been obtained with the catalytically deficient mutants E212Q and E217Q. Activity inhibition experiments with wild-type Cel7A were performed in conditions close to those used for crystallisation. Competitive inhibition constants for (R)- and (S)-propranolol were determined at 220 microM and 44 microM, respectively, corresponding to binding free energies of 20 kJ/mol and 24 kJ/mol, respectively. The K(i) value for (R)-propranolol was 57-fold lower than the highest concentration, 12.5 mM, used in co-crystallisation experiments. Still several attempts to obtain a complex with the (R)-enantiomer have failed. By using cellobiose as a selective competing ligand, the retention of the enantiomers of propranolol on the chiral stationary phase (CSP) based on Cel7A mutant D214N were resolved into enantioselective and non- selective binding. The enantioselective binding was weaker for both enantiomers on D214N-CSP than on wild-type-CSP.
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Abstract
Despite improvements in both diagnostic assessment and treatment of infertile couples, many couples still have no explanation for their infertility. Unexplained infertility (the failure to conceive of a couple in whom no definitive cause for infertility can be found) has an incidence of 10-20% in all infertile couples. The incidence varies with the population studied and with the criteria used. Unexplained infertility is not an absolute condition but rather a relative inability to conceive, and many of these couples may conceive without treatment. The treatment options for unexplained infertility are several and the treatment results are promising. Expectant management can be recommended if the woman is under 28-30 years of age and the infertility duration is less than 2-3 years. In vitro fertilization (IVF) has revolutionized the treatment of infertile couples, as well as profoundly increasing the basic understanding of human reproduction. IVF can be used as both a diagnostic and a therapeutic tool in couples with unexplained infertility. The pregnancy rates with IVF are good, at 40% per treatment cycle. In addition, the outcome of pregnancies among women with unexplained infertility is generally comparable to that of spontaneous and other pregnancies using assisted reproductive technologies.
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Review |
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Isaksson R, Paulsson G, Fridlund B, Nederfors T. Evaluation of an oral health education program for nursing personnel in special housing facilities for the elderly. Part II: Clinical aspects. SPECIAL CARE IN DENTISTRY 2000; 20:109-13. [PMID: 11203883 DOI: 10.1111/j.1754-4505.2000.tb00012.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In Sweden, efforts are being made to create strategies for evaluating realistic dental treatment needs among the elderly, who are retaining more natural teeth. These strategies focus on the importance of maintaining adequate oral hygiene. Elderly in long-term-care facilities often depend on nursing personnel for carrying out daily oral hygiene procedures. Therefore, the nursing personnel's knowledge about and attitudes toward oral health make oral health education for health care professionals an important concern. The purpose of this study was to evaluate the clinical oral health outcome in residents after their caregivers had undergone a one-session, four-hour oral health education program. The study consisted of an intervention with a pre- and a post-test and was carried out in three municipalities in the southwestern part of Sweden. A newly developed oral health screening protocol was carried out for 170 subjects living in long-term-care facilities both before and 3-4 months after nursing personnel had attended an oral health education program. Following the intervention, a statistically significant improvement was recorded for changes in oral mucosal color, a modified plaque index which measured oral hygiene status, and a mucosal index which recorded mucosal inflammation. This study indicated that a limited, one-session, four-hour oral health education, offered to caregivers within long-term-care facilities, had a positive impact on the oral health status of residents.
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Evaluation Study |
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Henriksson H, Ståhlberg J, Isaksson R, Pettersson G. The active sites of cellulases are involved in chiral recognition: a comparison of cellobiohydrolase 1 and endoglucanase 1. FEBS Lett 1996; 390:339-44. [PMID: 8706890 DOI: 10.1016/0014-5793(96)00685-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The cellulases cellobiohydrolase 1 (CBH 1) and endoglucanase 1 (EG 1) from the fungus Trichoderma reesei are closely related with 40% sequence identity and very similar in structure. In CBH 1 the active site is enclosed by long loops and some antiparallel beta-strands forming a 40 A long tunnel, whereas in EG 1 part of those loops are missing so that the enzyme has a more common active site groove. Both enzymes were immobilized on silica and these materials were used as chiral stationary phases for chromatographic separation of the enantiomers of two chiral drugs, propranolol and alprenolol. The CBH 1 phase showed much better resolution than did the EG 1 phase, suggesting that the tunnel structure of the protein may play an important role in the chiral separation. The chiral compounds were found to be competitive inhibitors of both enzymes when p-nitrophenyl lactoside (pNPL) was used as substrate. (S)-enantiomers showed stronger inhibitory effects and also longer retention time on the stationary phases than the (R)-enantiomers. The consistency between kinetic data and retention on the stationary phases clearly shows that the enzymatically active sites of CBH 1 and EG 1 are involved in chiral recognition.
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Comparative Study |
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Jönsson S, Schön A, Isaksson R, Pettersson C, Pettersson G. An unexpected temperature effect obtained on enantiomer separation using CBH I-silica as a chiral stationary phase: increase in retention and enantioselectivity at elevated column temperature: a chromatographic and microcalorimetric study. Chirality 1992; 4:505-8. [PMID: 1335749 DOI: 10.1002/chir.530040808] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Lehtinen M, Idänpään-Heikkilä I, Lunnas T, Palmroth J, Barr E, Cacciatore R, Isaksson R, Kekki M, Koskela P, Kosunen E, Kuortti M, Lahti L, Liljamo T, Luostarinen T, Apter D, Pukkala E, Paavonen J. Population-based enrolment of adolescents in a long-term follow-up trial of human papillomavirus vaccine efficacy. Int J STD AIDS 2006; 17:237-46. [PMID: 16595046 DOI: 10.1258/095646206776253453] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We evaluated a study setting for assessment of the long-term vaccine efficacy (VE) of human papillomavirus (HPV) virus-like-particle (VLP) vaccine against cervical carcinoma. A total of 22,412 16- to 17-year old adolescent women from seven cities in Finland were invited by letter to participate in a phase III study of a quadrivalent HPV (types 6, 11, 16, 18) VLP vaccine, between September 2002 and March 2003. A total of 30,947 18-year old women were invited to participate as unvaccinated controls. These women were asked about their willingness to participate in an HPV vaccination trial and to fill a health questionnaire. These three population-based cohorts of adolescent women, including women vaccinated with HPV vaccine or placebo vaccine and unvaccinated control women, are systematically followed over time. The study cohort database will be linked with the Finnish Cancer Registry using cervical carcinoma in situ (CIS) and invasive cervical carcinoma (ICC) as endpoints. Assuming that the cumulative incidence of CIS and ICC over 15 years is 0.45%, and that there is no loss to follow-up, and power of 80%, the determination of 70% total VE will require 3357 HPV vaccine recipients, 3357 placebo vaccine recipients, and 6714 unvaccinated controls. At the baseline, 2632 (12%) of the invited adolescents volunteered to the phase III vaccination trial, and 6790 (22%) responded to the questionnaire study. During a recruitment period of 10 months, 874 HPV vaccine recipients, 875 placebo recipients and 1919 unvaccinated controls were enrolled. Population-based enrollment of large cohorts of vaccinated and unvaccinated adolescents for passive registry-based follow-up with cervical carcinoma as the end-point is feasible and currently going on in Finland.
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Research Support, Non-U.S. Gov't |
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Gjörstrup P, Hårding H, Isaksson R, Westerlund C. The enantiomers of the dihydropyridine derivative H 160/51 show opposite effects of stimulation and inhibition. Eur J Pharmacol 1986; 122:357-61. [PMID: 3754814 DOI: 10.1016/0014-2999(86)90417-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
H 160/51 is a calcium agonistic 1,4-dihydropyridine. Its optical isomers were now found to have opposing actions in the cat papillary muscle and rat portal vein. The inhibitory (+)-enantiomer had potencies of the same order as those of the stimulatory (-)-enantiomer. However the racemate and the (-)-enantiomer had approximately the same potencies and intrinsic activities. A model is presented to account for the fact that the effects of the inhibitory (+)-enantiomer can be concealed in the effects of the racemate of H 160/51.
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Thorsteinsdóttir M, Isaksson R, Westerlund D. Performance of amino-silylated fused-silica capillaries for the separation of enkephalin-related peptides by capillary zone electrophoresis and micellar electrokinetic chromatography. Electrophoresis 1995; 16:557-63. [PMID: 7588526 DOI: 10.1002/elps.1150160191] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Enkephalin-related peptides were separated at low pH in a capillary with covalently bonded aminopropyl groups. The peptides are electrostatically repelled from the capillary surface and much higher efficiencies and faster separations were achieved compared to separations using uncoated capillaries. At low pH the amino groups are protonated, which results in reversed electroosmosis. The influence of voltage and ionic strength on the mobility and the separation efficiency was studied. The repeatability of migration times within one day was very good with relative standard deviations of 0.3-0.7%. Increasing the pH decreased the electroosmosis, eventually turning towards the cathode in the pH range 5-6; the separation performance, however, was lower at higher pH. Neutral and anionic micellar agents were added to the background electrolyte at different concentrations; the enkephalins had weak association with the neutral micellar agents but were distributed to the anionic taurodeoxycholic acid (TDC) micelles, giving rise to changes in separation selectivities. Very high efficiencies were obtained for peptides with a low distribution to the TDC micelles, while the efficiencies were impaired for those with a strong association with the micelles, which may indicate a slow mass transfer in the association process.
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Enlund AM, Isaksson R, Westerlund D. Capillary electrochromatography of tricyclic antidepressants on strong cation exchangers with different pore sizes. J Chromatogr A 2001; 918:211-20. [PMID: 11403450 DOI: 10.1016/s0021-9673(01)00738-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Four cation-exchange materials, possessing propanesulfonic acid ligands, for use in capillary electrochromatography were prepared from different commercially available 5-microm bare-silica particles ranging from 80 to 800 A in pore size. The performance of the materials was investigated at different compositions of the mobile phase (pH, ionic strength, and acetonitrile content) using tricyclic antidepressants and related quaternary ammonium analogues as test analytes. The wide-pore materials promoted pore flow, but this had no positive influence on the performance. The small-pore (highest surface area) particles gave, as could be expected, the best selectivity.
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Henriksson H, Muñoz IG, Isaksson R, Pettersson G, Johansson G. Cellobiohydrolase 58 (P.c. Cel 7D) is complementary to the homologous CBH I (T.r. Cel 7A) in enantioseparations. J Chromatogr A 2000; 898:63-74. [PMID: 11185624 DOI: 10.1016/s0021-9673(00)00807-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cellobiohydrolase 58 (EC 3.2.1.91, P.c. Cel 7D) from Phanerochaete chrysosporium was immobilized on silica and the resulting material, CBH 58-silica, was then used as a chiral stationary phase (CSP) in liquid chromatographic separations of enantiomers. The enantioselectivities obtained on CBH 58-silica were compared with those on CBH I-silica (a phase based on a corresponding cellulase from Trichoderma reesei). CBH 58-silica displayed higher selectivity than CBH I-silica for the more hydrophilic compounds, such as atenolol and metoprolol, although great similarities in chiral separation of beta-adrenergic antagonists were found between the two phases. None of the acidic compounds tested could be resolved on the CBH 58 phase. Moreover, the solutes were retained more on the CBH 58 phase in general, indicating an improved application potential in bioanalysis. Addition of cellobiose or lactose, both of which are inhibitors of cellulases, to the mobile phase impaired the enantioselectivity, indicating an overlap of the enantioselective and catalytic sites. The chiral analytes also functioned as competitive inhibitors and their inhibition constants were determined.
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Isaksson R, Tiitinen A, Cacciatore B. Uterine artery impedance to blood flow on the day of embryo transfer does not predict obstetric outcome. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2000; 15:527-530. [PMID: 11005123 DOI: 10.1046/j.1469-0705.2000.00133.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
OBJECTIVE To evaluate the influence of uterine artery impedance to blood flow on the day of embryo transfer for prediction of early pregnancy loss and obstetric outcome. METHODS The uterine artery pulsatility index (PI) and resistance index (RI) were evaluated prospectively by transvaginal Doppler in 102 infertile women, who conceived as the result of fresh or frozen embryo transfer. Uterine artery impedance to blood flow was compared to the obstetric outcome. RESULTS The 111 treatment cycles studied resulted in 31 spontaneous abortions, four ectopic pregnancies, and 76 deliveries. There were no differences in uterine artery PI and RI (mean +/- SD) between cycles resulting in normal delivery (2.69 +/- 0.71 and 0.88 +/- 0.06) and those resulting in spontaneous abortion (2.71 +/- 0.67 and 0.88 +/- 0.05) or ectopic pregnancy (2.36 +/- 0.54 and 0.85 +/- 0.06). There were no differences in PI and RI between uncomplicated singleton pregnancies (2.74 +/- 0.78 and 0.88 +/- 0.06) and those developing intra-uterine growth restriction (IUGR), pregnancy-induced hypertension (PIH), or preterm birth (2.54 +/- 0.47 and 0.87 +/- 0.04, pooled data). CONCLUSIONS Uterine artery PI and RI on the day of embryo transfer were unrelated to the risk of the pregnancy ending in spontaneous abortion or ectopic pregnancy. These values were of no value in the prediction of IUGR, PIH or preterm birth.
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Comparative Study |
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Kumpiņa I, Isaksson R, Sävmarker J, Wannberg J, Larhed M. Microwave Promoted Transcarbamylation Reaction of Sulfonylcarbamates under Continuous-Flow Conditions. Org Process Res Dev 2016. [DOI: 10.1021/acs.oprd.5b00323] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Isaksson R, Tiitinen A. Superovulation combined with insemination or timed intercourse in the treatment of couples with unexplained infertility and minimal endometriosis. Acta Obstet Gynecol Scand 1997; 76:550-4. [PMID: 9246961 DOI: 10.3109/00016349709024582] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND To compare intrauterine insemination (IUI), direct intraperitoneal insemination (DIPI), and timed-intercourse (TI), each combined with superovulation, in the treatment of couples with unexplained infertility, including couples with minimal endometriosis. METHODS A retrospective analysis of 233 superovulation cycles in 70 couples with unexplained infertility or minimal endometriosis. Stimulation protocol, pregnancy rate, pregnancy outcome, and complications of treatment were analyzed. RESULTS The pregnancy rare was 8.6% per cycle and 28.5% per couple. A majority of all treatment pregnancies (85%) occurred during the first four cycles of treatment. The duration of infertility did not influence the pregnancy rate. The pregnancy rate in patients with unexplained infertility was higher, but not significantly, than in patients with minimal endometriosis (27.7% versus 18.4%). No predictive marker for successful stimulation was found, except for the higher luteal progesterone level in cycles resulting in pregnancy. The multiple pregnancy rate was high: 30% of all pregnancies and 40% of all deliveries were multiple. CONCLUSIONS Superovulation in combination with insemination or intercourse is effective and is still recommended in the treatment of couples with unexplained infertility.
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Clinical Trial |
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Hedeland M, Jönsson S, Isaksson R, Pettersson C. Unexpected difference in enantioselective retention on cellulase (CHB I) silica stationary phase caused by exchange of potassium for sodium ion in the mobile phase. Chirality 2000; 10:513-8. [PMID: 9725010 DOI: 10.1002/(sici)1520-636x(1998)10:6<513::aid-chir2>3.0.co;2-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An increase in both retention and enantioselectivity for some beta-blocking agents was observed when exchanging potassium to sodium ion in the buffer used as mobile phase. A large effect of ionic strength on retention was observed, while the enantioselectivity was constant.
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Isaksson R, Lamm B. Semipreparative separation of cyclic carbamates of beta-blocking agents by liquid chromatography on swollen microcrystalline triacetylcellulose. J Chromatogr A 1986; 362:436-8. [PMID: 2876003 DOI: 10.1016/s0021-9673(01)86998-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Hedeland M, Nygård M, Isaksson R, Pettersson C. Cellulases from the fungi Phanerochaete chrysosporium and Trichoderma reesei as chiral selectors in capillary electrophoresis: applications with displacer plugs and sample preconcentration. Electrophoresis 2000; 21:1587-96. [PMID: 10832892 DOI: 10.1002/(sici)1522-2683(20000501)21:8<1587::aid-elps1587>3.0.co;2-n] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The cellulases CBH 58 from the fungus Phanerochaete chrysosporium and CBH I from the fungus Trichoderma reesei were compared as chiral selectors in capillary electrophoresis (CE) applying the partial filling technique. Amines, e.g., norephedrine, two bambuterol analogs, as well as acids, e.g., di-p-toluoyl tartaric acid and dibenzoyl tartaric acid, which could not be enantioseparated in the liquid chromatographic use of the selectors, could be separated in the corresponding CE experiments. Due to the very high enantioselectivities, terbutaline, alprenolol and propranolol could be completely enantioresolved with selector plugs shorter than the sample plugs. The affinity of propranolol to CBH 58 was so high at pH 7.0 that neither of the enantiomers reached the detector; therefore, a plug of the displacing disaccharide cellobiose was injected after the sample to elute the propranolol enantiomers. The enantiomers could also be made to leave the capillary at opposite ends, thereby causing an infinite enantioresolution. A new preconcentration technique was introduced, which takes advantage of the very high affinity of propranolol to CBH 58 and the eluting ability of cellobiose. A 12.5 cm long plug of rac-propranolol could be preconcentrated and enantioseparated in a single procedure.
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Berg U, Isaksson R, Sandström J, Sjöstrand U, Eiglsperger A, Mannschreck A. Enantiomers of polarized alkenes: chromatographic enrichment and thermal interconversion. Tetrahedron Lett 1982. [DOI: 10.1016/s0040-4039(00)88713-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Isaksson R, Tiitinen A, Reinikainen LM, Cacciatore B. Comparison of uterine and spiral artery blood flow in women with unexplained and tubal infertility. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2003; 21:174-180. [PMID: 12601842 DOI: 10.1002/uog.27] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
OBJECTIVE To evaluate the possible difference in uterine and spiral artery impedance to blood flow among women with unexplained and tubal infertility during spontaneous and gonadotropin-stimulated cycles. METHODS We prospectively compared uterine and spiral artery pulsatility index and peak systolic velocity in a longitudinal study in women with either unexplained infertility (n = 20) or tubal infertility (n = 18). Measurements of uterine and spiral artery impedance were taken on days 11-12, 16-17 and 21-23 of the spontaneous cycle and on days 1, 5 and 10 during gonadotropin stimulation. In addition, measurements were taken on the days of oocyte pick-up and embryo transfer. RESULTS A clinical pregnancy was achieved in 8/20 (40%) women with unexplained and 6/18 (33.3%) women with tubal infertility with in-vitro fertilization treatment. There were no differences in the uterine artery pulsatility index or peak systolic velocity during the spontaneous or the in-vitro fertilization cycle between the two groups. The impedance to blood flow in the uterine or spiral artery did not differ between women conceiving with in-vitro fertilization-embryo transfer and those who did not. However, the spiral artery pulsatility index on the 5th day of gonadotropin stimulation was significantly lower among women with unexplained infertility (0.96 +/- 0.25) compared to women with tubal infertility (1.24 +/- 0.30; P < 0.05), but on the other days of gonadotropin stimulation the spiral artery pulsatility index and peak systolic velocity were similar. CONCLUSIONS Impaired uterine or spiral artery blood flow is not an important factor in unexplained infertility.
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Isaksson R, Lindman J, Wannberg J, Sallander J, Backlund M, Baraldi D, Widdop R, Hallberg M, Åqvist J, Gutierrez de Teran H, Gising J, Larhed M. A Series of Analogues to the AT 2R Prototype Antagonist C38 Allow Fine Tuning of the Previously Reported Antagonist Binding Mode. ChemistryOpen 2019; 8:114-125. [PMID: 30697513 PMCID: PMC6346239 DOI: 10.1002/open.201800282] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/02/2019] [Indexed: 01/09/2023] Open
Abstract
We here report on our continued studies of ligands binding to the promising drug target angiotensin II type 2 receptor (AT2R). Two series of compounds were synthesized and investigated. The first series explored the effects of adding small substituents to the phenyl ring of the known selective nonpeptide AT2R antagonist C38, generating small but significant shifts in AT2R affinity. One compound in the first series was equipotent to C38 and showed similar kinetic solubility, and stability in both human and mouse liver microsomes. The second series was comprised of new bicyclic derivatives, amongst which one ligand exhibited a five-fold improved affinity to AT2R as compared to C38. The majority of the compounds in the second series, including the most potent ligand, were inferior to C38 with regard to stability in both human and mouse microsomes. In contrast to our previously reported findings, ligands with shorter carbamate alkyl chains only demonstrated slightly improved stability in microsomes. Based on data presented herein, a more adequate, tentative model of the binding modes of ligand analogues to the prototype AT2R antagonist C38 is proposed, as deduced from docking redefined by molecular dynamic simulations.
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research-article |
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Harbottle D, Bueno P, Isaksson R, Kretzschmar I. Coalescence of particle-laden drops with a planar oil-water interface. J Colloid Interface Sci 2011; 362:235-41. [PMID: 21737091 DOI: 10.1016/j.jcis.2011.05.077] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 05/24/2011] [Accepted: 05/27/2011] [Indexed: 10/18/2022]
Abstract
The coalescence mechanism of a particle-laden drop resting at an oil-water interface has been studied. Two mechanisms for drop coalescence are observed; (i) complete coalescence, in which the drop experiences total coalescence in one event, and (ii) partial coalescence, where a drop is observed to separate during coalescence, producing a smaller secondary drop that rebounds and comes to rest at the planar oil-water interface. For particle-laden drops of approximately 4mm in diameter, we show the critical condition for partial to complete coalescence to be dependent on the particle concentration, and the interparticle interaction energy. Colloidal silica spheres dispersed in 10(-4) M KNO(3) electrolyte solution are highly charged and remain dispersed in the drop. By increasing the solids concentration, we measure the transition from partial to complete coalescence at 20 wt.%. However, this critical condition can be reduced by increasing the interparticle interaction energy. In 1 M KNO(3) electrolyte solution, the particle surface charge is sufficiently screened such that particle clusters readily form in the water drop. With particle clustering, transition from partial to complete coalescence is measured at 8 wt.% solids.
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Journal Article |
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Jansen JM, Copinga S, Gruppen G, Isaksson R, Witte DT, Grol CJ. Semipreparative enantiomeric separation of a series of putative melatonin receptor agents using tri-acetylcellulose as chiral stationary phase. Chirality 1994; 6:596-604. [PMID: 7986673 DOI: 10.1002/chir.530060714] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In order to obtain milligram amounts of the enantiomers of a series of compounds to be tested for binding to the melatonin binding site, a system for semipreparative enantiomeric separation was set up using tri-acetylcellulose as the chiral stationary phase. Interactions of this class of compounds with tri-acetylcellulose were examined on an analytical scale with a series of 20 compounds. Apparently, both steric and electrostatic interactions determine retention behavior on tri-acetylcellulose. Semipreparative separations were carried out for a subset of seven compounds. The purity of the first eluting enantiomer usually was around 99%, whereas the purity of the second eluting enantiomer was slightly less. The system described is easy to use and has the major advantage that a series of compounds can be separated with one technique. The purities obtained are sufficient for a first screen of their affinity.
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Isaksson R, Sandström J, Eliaz M, Israely Z, Agranat I. Enantiomer resolution of nefopam hydrochloride, a novel analgesic: a study by liquid chromatography and circular dichroism spectroscopy. J Pharm Pharmacol 1988; 40:48-50. [PMID: 2896773 DOI: 10.1111/j.2042-7158.1988.tb05148.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Nefopam, a potent analgesic, has been completely resolved into enantiomers on a preparative scale by low-pressure liquid chromatography on swollen, microcrystalline triacetylcellulose. The enantiomerically pure hydrochlorides were prepared from the base, and the circular dichroism spectra of the free base and the hydrochloride are reported.
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