Biomedical subjects

C Romijn

Publications and source records attributed to C Romijn.

11 recordsLinked to original sources

PubMed1999

Electronic monitoring of treatment compliance in patching for amblyopia.

We developed a coinsized occlusion dose monitor (ODM) to measure compliance with patch-wearing during the treatment of amblyopia objectively. It measures the temperature difference between the front and back of the ODM every 2-5 minutes by means of two thermistors. The data is stored in EEPROM memory and read out after recording for a week by connecting it to a PC. The ODM measures 35x23x4 mm and weighs 6 g. The back of the ODM is glued to the front of the amblyopia patch with double-sided Scotch tape. When the patch with the ODM is on the eye, the temperature at the back of the ODM is higher than at the front. Compliance is being studied in children taking part in a large amblyopia cohort study. The parents were instructed during home visits every three months to put the ODM on the patch. After a week, the ODM was collected and read out. Although the parents knew that a recording was being made, compliance was mediocre in many cases. Children were patched infrequently, for 5 minutes only, for long periods on the last days of the recording, at night, etc. Diaries detailing patch time were unreliable.

Amblyopia↗

PubMed1993

[A closer look at the Scale for Subjective Well-being of the Elderly].

The Dutch Scale for Subjective Well-being of the Elderly (SSWO, 30 items) is a reliable and valid measure of well-being of the elderly. In this article, this instrument is subjected to a psychometric evaluation. First, as it is known that the SSWO has a weak subscale 'SSWO-Contacts', a new and reliable subscale 'SSWO-Contacts' was developed. Four SSWO-items were replaced by six items from an existing and valid Loneliness-scale. Cronbach's alpha for the new subscale increased from .61 to .86. This also led to a slight increase in reliability of the new SSWO (32 items) as a whole from .88 to .90. Secondly, the hierarchical order of the items in the SSWO-subscales was tested with a Mokken-scaling procedure. Of the five subscales, four showed a (weak to rather strong) hierarchy. Thirdly, a short version (8 items) was developed to maximize the possibilities of implementing the SSWO. This short version has 85% of variance in common with the 32-item version. Validity of the SSWO-32 and SSWO-8 was explored by correlating the instruments with measures of health and personality. All expected relations were found. Also, the newly developed instruments proved to be reliable measures in a dataset of 119 elderly persons. The SSWO-32 is recommended for the investigation of specific dimensions of well-being in elderly people. The SSWO-8 can be used to obtain a quick and global impression of well-being.

Activities of Daily Living↗

PubMed1987

Preparation of cell envelopes of large numbers of individual bacterial strains with the use of an automatic cell disruptor.

Analysis of the cell envelopes of large numbers of bacterial strains is used for the epidemiological and taxonomic investigation of clinical, veterinarian, and ecological isolates. Isolation of cell envelopes requires lysis of the bacteria. We developed an apparatus to disrupt bacterial cells of 200 different isolates in suspension by ultrasonication automatically. It is composed of modified standard laboratory equipment (fraction collector, cooling unit, pump), a standard ultrasonifier, and a newly designed control unit, which includes a sampler. This apparatus was applied to the analysis of cell envelope proteins of 96 Haemophilus influenzae strains on sodium dodecyl sulfate-polyacrylamide gel electrophoresis within 3 days after the first culture.

Bacterial Outer Membrane Proteins↗

PubMed1986

Tissue-specific markers in flow cytometry of urological cancers. II. Cytokeratin and vimentin in renal-cell tumors.

Nine primary human renal-cell tumors (RCT), one lymph-node metastasis, 4 human xenografts of a RCT in nude mice and a rat RCT line were analyzed by flow cytometry (FCM) using propidium iodide for DNA analysis and antibodies to cytokeratin and vimentin in the indirect immunofluorescence technique for labelling of specific tumor-cell populations. By means of 2-dimensional FCM analysis, vimentin- and cytokeratin-positive (tumor) cells were compared and their DNA content and proliferative fraction analyzed separately from those of cytokeratin-negative stromal and inflammatory cells. In primary human RCT, 2 subpopulations of cells were detected and analyzed separately. Small numbers of tumor cells with an abnormal DNA stemline were also detected. In addition, co-expression of intermediate filament proteins of both the cytokeratin and the vimentin types was detected in the aneuploid cell population. Comparison of 2 model systems of RCT with primary human RCT revealed a similar pattern of tumor-cell subfractions within these tumors. The 2-parameter FCM analysis permits the detection of subpopulations in complex cell suspensions and the quantification of these fractions, as well as analysis of their cellular DNA content.

Animals↗

PubMed1978