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Biomedical subjects

A Sjögren

Publications and source records attributed to A Sjögren.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1991

Interleukin-1 alpha modulates luteinizing hormone stimulated cyclic AMP and progesterone release from human granulosa cells in vitro.

This study examines the possible direct effect of interleukin-1 alpha (IL-1 alpha) upon human granulosa cells. The cells were isolated from follicles of stimulated cycles in women undergoing oocyte retrieval for in-vitro fertilization. Purified cell preparations were cultured for different time periods in the presence of IL-1 alpha and human luteinizing hormone (LH) or follicle stimulating hormone. IL-1 alpha stimulated basal as well as LH-induced progesterone accumulation. The response in terms of cyclic AMP was more complex, there was no effect of IL-1 alpha on basal cyclic AMP accumulation. However, at the highest concentration tested (50 IU/ml), IL-1 alpha enhanced cyclic AMP accumulation over that seen with LH alone. At a lower concentration, IL-1 alpha either had no effect or was slightly inhibitory to the LH-induced cyclic AMP accumulation, depending on the culture period. Our results, taken together with other findings, are compatible with the view that IL-1 alpha has a potential regulatory role in the granulosa-luteal cell transition in the human ovary.

Cells, Cultured↗
PubMed1990

Human immunodeficiency viral protease is catalytically active as a fusion protein: characterization of the fusion and native enzymes produced in Escherichia coli.

Processing of the gag and pol gene precursor proteins of retroviruses is essential for the production of mature infectious virions. The processing is directed by a viral protease that itself is part of these precursors and is presumed to cleave itself autocatalytically. To facilitate study of this process, the protease was produced as a fusion protein in Escherichia coli. In this construct, the 10,793-Da protease was preceeded by two copies of a modified IgG binding domain derived from protein A. The IgG binding domain was linked to the protease by an Asp-Pro peptide bond which could not be cleaved by the viral protease. A dimer of the 25,400-Da fusion protein was catalytically active, specifically cleaving a substrate peptide at the correct Tyr-Pro bond. Thus, the fusion protein could serve as a model of the viral gag-pol polyprotein. The finding that the fusion protein was catalytically active supports the suggestion that a gag-pol dimer can initiate a proteolytic cascade after budding of the immature virus. The fusion protein also provided a source of authentic protease. The protease was released from the fusion construct by incubation with formic acid, cleaving the Asp-Pro linkage which had been inserted between the IgG binding domain and the protease.

Amino Acid Sequence↗
PubMed1990

Prostaglandin-E2 released by pre-implantation human conceptuses.

This work investigates the production of prostaglandin E2 (PGE2), a well known modulator for the suppression of immune cells, by pre-implantation human conceptuses from the 4-cell stage to the hatched blastocyst and by cumulus oophorus cells, these being obtained from an IVF/ET program. Cumulus cell complexes cultured for 48 h produced considerable amounts of PGE2, necessitating complete removal of their influence on the conceptus cultures. All stages of the human conceptus studied produced PGE2 during 48-h cultures, the greatest amounts from late blastocysts, and from those cultured in media containing bovine serum albumin rather than human donor serum. Indomethacin-treated control blastocysts confirmed the synthesis and release from the human conceptuses. The production of PGF2a from human blastocysts could not be demonstrated.

Blastocyst↗
PubMed1989

Diagnosis of pulmonary embolism based upon alveolar dead space analysis.

Pulmonary embolism (PE) leads to an abnormal alveolar deadspace that is expired in synchrony with gas from normally perfused alveoli. This feature of PE separates it from pulmonary diseases affecting the airways, which are characterized by nonsynchronous emptying of compartments with an uneven ventilation/perfusion relationship. An analysis of the single breath test (SBT) for CO2, SBT-CO2, focusing on the late tidal expirate, was made in order to evaluate the feasibility to use the SBT-CO2 for the diagnosis of PE. The test was evaluated in 38 patients with suspected PE where pulmonary angiography showed that nine had PE and 29 did not. It was also tested in a reference population consisting of patients with normal lung function, obstructive lung disease and interstitial lung disease. Previously suggested gas exchange measurements for the diagnosis of PE, ie, the physiologic deadspace fraction, VDphys/VT, and the arterial-to-end-tidal CO2 gradient, P(a-E')CO2, were also evaluated in the groups. SBT-CO2 achieved a nearly complete separation between the patients with PE and those without. The other measurements, however, showed a substantial overlap between patients with PE and those with obstructive or interstitial lung disease. The SBT-CO2 is simple and potentially widely available and warrants further study as a routine technique for the diagnosis of PE.

Angiography↗
PubMed1988

Digoxin, magnesium, and potassium levels in a forensic autopsy material of sudden death from ischemic heart disease.

In 91 cases where the cause of death was heart disease, digoxin, Mg and K concentrations in serum and ventricular myocardium were measured post mortem. Forty per cent were positive for digoxin in both serum and myocardium. The mean serum level was 5.1 +/- 2.4 nmol/l and the mean myocardial level was 42.6 +/- 27.5 ng/g. Correlation could be established between serum and myocardial concentrations of digoxin. There were statistically significant differences in serum as well as in myocardial digoxin levels in persons on 0.13 mg and 0.25 mg per day, respectively. Myocardial levels of Mg and K were low as generally found in persons with ischemic heart disease. There was no correlation between these levels and myocardial digoxin concentrations. Caution must be exercised in the assessment of digoxin results from cadaver samples because of the postmortem rise of digoxin serum concentrations. Considering this fact, the results still indicate that the prevalence of toxic digoxin concentrations might be more common than previously thought.

Adult↗
PubMed1988

Production and characterization of monoclonal antibodies against Staphylococcus aureus alpha-toxin.

Murine monoclonal antibodies against staphylococcal alpha-toxin were produced using a well-characterized alpha-toxin fragment preparation as immunizing agent. Three monoclonal antibodies were selected for anti-alpha-toxin activity in an ELISA using alpha-toxin as antigen. The monoclonal antibodies (MAbs) belonged to different immunoglobulin classes/subclasses and showed different abilities to neutralize the hemolytic, cell-membrane-damaging, dermonecrotizing and lethal action of alpha-toxin. One MAb was superior to mouse polyclonal antiserum in all test systems except for hemolysis, whereas another MAb neutralized essentially as the polyclonal serum. The third MAb did not neutralize the hemolytic or dermonecrotic effect but still inhibited the lethal and membrane-damaging effect of alpha-toxin. These results indicate that the three MAbs recognize different epitopes on the toxin molecule and that different biological activities might correspond to these epitopes.

Animals↗