[Cases of measles in Denmark are caused by reintroduction of virus from abroad]

Measles vaccination was implemented in the child vaccination programme in Denmark in 1987 and produced a rapid decline in the incidence. Few cases were recorded annually until 1999. The measles virus isolated in Denmark during 1997-1998 was compared by partial sequencing of the haemagglutinin-coding region with Danish strains from the prevaccination era collected in 1965-1983, as well as with representatives of globally circulating strains of today. The dissimilarity of the prevaccination era strains identified in Denmark in 1997-1998 along with the similarity of these five strains with globally circulating strains at present, substantiate the conclusion that there is no persistent circulation of the measles virus in Denmark.

Processing of N-linked oligosaccharides on the measles virus glycoproteins: importance for antigenicity and for production of infectious virus particles

The envelope of measles virus (MV) particles contains two viral glycoproteins, the haemagglutinin (H) and the fusion (F) protein, which together induce the entry of MV into cells. In the present study, we investigated the role of oligosaccharide processing for the function and antigenicity of the MV glycoproteins by means of glycosidase inhibitors. Golgi alpha-mannosidase inhibitors (1-deoxymannojirimycin and swainsonine) prevented the oligosaccharides on the MV glycoproteins from obtaining Endo H resistance, but that did not appear to influence in vitro MV infections, indicating that conversion of oligosaccharide chains into the complex form was not required for the function of the MV glycoproteins. The alpha-glucosidase inhibitor castanospermine (CSP) quantitatively reduced the production of infectious MV particles in cells infected with both vaccine strain and wild-type MV. CSP reduced the detection of the MV F protein by certain monoclonal antibodies (MAbs) that appeared to recognize nonlinear epitopes. CSP also inhibited syncytium formation in MV infected cells, but did not affect MV induced CD46 downregulation, suggesting that CSP primarily influenced the F protein. We propose that CSP induces aberrant folding of MV glycoproteins in a manner that influences their function and antigenicity.

The role of subtilisin-like proprotein convertases for cleavage of the measles virus fusion glycoprotein in different cell types

The fusion (F) glycoprotein gene of measles virus (MV) encodes a nonfusogenic precursor protein (F0) that is activated by cleavage into the F1 and F2 subunits during transport to the cell surface. The F protein of both the Edmonston strain and a wild-type MV was found to be cleaved in the trans-Golgi cisternae and/or the trans-Golgi network (TGN). In HEp-2 cells, B lymphoblastoid cells, and PBMC, the cleavage process required calcium, and calcium deprivation prevented syncytium formation. The calcium dependence indicated the involvement of the pro-protein convertase (PC) endoprotease family. The expression of the presently recognized members of the PC family in human cell types known to be infected during measles was examined by RT-PCR. Among the PCs residing in the TGN, only furin was expressed in all cells. Soluble secreted human furin produced by a recombinant baculovirus cleaved MV F0 into proteins the exact size of F1 and F2 and increased the titer of MV particles released from calcium-deprived or endoprotease defective infected cells. These results strongly indicate that furin is the most important and maybe the only endoprotease involved in activation of the MV F protein.

Trials of Edmonston-Zagreb measles vaccine in Guinea-Bissau: serological responses following vaccination with Edmonston-Zagreb strain at 4-8 months versus vaccination with Schwarz strain at 9-12 months of age

In two trials of measles vaccination in Guinea-Bissau, children were randomized to receive either the Edmonston-Zagreb (EZ) virus at age 4-8 months or, as a control group, a standard dose (5000 p.f.u.) of the Schwarz (SW) virus at 9-12 months. In the first trial a medium dose of EZ virus (40,000 p.f.u.) was used and in the later trial a high dose (150,000 p.f.u.). Pre- and postvaccination blood samples were analysed with a haemagglutination inhibition (HAI) test and an enzyme-linked immunosorbent assay (ELISA). For the ELISA the blood samples were collected on filter paper. Of 362 prevaccination specimens, 18 and 55%, respectively, were positive in the ELISA and HAI tests. At 18-20 months, the children who had received the EZ vaccine had a seropositivity of 91% by the ELISA method and one of 89% by the HAI method. The equivalent values for the SW group of children were 100 and 96% respectively. Antibody levels in the EZ group, as measured by either method, were significantly lower than the levels in the SW group. The serological results of the present study suggest that lowering the age at measles vaccination to below 9 months is feasible. However, further studies are needed to determine which virus strain, dosage and age at vaccination will prove to be optimal in countries where severe measles is common before the age of 9 months.

Studies on manifestations of canine distemper virus infection in an urban dog population

An upsurge of canine distemper was recognized at the beginning of 1991 in the urban dog population of the Copenhagen area. The outbreak had the characteristics of a virulent morbillivirus introduction in a partly immune population, where the disease primarily was manifested in young individuals. Testing of single serum samples for the presence of canine distemper virus (CDV) IgM antibodies using an IgM ELISA confirmed current and recent CDV infections in an urban dog population, where the use of attenuated CDV vaccines was widespread. In 49 out of 66 sera from clinical cases suspected of canine distemper we detected CDV IgM antibodies, as compared to the detection of viral antigen by indirect immunofluorescence in 27 of 65 specimens of conjunctival cells. The antigenic make-up of isolates from acute and subacute clinical cases was investigated with a panel of 51 monoclonal antibodies directed against CDV and the related phocine distemper virus. The isolates exhibited an homogeneous reaction pattern and shared overall antigenic characteristics of the CDV prototype. The majority of cases were diagnosed among unvaccinated dogs and individuals with unknown or obscure vaccination record. However, severe clinical cases were also diagnosed in vaccinated individuals.

[Complications of second-look surgery for ovarian cancer]

All complications were registered in 139 consecutive second-look operations for ovarian cancer. Forty-one complications were registered in 33 patients, none lethal. The most frequent complications were anaemia requiring blood-transfusion (10.7%) and acute cystitis (4.3%). Other complications were seen with frequencies between 0.7 to 2.8 percent. No differences with respect to complications were found between patients with residual tumour versus those without, nor between patients where only biopsies were taken versus those who had organs removed. Although the patients were in clinical complete remission, 53% were found to have residual disease at second-look operation.

Iscom immunization with synthetic peptides representing measles virus hemagglutinin

Synthetic peptides representing the measles virus (MV) hemagglutinin (MVH) were incorporated into immunostimulating complexes (iscoms) and used for immunization of rabbits. Nine regions of MVH were selected on the basis of hydropathy and antigenicity profiles, by use of the known primary structure of MVH. Six linear and three branched types of peptides were synthesized and conjugated to palmitic acid before incorporation into the iscom structure. Five of the anti-peptide sera reacted by ELISA with the homologous peptide but did not react with MV in the native state, indicating that either the selected sites are not represented on the surface of MV, or they could be a conformational epitope. Human-anti MV and rabbit anti-MV did not react with the peptides.

[Permanent central venous catheters in oncologic patients]

Permanent central venous catheters play an important role in the treatment of patients with malignancies. Two systems are available, Hickman-Broviac Catheters (HB) and Port-a-Cath (PAC), the latter is fully implantable. Since 1982, the systems have been used in the Finsen Institute. In the period 01.01.1984 to 31.03.1988 a total of 232 HB and 52 PAC were inserted in 245 patients with solid malignant tumours with one exception. All the catheters were inserted with the venous cut-down technique and at the end of the period mainly in local analgesia. The total indwelling time was 36,859 days, mean 99 days (1-616 days) for HB and 92 days (8-519 days) for PAC. Seventeen catheters remained in place for more than 365 days. A total of 114 complications concerning 88 catheters were registered. The most serious complications were sepsis and thrombosis. The frequency of sepsis was low, 0.06 (HB) and 0.01 (PAC) per 100 catheter-days. The corresponding frequency of thrombosis was 0.03/100 catheter-days for both systems. Sixty-one HB and five PAC had to be removed because of complications. In general, the complication rate was lower for the PAC method. In addition, the nursing care was reduced to a minimum. The surgical cut-down method is preferable, as catheter implantation is possible even in patients with disorders of the coagulation system.

Appendectomy and carcinoma ovarii. Cytoreduction, palliation, or simple tradition?

The present article is based on a review of 187 patients with an ovarian cancer who had a "second-look" or debulking operation performed. Seventy-nine patients underwent appendectomy prior to or in connection with the primary cytoreductive surgery and were observed for a average of 16.6 months before secondary oncologic surgery was performed. The remaining 108 patients had their appendix in situ during the same period and were observed for an average of 14.7 months and 1 patient developed acute appendicitis. A total of 125 appendectomies were performed in patients with cancer of the ovary and 14 (11%) showed metastatic growth. The two groups were similar as regards age, period of observation, tumor type and stage. The risk of developing acute appendicitis did not exceed the incidence in healthy women and no surgical problems were experienced in observing either of the two groups during the total period of 2,900 months. The need for surgical surveillance, however, was significantly greater for those who kept their appendix during the medical oncologic treatment. It is concluded that the cytoreductive effect of an appendectomy is limited, but that the appendix should be extirpated if possible as part of the primary staging effort. Leaving an appendix in situ at primary cytoreductive surgery does not expose the patient to any significantly increased risk, but an appendectomy prevents the patient from experiencing the additional burden of an acute appendicitis during medical oncologic treatment.

Detection of IgM antibodies against canine distemper virus in dog and mink sera employing enzyme-linked immunosorbent assay (ELISA)

An enzyme-linked immunosorbent assay (ELISA) for the detection of IgM antibodies against canine distemper virus (CDV) in canine and mink serum is described. The diagnostic potential of this technique was evaluated by analyzing sera from natural or experimental infections in dog and mink and negative control sera. These results were compared with results obtained in the developed CDV IgG ELISA and in the virus neutralization test. The IgM test, which requires only a single serum specimen, is a useful method for diagnosing current or recent CDV infections in dog and mink.

Subclinical measles infection in vaccinated seropositive individuals in arctic Greenland

Measles vaccination was performed in the arctic district of Scoresbysund, Greenland in 1968, which had never been exposed to natural measles. More than 90% of the total population was vaccinated and a 94-100% seroconversion was obtained. During a serological survey to examine the immunity status of the vaccinees, it was discovered that a temporary increase in measles antibodies took place in the majority of the population 2-4 years after the vaccination. This was not accompanied by clinically observed measles. Most likely, it was due to an inapparent measles infection in a population considered highly immune after vaccination.

Child mortality related to seroconversion or lack of seroconversion after measles vaccination

When blood samples were analyzed for seroconversion after measles vaccination, it was discovered that the vaccine had been ineffective for a certain period. During the 2 years between vaccination and the time of seroanalysis, nonseroconverters had a significantly higher mortality than seroconverters (P less than 0.05). The incidence of measles among nonseroconverters was 30% during the period. Between 9 months and 3 years of age, cumulative mortality was 15.1% for nonseroconverters and 4.5% for seroconverters. The difference in mortality was larger when high risk groups (twins, motherless children) were excluded from the analysis (P less than 0.01). The difference in mortality was particularly marked among children vaccinated in the age group 9 to 11 months. This as well as other community studies suggest that measles vaccination reduces child mortality from the age of vaccination by at least 30%.

Vaccinated children get milder measles infection: a community study from Guinea-Bissau

We studied the occurrence of measles in vaccinated children from an urban area of Guinea-Bissau where measles causes high mortality. Vaccinated children who developed measles required more-intense exposure to become infected (they had a higher ratio of secondary cases [infected in the house] to index cases [infected outside the house]), had a lower mortality among secondary cases, and were less infectious (they generated fewer secondary cases than did unvaccinated children with measles). The attack rate among vaccinated children was significantly higher in households in which someone died of measles. Both severity of infection and development of measles in vaccinated children were related to intensity of exposure. Vaccine efficacy was 72%, and 33% of cases occurred among vaccinated children; however, most mothers remained confident that vaccinated children get milder measles. Moreover, there was significantly greater vaccination coverage among younger siblings of vaccinated children who had contracted measles than among other children in the community.

Long-term antibody response after measles vaccination in an isolated arctic society in Greenland

Scoresbysund is an isolated district on the east coast of Greenland with 500 inhabitants, mainly Polar Eskimos, which had never been exposed to natural measles. In 1968 more than 90% of the population were vaccinated with the Schwarz live further-attenuated measles vaccine and subsequently children born after 1968 likewise received the measles vaccination. Upon the initial measles vaccination no clinical cases of measles have been observed. The immunity status of the isolated population has been followed for 16 years after vaccination by IgM, IgA, and IgG ELISA tests and by HI test on a series of serum samples taken at intervals. Immunoblotting was performed on sera obtained 16 years after the vaccination. In general, antibody studies have demonstrated some decline in antibody titres after the initial measles vaccination. However, a temporary moderate increase in measles antibodies occurred in some individuals 2-4 years after vaccination, probably due to a reinfection of vaccinees. Most of these individuals did not have demonstrable IgA antibodies prior to the supposed reinfection.

High measles mortality in infancy related to intensity of exposure

In a West African urban community, measles infection in infants was examined over 5 years (1979-1983). In the age group 0 to 11 months, measles mortality was higher among secondary cases (infected in the house) than among index cases (infected outside the house), and the proportion of secondary cases was significantly higher for this age group than for older children. Intensive exposure related to the social pattern of disease transmission may be important in explaining the high infant mortality observed with measles in developing countries. Mortality during the first 12 months of life increased with age, presumably because of the decrease of maternally derived measles antibodies. In children younger than 6 months of age, who are usually considered to be protected by maternal antibody, intensive exposure may lead to infection, as demonstrated by a high level of measles-specific antibodies in some children exposed to an older sibling with measles. The aim of public health policies should be to change conditions of exposure.

Detection of measles IgM antibodies by enzyme-linked immunosorbent assay (ELISA)

An enzyme-linked immunosorbent assay (ELISA) for the detectors of IgM antibodies in serum during acute or recent measles infections is described. False positive reactions due to rheumatoid factors (RF) were not observed in the test of human sera to which were added sera containing RF. Monospecific antisera against the haemagglutinin, nucleoprotein and polymerase of measles virus were used in a blocking IgM ELISA, revealing a sensitive method for the detection of the antibodies that take part in the immune reactions. An ELISA for the detection of measles-specific IgG in order to reveal IgM or IgG antibodies in the human sera is also described.

Production of antiserum to respiratory syncytial virus polypeptides: application in enzyme-linked immunosorbent assay

By use of crossed immunoelectrophoresis techniques, respiratory syncytial (RS) virus-specific precipitates were produced between RS virus cellular antigen [solubilized in tris(hydroxymethyl)aminomethane-glycine buffer, pH 9] and antiserum raised in rabbits against semipurified RS virus. When these precipitates were employed as antigens for further immunizations in rabbits, antibodies (anti-RSV-precip.I) were produced which reacted with only one RS virus antigen when tested by the crossed immunoelectrophoresis technique. Precipitates obtained between RS virus cellular antigen (labeled with L-[35S]methionine) and anti-RSV-precip.I were examined by polyacrylamide gel electrophoresis, which showed that anti-RSV-precip.I precipitated RS virus polypeptides of molecular weights 28,000 to 84,000. Anti-RSV-precip.I was employed as capture antibodies in the enzyme-linked immunosorbent assay, in which RS virus cellular antigen was used as the second layer. Determination of human RS virus immunoglobulin G antibodies by this enzyme-linked immunosorbent assay technique showed a high degree of sensitivity, specificity, and reproducibility.

New method for production of influenza A virus subtype specific antisera: employment of precipitate obtained by crossed immunoelectrophoretic techniques as antigen

The crossed immunoelectrophoretic technique was employed for the production of subtype-specific influenza A virus antisera. Glycoprotein-containing precipitates were produced by this technique by using detergent solubilized influenza A virus glycoproteins as antigens in the first dimension gel and rabbit antisera against these antigens in the second dimension gel. By cutting these precipitates out of the gel and using them for the immunization of rabbits, antisera were produced which showed the presence of subtype-specific antibodies in haemagglutination inhibition and immunofluorescent antibody tests but no antibodies in neuraminidase inhibition tests.

Characterization of ribonucleoproteins and ribosomes isolated from lymphocytic choriomeningitis virus

Disruption of purified lymphocytic choriomeningitis (LCM) virus with Nonidet P-40 in 0.5 M KCl followed by sucrose gradient centrifugation in 0.3 M KCl led to the isolation of two viral nucleoproteins (RNPs) as well as 40S and 60S ribosomal subunits. The largest viral RNP sedimented heterogenously at 123S to 148S and was associated with 23S and 31S viral RNA. The other viral RNP sedimented at 83S and was associated with 23S viral RNA. The buoyant density in CsCl was determined to be 1.32 g/cm3 for the viral RNP. Densities of 1.52 and 1.60 g/cm3 were determined for the 40S and 60S subunits, similar to those of the BHK-21 cells subunits dissociated by 0.5 M KCl. The viral RNPs were partly sensitive to RNase.

Different classes of ribonucleic acid isolated from lymphocytic choriomeningitis virus

Purified preparations of lymphocytic choriomeningitis virus (LCM virus) contain three classes of RNA. The previously described 18s, 23s, 28s, and 31s RNAs, where the 23s and 31s RNAs are viral-specific, and the 18s and 28s RNAs probably are host RNAs incorporated in the virion. Now, 4s, 5s, and 5.5s RNAs can be isolated as well. Thus five RNAs which migrate by acrylamide gel electrophoresis as ribosome-derived RNA can be isolated from purified LCM virus. This observation further supports the reports that arenaviruses may contain ribosomes. The ribosome-derived RNA can be synthesized both before and after the virus infection. The viral 23s could be a hydrogen-bonded complex forming the 31s RNA, or it could be contained in defective interfering LCM virus particles; these possibilities are examined.

Density gradient centrifugation studies on lymphocytic choriomeningitis virus and on viral ribonucleic acid

Lymphocytic choriomeningitis (LCM) virus, Traub strain, was purified from BHK-21 tissue culture medium. The virus was then analyzed by equilibrium centrifugation and rate zonal centrifugation in sucrose gradients. A buoyant density in sucrose of 1.18 g/ml was found and the S(20, w) value was estimated to be about 470 to 500S. Furthermore, the (3)H-uridine-labeled ribonucleic acid (RNA) from virus was extracted from LCM virus and analyzed by rate zonal centrifugation. Two major and one minor single-stranded RNA components were found with sedimentation coefficients of 28, 22, and 18S.