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Biomedical subjects

A Sjögren

Publications and source records attributed to A Sjögren.

At least 19 recordsLinked to original sources
PubMed2001

Chromatographic interactions between proteins and sulfoalkylbetaine-based zwitterionic copolymers in fully aqueous low-salt buffers.

Macroporous monoliths containing N,N-dimethyl-N-methacryloyloxyethyl-N-(3-sulfopropyl)ammonium betaine (SPE) have been synthesized via in situ photopolymerization, yielding a stoichiometric balance between sulfur and nitrogen in the final polymer, which is indicative of a genuine strong/strong zwitterionic character. The chromatographic properties of these zwitterionic resins were evaluated with respect to the retention behavior of inorganic ions and proteins. The weak electrostatic nature of the interaction between the sulfobetaine monoliths and proteins provided a high selectivity between basic proteins and peptides. Elution was accomplished with low-ionic-strength fully aqueous mobile phases, whereby high recovery was obtained, even for hydrophobic proteins. Chaotropic ions such as perchlorate or thiocyanate were used as mobile phase modifiers to modulate the apparent ion exchange group density, thus introducing a route for the modulation of the ionic strength that is required to competitively elute the protein. The promising features of polymeric sulfoalkylbetaine interaction layers for separation and analysis of biological extracts was also manifested in an application involving purification of biologically active peptide-pheromone obtained from Enterococcus faecium.

Journal Article↗
PubMed2001

The development of reflective learning in the context of health counselling and health promotion during nurse education.

AIMS AND BACKGROUND: The purpose of this follow-up study was to describe the development of reflective learning of 16 student nurses in the context of health counselling and promotion during clinical training of a 3-year nursing education programme in two Finnish polytechnics. The first aim was to analyse the levels of reflectivity in the student nurses' reflections on their videotaped counselling situations. The second aim was to explore the qualitative features of the reflective health counselling learning process in the context of health promotion. The theoretical background of the study was based on a transformative learning theory. METHODS: The data consisted of stimulated recall interviews with 16 student nurses conducted once a year between 1998 and 2000. The data were analysed using categorization and thematic analysis. FINDINGS: The findings of the study showed that half of the students in the research group reached the level of critical consciousness during their nursing education. The others remained at the level of consciousness. Two students who represented thoughtful action without reflection in the first study year were able to reach reflection and even critical reflection later during their education. The meaning schemas of counselling developed and were enriched when the students moved into the higher stages of reflection. There were features of an empowerment approach to health promotion only in the meaning schemas and perspectives of critical reflectors. CONCLUSIONS: These results may indicate that the empowerment approach to health promotion within the modern health promoting role of nurses requires critical reflection. Therefore, effective methods and evaluation tools of reflective learning are needed to support learning from practice via critical reflection.

Adolescent↗
PubMed2001

Investigating student nurses' constructions of health promotion in nursing education.

This article describes student nurses' constructions of health promotion and the change of these constructions during their nursing education in two Finnish polytechnics. The data consisted of essays written by the 19 student nurses before they began their nursing education in 1997 and of stimulated recall interviews with the same students during the second year of their education in 1998. The data were analyzed by using thematic analysis. During the first study year, 13 students' constructions of health promotion changed. Six students had initially broad constructions of health promotion and their constructions remained unchanged. Four basic changes were found in the students' constructions: (1) the emphasis shifted from physical to multidimensional health promotion, (2) health promotion became more concrete and contextual, (3) the conception of perfect health became more permissive and relative, and (4) the interpretation of health promotion shifted from performing towards being there for the patient. These results may indicate that student nurses in Finnish polytechnics were attempting to adopt the empowerment approach to health promotion for their constructions. Moreover, the results represent a major challenge concerning nursing education and health promotion learning from the constructivistic approach to knowledge building.

Attitude of Health Personnel↗
PubMed2001

Human embryos with unevenly sized blastomeres have lower pregnancy and implantation rates: indications for aneuploidy and multinucleation.

Uneven blastomere cleavage in human embryos of 'good morphology', i.e. those normally used for transfer, is a phenomenon which has been poorly investigated. The main objective in this study was to probe deeper into the aetiology behind previous findings that embryos with uneven cell cleavage have a lower developmental capacity in comparison with evenly cleaved embryos. Our hypothesis was that uneven cleavage may result in embryos with a higher degree of aneuploidy and/or multinuclear rate, which in turn might help to explain their low implantation rate. In the first part of the study, 378 embryo transfers performed over a 3-year period were analysed retrospectively, where all the transferred embryos in each cycle were of identical morphology score and cleavage stage. In the second part of the study, multicolour fluorescence in-situ hybridization (FISH) analyses on good quality embryos, representing the uneven (n = 11) and even (n = 13) study groups were performed. When comparing day 2 transfers between 4-cell embryos, it was found that unevenly cleaved embryos had significantly lower implantation (23.9 and 36.4%) and pregnancy rates (37.6 and 52.9%) compared with evenly cleaved embryos. A significantly higher degree of aneuploidy (29.4 and 8.5%) and multinuclear rate (21.1 and 2.1%) in blastomeres from uneven embryos was also found. It is concluded that uneven blastomere cleavage has a negative effect on both pregnancy and implantation rates in human IVF, and that this can partly be explained by a higher degree of aneuploidy/multinuclear rate. In the light of the results obtained, a new approach in the current embryo scoring system, placing more emphasis on blastomere size, is recommended.

Adult↗
PubMed2001

Taciturn patients in health counseling at a hospital: passive recipients or active participators?

This study explored patients' taciturnity as observed on videotape during hospital health counseling situations with a nurse. Health counseling sessions, 38 in number, were videotaped, transcribed verbatim, and analyzed by using an adaptation of conversation analysis. The data analysis included information on 18 selected patients who spoke little and did not introduce new topics, but rather supported the discussion on the theme chosen by the nurse. When we examined nurses' and patients' speech word by word, we discovered four participation frames that produced taciturnity: in the hands of professionals, compliant, guilty, and polite. These could fluctuate during interaction. The findings indicate that there is a need for a more extensive description of taciturn, or silent, patients. What has been interpreted as passivity in the literature can be interpreted more constructively. This insight can be useful for developing health counseling practice in hospitals.

Adolescent↗
PubMed2001

Preimplantation genetic diagnosis (PGD): the Gothenburg experience.

BACKGROUND: A program for preimplantation genetic diagnosis of pre-embryos from patients with hereditary disorders was set up in our unit at Sahlgrenska University Hospital in 1994. The majority of the patients were carriers of X-chromosome linked disorders; a few patients were translocation carriers. In this paper we describe our experiences of our first 36 cycles, 30 gender determinations and six analyses of embryos with possible translocations. METHODS: Conventional hormone replacement treatment with intracytoplasmic sperm injection to fertilize the eggs followed by blastomere biopsy and fluorescent in situ hybridization at the eight cell stage was used for sexing as well as detection of translocations. RESULTS: Out of the 30 cycles in 13 patients for gender determination, blastomere biopsies could be carried out in 25 cycles. Transfer of normal female embryos (XX) was performed in 18 cycles, resulting in five pregnancies (pregnancy rate 27.8%) and an implantation rate of 20% per transfer. Three girls have been born. Hence the take home baby rate was 16.7% per transfer and 10% per started cycle. Six cycles (three patients) for detection of translocations in embryos were performed. Diagnosis was possible in four cycles. Transfer of normal embryos was carried out in one cycle. No pregnancy was achieved. CONCLUSION: Successful PGD in its clinical application demands close collaboration between a large group of specialists. Even so, the success rate is considerably lower than after conventional IVF or ICSI procedures. Taking into account the stress caused to the parents facing late interruption of pregnancy following conventional prenatal diagnosis we are convinced that this technique is well worthwhile continuing and refining.

Cytogenetic Analysis↗
PubMed2000

Induction of VEGF and VEGF receptors in the spinal cord after mechanical spinal injury and prostaglandin administration.

Vascular endothelial growth factor (VEGF) is an angiogenetic factor that promotes endothelial cell proliferation during development and after injury to various types of tissue, including the central nervous system (CNS). Using immunohistochemical and in situ hybridization methods we have here demonstrated that VEGF and its receptors Flk-1, Flt-1 and Neuropilin-1 mRNAs and proteins are induced after incisions in the rat spinal cord. The inducible enzyme for prostaglandin synthesis cyclooxygenase-2 (COX-2) is known to be upregulated after spinal injury, cerebral ischemia and to stimulate angiogenesis. To test the hypothesis that prostaglandins may be involved in the VEGF response after lesion we investigated whether intraspinal microinjections of prostaglandin F2alpha (PGF2alpha) alters VEGF expression in the spinal cord. Such treatment was followed by a strong upregulation of VEGF mRNA and protein in the injection area. Finally, by use of an in vitro model with cell cultures of meningeal fibroblast and astrocyte origin, resembling the lesion area cellular content after spinal cord injury but devoid of inflammatory cells, we showed that VEGF is expressed in this in vitro model cell system after treatment with PGF2alpha and prostaglandin E2 (PGE2). These data suggest that cells within a lesion area in the spinal cord are capable of expressing VEGF and its receptors in response to mechanical injury and that prostaglandins may induce VEGF expression in such cells, even in the absence of inflammatory cells.

Animals↗
PubMed2000

Health promotion in the curricula and teaching of two polytechnics in Finland.

The purpose of this study was to examine the manifestation of health promotion in two Finnish health care and nursing polytechnic curricula for students starting their studies in August 1997. Another goal was to explore students' and their teachers' perceptions of which modules contained health promotion, as well as to find out which modules contained integrated health promotion. In this study, data and investigator triangulation were used. The data consisted of the curricula of two polytechnics of health care and of interviews with 20 student nurses and their teachers. The data were analysed using content analysis. Health promotion studies were integrated with other studies in the curriculum of the first polytechnic, whereas the second polytechnic had two separate health promotion modules. While most students were in favour of separate health promotion modules, teachers supported integrated modules. Students also reported that their teachers integrated health promotion in modules which were not named as such, for example, in language modules. The results represent a major challenge concerning the content of health promotion in the curricula and, also, the methods for teaching health promotion. More cooperation between teachers during the process of planning curricula is recommended.

Curriculum↗
PubMed2000

Ultrastructure of human blastocyst-endometrial interactions in vitro.

The interactions of seven human blastocysts with cultured endometrial cells were investigated by light microscopy and transmission electron microscopy. Trophoblastic-endometrial contact was observed at the lateral border of endometrial epithelial cells where trophoblast and endometrial epithelial cells shared apical junctional complexes and desmosomes. The first sign of penetration was invasion of a trophoblastic cytoplasmic protrusion between endometrial epithelial cells. In broad contact areas, lateral displacement of endometrial epithelial cells and formation of a peripheral pseudostratified epithelium were observed. When trophoblastic cells were interposed fully among endometrial epithelial cells, they formed a penetration cone and appeared to dislodge endometrial epithelial cells from the stromal compartment. A single penetration cone only was found in each specimen. Endometrial or trophoblastic degeneration was not observed. Formation of multinucleate (>/= three nuclei per cell) trophoblast cells was not observed, but many cells displayed areas with abrupt disappearance of well-defined plasma membranes, which is indicative of syncytium formation. In this study, adhesion and penetration occurred at the same time. The human blastocysts penetrated the endometrial surface epithelium by intrusive penetration. Epithelial penetration was achieved primarily by cellular syncytiotrophoblast-like cells and the first indications of syncytium formation were observed simultaneously with penetration of the epithelium.

Cell Adhesion↗
PubMed1999

Presence of uterine pinopodes at the embryo-endometrial interface during human implantation in vitro.

In order to study changes occurring on the surfaces of human endometrial epithelial cells in the presence of an implanted blastocyst, we used scanning electron microscopy for investigation of five endometrial biopsies and three human implantation sites obtained in vitro. All specimens showed areas with endometrial pinopodes, separated by cells displaying microvilli or cilia at the apical surface. Pinopode formation was more pronounced in endometrial biopsies than in cell cultures. All blastocysts adhered to pinopode presenting cells. Endometrial surface changes were not seen around the blastocysts. The results of this study demonstrate that cultured endometrial epithelial cells are capable of pinopode formation. Furthermore, endometrial epithelial pinopodes, generally considered as a marker of endometrial receptivity, seem to be directly involved in the adhesion of the blastocyst to the endometrial surface.

Blastocyst↗
PubMed1998

Hydrosalpinx fluid does not adversely affect the normal development of human embryos and implantation in vitro.

Several retrospectively designed studies have shown an association between the presence of hydrosalpinx and impaired implantation and pregnancy rates among in-vitro fertilization (IVF) patients. In the present study we have evaluated the influence of hydrosalpinx fluid on normal human embryo development and implantation. Surplus, donated frozen embryos (n = 183) from IVF patients were used to study the effects on blastocyst development of hydrosalpinx fluid at concentrations of 50 and 100% compared with controls in S2 medium. The fluids were analysed for concentrations of electrolytes, osmolarity, protein content, endotoxin levels, bacterial or fungal contamination, pH and haemoglobin content. There was no difference in blastocyst development in cultures under mineral oil when control cultures (15/42 = 36%) were compared with cultures in 50% hydrosalpinx fluid (32/96 = 33%). The only biochemical parameter which correlated with capacity for blastocyst development was pH in hydrosalpinx fluid/medium (50/50%) after equilibration in 5% CO2 in air. When embryos were cultured in 100% hydrosalpinx fluid the blastocyst development was 14% (5/36) in comparison to control 33% (3/9). The original experiment was repeated in an open culture system without the protection of mineral oil but still in the presence of 50% hydrosalpinx fluid. The rate of blastocyst development was within the same range in the open system. In three separate experiments, the capability of expanded blastocyst to implant on multilayer artificial endometrium was tested. In these experiments, 1/3, 4/5 and 9/9 blastocysts implanted. The present study demonstrates that hydrosalpinx fluid does not generally exert any major negative effects on in-vitro development of human embryos or on the implantation process in vitro.

Adult↗
PubMed1998

Indications for intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is the latest of several microfertilization techniques that have been utilized predominantly to overcome severe male subfertility, giving fertilization and term pregnancy rates similar to conventional in-vitro fertilization (IVF) (but for other indications). Even though available data on children born after ICSI are very encouraging, the procedure must still be considered as novel and the safety aspect to a great extent unexplored. In our opinion, therefore, ICSI should only be used for specific indications, and in this communication the non-existent, relative and absolute indications for performing ICSI are outlined and discussed. With an apparently normal sperm sample, ICSI should not be used in a first cycle even if only few oocytes are obtained. When there is reason to suspect poor fertilization, ICSI can be used in combination with conventional IVF in a split cycle. This includes cases of 'subnormal' sperm samples, high titres of antisperm antibodies, or following a single cycle of poor fertilization using conventional IVF. Absolute indications for ICSI include two previous fertilization failures with conventional IVF, use of epidiymal or testicular sperm samples, or when only acrosomeless or immotile spermatozoa are available. The fertilization of oocytes prior to preimplantation genetic diagnosis is another absolute indication. It is, however, important to keep in mind that for this novel technique, indications should not be rigid, but remain variable with respect to new findings.

Ciliary Motility Disorders↗
PubMed1996

Interaction of the C-polysaccharide of Streptococcus pneumoniae with the receptor asialo-GM1.

C-polysaccharide (PnC) is the major surface component of pneumococci containing phosphoryl choline residues. In order to investigate the possibility that PnC can bind to glycolipid receptors present on epithelial cells we extracted carbohydrate material from a nonencapsulated strain of pneumococci. The components of the extract were separated by gel permeation chromatography. An ELISA was used for detection of fractions binding to the pneumococcal glycolipid receptor asialo GM1. These fractions were pooled and analysed by nuclear magnetic resonance spectroscopy (NMR). The 1H NMR spectrum showed good agreement with a reference spectrum of pure PnC showing that this substance was the major component. Binding of the purified PnC to asialo-GM1 was unaffected by protease K treatment. Immunoblots of the purified PnC after separation by SDS-PAGE resulted in a characteristic banding pattern. PnC could be released from pneumococci by heat treatment of whole bacteria in buffer as shown by reaction with a monoclonal antibody specific for the phosphoryl choline determinant. After separation by SDS-PAGE of the components of the heat extract, immunoblots showed the presence of bands characteristic for PnC. Eluates from the characteristic bands in the gel were shown to contain material binding to asialo-GM1. This binding was not reduced upon treatment with protease K. Pneumococci deprived of choline by cultivation in a medium containing ethanolamine as the only amino alcohol source did not bind to asialo-GM1, indicating that the phosphoryl choline residue of PnC is essential for the interaction between PnC and the glycolipid receptor. These data provide evidence that PnC containing an intact phosphoryl choline residue is a ligand responsible for binding of pneumococci to the receptor asialo-GM1.

Bacterial Adhesion↗
PubMed1996

Reinsemination of one-day-old oocytes by use of intracytoplasmic sperm injection.

OBJECTIVE: To evaluate the possible advantages of reinseminating oocytes by use of intracytoplasmic sperm injection (ICSI). DESIGN: Clinical study. SETTING: In vitro fertilization unit with research facilities. PATIENTS: Fifty-seven couples who were part of our regular IVF program. INTERVENTIONS: Nonfertilized oocytes from IVF cycles with no or very low fertilization were microinjected with spermatozoa approximately 25 hours after oocyte pick-up. MAIN OUTCOME MEASURES: Fertilization and pregnancy rates. RESULTS: A mean fertilization rate of 46.5% was obtained when reinseminating the oocytes on day 2 using the ICSI procedure. Of 57 cycles with completely or almost completely failed fertilization, 29 patients received ET after reinsemination by ICSI. Two of these transfers resulted in pregnancies (6.9% per ET) and two healthy babies were born. CONCLUSION: Despite this relative success, considering both the extra work involved and the potential genetic risk, it is doubtful whether ICSI on day 2 should be recommended as a routine procedure. For training and research purposes, however, this approach can be of value.

Cellular Senescence↗
PubMed1995

Microfertilization techniques--the Swedish experience.

Intracytoplasmic sperm injection (ICSI) has been studied in this animal research programme since 1990. In 1993, the technique was first applied clinically and up to the present time (September 1994), a total of 456 couples have been studied in 538 cycles. The principal indication for the use of ICSI has been severe male sub-fertility as judged by a semen analysis. In addition, men with high titres of antisperm antibodies, blockage of the vas deferens and neurological disorders such as spinal cord lesions have been included in the programme. Men with genetic disorders such as cystic fibrosis and acrosome-deficient spermatozoa have also been treated successfully. The overall fertilization rate using ICSI was 59%, which is similar to the conventional in vitro fertilization (IVF) programme in Göteborg, however, the pregnancy rate per embryo transfer (29%) and the ongoing pregnancy rate per transfer (22%) were slightly lower. The total number of pregnancies was 144 with 111 of the pregnancies either ongoing or already delivered. To date, 36 healthy children have been born following 29 deliveries and no major malformations have been diagnosed. Being the first programme in Scandinavia to perform ICSI, this unit has experienced long waiting lists which indicates that severe male sub-fertility will be one of the major groups for treatment with assisted reproductive technologies in the future.

Cryopreservation↗