[Vaccination of young children, at school entrance and completion in the Bern canton 1998]. / Durchimpfung bei Kleinkindern, nach Schuleintritt und -austritt im Kanton Bern 1998.

Vaccine coverage and role of school physicians for vaccination was evaluated among 1260 and 840 children respectively, in the State of Berne, in 1998. Vaccine coverage (three doses) was sufficient for diphtheria, tetanus and poliomyelitis (95%), but unsatisfactory for pertussis (90%) and measles-mumps-rubella (MMR, 78-80%). The situation was stable in comparison to the year 1995, only vaccine coverage against Haemophilus influenzae Typ b increased (15-20%). School children of non-Swiss origin, especially those born outside Switzerland had partially low vaccination coverage. The percentage vaccinate was 88%, 84% and 68% for MMR. There was no association between vaccine coverage and school examination by family or school physician. The Swiss Public Office of Health should be more involved with the promotion of vaccinations.

A waterborne outbreak of small round structured virus, campylobacter and shigella co-infections in La Neuveville, Switzerland, 1998.

An outbreak of gastro-enteritis occurred in La Neuveville, township with 3358 inhabitants. A retrospective cohort study of 1915 participants showed that 1607 (84%) had been ill. Campylobacter jejuni was isolated from 28 patient faecal samples, Shigella sonnei from 21 patients and small round structured viruses (SRSV) from 6 patients. More than one pathogen was identified in eight persons. The epidemic curve was characteristic of a point-source outbreak. The risk for illness was significantly higher among persons who had drank unboiled drinking water than among those who had not (1290 [80.3%] of 1607 vs. 86 [27.9%] of 308; RR = 2.87; 95% CI 2.40-3.45). Risk increased significantly with the quantity of water consumed (P < 0.00 x 10(-6)). An SRSV isolate from water and one human faeces had an identical DNA sequence. The outbreak was due to a pump failure producing a spill of sewage into the groundwater. We conclude that transmission was waterborne and that measures including early warning, basic hygiene and sanitation improvements controlled this epidemic.

Ex vivo expansion of megakaryocytic cells.

The use of platelet transfusion to ensure the recovery of thrombopoiesis in patients constitutes high-cost support. The identification and cloning of recombinant human thrombopoietin (TPO) and the development of efficient methods of purification of hematopoietic stem cells and progenitor cells have ameliorated the development of strategies of ex vivo expansion of megakaryocyte (MK) progenitor cells and mature MKs. Synergistic combinations of cytokines including TPO, interleukin (IL)-1, IL-3, IL-11, stem cell factor, and FLT-3 ligand induce the ex vivo expansion of colony-forming unit-MK progenitors and MKs from cytokine-mobilized peripheral blood cells, bone marrow, and cord blood CD34+ cells. Depending on the various culture conditions, i.e., combinations of growth factors, initial concentration of CD34+, serum or serum-free cultures, and/or oxygen tensions, the expansion-fold of MKs and their progenitor cells vary greatly. The clinical applications of the reinfusion of ex vivo-generated MK cells have been investigated successfully in cancer patients following high-dose chemotherapy. This review reports the latest information concerning ex vivo expansion of MKs and the current status of clinical trials.

[Diagnosis and treatment of pulmonary tuberculosis in asylum seekers and refugees in the Bern canton 1993-1997]. / Diagnose und Behandlung der Lungentuberkulose bei Asylsuchenden und Flüchtlingen im Kanton Bern 1993-1997.

As part of a preventive program asylum seekers and refugees are screened for tuberculosis. Necessary treatments have to be administered in the accepting canton. Aim of this cohort study was to assess the way of diagnosis and the outcome of treatment in 64 cases of pulmonary tuberculosis and positive culture in the Canton of Berne between 1993 and 1997. Results existed for 62 of them (96.9%). 34 cases of tuberculosis were discovered by screening and 23 more than 6 months afterwards. 87.1% of all cases were treated for more than 6 months. Among patients with unfavourable outcome four disappeared, three were transferred out. Efficacy of screening for tuberculosis depends also on follow-up during treatment which took place in the Canton of Berne. A strict organisation like the one applied in Berne or directly controlled treatment are necessary to warrant curative treatment.

Ruthenium hexaammine trichloride chemography for aggrecan mapping in cartilage is a sensitive indicator of matrix degradation.

We developed a new quantitative histochemical method for mapping aggrecan content in articular cartilage and applied it to models of cartilage degradation. Ruthenium hexaammine trichloride (RHT) forms co-precipitates with aggrecan, the main proteoglycan component of cartilage, and was previously found to be a good fixative in aiding the maintenance of chondrocyte morphology. We show that these RHT-aggrecan precipitates generate a positive chemographic signal on autoradiographic emulsions, in the absence of any radioactivity in the tissue section, via a process similar to the autometallographic process used previously for localization of trace metals ions in tissues. By exploiting the inherent depth-dependence of aggrecan concentration in adult articular cartilage, we demonstrated that the density of silver grains produced by RHT-derived chemography on autoradiographic emulsions correlated with locally measured aggrecan concentration as determined by the dimethylmethylene blue assay of microdissected tissue from these different depths of cartilage. To explore the benefits of this new method in monitoring tissue degradation, cartilage explants were degraded during culture using interleukin-1 (IL-1) or digested after culture using chondroitinase and keratinase. The RHT chemographic signal derived from these samples, compared to controls, showed sensitivity to loss of aggrecan and distinguished cell-mediated loss (IL-1) from degradation due to addition of exogenous enzymes. The RHT-derived chemographic grain density represents an interesting new quantitative tool for histological analysis of cartilage in physiology and in arthritis.

[Measles outbreaks in the Bern canton]. / Masern-Ausbrüche im Kanton Bern.

Currently, overall vaccination coverage against measles among infants ranges between 77% and 89% in Switzerland. Experience in other countries has shown that this level of vaccination is not sufficient to prevent measles outbreaks, especially among schoolchildren. During 1992 surveillance for measles outbreaks in closed populations was conducted in the Canton of Berne. Outbreaks were investigated for vaccine efficacy. Two measles outbreaks in schoolchildren were observed during the study period. In 2 Bernese suburban schools 6 measles cases in children (median age 12.5 years) occurred over a period of 37 days. One of the cases had been vaccinated. Vaccination rate in the healthy control children was 89.7%. Estimated vaccine efficacy was 97.7% (95% confidence interval [CI]: 68%, 99%). The second outbreak occurred in a rural region and comprised 21 measles cases (median age 7.5 years) within 43 days. 10 (47.6%) of the cases attended the same school. None of the cases had been vaccinated. Of the healthy control children 82.6% had received measles vaccine. Estimated vaccine efficacy was 100% (CI: 87%, 100%). These two measles outbreaks were due to failure to vaccinate rather than low vaccine efficacy. Surveillance for measles cases is currently not sufficient for the detection of measles outbreaks in our population. Laboratory confirmation of measles, especially in vaccinated persons, has become more important in a time of relatively low measles incidence.

[Chemokines and the regulation of hematopoiesis]. / Les chémokines et la régulation de l'hématopoièse.

Chemokines are a large family of cytokines that act not only as immune and inflammatory regulators but also as regulators of hematopoiesis. Two major subfamilies of chemokines are distinguished on the basis of whether the first two cysteines are separated by a single residue (CXC) or three residues (CX3C) or they are adjacent (CC) or there is a single C. The Macrophage Inflammatory Protein 1 alpha (MIP-1 alpha), which belongs to CC family is a powerful inhibitor of hematopoisis in vitro and in vivo. The sub-family CXC comprises two main groups. The first sub-group includes the ELR chemokines, in which interleukin-8 (IL-8) is the most prototypic and possesses suppressive activities on hematopoiesis. Platelet Factor 4 (PF4) belongs to the sub-group of non-ELR CXC chemokines. PF4 acts as an inhibitor of hematopoiesis, particularly of the megakaryocytopoiesis. Recently, it has been shown that a peptide of PF4, 34-58 which does not contain the site of heparin binding, is able to inhibit the growth of hematopoietic progenitors in vitro, providing evidence for a model of heparin dependent and independent pathways of PF4 action on hematopoiesis. PF4 can reduce the chimiosensitivity of hematopoietic cells in mice treated by the cytotoxic drug 5-Fluorouracyl, suggesting a potential clinical application of PF4 in cancer therapy.

[Vaccination coverage in young children and school children in the Bern canton]. / Durchimpfung bei Kleinkindern und Schulkindern im Kanton Bern.

In 1995 immunization coverage at 24 months of age and after the first school year was estimated according to the method recommended by the WHO. Vaccination booklets of 840 children born in 1986, 1987, 1988 or 1991 in the Canton of Berne were reviewed. The response rate was high (96%). The immunization coverage at 24 months of age were for measles 74%, for mumps and rubella (MMR) 72% higher than for diphteria (D), tetanus (T) (62%) and poliomyelitis (polio) (60%) (4 doses) (p < 0.0001). Of the Swiss children born in 1991 32% were vaccinated against tuberculosis. Children 24 months of age of all years had generally a similar immunization coverage. The 101 children of foreign nationalities showed somewhat lower vaccination rates. Immunization uptake for MMR, DT and polio (4 doses) increased over time, so that children born in 1986 at 8.5 years of age had the rate (> 95%) to be reached at the end of the second year of life. After the first school year 88% of the 8.5 years old children presented a vaccination against MMR and 91% a vaccination against measles. Intensified efforts are necessary to achieve a higher immunization coverage at 24 months of age especially among children of foreign nationality, a timely administration of vaccines according to recommended immunization schedule and to restrict BCG vaccine to children at increased risk of tuberculosis.

A method of quantitative autoradiography for the spatial localization of proteoglycan synthesis rates in cartilage.

Incorporation of [35S]-sulfate into cartilage tissue indicates the synthesis of aggrecan, the large aggregating proteoglycan (PG) that endows cartilage with resistance to compression. Scintillation counting of tissue digests provides a quantitative measure of incorporated sulfate but does not provide information on the spatial location of synthesis within the tissue. Such spatially specific information is necessary to determine which cell populations respond to diffusible factors and to correlate local mechanical events (e.g., deformation, interstitial fluid stress) to cellular biosynthetic responses. The aim of this study was to develop and characterize a liquid emulsion autoradiography technique, including an automated grain counting procedure, to derive spatial profiles of aggrecan synthesis rates in cartilage. We chose mature 10-14-month-old bovine humeral head articular cartilage as a model system and applied a liquid emulsion autoradiography technique to [35S]-sulfate-labeled, resin-embedded, and semithin-sectioned tissue explants. High-magnification light microscopy color images were captured on a computer. Automated image analysis for grain number determination included a color thresholding procedure to discriminate grains from the lightly stained structural image and computation of the average area of a single grain from each image. Determination of grain number, whether originating from single grains or grain clusters, was performed by dividing the total grain area in the image by the average area of a single grain in the same image. This procedure largely eliminated the effects of variations of microscope light intensity, camera performance, image focus, section stain intensity, and thresholding on the resulting grain numbers. By altering the specific activity of the medium radiolabel and the emulsion exposure times, we demonstrated a linear dose dependence, without saturation, of grain number on radioactive content in the underlying section. By cutting specimens in half and performing liquid scintillation counting on one half and autoradiography on the other half, we found that each disintegration occurring in the section during exposure resulted in 0.67 +/- 0.21 grains (mean +/- SD; n = 58). Therefore, counted grain numbers can be directly converted to incorporated sulfate, largely reflecting the synthesis of the PG aggrecan. As an example of calculated intratissue profiles of aggrecan synthesis rates, we found for the mature bovine tissue in serum-free medium that aggrecan synthesis increases monotonically from the articular surface to the radial zone by as much as tenfold.

Inhibitory effect of platelet factor 4 on human erythroleukemic cells is dependent on cell surface heparan sulfate.

We have previously reported that platelet factor 4 (PF4) inhibits human erythroleukemic (HEL) cell growth in a dose-dependent fashion in vitro and that PF4 binds to HEL cells in a specific, saturable, and concentration-dependent manner. In this article we demonstrate that the binding of PF4 on HEL cells and its inhibitory effect on HEL cell growth were mediated by heparan sulfate. We found that binding of iodine 125-labeled PF4 to HEL cells was inhibited by heparin, heparan sulfate, and dermatan sulfate and to a smaller extent by chondroitin sulfate. Ninety percent of 125I-labeled PF4 bound to HEL cells was released by cells after exposure to heparin and heparan sulfate. Treatment of cells with heparitinase and heparinase induced a decrease in the binding of 125I-labeled PF4 to cells. Binding of 125I-labeled PF4 was partially inhibited by the presence of increasing concentrations of protamine sulfate and basic fibroblast growth factor. To test whether PF4 bound to cell surface proteoglycans, proteoglycan synthesis was inhibited by using 4-methylumbelliferyl-beta-D-xyloside. The binding of 125I-labeled PF4 on treated cells was decreased, and xyloside treatment of cells abrogated the biologic activity of PF4 in a plasma clot culture system. The inhibitory effect of PF4 was retained in a serum-free agar culture system, which indicates that the binding of PF4 to HEL cells induces cell growth inhibition in a direct fashion. Taken together, these findings suggest that PF4 directly acts on HEL cell growth by fixation on heparan sulfate proteoglycans on the HEL cell surface.

[A look back at 2 mumps outbreaks]. / Rückblick auf zwei Mumpsausbrüche.

Two studies are presented. The first one concerns a mumps outbreak in a kindergarten in Geneva in June 1991. Of 26 children, nine (34.6%) got mumps. Of nine children vaccinated with the Rubini vaccine strain, seven had the disease as opposed to only one of 14 children vaccinated with the Urabe strain. The vaccine efficacy of the Rubini strain was estimated at 22% with a 95% confidence interval of -10% to 45%. The second study concerns a cluster of 112 mumps patients seen by a pediatrician in the Bernese Jura region between September 1992 and May 1993. A case-control study was carried out resulting in a vaccine efficacy estimate of 50% with a 95% confidence interval of -19% to 81%. Of the cases, 51 (45.5%) had been vaccinated against mumps, 50 of them (98%) with the Rubini vaccine strain. Of the controls, 30 (61.2%) had been vaccinated, 86.7% of them with Rubini. Methodological problems of case selection and their possible effects on the estimated vaccine efficacy are discussed. The results of these two studies have been confirmed by more recent investigations. In retrospect, we therefore conclude that small studies can serve as early indicators for epidemiological evidence and that they can be finally integrated into a more complete picture.

Glycosaminoglycans enhance human leukemic cell growth in vitro.

We have previously shown that heparin and heparan sulfate stimulate the growth of human erythroleukemia cells in vitro in the presence of serum or plasma. To determine whether heparin and other glycosaminoglycans (GAGs) are involved in the growth of leukemia cells, effects of GAGs on the growth of three leukemia cell lines expressing different phenotypes, the HEL, HL60 and U937 cell lines were studied using both plasma clot and serum-free agar systems. The cells were cultured with different doses of six GAGs: hyaluronic acid, chondroitin sulfate, dermatan sulfate, keratan sulfate, heparin and heparan sulfate. It was found that, in serum-free agar system, no GAG was able to stimulate (HEL) cell growth. In contrast, when serum-containing culture systems were used, all six GAGs promoted colony formation of HL60 and U937 cells. In addition, all GAGs, except keratan sulfate, stimulated the growth of HEL cells. The findings suggest that the GAGs may play an indirect role in enhancing leukemia cell proliferation by different mechanisms.

Spontaneous megakaryocyte colony formation in myeloproliferative disorders is not neutralizable by antibodies against IL3, IL6 and GM-CSF.

Megakaryocyte progenitor growth in 42 patients with myeloproliferative disorders (MPD), including 23 essential thrombocythaemia (ET), eight polycythaemia vera (PV), six chronic myelogenous leukaemia (CML) and five primary myelofibrosis (PMF), was studied in vitro using plasma clot assay and serum-free agar culture. Spontaneous megakaryocyte colonies (CFU-MK) were found in 34/40 (80%) blood and 14/18 (77.8%) bone marrow plasma clot cultures, and also observed in 27/35 (77.1%) blood and 10/18 (55.6%) bone marrow serum-free agar cultures. In the blood of 27 patients with MPD (15 ET, four PV, four CML and four PMF) and the bone marrow of 10 patients (five ET, four CML and one PV), spontaneous colony formation was observed in both plasma clot and serum-free agar cultures. However, spontaneous CFU-MK was only found in plasma clot culture, but not in agar culture in two blood (one ET and one CML) and four bone marrow cultures (one ET, two PV, one CML). The colony numbers were greatly increased in the presence of aplastic anaemia serum (AAS) under both conditions. In 17 patients (12 ET, two CML and three PV) with spontaneous megakaryocyte colonies, anti-cytokine antibody neutralizing experiments were carried out in blood cultures. Anti-IL3, anti-IL6 and anti-GM-CSF antibody, alone or in combination, at different concentrations (1, 5 and 10 micrograms/ml), were added into plasma clot or agar cultures without exogenous stimulating growth factors. The results showed that the numbers of spontaneous megakaryocyte colonies were not significantly decreased in the presence of these monoclonal antibodies in the cultures. The data indicated that the megakaryocyte progenitor growth in MPD under in vitro conditions was heterogenous, and independent of exogenous stimulatory factors in most patients and that optimal megakaryocyte colony development in MPD still requires exogenous growth factors. Three possibilities are discussed with regard to the phenomenon that the spontaneous colony formation was not decreased with the addition of anti-IL3, anti-IL6 and anti-GM-CSF antibodies.

Cellular uptake of titanium and vanadium from addition of salts or fretting corrosion in vitro.

The use of titanium and titanium-6% aluminum-4% vanadium alloy for dental and orthopedic implants has increased in the last decade. The implants are presumed to be compatible because osseointegration, bony apposition, and cell attachment are known. However, the cellular association of titanium and vanadium have remained unknown. This study examined the uptake of salts or fretting corrosion products. Titanium was not observed to be toxic to the cells. Vanadium was toxic at levels greater than 10 micrograms/mL. The percentage of cellular association of titanium was shown to be about 10 times that of vanadium. The percentage of cellular association of either element was greater from fretting corrosion than from the addition of salts. The presence of vanadium did not affect the cellular uptake of titanium. The presence of titanium decreased the cell association of vanadium.

Reduction of fretting corrosion of Ti-6Al-4V by various surface treatments.

Titanium and titanium-6% aluminum-4% vanadium (Ti-6Al-4V) are known to be biocompatible and corrosion resistant. However, there have been numerous reports of elevated tissue levels of titanium due to passive dissolution, wear, or fretting corrosion of implants. Studies were undertaken to determine whether the fretting corrosion of Ti-6Al-4V could be reduced by surface treatment of one or both surfaces in a fretting situation. Three different surface treatments were studied: ion implantation, physical vapor deposition nitriding, and plasma ion nitriding. The specimens used were screws fretting against the countersinks of a two-hole plate. Fretting corrosion was assessed by weight loss, by chemical analysis of test solutions, and by scanning electron microscopy. Surface treatment of one component, the screws, resulted in reduction in the release of titanium to only 18-32% of that seen with the untreated controls. Weight loss of the untreated plates fretted against physical vapor deposition nitrided screws and plasma ion nitrided screws was reduced to 31 and 38% of the control, respectively. The weight loss of plasma nitrided screws was only 30% that of the control. Nitriding of both plates and screws resulted in a further decrease in plate weight loss and metal release. Plasma ion nitriding of both components had the most significant effect, with the weight loss and titanium release being only 11 and 2% of the control values, respectively.

Molecular approach to identifying route of transmission of tuberculosis in the community.

There is growing concern that tuberculosis is spread in Europe in the way that it is in the USA. We have used DNA "fingerprinting" in a systematic evaluation of tuberculosis cases notified in our community to uncover foci of transmission. An IS6110 probe was used to test all isolates from culture-confirmed tuberculosis cases (163 patients) notified in 1991-92 in the Canton of Berne. In total, 45 patients (27.6%), potentially linked on the basis of restriction fragment length polymorphism, were investigated epidemiologically. The largest group (n = 22) included members of a defined social group (drug addicts, homeless persons, alcoholics), from whom tuberculosis spread to the general population. A key patient developed multidrug-resistant tuberculosis during the surveillance period. This population study showed that (i) extensive transmission of Mycobacterium tuberculosis is now taking place in Europe in the same social setting as in the USA; (ii) there is definite "spillover" to the general population; (iii) the dimensions of the problem cannot be recognised easily by routine public health service activities because of the complexity of the transmission network; and (iv) multidrug-resistant tuberculosis develops in this setting.

Inhibitory effect of platelet factor 4 (PF4) on the growth of human erythroleukemia cells: proposed mechanism of action of PF4.

The effect of platelet factor 4 (PF4) on the growth of human erythroleukemia cell line (HEL) and the binding characteristics of iodine 125-labeled PF4 to cells were studied to determine the mechanism of action of PF4. HEL cells were cocultured with various doses of PF4 in either a plasma clot system for colony assay or a liquid system for tritiated thymidine incorporation. A significant inhibition of HEL colony growth and tritiated thymidine incorporation was seen at PF4 doses of 1 microgram/ml and 0.5 microgram/ml, respectively. The inhibitory effect of PF4 could be abrogated by the addition of heparin (5 to 10 micrograms/ml). Enzyme-linked immunosorbent assay showed that PF4 had no obvious effect on the expression of platelet glycoprotein IIb/IIIa of HEL cells. Binding of 125I-PF4 to HEL cells reached equilibrium within 20 to 30 minutes with dissociation constant of 1.3 x 10(-10)M and Bmax of 6.3 pmol/10(5) cells and was inhibited by an excess of unlabeled PF4, beta TG, and heparin but was not affected by PMA, IL-3, IL-6, GM-CSF, and interferon-alpha. PF4 did not affect the binding of 125I-IL-3 and 125I-IL-6 to HEL cells. These data demonstrate that PF4 inhibits the growth of HEL cells by specific binding to HEL cells and suggest that the action of PF4 may be associated with the heparin-binding sites of the molecule.