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Biomedical subjects

A Sjögren

Publications and source records attributed to A Sjögren.

At least 19 recordsLinked to original sources
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↗
PubMed1995

Monoclonal antibodies against human blastocysts.

A panel of monoclonal antibodies against the implanting mouse blastocyst was tested for cross-reactivity to human blastocysts. The monoclonal antibodies were produced by intrasplenic immunization with living mouse blastocysts or egg-cylinders. Among the 13 anti-mouse blastocyst antibodies checked, 6 ones detected antigen epitopes also in human blastocysts. If the mouse-human cross-reacting antibodies detect similar antigens in blastocysts of the two species, the results imply that anti-mouse blastocyst antibodies with specific properties could be used for studying human blastocysts. This procedure opens for a way to obtain monoclonal antibodies for analysing human blastocysts.

Animals↗
PubMed1995

[Patient insurance in preventive activities. Wealth of injury material demonstrates risks of complications].

The patient insurance system in Sweden has manifest advantages where the mapping out of complications to medical treatment is concerned. The insurance data base contains a wealth of information which can be used for preventive purposes--not only overall statistics, but also patients' records and expert opinions in damage cases. During the 20 years since patient insurance was introduced, cases of special fundamental interest have been published, injury statistics have reported to clinics and departments, and certain issues have undergone special scrutiny--e.g. neural damage during surgery, infections arising from cataract surgery, bile duct injuries, injuries at delivery and damage resulting from physiotherapy.

Adult↗
PubMed1994

Specific binding of Streptococcus pneumoniae to two receptor saccharide structures.

Specific binding of Streptococcus pneumoniae to two proposed receptor structures was studied in a solid-phase assay. The assay was based on immunodetection of the pneumococci adhering to the receptors coated to microtiter plates. Non-specific binding owing to hydrophobic forces to uncoated wells could be abolished by treatment of the plates with a blocking buffer. Binding of the pneumococcal cells was demonstrated with the glycolipid asialo-GM1 as receptor with a previously suggested specificity for the disaccharide GalNAc beta 1-4Gal. A non-capsulated mutant bound with high efficiency to this receptor. Two capsulated strains also bound well, but with lower efficiency. Binding of the non-capsulated strain was also demonstrated with lactotriaosylceramide as receptor with a suggested specificity for the disaccharide GlcNAc beta 1-3Gal. The binding assay enables the comparison of the adherence of different strains to purified receptor molecules.

Bacterial Adhesion↗
PubMed1994

Fertilization and pregnancy after intracytoplasmic microinjection of acrosomeless spermatozoa.

Spermatozoa lacking acrosomes were injected into the cytoplasm of mature human oocytes. In two subsequent cycles, 12 of 28 (43%) oocytes were fertilized, and the ET of the second cycle resulted in a twin pregnancy. This report describes, to the best of our knowledge, the first case of successful fertilization and delivery after using acrosomeless spermatozoa. Our hope is that with increasing experience with microinjection, in the near future, this type of infertility will not remain a serious problem.

Acrosome↗
PubMed1993

Effects of terbutaline on basal thermogenesis of human skeletal muscle and Na-K pump after 1 week of oral use--a placebo controlled comparison with propranolol.

1. A double-blind placebo-controlled study was conducted on the effects of oral terbutaline (beta 2-adrenoceptor agonist) and propranolol (beta 1 beta 2-adrenoceptor antagonist) on basal heat production of skeletal muscle, measured ex vivo by direct microcalorimetry. Terbutaline slow-release 7.5 mg, propranolol 80 mg, and matching placebo were randomly administered twice daily for 1 week to 15 healthy males, using a cross-over design. 2. Resting heat production in biopsied vastus lateralis was lowered by median 27% (P < 0.01) after terbutaline medication as compared with placebo. The cause of this hypometabolism at the cellular level is obscure but may possibly be explained by desensitization of beta 2-receptors. 3. Propranolol decreased the metabolic rate by 17% (P > 0.3); this might imply that the sympathetic nervous system is playing only a minor role in the regulation of basal metabolic rate in muscle, or that up-regulation of beta-receptors had influenced the decline. 4. The muscle utilized about 6% of its total energy for the Na-K pump as assessed after inhibition by ouabain. 5. Serum potassium was significantly lowered by terbutaline and slightly increased by propranolol with no relationship between changes in extracellular levels and muscle content of potassium under resting conditions. Energy values for the Na-K pump in muscle after 1 week of terbutaline or propranolol medication were similar to placebo. The results are not consistent with the hypothesis that decreased serum potassium during continuous beta 2-adrenoceptor agonist treatment is due to a chronically activated Na-K pump, at least not in resting muscle.

Adult↗
PubMed1992

Culture of human spare preembryos: association between blastocyst formation and pregnancy.

The rate of blastocyst development was studied in cultures of human fertilized eggs. A total of 195 spare embryos from 86 cycles in 73 in vitro fertilization (IVF) patients resulted in a total of 77 expanded blastocysts, corresponding to an overall blastocyst development of 39%. In the group of patients where pregnancy occurred, at least one of the spare embryos developed into the blastocyst stage in 100% of the patients, while the corresponding figure for nonpregnant patients was 53%. Superficially these results seem to indicate that blastocyst development could be of decisive importance for the success rate in IVF. A detailed analysis revealed, however, that this is not the case as long as in vitro culture before replacement is limited to 2-3 days.

Adult↗
PubMed1991

Intrauterine capsules for incubation of gametes and subsequent release of embryos.

In order to obtain incubation in uteri of spermatozoa, oocytes, and embryos, for treatment of patients referred for in vitro fertilization, a capsule was produced which could contain the human gametes and allow human fertilization and embryo growth after intrauterine introduction. Agar was chosen for capsule material and a mold was constructed for the production of capsules. The material was tested in vitro using mouse embryos and human oocytes and sperm. Intrauterine resolution was tested on mice and by insertion on 11 women. Empty capsules were inserted into the uterine cavity in 15 cycles the day after the luteinizing hormone peak and followed by daily ultrasound examinations. The resolution time was adjusted by changing the wall thickness of the capsules. The final type was dissolved after 3 to 4 days. No complications were observed and capsules could be inserted on all occasions. The major problem was expelling of capsules, which occurred in seven cycles. The problem seemed to be solved by the administration of indomethacin at the day of insertion.

Adult↗