Biomedical subjects

J Mulder

Publications and source records attributed to J Mulder.

151 records · Page 9Linked to original sources

PubMed1966

Studies on the content of antibodies for equine influenza viruses in human sera.

Previous workers had demonstrated that some of the viruses that caused the influenza epizootics of 1956 and 1963 among horses are antigenically related to certain human influenza viruses. The present authors therefore studied the distribution of antibodies for the equine influenza viruses in human sera. They found that three strains of A/Equi 2 virus (1963 Miami, 1963 Richelieu and 1963 Milford) are antigenically related and that there is a cross-relationship between the mouse line of the equine influenza A/Equi 1 (1956 Praha) antiserum and the 1963 A/Equi 2 strains. Haemagglutination-inhibition (HI) antibodies for A/Equi 2/Richelieu/63 were found in only 2 of 434 sera taken in 1963 from people aged less than 60 years but in 50 of 435 sera from people aged 60 years or more. These results suggest that infection with a virus resembling the A/Equi 2 1963 strain occurred some 7-10 years after the 1889-90 influenza pandemic; this virus was probably a mutant of the influenza A2 virus, which may have been the cause of the 1889-90 pandemic.

Animals↗

PubMedDate not supplied

Prognostic value of Laurén classification and c-erbB-2 oncogene overexpression in adenocarcinoma of the esophagus and gastroesophageal junction.

BACKGROUND: The prognostic value of the Laurén classification and of c-erbB-2 oncogene overexpression has been described for gastric cancer. The aim of this study was to investigate the clinical significance of these factors in adenocarcinoma of the esophagus and/or gastroesophageal junction (GEJ). METHODS: Forty-one adenocarcinomas of the esophagus and/or GEJ were reviewed for tumor stage, lymph node status, Laurén classification, and c-erbB-2 overexpression, as assessed by immunohistochemical analysis. RESULTS: According to the Laurén classification, tumors were classified as intestinal-, mixed-, or diffuse-type (54%, 32%, and 15%, respectively). Diffuse-type tumors were associated with a significantly worse prognosis than were intestinal-type tumors (P = .018; log-rank test). The prognostic value of the Laurén classification was independent of stage (P = .048; Cox regression model). Overexpression of c-erbB-2 was detected in 24% of the tumors and was present exclusively in intestinal-type tumors and in intestinal-type areas of mixed-type tumors. Ten of the 30 stage III/IV tumors (33%) were c-erbB-2-positive, whereas none of the 11 stage I/II tumors (0%) overexpressed the oncogene product (P = .04; Fisher exact test). The prognostic value of c-erbB-2 overexpression was not independent of stage (P = .7; Cox regression model). CONCLUSIONS: (1) The Laurén classification is an independent prognostic factor in adenocarcinoma of the esophagus and GEJ. (2) c-erbB-2 overexpression is limited to (areas of) intestinal-type tumors, indicating that intestinal- and diffuse-type tumors differ oncogenetically. (3) c-erbB-2 overexpression is associated with the stage of disease, indicating that it is a late event during tumor progression.

Adenocarcinoma↗

PubMedDate not supplied

Atmospheric deposition, mineralization and leaching of nitrogen in subtropical forested catchments, South China.

In recent years, China has conducted considerable research focusing on the emission and effects of sulphur (S) on human health and ecosystems. By contrast, there has been little emphasis on anthropogenic nitrogen (N) so far, even though studies conducted abroad indicate that long-range atmospheric transport of N and ecological effects (e.g. acidification of soil and water) may be significant. The Sino-Norwegian project IMPACTS, launched in 1999, has established monitoring sites at five forest ecosystems in the southern part of PR China to collect comprehensive data on air quality, acidification status and ecological effects. Here we present initial results about N dynamics at two of the IMPACTS sites located near Chongqing and Changsha, including estimation of atmospheric deposition fluxes of NOx and NHx and soil N transformations. Nitrogen deposition is high at both sites when compared with values from Europe and North America (25-38 kg ha(-1) yr(-1)). About 70% of the deposited N comes as NH4, probably derived from agriculture. Leaching of N from soils is high and nearly all as NO3-. Transformation of N to NO3- in soils results in acidification rates that are high compared to rates found elsewhere. Despite considerable leaching of NO3- from the root zone of the soils, little NO3- appears in streamwater. This indicates that N retention or denitrification, both causing acid neutralization, may be important and probably occur in the groundwater and groundwater discharge zones. The soil flux density of mineral N, which is the sum of N deposition and N mineralization, and which is dominated by the N mineralization flux, may be a good indicator for leaching of NO3- in soils. However, this indicator seems site specific probably due to differences in land-use history and current N requirement.

Air Pollutants↗

PubMedDate not supplied

Loss of pesticides from agricultural fields in SE Norway--runoff through surface and drainage water.

Loss of two pesticides with different mobility characteristics, bentazone (Koc approximately 34) and propiconazole (Koc approximately 1800), were studied at three agricultural fields (Askim, Bjørnebekk and Syverud) in SE Norway. A conservative tracer (Br) was used to follow the flow of water. The loss of pesticides varied among the fields, depending on hydrological characteristics and soil properties. The loss of pesticides was higher from two artificially levelled silty clay loam soils with poor aggregate stability (Askim and Bjørnebekk) compared to a loam/silt loam soil with increased content of organic carbon and better aggregate stability (Syverud). The total accumulated loss was <0.5% from all fields. The highest pesticide concentrations were measured at the first runoff episode after application for both the mobile (bentazone) and less mobile pesticide (propiconazole) in the surface runoff. In the drainage water, the peak for the less mobile pesticide coincided with the Br tracer, while the peak for mobile pesticide appeared earlier than the Br tracer. Rapid movement of water, particles and pesticides through soils indicate flow through macropores. Larger proportions (in percent of total applied) of both the mobile and the strongly sorbed pesticides were lost through the drainage as compared to the loss through surface runoff at Askim. Here, it is suggested that macropore flow contribute to the increased loss of pesticides through the drainage. At Syverud, high infiltration capacity reduces the amount of water available for surface runoff, and somewhat higher loss of the mobile pesticide was registered in the drainage compared to the surface runoff. For the strongly sorbed pesticide, however, propiconazole was neither detected in surface nor in drainage water at Syverud. Generally, there was a higher percentage loss of the mobile compared to the strongly sorbed pesticide in both surface and drainage water, which is in agreement with the pesticides mobility characteristics in soil. An exception was, however, the erodible soil Bjørnebekk, where a higher fraction of propiconazole was lost in the surface runoff compared to bentazone. Large amounts of sediment transport from the Bjørnebekk field probably contributed to enhanced transport of the strongly sorbed pesticide.

Adsorption↗

PubMedDate not supplied

Influences of suspended particles on the runoff of pesticides from an agricultural field at Askim, SE-Norway.

Field and laboratory experiments were conducted to study the loss of particles from agricultural fields, and the role of suspended particles in carrying pesticides in surface runoff and drainage water. Propiconazole, a widely used fungicide was applied to experimental fields located at Askim, SE-Norway. Samples from surface runoff and drainage water were collected and analyzed for sediment mass, pesticides, particulate and dissolved organic carbon through a whole year. The surface soil and the runoff material were characterized by its particle size distribution, organic carbon content in size fractions and its ability to bind propiconazole. The results show that (1) particle runoff mostly occurred during the rainfall event shortly after harrowing in autumn. The highest particle concentration observed in the surface runoff water was 4600 mg l(-1), and in the drainage water 1130 mg l(-1); (2) the erosion of surface soil is size selective. The runoff sediment contained finer particle/aggregates rich in organic matter compared to its original surface soil; (3) the distribution coefficient (Kd) of propiconazole was significantly higher in the runoff sediment than in the parent soil. According to our calculation, particle-bound propiconazole can represent up to 23% of the total amount of propiconazole in a water sample with a sediment concentration of 7600 mg l(-1), which will significantly influence the transport behavior of the pesticide.

Adsorption↗

PubMedDate not supplied

Caries trends 1996-2002 among 6- and 12-year-old children and erosive wear prevalence among 12-year-old children in The Hague.

In 2002 a dental survey amongst 6- and 12-year-old schoolchildren (n = 832) in The Hague was carried out. The caries findings were compared with findings from earlier studies in The Hague. Caries prevalence (% of caries-free children) and caries experience (mean dmfs scores) among 6-year-old children had not changed significantly in the period 1996-2002. However, a significant increase of caries-free 12-year-old children of low socio-economic status was found in the period 1996-2002. The proportions of caries-free 12-year-old Dutch, Turkish and Moroccan children of low socio-economic status were 88, 69 and 78%, respectively, in 2002. The average DMFT score of 12-year-olds reached a minimum of 0.2. In 2002, 24% of the 12-year-olds exhibited signs of erosion, indicating that the presence of erosive wear was high among youngsters in The Hague.

Analysis of Variance↗

PubMedDate not supplied

Vascular and interstitial changes in the peritoneum of CAPD patients with peritoneal sclerosis.

OBJECTIVE: To analyze morphological changes in the peritoneum of peritoneal sclerosis (PS) patients. Emphasis was put on vascular abnormalities, because the continuous exposure to glucose-based dialysis solutions could cause diabetiform changes and because longitudinal transport studies suggested the development of a large peritoneal vascular surface area. DESIGN: Peritoneal biopsies from continuous ambulatory peritoneal dialysis (CAPD) patients were investigated in two studies. Diabetic patients were excluded. In study 1, 11 PS biopsies were compared to three control groups varying in duration of CAPD treatment: 0 months (n = 15), 2 - 25 months (n = 7), and > 25 months CAPD (n = 7). The second study was a case-control study, comparing six biopsies from the long-term control group to six PS biopsies, matched for age and duration of CAPD. All biopsies were scored for presence and type of fibrosis [Picro Sirius red, type IV collagen, alpha-smooth muscle actin (alphaSMA)] and for neoangiogenesis (factor VIII). Thickening of vascular walls by type IV collagen and vasodilation of capillaries were measured by computer-aided planimetry. RESULTS: In study 1 the presence of sclerosing fibrosis, deposition of interstitial type IV collagen, and the number of myofibroblasts (alphaSMA-positive cells) was greater in the PS biopsies than biopsies from all control groups (p < 0.002). Moreover, the number of vessels per field was higher in PS biopsies (p < 0.01). Vascular wall thickening of small arteries (p < 0.008) and vasodilation of capillaries were found in PS biopsies compared to all control groups (p < 0.007). The second study revealed differences in the presence of sclerosis but not in the extent of fibrosis between PS biopsies and their controls. The number of vessels per field in PS biopsies was higher compared to controls (p = 0.04). Also, thickening of the vascular wall was more marked in PS biopsies (p = 0.03). Vasodilation of capillaries was greater in PS biopsies than in controls (p = 0.07). CONCLUSION: Fibrosis of the peritoneum may precede peritoneal sclerosis. The deposition of type IV collagen and the presence of myofibroblasts in the interstitial layer could be part of a pathologic process similar to the scarring in diabetic nephropathy. Neoangiogenesis and thickening of the vascular wall by type IV collagen are consistent with glucose-induced microangiopathy.These abnormalities and the vasodilation of the capillaries can explain the high dialysate-to-plasma ratios or mass transfer area coefficients of low molecular weight solutes that can be found in long-term CAPD patients.

Actins↗