Johan Hazekamp

Unilever · Advanced Measurement & Imaging

Topics (3)

Publications (15) View all

  • Article: Obstetric and neonatal outcome after oocyte donation in 106 women with Turner syndrome: a Nordic cohort study.
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    ABSTRACT: STUDY QUESTION: What are the obstetric and neonatal outcomes of deliveries after oocyte donation (OD) in women with Turner syndrome (TS)? SUMMARY ANSWER: Pregnancies among women with TS carry a substantial risk, particularly for hypertensive disorders. Potentially life-threatening complications occurred in 3.3% of pregnancies. The neonatal outcomes were generally reassuring, with similar rates of preterm birth and low birthweight (LBW) as after conventional IVF and better than previously reported in deliveries after OD in women with TS. WHAT IS KNOWN ALREADY: OD pregnancies in women with TS are known to be high-risk pregnancies. STUDY DESIGN, SIZE, DURATION: This retrospective cohort study included 106 women with TS who delivered after OD (n = 122 deliveries, n = 131 newborns) in three Nordic countries (Finland, Denmark, Sweden) between 1992 and 2011. PARTICIPANTS, SETTING AND METHODS: Women with TS who delivered after OD in three Nordic countries were identified (n = 110). Four women declined to participate or were lost to follow-up, thus 106 women were included in the study. The medical data from fertility clinics, antenatal clinics and the hospitals where the women had been treated and/or delivered were scrutinized. MAIN RESULTS AND THE ROLE OF CHANCE: In this cohort, the karyotype was 45,X in 44% of the women with TS. Ten women (9.4%) had a known cardiac defect before pregnancy. Single embryo transfer was performed in 70.3% of the cases and the multiple birth rate was 7.4%. In total, 35.0% of the pregnancies were associated with a hypertensive disorder including pre-eclampsia in 20.5%. Potentially life-threatening complications occurred in four pregnancies (3.3%), including one woman with aortic dissection, one with mild regurgitation of the tricuspid and mitral valve, one with a mechanical heart valve who developed HELLP syndrome (haemolysis, elevated liver enzymes, low platelets) and one who underwent a post-partum hysterectomy due to severe haemorrhaging. Neonatal outcomes were reassuring, with a preterm birth rate of 8.0% and LBW rate of 8.8% in singletons. Major birth defects were found in 3.8% of the children. The perinatal mortality was 2.3% (3/131), including a set of extremely preterm twins. LIMITATIONS, REASONS FOR CAUTION: Although this study was performed over a period of almost 20 years in three different countries, with a low drop-out rate and little missing data, much larger series are needed to assess rare events. This study also lacks an appropriate control group. WIDER IMPLICATIONS OF THE FINDINGS: This study suggests that cardiovascular evaluation before and during pregnancy may contribute to favourable obstetric outcomes in many cases. Maternal outcomes were in agreement with the literature while neonatal outcomes were generally better than previously reported. The outcomes were consistent across the three countries, supporting generalizability to similar populations. STUDY FUNDING/COMPETING INTEREST(S): No conflict of interest was reported. The study was supported by grants from the Gothenburg Medical Society, the Medical Care Executive Board of the Region Västra Götaland, grants from the ALF agreement at the Sahlgrenska University Hospital, the Hjalmar Svensson foundation, NFOG Nordic Fund, the Finnish Society of Paediatric and Adolescent Gynecology and Liv och hälsa Foundation in Finland. The Nordic Expert group's research work was unconditionally supported by MSD Finland, Norway and Denmark. TRIAL REGISTRATION NUMBER: None.
    Human Reproduction 03/2013; · 4.47 Impact Factor
  • Article: Straightforward preparation of organic colloidal particles by harnessing spontaneous non-covalent interactions of active molecules from natural origin.
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    ABSTRACT: We demonstrate a straightforward method to prepare organic colloidal particles based on the spontaneous molecular interactions between small molecular weight actives of natural origin. Representative reactive natural actives from three of the most researched classes of phytochemicals including berberine (isoquinoline alkaloid), tannic acid (polyphenol) and glycyrrhizin (olenane type saponin) were chosen for the study. Binding parameters (association constant, binding enthalpy and entropy) obtained from isothermal titration calorimetry indicated that berberine strongly interacted with tannic acid to form insoluble colloidal complex which could be stabilised in the presence of glycyrrhizin (due to its interaction with both berberine and tannic acid and also due to its amphiphilic nature). Working on this principle, the mutual interactions of these three natural actives were exploited to obtain stable spherical particles with a mean diameter of less than 100 nm (77 nm) simply by mixing the aqueous solutions of berberine:tannic acid:glycyrrhizin at molar ratio of 2:1:1. The involvement of aromatic chromophore (π-π*) system and charged N atom of berberine in the spontaneous interaction between berberine and tannic acid was confirmed from spectral analysis. X-ray diffraction study suggested formation of amorphous organic colloidal particles, and the spherical shape of colloidal particles was confirmed by transmission electron microscopy.
    Journal of Colloid and Interface Science 02/2012; 374(1):150-6. · 3.07 Impact Factor
  • Article: Temperature responsive colloidal particles from non-covalently interacting small molecular weight natural bioactive molecules
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    ABSTRACT: We report generation of temperature responsive colloidal particles based on the spontaneous interactions of two small molecular weight actives of natural origins. This finding is an important step towards the development of controlled colloidal structures from natural and sustainable materials for food and drug delivery applications.
    Soft Matter. 01/2012; 8:3515-3517.
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    Article: Carotene location in processed food samples measured by cryo In-SEM Raman.
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    ABSTRACT: Cryo In-SEM Raman has been used for the first time to localise carotene compounds in a food matrix. Raman spectra of lycopene and β-carotene have been obtained from sampling oil droplets and plant cell structures visualised with cryo-SEM in tomato and carrot based emulsions containing 5% oil. It was possible to identify the carotenoids in both the oil droplets and the cell walls. Furthermore our results gave some indication that the carotenoids were in the non-crystalline state. It has been suggested that a higher amount of carotenes solubilised into the oil phase of the food matrix would lead to a higher bioaccessibility, thus understanding the effect of processing conditions on micronutrients distribution in a food matrix might help the design of plant based food products with a better nutritional quality. This shows improved structural characterisation of the cryo-SEM with the molecular sensitivity of Raman spectroscopy as a promising approach for complex biological problems.
    The Analyst 07/2011; 136(18):3694-7. · 4.23 Impact Factor
  • Article: Focussed ion beam milling at grazing incidence angles
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    ABSTRACT: SummaryA combined scanning electron microscope and focussed ion beam instrument is suitable for micro- and nanopatterning, cross-sectioning and subsequent imaging, of specimens at room temperature as well as under cryo conditions. In order to reveal internal details, samples are conventionally milled with the ion beam positioned perpendicular to the sample surface. Using this approach certain limitations are frequently encountered, e.g. accumulation of redeposited material, shadowing effects, image distortion and a limited imaging area. Here we show an approach in which samples are pre-trimmed using a microtome to obtain a sample block face that is parallel to the ion beam. This new grazing incidence geometry eliminates the need for removal of bulk material with the ion beam and enables immediate fine polishing of a pre-selected area of interest. Many of the limitations previously described are avoided and in addition milling time is reduced, whilst creating larger cross-sectional areas. Another advantage is that electron imaging can be accomplished by tilting the sample surface perpendicular to the electron beam, providing a geometrically undistorted image. The proposed approach is suitable for materials that can be microtomed, both in ambient and cryogenic conditions, and proves to be of particular benefit for biological and food samples.
    Journal of Microscopy 03/2011; 242(1):104 - 110. · 1.63 Impact Factor

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