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Biomedical subjects

A Ott

Publications and source records attributed to A Ott.

At least 19 recordsLinked to original sources
PubMed2004

[Outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in the Rijnmond region: the largest outbreak in the Netherlands].

UNLABELLED: EPIDEMIC: The annual number of new MRSA isolates in the Netherlands tripled in 2002 compared with previous years. This increase was in part due to a MRSA outbreak in the Rijnmond region. The outbreak occurred in two merged hospitals and is the largest ever to occur in the Netherlands. From November 2001 till June 2003 MRSA was isolated from 381 patients and 113 hospital employees. The worst affected departments were Surgery and Internal Medicine. One MRSA strain (pulsed-field gel electroforesis (PFGE) type 16) remained initially unrecognised and was therefore able to spread unnoticed. Soon two additional epidemic MRSA strains (types 37 and 38) were discovered. DISCUSSION: Multiple factors played a role in the extent and duration of the outbreak. Because of the delayed detection and rapid spread of MRSA type 16, the outbreak grew too large once recognised to be resolved within the available infrastructure. Investments were needed at various fields, including the infection-control service and the microbiology laboratory. Employees had to be informed and motivated, and a separate MRSA ward and OPD were provided. New MRSA outbreaks occurred, despite extensive MRSA (contact) screening among patients and employees. The numbers of isolates began falling as from the beginning of 2003.

Cross Infection↗
PubMed2004

Effect of smoking on global cognitive function in nondemented elderly.

BACKGROUND: Contrary to early case-control studies that suggested smoking protects against Alzheimer disease (AD), recent prospective studies have shown that elderly who smoke may be at increased risk for dementia. OBJECTIVE: To examine prospectively the effect of smoking on cognition in nondemented elderly. METHOD: In a multicenter cohort, the European Community Concerted Action Epidemiology of Dementia (EURODEM), including the Odense, Personnes Agées Quid (Paquid), Rotterdam, and Medical Research Council: Ageing in Liverpool Project-Health Aspects (MRC ALPHA) Studies, 17,610 persons aged 65 and over were screened and examined for dementia. After an average 2.3 years of follow-up, 11,003 nondemented participants were retested. Excluding incident dementia cases and those without baseline information on smoking gave an analytical sample of 9,209 persons. Average yearly decline in Mini-Mental State Examination (MMSE) score was compared among groups, adjusting for age, sex, baseline MMSE, education, type of residence, and history of myocardial infarction or stroke. RESULTS: MMSE score of persons who never smoked on average declined 0.03 point/year. The adjusted decline of former smokers was 0.03 point greater and of current smokers 0.13 point greater than never smokers (p < 0.001). Higher rates of decline by smoking were found in men and women, persons with and without family history of dementia, and in three of four participating studies. Higher cigarette pack-year exposure was correlated with a significantly higher rate of decline. CONCLUSION: Smoking may accelerate cognitive decline in nondemented elderly.

Age Distribution↗
PubMed2003

MEDIANOVO - a media database for medical education, research and health care.

MEDIANOVO provides a high quality, scientifically indexed multi-media database with comfortable authoring and download functions through a web-based frontend. Currently, MEDIANOVO is used by medical teachers as a repository for storing and sharing media for educational purposes. However a database was created which could also serve with training and further education, in computer based learning systems as well as medical publishers and for individual patient information. Through the web-frontend the content is available worldwide.

Databases as Topic↗
PubMed2002

Serologic evidence of ehrlichiosis among humans and wild animals in The Netherlands.

The seroprevalence of antibodies directed against granulocytic and monocytic Ehrlichia was determined by use of human granulocytic ehrlichiosis agent and Ehrlichia chaffeensis as surrogate antigens. Seven hundred twenty-one serum samples were collected between 1992 and 1999 from febrile patients with unresolved aetiology (n=108), patients suspected of having Lyme disease (n=174), forestry workers (n=154) and healthy controls (n=54) as well as from wild deer (n=96), hares (n=60), wild boar (n=15) and red foxes (n=60). Reactive antibodies against granulocytic Ehrlichia were detected in 4% of febrile patients with unresolved aetiology and in 4% of patients suspected of having Lyme disease. Among the forestry workers, 1% tested positive for antibodies against granulocytic Ehrlichia, whereas all the healthy controls were negative. Antibody reaction against monocytic Ehrlichia was detected in only 2% of the febrile patients. Granulocytic Ehrlichia and monocytic Ehrlichia-reactive serum antibodies were detected in 22% and 3% of the deer samples, respectively, and in 2% of the hares. In wild boars and in red foxes, only serum antibodies reactive against monocytic Ehrlichia were detected in 13% and 7%, respectively. The demonstration of the presence of both granulocytic and monocytic Ehrlichia-reactive serum antibodies among humans and wild animals in The Netherlands indicates that patients suspected of having Lyme disease and febrile patients with unresolved aetiology should be tested for the presence of granulocytic and monocytic Ehrlichia antibodies or by polymerase chain reaction. Furthermore, granulocytic Ehrlichia are most prevalent in humans and animals in The Netherlands.

Adult↗
PubMed2000

Osmotic stress response in Dictyostelium is mediated by cAMP.

DokA, a homolog of bacterial hybrid histidine kinases, is essential for hyperosmotic stress resistance in Dictyostelium: We show that a transient intracellular cAMP signal, dependent on the presence of DokA, is generated in response to an osmotic shock. This variation of cAMP levels contributes to survival under hypertonic conditions. In contrast to the low cAMP levels observed in dokA(-) strains, overexpression of the receiver domain of DokA causes an increase in cAMP levels, resulting in a rapidly developing phenotype. We present biochemical and cell biological data indicating that the DokA receiver domain is a dominant-negative regulator of a phosphorelay, which controls the intracellular cAMP phosphodiesterase RegA. The activity of the DokA receiver domain depends on a conserved aspartate, mutation of which reverses the developmental phenotype, as well as the deregulation of cAMP metabolism.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2000

The alpha2-macroglobulin gene in AD: a population-based study and meta-analysis.

BACKGROUND: Whereas several authors recently reported a positive association between the alpha2-macroglobulin gene (A2M) and late-onset AD (LOAD), others were unable to replicate these findings. Early-onset AD (EOAD) is defined as onset age <65 years. Virtually all patients with LOAD are >65 years of age. OBJECTIVE: To evaluate the role of A2M in AD, the authors conducted a population-based study of EOAD and LOAD as well as a meta-analysis of all studies conducted to date. METHODS: Patients with EOAD (n = 100) were derived from a population-based study in four northern provinces of the Netherlands and the area of metropolitan Rotterdam. Patients with LOAD (n = 344) were drawn from the Rotterdam Study, a population-based prospective study on residents aged 55 years and over of a Rotterdam suburb in the Netherlands. Two polymorphisms were studied, A2M-I/D and A2M-Ile1000Val, in relation to the APOE epsilon4 allele (APOE*4). RESULTS: No genotypic or allelic association was found for either polymorphism in the population-based series of patients with LOAD. In patients with EOAD without APOE*4, a significant increase of carriers of A2M-1000Val was found. The meta-analysis of available published case-control data on these polymorphisms in white and mixed ethnic populations yielded no significant differences between cases and controls. Pooling the Asian studies conducted to date showed a significant decrease in the frequency of A2M-D among patients. CONCLUSIONS: These results suggest that A2M is not genetically associated with LOAD in white patients or mixed populations as found in the United States. In these populations A2M does not have clinical relevance. From a scientific perspective, the findings on EOAD and Asian patients require replication and further research in the A2M region.

Aged↗
PubMed2000

Education and the risk for Alzheimer's disease: sex makes a difference. EURODEM pooled analyses. EURODEM Incidence Research Group.

The hypothesis that a low educational level increases the risk for Alzheimer's disease remains controversial. The authors studied the association of years of schooling with the risk for incident dementia and Alzheimer's disease by using pooled data from four European population-based follow-up studies. Dementia cases were identified in a two-stage procedure that included a detailed diagnostic assessment of screen-positive subjects. Dementia and Alzheimer's disease were diagnosed by using international research criteria. Educational level was categorized by years of schooling as low (< or =7), middle (8-11), or high (> or =12). Relative risks (95% confidence intervals) were estimated by using Poisson regression, adjusting for age, sex, study center, smoking status, and self-reported myocardial infarction and stroke. There were 493 (328) incident cases of dementia (Alzheimer's disease) and 28,061 (27,839) person-years of follow-up. Compared with women with a high level of education, those with low and middle levels of education had 4.3 (95% confidence interval: 1.5, 11.9) and 2.6 (95% confidence interval: 1.0, 7.1) times increased risks, respectively, for Alzheimer's disease. The risk estimates for men were close to 1.0. Finding an association of education with Alzheimer's disease for women only raises the possibility that unmeasured confounding explains the previously reported increased risk for Alzheimer's disease for persons with low levels of education.

Age Distribution↗
PubMed2000

[Therapy of lymphomatoid papulosis with balneo-PUVA-photochemotherapy]].

Lymphomatoid papulosis is a rare lymphoproliferative disorder of the skin. The standard therapeutic regimen is systemic (oral) photochemotherapy (PUVA). We examined the efficacy of PUVA-bath photochemotherapy in a patient requiring heart transplantation because of idiopathic dilatated cardiomyopathy and a relative contraindication against systemic 8-methoxypsoralen. The 42-years old male patient had suffered for 15 years with itching papules and plaques which clinically, immunohistochemically and molecular biologically were diagnosed as lymphomatoid papulosis. PUVA-bath photochemotherapy with 8-MOP was initiated. After 29 treatments the plaques disappeared completely. After 44 sessions (cumulative UV-A dose 206 J/cm2) the patient's skin almost was clear. PUVA-bath photochemotherapy proved to be a therapeutic alternative to systemic PUVA-treatment in this case of lymphomatoid papulosis.

Adult↗
PubMed2000

Measurement of the elasticity of the actin tail of Listeria monocytogenes.

We report biophysical experiments performed on the bacterium Listeria monocytogenes, a model system to study actin-based motility. Using optical tweezers and electrophoresis experiments, we find that the bacterium is firmly attached to its tail, and we demonstrate that the tail responds as an elastic gel when deformed. We have measured its elastic modulus at a value of 10(3)-10(4) Pa, which is 10 times higher than the rigidity of the eukaryotic cytoplasm. These results demonstrate that the bacterium and its tail form a very robust system, consistent with the steadyness of the motion observed in vivo. We propose an elastic model for the propulsion mechanism which takes into account the connection and thus the interaction between the actin filaments. It provides a generic description of the various aspects of actin-tail based movements.

Actins↗
PubMed2000

Prevalence of serum antibodies against bloodborne and sexually transmitted agents in selected groups in Somalia.

Somalia has suffered from a civil war during the last 10 years. In this period the use of whole blood has increased at least twofold in Mogadishu, Somalia compared with pre-war. Screening possibilities are limited. Recent data concerning the prevalence of infections with blood-borne and sexually transmitted agents are not available from this country. To investigate the spread of human immunodeficiency virus (HIV-1/2) and other blood-borne or sexually transmitted agents we tested a total of 256 serum samples collected in the summer of 1995 from blood donors, hospitalized children and adults in Mogadishu. The hepatitis B surface antigen (HbsAg) carrier rate was 191%, 5.6% and 21.3 % among blood donors, hospitalized children and hospitalized adults, respectively. However, no children under 2 years of age were HbsAg positive. The overall presence of antibodies against hepatitis C virus (HCV) was 2.4% (6/256). In blood donors this was 0.6% (1/157). In none of the samples tested, antibodies against HIV 1 and 2 or human T-cell lymphotropic viruses (HTLV I and II) were detected. Our results indicate that, during the civil war in Somalia, no evidence of an increase of HIV infections was found. Our findings indicate that preventive measures in Somalia should focus mainly on prevention of HBV-infections. HBV-vaccine could be administered within the framework of the expanded programme on immunization, as none of the children less than 2 years of age were HbsAg positive.

Adolescent↗
PubMed2000

Sensory investigation of yogurt flavor perception: mutual influence of volatiles and acidity.

The sensory properties of traditional acidic and mild, less acidic yogurts were characterized by a trained panel using a descriptive approach. Many of the descriptive attributes varied almost linearly with pH, showing either a positive or negative correlation with increasing acidity. The panel was very sensitive to acidity differences, as demonstrated by the linear relationship between acidity perception and pH. Important flavor differences were found between the two classes of yogurt. They were mainly due to differences in acidity and not to different concentrations of the three impact aroma compounds, acetaldehyde, 2,3-butanedione, and 2, 3-pentanedione. This emphasizes the importance of acidity in yogurt flavor. Deodorization and impact aroma compound addition had much less influence on yogurt flavor than pH variations.

Hydrogen-Ion Concentration↗
PubMed2000

Origin of acetaldehyde during milk fermentation using (13)C-labeled precursors.

Acetaldehyde formation by Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus during fermentation of cow's milk was investigated using (13)C-labeled glucose, L-threonine, and pyruvate with a recent static-and-trapped-headspace technique that does not require derivatization of acetaldehyde prior to gas chromatography-mass spectrometry. Over 90% and almost 100% of acetaldehyde originated from glucose during fermentation by L. delbrueckii subsp. bulgaricus and S. thermophilus, respectively, taking into account both singly and doubly labeled acetaldehyde. As both microorganisms showed threonine aldolase activity and formed labeled acetaldehyde from (13)C-labeled threonine during the fermentation of milk, this amino acid should also contribute to the acetaldehyde produced.

Acetaldehyde↗
PubMed2000

Vicinal diketone formation in yogurt: (13)C precursors and effect of branched-chain amino acids.

Addition of branched-chain amino acids (BCAA) or an inhibitor of the BCAA biochemical pathways during fermentation of milk with a lac(-) mutant of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strongly influenced the formation of two aroma-impact compounds, 2,3-butanedione and 2,3-pentanedione, as well as their direct precursors 2-acetolactate and 2-acetohydroxybutyrate. This suggests a connection between vicinal diketone formation and BCAA biosynthesis in yogurt bacteria. A recently developed static-and-trapped headspace technique combined with gas chromatography-mass spectrometry demonstrated incorporation of (13)C from [U-(13)C(6)]-D-glucose and [U-(13)C(4)]-L-threonine into both vicinal diketones. For 2,3-butanedione, glucose is the major precursor via pyruvate and activated acetaldehyde. For 2, 3-pentanedione, L-threonine is a precursor via 2-ketobutyrate, but glucose is the major contributor via activated acetaldehyde and, possibly, also via 2-ketobutyrate, which is a degradation product of 3-methylaspartate, an intermediate in glutamate synthesis.

Amino Acids, Branched-Chain↗
PubMed2000

Prevalence and determinants of fecal colonization with vancomycin-resistant Enterococcus in hospitalized patients in The Netherlands.

OBJECTIVE: To determine the prevalence and determinants of fecal carriage of vancomycin-resistant enterococci (VRE) in intensive care unit (ICU), hematology-oncology, and hemodialysis patients in The Netherlands. DESIGN: Descriptive, multicenter study, with yearly 1-week point-prevalence assessments between 1995 and 1998. POPULATION: All patients hospitalized on the testing days in ICUs and hematology-oncology wards in nine hospitals in The Netherlands were included. METHODS: Rectal swabs obtained from 1,112 patients were screened for enterococci in a selective broth and subcultured on selective media with and without 6 mg/L vancomycin. Resistance genotypes were determined by polymerase chain reaction. Further characterization of VRE strains was done by pulsed-field gel electrophoresis (PFGE). We studied possible determinants of VRE colonization with a logistic regression analysis model. Determinants analyzed included gender, age, and log-transformed length of prior hospital stay. RESULTS: The results showed that 614 (55%) of 1,112 patients were colonized with vancomycin-sensitive enterococci, and 15 (1.4%) of 1,112 carried VRE. No increase in VRE colonization was observed from 1995 to 1998. Eleven strains were identified as Enterococcus faecium and four as Enterococcus faecalis. All E faecium and one E faecalis carried the vanA gene; the other E faecalis strains harbored the vanB gene. PFGE revealed that three vanB VRE isolated from patients hospitalized in one single ICU were related, suggesting nosocomial transmission. Though higher age seemed associated with VRE colonization, exclusion of patients with the nosocomial strain from the regression analysis decreased this relation to nonsignificant. Duration of hospital stay was not associated with VRE colonization. CONCLUSION: VRE colonization in Dutch hospitals is an infrequent phenomenon. Although nosocomial spread occurs, most observed cases were unrelated, which suggests the possibility of VRE acquisition from outside the hospital. Prolonged hospital stay, age, and gender proved unrelated to VRE colonization.

Adolescent↗
PubMed2000

An epidemiological study on the occurrence of Staphylococcus aureus in superficial abscesses of patients presenting for surgery in a teaching hospital in Khartoum, Sudan.

A group of patients (n=86) suffering from superficial abscesses was recruited in the Khartoum Teaching Hospital, Sudan. Detailed clinical and socio-economic data were collected. It appeared that 83% of all patients were younger than 40. Labourers were most prevalent (28%), followed by students (23%) and housewives (16%). The head and neck were most often affected (22%), with hands being second (19%). In 92% of all pus cultures a microbial agents was identified, the large majority being Staphylococcus aureus (69%). Among patients, 47% were nasal carriers of S. aureus, similar to the carriage rate measured among controls, suggesting that nasal carriage is no risk factor for abscess development. Multivariate logistic regression analysis revealed that a history of abscess, recent traditional medical treatment, poor hygiene and low socio-economic status were significantly and independently associated with the occurrence of superficial abscesses.

Abscess↗
PubMed2000

Physical activity stages of change in African American women: implications for nurse practitioners.

We examined stages of change in the physical activity in African American women aged 17 to 64 years (N = 104) who obtain primary health care. Forty-seven percent of the women had at least 1 chronic health problem that required treatment. Overweight or obesity was found in 66% of the women. The majority of women were in the precontemplation (21%) and contemplation (19%) stages of change; 27% were preparing to become active. Forty percent were classified as very low active; 34%, low active; and only 26% were moderate or high active. Simple logistic regressions showed that women who were inactive during adolescence were 6 times more likely than other women to be in an early stage of change in physical activity (precontemplation or contemplation stage). Women who were self-motivated to be physically active, had support of friends and family, and enjoyed physical activity were more likely than other women to be in maintenance stage of activity. This article provides information on ways to use the stages of change and associated factors to move patients from inactivity to activity and help them remain active in the long term.

Adolescent↗