Managing Epstein-Barr virus and other risk factors in MS-Future perspectives

Here, we discuss the rationale and feasibility of treatment directed against the modifiable risk factors in multiple sclerosis. The established environmental risk factors vitamin D insufficiency, cigarette smoke exposure, adolescence overweight, and Epstein-Barr virus infection are reviewed. Already available measures to target these risk factors are discussed.

Sick leave and professional assistance for multiple sclerosis individuals in Vä sterbotten C ounty, northern Sweden

The aims of this study of a cross-sectional multiple sclerosis (MS) population in V ä sterbotten C ounty, northern Sweden, were to estimate the prevalence of sick leave, professional assistance and housing; to study risk factors for sick leave; and to estimate the odds for sick leave in comparison with the general population of the county. The consequences of MS-related incapacity on the socioeconomic factors studied were considerable. A lmost half (45%) of prevalent MS cases aged 18-64 years were fully sick listed and only one-third (35%) were not sick listed at all. Every fourth individual in the prevalence population received professional assistance, and 9% were living in care homes or special apartments for the disabled. Multiple logistic regression analysis identified the Expanded Disability Status Scale (EDSS) as the strongest predicto r of sick leave. The time from symptom onset to full sick leave leading to temporary or permanent disability pension was significantly shorter for cases with progressive onset, higher age at onset and in males. The risk of full sick leave due to MS was six times higher than in the general population.

Vitamin D and multiple sclerosis—from epidemiology to prevention

In the present review, we discuss observational and experimental data suggesting a protective effect from sun exposure and/or vitamin D in multiple sclerosis (MS). These data include geographic variations in MS occurrence, temporal trends, genetics, biobank, and questionnaire data. We look more closely at the differentiation between general effects from UV exposure, and those of vitamin D per se, including plausible mechanisms of action. Finally, primary prevention is touched upon, and we suggest actions to be taken while awaiting the results from ongoing randomized controlled trials with vitamin D in MS.

Increasing prevalence of multiple sclerosis in Västerbotten County of Sweden

OBJECTIVES

To update the incidence and prevalence of multiple sclerosis (MS) in Västerbotten County, Sweden, and to compare this to previous investigations in the same area.

BACKGROUND

Northern Sweden is a high-risk area for developing MS. Västerbotten County has previously been surveyed in detail regarding the occurrence of MS. In several countries, increases in MS prevalence and incidence as well as a change in the sex ratio have been reported.

MATERIALS AND METHODS

Multiple sources were used to identify MS cases in Västerbotten that either had their onset of the disease from 1998 to 2010 and/or lived in Västerbotten, the two dates chosen for prevalence calculation: the 31st of December 2005 and 2010.

RESULTS

The mean yearly incidence of MS in Västerbotten during the entire period 1998-2010 was 6.0/100,000. The female to male ratio was 2.1. The prevalence of MS in Västerbotten was 188/100,000 on 31st of December 2005 and 215/100,000 on 31st of December 2010. The MS prevalence increased over time from 1990 to 2010.

CONCLUSIONS

The prevalence of MS in Västerbotten County has increased between 1990 and 2010, while no statistically significant increase in incidence was seen.

Vitamin D and axonal injury in multiple sclerosis

Background:

Previous studies in patients with multiple sclerosis (MS) have shown an association between high serum 25-hydroxyvitamin D (25[OH]D) levels and decreased inflammatory activity.

Objective:

The purpose of this study was to examine the association between 25(OH)D levels and axonal injury in MS. Cerebrospinal fluid neurofilament light (CSF-NFL) was used as a marker for axonal injury.

Methods:

Patients were identified through clinical practice at the Department of Neurology in Umeå University Hospital, Sweden. Blood draw, magnetic resonance imaging, scoring of disability and lumbar puncture were performed at inclusion in 153 patients, and also at median 12 months follow-up in 87 patients. For analyses of serum 25(OH)D levels and CSF-NFL, enzyme-linked immunosorbent assays were used.

Results:

There was an inverse association between serum 25(OH)D and CSF-NFL levels in categorical (dichotomized at 75 or 100 nmol/l) analyses. A dose-response effect for 25(OH)D levels on CSF-NFL levels ( p for trend=0.034) was also present. Serum 25(OH)D levels above 100 nmol/l were associated with lower CSF-NFL levels independently of ongoing MS treatment.

Conclusion:

High 25(OH)D levels are associated with decreased axonal injury in MS.

Targeting Epstein-Barr virus infection as an intervention against multiple sclerosis

We here review contemporary data on genetic and environmental risk factors, particularly Epstein-Barr virus infection, for multiple sclerosis. There is an important immunogenetic etiological factor for multiple sclerosis. However, a general assumption is that immune defense genes are activated by the environment, basically by infections. We contend that the relationship between infectious mononucleosis and multiple sclerosis cannot be completely explained by genetics and inverse causality. Epstein-Barr infection as indicated by positive serology is an obligatory precondition for multiple sclerosis, which is a stronger attribute than a risk factor only. Data on events in the early pathogenesis of multiple sclerosis are cumulating from bio-banks with presymptomatic specimens, but there is only little information from the critical age when Epstein-Barr infection including infectious mononucleosis is acquired, nor on the detailed immunological consequences of this infection in individuals with and without multiple sclerosis. We discuss how focused bio-banking may elaborate a rationale for the development of treatment or vaccination against Epstein-Barr virus infection. A cohort in which intervention against Epstein-Barr infections was performed should be the object of neurological follow-up.

Cytomegalovirus seropositivity is negatively associated with multiple sclerosis

BACKGROUND

Epidemiological data suggest a role for common viruses in the pathogenesis of multiple sclerosis (MS), and recent data showed a negative association of past cytomegalovirus (CMV) infection on pediatric MS risk.

OBJECTIVE

Our aim was to analyze the association of CMV infection with MS risk in an adult case-control material. A meta-analysis was performed to validate our findings.

METHODS

Epidemiological Investigation in MS (EIMS) is a case-control study with incident cases and population-based controls. Anti-CMV antibody titers were measured with ELISA, and HLA-A and DRB1 genotyping was performed with SSP-PCR, in 658 MS cases, who all fulfilled the McDonald criteria for MS, and 786 controls.

RESULTS

CMV seropositivity was associated with a decreased MS risk, OR = 0.73 (0.58-0.92 95% CI), p = 0.005, adjusted for index age, gender, smoking, sun exposure, EBNA1 IgG titer and HLA-A*02 and DRB1*15. When we removed all cases and controls younger than 18 years at index, the protective effect was still apparent.

CONCLUSIONS

CMV is negatively associated with adult-onset MS pathology, consistent with results from a study on pediatric MS cases. It remains to be shown whether this negative association is due to a true protective effect of CMV infection on MS risk.

Automated determination of brain parenchymal fraction in multiple sclerosis

BACKGROUND AND PURPOSE

Brain atrophy is a manifestation of tissue damage in MS. Reduction in brain parenchymal fraction is an accepted marker of brain atrophy. In this study, the approach of synthetic tissue mapping was applied, in which brain parenchymal fraction was automatically calculated based on absolute quantification of the tissue relaxation rates R1 and R2 and the proton attenuation.

MATERIALS AND METHODS

The BPF values of 99 patients with MS and 35 control subjects were determined by using SyMap and tested in relationship to clinical variables. A subset of 5 patients with MS and 5 control subjects were also analyzed with a manual segmentation technique as a reference. Reproducibility of SyMap was assessed in a separate group of 6 healthy subjects, each scanned 6 consecutive times.

RESULTS

Patients with MS had significantly lower BPF (0.852 ± 0.0041, mean ± SE) compared with control subjects (0.890 ± 0.0040). Significant linear relationships between BPF and age, disease duration, and Expanded Disability Status Scale scores were observed (P < .001). A strong correlation existed between SyMap and the reference method (r = 0.96; P < .001) with no significant difference in mean BPF. Coefficient of variation of repeated SyMap BPF measurements was 0.45%. Scan time was <6 minutes, and postprocessing time was <2 minutes.

CONCLUSIONS

SyMap is a valid and reproducible method for determining BPF in MS within a clinically acceptable scan time and postprocessing time. Results are highly congruent with those described using other methods and show high agreement with the manual reference method.

Epstein-Barr virus and multiple sclerosis: interaction with HLA

Epstein-Barr virus (EBV) infection, history of infectious mononucleosis (IM) and HLA-A and DRB1 have all been proposed as risk factors for multiple sclerosis (MS). Our aim was to analyse possible interactions between antibodies against Epstein-Barr virus nuclear antigen 1 (EBNA1) or EBNA1 fragments, presence of DRB1*15 and absence of A*02. The study population includes newly diagnosed cases and matched controls. Interaction on the additive scale was calculated using attributable proportion due to interaction (AP), which is the proportion of the incidence among individuals exposed to two interacting factors that is attributable to the interaction per se. IM showed association with MS, odds ratio (OR)=1.89 (1.45-2.48% confidence interval (CI)), as did raised EBNA1 IgG OR=1.74 (1.38-2.18 95%CI). All EBNA1 fragment IgGs were associated with MS risk. However, EBNA1 fragment 385-420 IgG levels were more strongly associated to MS than total EBNA1 IgG, OR=3.60 (2.75-4.72 95%CI), and also interacted with both DRB1*15 and absence of A*02, AP 0.60 (0.45-0.76 95%CI) and AP 0.39 (0.18-0.61 95%CI), respectively. The observed interaction between HLA class I and II genotype and reactivity to EBV-related epitopes suggest that the mechanism through which HLA genes influence the risk of MS may, at least in part, involve the immune control of EBV infection.

Combined effects of smoking, anti-EBNA antibodies, and HLA-DRB1*1501 on multiple sclerosis risk

OBJECTIVE

To examine the interplay between smoking, serum antibody titers to the Epstein-Barr virus nuclear antigens (anti-EBNA), and HLA-DR15 on multiple sclerosis (MS) risk.

METHODS

Individual and pooled analyses were conducted among 442 cases and 865 controls from 3 MS case-control studies-a nested case-control study in the Nurses' Health Study/Nurses' Health Study II, the Tasmanian MS Study, and a Swedish MS Study. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% CIs for the association between smoking, anti-EBNA titers, HLA-DR15, and MS risk. Study estimates were pooled using inverse variance weights to determine a combined effect and p value.

RESULTS

Among MS cases, anti-EBNA titers were significantly higher in ever smokers compared to never smokers. The increased risk of MS associated with high anti-EBNA Ab titers was stronger among ever smokers (OR = 3.9, 95% CI = 2.7-5.7) compared to never smokers (OR = 1.8, 95% CI = 1.4-2.3; p for interaction = 0.001). The increased risk of MS associated with a history of smoking was no longer evident after adjustment for anti-EBNA Ab titers. No modification or confounding by HLA-DR15 was observed. The increased risk of MS associated with ever smoking was only observed among those who had high anti-EBNA titers (OR = 1.7, 95% CI = 1.1-2.6).

CONCLUSIONS

Smoking appears to enhance the association between high anti-EBNA titer and increased multiple sclerosis (MS) risk. The association between HLA-DR15 and MS risk is independent of smoking. Further work is necessary to elucidate possible biologic mechanisms to explain this finding.

Season of birth and multiple sclerosis in Sweden

OBJECTIVE

To estimate the risk of multiple sclerosis (MS) by month of birth in Sweden.

MATERIALS AND METHODS

Cases (n = 9361) were obtained from the Swedish MS Registry. All births in Sweden 1900-2007 served as controls (n = 12,116,853). The risk of MS was analyzed for each month of birth separately compared with birth during the other 11 months.

RESULTS

More (11%) cases with MS than expected were born in June. Fewer (8% and 10%) cases with MS than expected were born in December and January (non-significant after correction for multiple analyses). More (5%) cases with MS than expected were born in February-July as compared with August-January.

CONCLUSIONS

This study supports previous results suggesting an association between the risk of MS and the season of birth. Decreased exposure to sun in the winter leading to low vitamin D levels during pregnancy is a possible explanation that needs further research.

Smoking worsens the prognosis in multiple sclerosis

OBJECTIVE

To estimate the effect of smoking on the risk for progression in multiple sclerosis (MS).

METHODS

Self-reported data were used on smoking habits in 122 incident cases with disability assessments made after a median of 6 years disease duration.

RESULTS

Ever smokers were more likely to have progressive disease compared with never smokers (P < 0.01). This was most pronounced in ever smokers with early smoking debut (< or = 15 years of age) for whom progressive disease was significantly more likely and occurred at an earlier age, compared with those with later smoking debut (P < 0.01 for both) or never smokers (P < 0.01 for both). Earlys moking start also predisposed to a progressive disease from onset when compared with never smokers (P = 0.012). A multivariate Cox regression analysis of sex, age at disease onset (above vs. under median) and smoking (ever vs. never) status showed that cases with late disease onset had three times higher risk and ever smokers had twice as high a risk for progression.

CONCLUSION

Past smoking is associated with a worsened prognosis in MS. The negative effect from smoking is most obvious in ever smokers with early smoking debut, which also affects MS phenotype significantly.

EBNA-1 reactivity and HLA DRB1*1501 as statistically independent risk factors for multiple sclerosis: a case-control study

OBJECTIVES AND METHODS

The interaction between the two best documented risk factors (human leukocyte antigen [HLA] class II [DRB1*1501 positivity] and Epstein-Barr virus [elevated Epstein-Barr nuclear antigen 1 (EBNA-1) antibody reactivity]) for multiple sclerosis (MS) was studied in a case-control study of biobank samples from 109 MS cases and 212 matched referents.

RESULTS

Multivariate logistic regression analysis showed that both were statistically significant in both sexes. HLA DRB1*1501-positive referents had higher EBNA-1 reactivity than HLA-negative referents. Less EBNA-1 reactivity was required to increase the MS risk in HLA DRB1*1501-positives than in HLA-negatives.

CONCLUSION

We suggest that HLA DRB1*1501-positive individuals have an increased vulnerability to EBV-induced autoimmunity.

An altered immune response to Epstein-Barr virus in multiple sclerosis: a prospective study

OBJECTIVE

To investigate the association between human herpesviruses and multiple sclerosis (MS), as well as between measles virus and MS.

METHODS

The authors identified prospectively collected serum samples from 73 MS cases and retrospective sera from 161 MS cases in two population-based serum bank registers. Analyses of IgG antibody responses in cases and matched referents were performed for Epstein-Barr virus (EBV [EBNA-1 and VCA]), human herpesvirus 6 (HHV-6), herpes simplex virus (HSV), varicella zoster virus (VZV), and measles.

RESULTS

All cases showed signs of past EBV infection. High activity to EBNA-1 and HHV-6 significantly (borderline significance for HHV-6) increased the risk for MS in prospective sera. A discrepancy between activities to EBNA-1 and VCA was striking in MS samples collected less than 5 years before relapsing-remitting MS onset, where high activity to EBNA-1 significantly increased, and high VCA activity significantly decreased the risk for MS. There was no support for major causal roles for HSV, VZV, or measles.

CONCLUSION

Individuals who will develop MS exhibit an altered immune response against the EBV virus characterized by a high IgG activity to EBNA-1 in the absence of high activity to VCA, this being most pronounced in the 5-year period preceding MS onset.

Neurofilament and glial fibrillary acidic protein in multiple sclerosis

OBJECTIVE

To evaluate levels of neurofilament light (NFL) and glial fibrillary acidic protein (GFAP) in CSF from patients with multiple sclerosis (MS) in relation to clinical progress of the disease.

METHODS

CSF levels of NFL and GFAP were determined by sensitive ELISAs in 99 patients with different subtypes of MS, classified in terms of "ongoing relapse" or "clinically stable disease," and 25 control subjects. Levels were compared with paraclinical data such as immunoglobulin G index and inflammatory cell count in the CSF, and the levels were related to Expanded Disability Status Scale score and progression index at clinical follow-up evaluations later in the disease course.

RESULTS

NFL and GFAP levels were elevated in MS patients as compared with control subjects (p < 0.001). The NFL levels were higher at relapses, whereas GFAP levels were unaffected. High NFL levels correlated with progression in patients with an active relapse (r = 0.49; p < 0.01) and in clinically stable patients (r = 0.29; p < 0.05). GFAP correlated to progression in the total patient cohort (r = 0.24; p < 0.05). Moreover, a strong correlation between NFL levels and inflammatory cell counts was evident in the group of patients with an ongoing relapse (r = 0.52; p = 0.001).

CONCLUSIONS

CSF levels of neurofilament light and glial fibrillary acidic protein may have prognostic value in multiple sclerosis.

Clinical characteristics of multiple sclerosis in Västerbotten County in northern Sweden

BACKGROUND

Most clinical data for multiple sclerosis are hospital based-that is, derived from patients referred to clinics specialising in the disease.

OBJECTIVES

To present data derived from two population based multiple sclerosis populations, an incidence cohort and a prevalence population, from Västerbotten County, northern Sweden.

METHODS

The two populations were identified from multiple sources, and case ascertainment was assured through a personal clinical review, including interviews and examination of the patients.

RESULTS

Characteristics at onset for the different clinical subtypes of multiple sclerosis are presented, including the clinical spectrum of the first attack, the anatomical correlation between the first and second attacks, sex distribution, and disability distribution.

CONCLUSIONS

Based on the comparison of present and earlier natural history data, multiple sclerosis appears to be a slightly more benign disease than previously recognised.

Native and transformed alpha2-macroglobulin in plasma from patients with multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease with unknown etiology. Various proteinases have been observed in increased levels in the central nervous system of patients with MS, which may contribute to the release of immunogenic myelin components. alpha2-Macroglobulin (alpha2M) inhibits a broad spectrum of proteinases sterically, undergoing major conformational changes induced by the proteinases themselves. Moreover, alpha2M acts as a carrier of several cytokines in the systemic circulation. By use of radial immunodiffusion, we determined the total alpha2M levels in plasma from 28 MS patients and 15 control subjects [14 patients with other neurologic diseases (OND) and one healthy individual]. No significant differences in total alpha2M concentration were observed between the MS patients and the control subjects. A comparison of the degree of alpha2M transformation in MS patients with different disease courses and controls was performed, using monoclonal antibodies (mAbs) specific for binding to native and transformed alpha2M, respectively. The fractions of transformed alpha2M were significantly increased in patients with secondary or primary progressive disease course compared with the controls. No significant differences were obtained using a native-specific mAb. At least a major proportion of alpha2M from the MS patients was able to change conformation from its native to its transformed state, as demonstrated by a shift in mAb reactivity, following methylamine treatment of the plasma samples. In conclusion, the results indicate that plasma alpha2M may be inactivated at a higher degree in patients with chronic progressive MS compared with patients with OND. This may influence the levels of proteinases and cytokines in the systemic circulation and may furthermore have diagnostic implications.

Incidence (1988-97) and prevalence (1997) of multiple sclerosis in Västerbotten County in northern Sweden

OBJECTIVE

To investigate the incidence and prevalence of multiple sclerosis in Västerbotten County in northern Sweden.

METHODS

Multiple sources were used in the case identification process. Follow up interviews with clinical examinations were undertaken and, when indicated, additional paraclinical investigations were done. In this way case ascertainment was assured and supplemental clinical data were collected. The incidence rate was based on symptom onset. Onset adjusted prevalence was applied.

RESULTS

The crude incidence rate of multiple sclerosis in 1988-97 in Västerbotten County was 5.2/10(5) (95% confidence interval, 4.4 to 6.2): 6.7/10(5) (6.0 to 8.3) in women and 3.7/10(5) (2.7 to 4.9) in men. The onset adjusted prevalence for 31 December 1997 was 154/10(5) (139 to 170): 202/10(5) (179 to 228) in women and 105/10(5) (89 to 125) in men. When compared with a previous estimate of prevalence, a yearly 2.6% increase in prevalence between 1990 and 1997 was found, mainly attributable to a higher incidence than mortality.

CONCLUSIONS

The present incidence rate and prevalence confirms earlier findings that Västerbotten is a high risk area for multiple sclerosis. The adjusted incidence was twice as high as the incidence from 1974-88 in the only previous Swedish population based study from Göteborg, but comparable with other recent Fennoscandian multiple sclerosis incidence rates.

Confocal laser fluorescence scanning microscopy of the oolemma distribution of monoclonal antibodies against mouse and human egg surface membrane

Monoclonal antibodies were raised against zona-free mouse oocytes by intrasplenic immunizations. Antibodies, which detected antigen epitopes in unfertilized but not in fertilized mouse eggs (fertilization-specific antibodies) and which in addition recognized epitopes in unfertilized human oocytes (mouse-human cross-reacting antibodies) were used to visualize the distribution of their corresponding antigens by confocal laser fluoresence scanning microscopy (CLFSM). We found that among 26 antibodies tested, two ones showed a patch pattern. Since a patchy distribution of cell membrane molecules indicates the presence of integral proteins with ability to transduce signals to the cytoplasm, we suggest that the method here applied will select for those oolemma molecules that could be involved in the fusion of sperm cells.

Prevalence of multiple sclerosis in Västerbotten County in northern Sweden

OBJECTIVE

To estimate the prevalence and clinical characteristics of multiple sclerosis (MS) in Västerbotten County in northern Sweden.

METHODS

Individuals with MS were identified from several sources. A follow-up interview and/or examination was performed in 94% of cases still living in the area during 1997-99. Onset adjusted prevalence and a definition of onset symptoms were applied.

RESULTS

A total of 313 cases were identified, resulting in an onset adjusted crude prevalence of MS for January 1990 of 125/105 (95% confidence interval (CI): 112-140). Female predominance was evident (163/105 (95% CI: 142-187) vs 86/105 (95% CI: 71-104)). Diagnostic coding registers were the most important source for identification of cases.

CONCLUSIONS

The crude prevalence of MS in Västerbotten was higher than previous reports from other major areas in Scandinavia. The adjusted prevalence was significantly higher when compared with a previous study from Göteborg, south-western Sweden. The methodology used in this study gives a high degree of case ascertainment and increases the comparability of multiple sclerosis epidemiological studies.

Expression of envelope proteins of endogeneous C-type retrovirus on the surface of mouse and human oocytes at fertilization

Retrovirus genomes express, among other products, the envelop (env) proteins SU (gp70) and TM (p15E). They coexist at the viral surface membrane and are able to promote immunosuppression and membrane fusion. In mouse oocytes, endogeneous retroviruses (ERV) genomes are expressed at fertilization, and antigen epitopes of the Moloney murine leukemia virus (MuLV) env protein gp70 are recognized in the cytoplasm of the oocytes before but not after fertilization. By using a panel of monoclonal antibodies (mAbs) raised against env components, we checked with laser scanning confocal microscopy (LSCM) whether gp70 and p15E were expressed also on the oocyte surface membrane (oolemma). Since we found that both mouse and human unfertilized oocytes expressed these ERV proteins on the oolemma and that the expression enfeebled significantly after fertilization, we assume that ERV genomes could play a role at the sperm-egg binding and fusion.

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.

Interpreting the notion that technology is value-neutral

Value-freedom or value-neutrality is a well-known topic in the philosophy of science. But what about the value-neutrality of technology, medical or other? Is it too far-fetched to imagine technology as in some sense value-neutral--in view of its intimate connection with purposeful human action? No; unexpected perhaps, but less far-fetched than expected. If we try to conceive of technology as a cognitive possibility abstracted from each and every specific social context, we shall find (at least) three senses in which it may be regarded as value-neutral: (1) neutral vis-à-vis different possible uses and ends; (2) neutral before action; (3) neutral qua cognitive object, analogous to the cognitive core of science. The further meanings and implications of these three senses of value-neutrality are discussed. What is this exercise good for? The nature of technology is indeed worth pondering in its own right, not least from this rather unusual angle. But beyond that: as the possible meanings of value-neutrality are tried out, the radical nature of human responsibility for the social implementation of technology will be highlighted.

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.

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.

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.

[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.

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.

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'.

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.

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.

Meiotic and cytoplasmic maturation of oocytes collected in stimulated cycles is asynchronous

Oocytes collected in stimulated cycles are more readily fertilized after preincubation than are oocytes inseminated immediately after collection. It has not been ascertained, however, whether this increase in the fertilization rate is due to extrusion of the first polar body (meiotic maturation) during this period, or to some conclusive cytoplasmic maturation subsequent to the polar body extrusion. When analysing oocytes with a polar body (n = 14) by transmission electron microscopy, differences were observed in the appearance of cytoplasmic features which were correlated to the total durations both of systemic human chorionic gonadotrophin influence before collection and of oocyte culture. These differences were manifested as a delayed formation in aggregates of the smooth endoplasmic reticulum in the ooplasm of oocytes having a polar body and might have signified a cytoplasmic maturation. The degree of asynchrony in the oocytes varied and this could explain why some oocytes can be fertilized when inseminated shortly after collection and others not until 8 h or even more after collection. Thus, although meiotic and cytoplasmic maturation is likely to be synchronized at ovulation of an oocyte in a natural cycle, they appear to be mainly asynchronous in oocytes collected in stimulated cycles.

Pregnancy rate in relation to number of cleaved eggs replaced after in-vitro fertilization in stimulated cycles monitored by serum levels of oestradiol and progesterone as sole index

A simple model for monitoring ovarian stimulation in in-vitro fertilization cycles was designed using daily serum levels of 17 beta-oestradiol and progesterone as the only index to determine the day of ovum retrieval. Human chorionic gonadotropin was administered in the evening 2 days after a level of 2500 pmol/l oestradiol in serum was exceeded provided the serum progesterone level was less than 5 nmol/l. Ovarian stimulation was initiated in 128 women scheduled for laparoscopic oocyte retrieval. Twelve cycles (9%) were cancelled before ovum pick up due to sub-optimal hormone levels in serum and five for other reasons. In 107 successful laparoscopies, 616 oocytes (mean 5.8 per laparoscopy) were recovered. The cleavage rate after IVF was 65% in the egg replacement group. In 87 women, a total of 271 cleaved eggs (range 1-6, mean 3.1) were replaced. The most important factor for establishing a pregnancy was the number of eggs replaced at the same time. Clinical pregnancies were achieved after 30% of replacements, increasing to 50% after replacement of 5-6 eggs. The ongoing/delivered pregnancy rate after the 18th week of gestation was 69%. It was concluded that the simple monitoring model used was consistent with a high pregnancy rate and a low rate of cancelled cycles.