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Biomedical subjects

W Feller

Publications and source records attributed to W Feller.

14 recordsLinked to original sources
PubMed2002

Use of illicit substances in a psychosis incidence cohort: a comparison among different ethnic groups in the Netherlands.

OBJECTIVE: Use of illicit substances has been suggested as an explanation for the increased incidence of psychosis among some immigrant groups. The aim of the present study is to compare the rates of illicit substance use among immigrants with a first psychosis with that among non-migrants. METHOD: A population-based, first-contact incidence study in the Netherlands. Patients and key informants were interviewed about drug use in the preceding year. RESULT: One hundred and eighty-one subjects were examined. Proportions of patients who misused any illicit substance were 23% for Dutch, 17% for Moroccans, 27% for Surinamese, 30% for Turkish subjects, and 33% for other immigrants. Logistic regression analysis, controlling for age and sex, showed that ethnicity did not significantly contribute to the prediction of substance misuse. CONCLUSION: A higher rate of drug misuse is an unlikely explanation for the increased incidence of psychotic disorders among Moroccan and Surinamese immigrants to the Netherlands.

Adult↗
PubMed2001

Incidence of psychotic disorders in immigrant groups to The Netherlands.

BACKGROUND: Previous reports on the incidence of schizophrenia in immigrant groups to The Netherlands were based on hospital data. AIMS: To compare the incidence of psychotic disorders in the immigrant groups to that in natives. METHOD: Two-year first-contact incidence study in The Hague. RESULTS: The risks of schizophrenia, schizophreniform or schizoaffective disorder (DSM-IV criteria) were increased for subjects born in Morocco (gender and age-adjusted relative risk=4.5; 95% Cl 1.4-8.5), Surinam (relative risk=3.2; 1.8-5.7), The Netherlands Antilles (relative risk=2.9; 0.9-9.5) and other non-Western countries (relative risk=2.4; 1.3-4.7). This risk was also increased for Moroccans (relative risk=8.0; 2.6-24.5) and Surinamese (relative risk=5.5; 2.5-11.9) of the second generation. The risks for Turkish immigrants, first or second generation, and for immigrants from Western countries were not significantly increased. CONCLUSIONS: This study indicates that the incidence of schizophrenia is increased in several, but not all, immigrant groups to The Netherlands. It is possible that factors associated with a process of rapid westernisation precipitate schizophrenia in people who are genetically at risk.

Adult↗
PubMed2000

Clinical, microbiological and pathological observations in laboratory beagle dogs infected with leptospires of the serogroup Sejroe.

In beagle dogs infections with two different serovars of serogroup Sejroe are described. Saxkoebing titres of 27 beagle dogs were controlled for 7 to 9 months. Dogs serologically positive for saxkoebing showed no clinical symptoms. From the urine, an isolation of the microorganisms was possible. At necropsy, there was no evidence of any changes related to the proven infection. Histopathologically, in animals with persistent titres a mild interstitial nephritis was found. No changes were observed in the liver. Another three beagle dogs died after about two days of acute clinical illness with febrile temperature, exsiccosis and hematuria. Histopathologically, incipient inflammation was seen in the liver and kidneys. Besides, hepatic cholestasis, renal hemoglobin casts and degeneration of renal tubular epithelia were observed. In concurrent animals, an infection with another serovar of serogroup Sejroe was proven serologically. This serovar was also isolated. Transmission and spreading of leptospirosis within animals shelters or laboratories from clinically healthy carriers and its prevention as well as the protection of animal caretakers are discussed. Since leptospires are sensitive to physical and chemical methods of disinfection, this is easily feasible. However, the optimal prevention appears to be a stock- or population-specific vaccination.

Animals↗
PubMed1985

Healing of malignant hypertensive arteriopathy in Dahl rats by nifedipine.

Pathomorphological studies were undertaken to investigate the therapeutic effect of the Ca2+-antagonist nifedipine on malignant hypertensive arteriopathy in Dahl salt-sensitive rats. The individual course of disease was followed by comparing pre-treatment biopsies of the mesenteric arteries with post-treatment findings at necropsy. Within seven weeks, continuous therapy with nifedipine resulted in healing of early vascular lesions and in partial repair of the more advanced ones. Under normalization of blood pressure, vascular fibrinoid exacerbations were prevented and existing intramural fibrin insudates were completely or partially removed. Lamellar fibroelastosis of the intima occurred as a characteristic of repair.

Animals↗
PubMed1983

Control of an outbreak of mouse coccidiosis in a closed colony.

In 1979 severe coccidiosis occurred within a closed colony of C57bl/6J Bom mice. The coccidiosis caused diarrhoea, weight loss and deaths. Pathogenicity and response to chemotherapy were studied in experimentally infected Bor: CFW1 (SPF) mice. Histological and other studies indicated that infection was caused by more than 1 Eimeria species which have not yet been determined. Treatment with different anticoccidial drugs was unsuccessful, but use of 2 triazinone-derivatives (Bay g 7183, Bay i 9142) added to the food (15 ppm) succeeded in completely eradicating the organisms from the breeding houses. Experimental findings on the sensitivity of the coccidia to other anticoccidial drugs are described.

Animals↗
PubMed1980

Deoxyribonucleotide biosynthesis in synchronous algae cells.

Synchronous cells of the green alga, Scenedesmus obliquus, cultured in a 14-h/10-h light/dark regime, contain a peak of ribonucleoside-diphosphate reductase activity and maximum deoxyribonucleoside 5'-triphosphate concentrations at the 12th hour of the cell cycle, coinciding with DNA synthesis and preceding the formation of eight daughter cells. The intracellular dTTP pool reaches 4.5 pmol and the other pools 2-3 pmol/10(6) cells. Algal reductase activity is sensitive to cycloheximide, but not to lincomycin. These correlations demonstrate the functioning of the NDP leads to dNDP leads to dNTP pathway of DNA precursor biosynthesis in plant cells. In the presence of 20 micrograms 5-fluorodeoxyuridine/ml, an inhibitor of thymidylate synthesis, the dTTP pool is rapidly depleted and DNA synthesis ceases. 5-Fluorouracil and methotrexate produce similar effects. At the same time the ribonucleotide reductase activity and also the dATP pool are greatly increased, especially when fluorodeoxyuridine treatment is combined with continued illumination of the algae. In contrast, arabinosylcytosine, an inhibitor of DNA replication, has no effect on ribonucleotide reduction. The control of de novo enzyme synthesis in the eucaryotic algae therefore appears to depend on the presence of dTTP (or a related nucleotide), but not directly coupled to DNA synthesis. This interdependence resembles the situation observed in HeLa cells, while it may differ in detail from control mechanisms of ribonucleotide reductase studied in bacteria.

Cell Cycle↗
PubMed1969

On the fluctuations of sums of independent random variables.

If X(1), X(2),... are independent random variables with zero expectation and finite variances, the cumulative sums S(n) are, on the average, of the order of magnitude S(n), where S(n) (2) = E(S(n) (2)). The occasional maxima of the ratios S(n)/S(n) are surprisingly large and the problem is to estimate the extent of their probable fluctuations.Specifically, let S(n) (*) = (S(n) - b(n))/a(n), where {a(n)} and {b(n)}, two numerical sequences. For any interval I, denote by p(I) the probability that the event S(n) (*) epsilon I occurs for infinitely many n. Under mild conditions on {a(n)} and {b(n)}, it is shown that p(I) equals 0 or 1 according as a certain series converges or diverges. To obtain the upper limit of S(n)/a(n), one has to set b(n) = +/- epsilon a(n), but finer results are obtained with smaller b(n). No assumptions concerning the under-lying distributions are made; the criteria explain structurally which features of {X(n)} affect the fluctuations, but for concrete results something about P{S(n)>a(n)} must be known. For example, a complete solution is possible when the X(n) are normal, replacing the classical law of the iterated logarithm. Further concrete estimates may be obtained by combining the new criteria with some recently developed limit theorems.

Journal Article↗