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Biomedical subjects

P Sundström

Publications and source records attributed to P Sundström.

At least 19 recordsLinked to original sources
PubMed1998

Establishment of a successful pregnancy following in-vitro fertilization with an endometrial thickness of no more than 4 mm.

Intrauterine pregnancy after superovulation with gonadotrophins and after in-vitro fertilization (IVF) and embryo replacement has not been reported to occur in cases where the thickness of the pre-ovulatory endometrium was <6 mm. We report a case where an intrauterine pregnancy was established where the endometrium was no more than 4 mm in thickness at the time of follicular aspiration. It is suggested that an IVF cycle should not necessarily be abandoned merely because the pre-ovulatory endometrium is thin, and especially if other parameters, including follicular development and serum oestradiol concentrations, are appropriate.

Adult↗
PubMed1996

Human autoantibodies recognizing human and mouse preimplantation stages.

PROBLEM: To find out whether autoantibodies against human preimplantation stages are present in some human sera and, if so, whether the antibodies could be capable to affect the egg development and/or to trigger an activation of the complement system at the procedures of assisted conception. METHODS: 1. Immunohistochemistry on blots of human preimplantation stages. 2. Immunohistochemistry on paraffin sections of human and mouse preimplantation stages. 3. Culture of mouse morulae to analyze complement activation. RESULTS: 1. Some human sera contained autoantibodies against human preimplantation stages. 2. Human-mouse cross-reacting antibodies against preimplantation stages occurred. 3. Immune complexes, formed on mouse preimplantation stages, activated the complement systems in egg cultures, resulting in a damaging of the eggs. CONCLUSION: The presence of natural autoantibodies to preimplantation stages may be associated with reproduction failure, caused by a direct effect by the autoantibodies and/or an activation of the uterine complement system by the immune complexes formed.

Animals↗
PubMed1995

Peter Singer and 'lives not worth living'--comments on a flawed argument from analogy.

The Australian bioethicist Peter Singer has presented an intriguing argument for the opinion that it is quite proper (morally) to deem the lives of certain individuals not worth living and so to kill them. The argument is based on the alleged analogy between the ordinary clinical judgement that a life with a broken leg is worse than a life with an intact leg (other things being equal), and that the broken leg therefore ought to be mended, on the one hand, and the judgement that the lives of some individuals, for example, severely disabled infants, are not worth living and therefore ought to be terminated, on the other. In the present article it is argued that Singer's argument is flawed, intellectually and/or ethically.

Bioethics↗
PubMed1994

Characterization of mouse-hamster-human cross-reacting antioocyte monoclonal antibodies produced by intrasplenic immunization of mice with 12 zona-free mouse oocytes.

Several intrasplenic immunizations with batches of approximately 15 or approximately 30 zona-free, unfertilized mouse oocytes resulted in 200-300 hybrids, respectively, among which about 20 positive clones were selected from each fusion between splenic plasma cells and SP2/0 myeloma cells. When nonimmunized splenic plasma cells were used, only one antibody, showing weak immunoreaction, was obtained from approximately 370 hybrids collected from 2 fusions. From one immunization with a total of 12 zona-free, unfertilized mouse oocytes, 15 positive clones were selected for further study. Eleven of these 15 antibodies reacted with antigens only in unfertilized oocytes but not in fertilized, pronuclear stage oocytes. Three antibodies, which recognized antigens in paraffin-embedded oocyte sections, did not label growing ovarian oocytes, indicating that the antibodies were specific to ovulated, unfertilized oocytes. These antibodies did not detect any antigen epitopes in the panel of tissues examined. The molecular weight of one antigen, corresponding to a IgM antibody that is present both in ooplasma and zona pellucida, was approximately 116 kDa. Cross-reactivity to blots of unfertilized zona-free hamster oocytes was demonstrated by 6 antibodies and to unfertilized human oocytes by 7 antibodies. Three antibodies cross-reacted with both hamster and human oocytes. The study indicates that the intrasplenic immunization is an appropriate means of raising antibodies against unfertilized, zona-free mouse oocytes and that the method applied offers an easy way to select antibodies against human oocytes for functional studies.

Animals↗
PubMed1993

[Past and present--the roots of our modern concept of disease in 19th century clinical practice and science].

Historically speaking, our current clinical conceptions of disease are derived from 19th century science and clinical practice. In the early 19th century, large hospitals with hundreds of patients were erected for the first time. This provided "material" to which the physicians could apply their new diagnostic techniques and tools: percussion and auscultation, aided by the newly invented stethoscope. Eventually, what was found at the bedside was systematically compared with what was discovered on the autopsy table. This clinical research programme was challenged by, though later combined with, the experimental physiology and "laboratory medicine" of men like François Magendie and Claude Bernard. Their strong programme to introduce pure science, i.e. physics and chemistry, into medicine was paralleled by further developments in the old solidistic pathological tradition; an improved microscope and new techniques for preparing tissues for the microscope, led to the development of truly microscopic anatomy and cellular pathology. The idea that disease may be caused by microscopic living organisms was tested by means of strict experimental, scientific methods by men such as Louis Pasteur and Robert Koch; and our current conception of infectious disease is still very similar to that of the first microbiologists of the 1870s and 80s. The last 19th century root of our modern conceptions of disease discussed in the present essay is the visualization of the interior of the body--indeed, the visualization of disease--by X-rays.

Anatomy↗
PubMed1992

Human oocytes express murine retroviral equivalents.

Unfertilized human oocytes expressed a gp70-related epitope as observed when staining section immunocytochemically with a panel of monoclonal antibodies against gp70 of murine leukemia virus. Some oocytes also expressed virus-like particles at the cell membrane. Follicular fluids, corresponding to these oocytes, contained p30- and gp70-related antigens, reverse transcriptase, and an increased titer of interferon. The three- to four-cell human cleavage stages did not contain the gp70-related epitope. It is concluded that human oocytes, but not early cleavage stages, express products that suggest the presence of an active endogenous retrovirus genome.

Antigens, Viral↗
PubMed1991

AIDS, myth, and ethics.

The present paper is a commentary on an article by Larry Churchill. Churchill has argued that the negative attitudes and adverse behavior we commonly encounter in connection with (suspected) AIDS patients may be understood in terms of a dualistic 'myth' inspiring a 'ritual' avoidance of 'dirt', of 'dirt' as something that does not belong to a 'clean' world order. The deep-seated mythical character of attitudes and behavior here makes them less accessible to the kind of rational argument commonly employed in ethics. Churchill also proposes a remedy for the (morally outrageous) dualistic mythical-ritual behavior he has focused - a remedy that may be overly intellectualistic. Three further comments are made: on the metaphorical meaning of 'myth', on a reductionist tendency in Churchill's 'deep'-looking project, and on an ethically crucial ambiguity in the meaning of the other person's 'otherness'. These (mildly critical) comments do not, however, detract from a positive overall evaluation of Churchill's basic idea that we will understand more about adverse attitudes and behavior in connection with AIDS if we think in terms of 'myth', 'ritual', 'dirt', and 'cleanliness'.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Evaluation of variations in pregnancy rates, implantation rates and early abortion rates within an in-vitro fertilization programme.

Despite the application at this clinic of a standardized programme for in-vitro fertilization of human oocytes over the last 27 months, great variations in the rates of implantation, clinical pregnancy and early abortion have been observed during certain periods. A retrospective evaluation of these results showed that these variations occurred in periods when various commercially available batches of Earle's medium (the medium was the only variable changed during the 27 months) were used and that two sub-optimal batches of Earle's medium from one of the sources used during one of three periods (period 2) was most likely to be responsible for sub-optimal embryo quality and, consequently, for a halving of the pregnancy rate (30 versus 15%) and of the implantation rate (11 versus 5%) and an increase in the early abortion rate (23 versus 50%). It is concluded that the quality of the culture medium is of major importance for the success of an IVF programme. The factor(s) in the medium responsible for the decrease in embryo quality has not been identified.

Abortion, Spontaneous↗
PubMed1989

Blastocyst implantation precedes induction of insulin-like growth factor II gene expression in human trophoblasts.

The cytotrophoblast cell population of the human embryonic conceptus proliferates rapidly during the first month following blastocyst implantation. Since the trophectoderm lineage is established in preimplantation morula/blastocysts, the scenario underlying initiation and maintenance of the rapid proliferative phenotype of cytotrophoblasts is a central issue. The insulin-like growth factor II (IGF-II) gene is highly expressed in proliferative cytotrophoblasts of first trimester placenta and performs as a placenta growth factor. To establish a temporal correlation between IGF-II expression and initiation of highly proliferative trophoblasts in human development, we employed in situ hybridization analysis of the expression of the IGF-II and human chorionic gonadotropin beta-subunit (beta-HCG) genes in human pre- and postimplantation development. The data show that the appearance of high steady-state levels of IGF-II transcripts in trophoblasts is a postimplantation event, whereas beta-HCG transcripts can already be detected in preimplantation development. This observation makes a role for endogenously produced IGF-II in the normal development of preimplantation embryos unlikely, but suggests that endogenously produced IGF-II participates in the formation and subsequent expansion of the rapid proliferative phenotype of the trophoblastic shell, following implantation.

Blastocyst↗