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Biomedical subjects

O Jørgensen

Publications and source records attributed to O Jørgensen.

18 recordsLinked to original sources
PubMed2003

Cellulosic building insulation versus mineral wool, fiberglass or perlite: installer's exposure by inhalation of fibers, dust, endotoxin and fire-retardant additives.

A task-specific exposure matrix was designed for workers installing building insulation materials. A priori, a matrix element was defined by type of task (installer or helper), type of work area (attic spaces or wall cavities) and type of insulation material (slabs from mineral wool, fiberglass or flax; loose-fill cellulosic material or perlite). In the laboratory a mock-up (full scale) of a one-family house was used for simulated installation of insulation materials (four replicates per matrix element). Personal exposure to dust and fibers was measured. The dust was analyzed for content of endotoxin and some trace elements (boron and aluminum) from fire-retardant or mold-resistant additives. Fibers were characterized as WHO fibers or non-WHO fibers. In support of the exposure matrix, the dustiness of all the materials was measured in a rotating drum tester. For installers in attic spaces, risk of exposure was low for inhalation of dust and WHO fibers from slab materials of mineral wool or fiberglass. Slab materials from flax may cause high risk of exposure to endotoxin. The risk of exposure by inhalation of dust from loose-fill materials was high for installers in attic spaces and for some of the materials risk of exposure was high for boron and aluminum. Exposure by inhalation of cellulosic WHO fibers was high but little is known about the health effects and a risk assessment is not possible. For the insulation of walls, the risk of installers' exposure by inhalation of dust and fibers was low for the slab materials, while a high risk was observed for loose-fill materials. The exposure to WHO fibers was positively correlated to the dust exposure. A dust level of 6.1 mg/m3 was shown to be useful as a proxy for screening exposure to WHO fibers in excess of 10(6) fibers/m3. In the rotating drum, slabs of insulation material from mineral wool or fiberglass were tested as not dusty. Cellulosic loose-fill materials were tested as very dusty, and perlite proved to be extremely dusty.

Aluminum Oxide↗
PubMed2001

Analysis of the hydrology and flow of nitrogen in 17 Danish catchments.

In the search for tools for evaluating the effects of national action plans combating diffuse nutrient pollution causing eutrophication of surface waters, a study of the nitrogen (N) flow in 17 Danish agricultural catchments was carried out. Data on N input and N harvest for the agricultural year of 1993/1994 was obtained from questionnaire surveys facilitating the set up of N balances. Net export of N from the catchments measured at the outlet was obtained from time-series of stream water chemistry and discharge from 1993-1997. N leaching from the root zone of each field was calculated using an empirical model. A physically based lumped rainfall-runoff model was used for separating the hydrograph time-series into three runoff components: baseflow, interflow and overland flow. Large regional variations in net N input were found ranging from 62 kg N ha(-1) yr(-1) in the loamy eastern part of the country dominated by cereal production to 137 kg N ha(-1) yr(-1) in the western part characterised by less fertile sandy soils and dominated by animal husbandry. N leaching from the root zone showed a corresponding variation with regional averages ranging from 34.5 kg N ha(-1) yr(-1) to 90.9 kg N ha(-1) yr(-1). No similar regional pattern could however be found regarding net N export, and no relationship could be established between net N export and root zone N leaching. This finding was ascribed to a varying and in some catchments very high (>80%) N retention during subsurface transport to the stream. The hydrological modelling revealed that loamy catchments had a high proportion of quick flow (overland flow + interflow), whereas baseflow dominated the sandy catchments. Further, a highly significant relationship between N retention and proportion of quick flow was found emphasising the importance of understanding the hydrological pathways. This should be taken into consideration when evaluating the N loading of surface waters resulting from a given agricultural practice and the effects of possible changes in this practice.

Denmark↗
PubMed1998

Development of a method for the determination of low contents of asbestos fibres in bulk material.

Asbestos is a category 1 carcinogen under the EU classification, but in the absence of a method to quantify asbestos in a matrix at the 0.1% level, there has been a delay in implementing relevant directives to asbestos. An analytical scheme for identification and quantification of asbestos using polarised light microscopy (PLM) and phase contrast optical microscopy (PCM) has now been developed. When used on artificial mixtures by an experienced laboratory, it achieved the required target performance, at 0.1% asbestos concentration by mass in a bulk sample, to obtain a result, which with 90% probability, is correct within a factor of two. The method of identification by PLM and quantification by PCM has been assessed by interlaboratory comparisons. The method begins with an initial identification using PLM, and depending on asbestos type and matrix a combination of preparation procedures are used to produce the analytical filter. A gentle comminution method was used which reduces the risk of overmilling. The asbestos mass percentage on the filter is quantified using PCM in combination with a PLM attachment for identification of possible non-asbestos fibres. The final method is supported by efficient methods for fibre identification for size determination and calculation of total fibre volume. A statistical analysis of mass concentration estimates was made and the effect of preferred orientation of fibres on the analytical filter was quantified.

Asbestos↗
PubMed1996

Mobilization of "nonmobilizable" plasmids by the aggregation-mediated conjugation system of Bacillus thuringiensis.

The aggregation-mediated conjugation system of Bacillus thuringiensis subsp, israelensis (Bti), encoded by the 200-kb plasmid pXO16, is highly potent in transferring itself and efficient in mobilizing other nonconjugative plasmids. In the present study we have analyzed the native Bacillus cereus plasmid pBC16. This plasmid has previously been shown to harbor a mob gene (ORF beta) and a locus functioning as an oriT site in plasmid pLS20-mediated conjugation in Bacillus subtilis. However, in the conjugation system of Bti we found that a derivative of pBC16 deleted for both these loci was mobilizable, although at a reduced frequency. Another derivative of pBC16, containing a deletion spanning the first half of the coding region of the mob gene, was found to be nearly as mobilizable as the intact pBC16, suggesting its dispensability in the transfer process. Other plasmids based on the theta-replicating origins, pAM beta 1, pLS20, ori43, ori44, and ori60, were also consistently mobilized in the conjugation system encoded by Bti plasmid pXO16. Analyzing the conjugation process by the use of scanning electron microscopy revealed the presence of connections between cells in the mating mixtures. These connections did not appear in monocultures of the donor strain or the recipient strain and may be conjugational junctions.

Bacillus thuringiensis↗
PubMed1990

[Increased use of resources at psychiatric departments after the introduction of legislation on limitation of liberty and other forms of restriction in psychiatry. A prospective 3-month study].

The Danish legislation on restriction of liberty and other forms of compulsion in psychiatry was introduced on 1.10.1989. This legislation has involved an increased workload for psychiatric departments. A prospective investigation during a period of three months in an acute closed admission department in Frederiksberg Hospital revealed, as minimum figures, increased weekly working time for the caring staff of 28 1/2 hours, for doctors 6 1/4 hours and one hour for secretaries. In addition, the department registered an increased bed-day employment resulting from the new legislation. As the department has not received any new resources of note, this time must be taken from the time available for therapeutic work for all of the patients. Unless new resources are awarded to psychiatry, it is to be feared that the general psychiatric service will deteriorate.

Commitment of Persons with Psychiatric Disorders↗
PubMed1990

[Admission of patients with dementia to a psychiatric hospital. Social circumstances, circumstances of admission, treatment and further referral].

This investigation is a retrospective registration on the basis of the case histories of 290 patients with the main diagnosis dementia who were admitted to a psychiatric hospital in the years 1982 and 1983. The average age was 77 years. Patients with their own homes comprized 61% but only 28% were admitted from their own homes. More than 70% of the patients admitted were described as suffering from moderate or severe dementia on admission. 93% were admitted voluntarily and 91% during the daytime. The reason for admission most frequently registered was the patient's suffering. In 66% of the cases, the general practitioner had attempted treatment prior to admission. During hospitalization the majority of the patients received medicinal treatment. At the conclusion of treatment, 52% were found to be improved and 34% unchanged. 46% of the patients were assessed as requiring maximum nursing-home treatment and 29% were considered to need psychiatric nursing-home treatment. 8% could be discharged to their own homes. The average durations of hospitalization, duration of treatment and waiting-time were reviewed. It is noteworthy that the waiting-time, 311 days, was found to be nearly as long as the duration of treatment, 316 days. In addition, the waiting-times for nursing-homes with maximum care were calculated to be 229 days on an average and for psychiatric nursing homes 596 days.

Aged↗
PubMed1985

Body temperature elevation, exercise and serum prolactin concentrations.

Ten young healthy normal-weight males were studied in four test situations designed to elucidate the relative role of body temperature increase vs that of exercise per se for pituitary hormone release. Tympanic temperature was recorded continuously during the tests. Elevation of body temperature at rest induced by external heating resulted in parallel changes in serum prolactin (Prl), also found when temperature spontaneously returned towards normal. In contrast, temperature elevation of the same magnitude through exercise (450 kpm/min for 40 min) induced no change in Prl secretion. It is concluded that increase in core temperature is a stimulus of Prl secretion and suggested that exercise apparently inhibits the stimulatory effect.

Adult↗
PubMed1984

Estrogen receptors and long-term prognosis in breast cancer.

The long-term prognosis in 233 primary breast cancer patients, most of whom had received ovarian irradiation, has been related to the estrogen-receptor status of the primary tumors. The median observation time was 9 years. The receptor status did influence disease-free interval and survival only in patients having metastases in axillary nodes. Thus, in the postmenopausal patients with axillary metastases, the disease-free interval and survival time were longer in receptor-positive than in receptor-negative patients during the first few years of observation. However, this difference disappeared in the course of the subsequent years. In the premenopausal women with axillary metastases the receptor status did not influence the short-term prognosis, and, unexpectedly, seemed to affect adversely the long-term prognosis. It is concluded that the long-term prognosis is no better in breast cancer patients having estrogen receptors in their primary tumors than in those with receptor-negative tumors.

Aged↗
PubMed1979

Polypeptides of the synaptic membrane antigens D1, D2, and D3.

The rat brain synaptic membrane antigens D1, D2, and D3 were labelled by 125I and precipitated by antibodies in a crossed immunoelectrophoresis. The precipitates were stained, scraped off, reduced, and analysed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. The D1 antigen was composed of two polypeptide chains, apparent molecular weights 50 300 and 116 000 D2 of only one polypeptide chain, apparent molecular weight 139 000, and D3 of three polypeptides, apparent molecular weights 14 100, 23 500, and 34 400. Higher apparent molecular weight polypeptides were present in variable amounts in the D3 precipitate, except when the synaptic membrane extracts had been pre-treated with phospholipase D.

Animals↗
PubMed1979

Cellular antitumor immune response in women with risk factors for breast cancer.

The leukocyte adherence inhibition technique was used to study cell-mediated immunoactivity to breast adenocarcinoma. In a group of 74 patients with untreated breast cancer in Stages I and II, 69% showed a positive response, while 48% of the 25 patients in Stages III and IV had reactive leukocytes. Among 43 control persons, only 2 women showed positive responses. In a group of 161 women with benign breast diseases, 24% showed a positive reaction against breast carcinoma extract. The percentage of positive responses was higher than the average of women with benign disease among those who had a mother or a sister with breast cancer, who had previously had benign breast lumps removed, who had microcalcifications in their breasts, or for whom an increased intraductal epithelial proliferation was found in their biopsies. Twenty-eight women with benign breast diseases and two or more of the above factors were assigned to the high-risk group, in which 43% had reactive leukocytes. Of the 50 women with one risk factor, 34% showed a positive response, while of the 83 women in the low-risk group, with none of the above factors, only 11% had a positive reaction. The results suggest that the leukocyte adherence inhibition test may be used to identify groups of women who have a high risk for breast cancer.

Adenocarcinoma↗
PubMedDate not supplied

Sorption of polycyclic aromatic compounds to humic and fulvic acid HPLC column materials.

Two different humic acids (HA) and a fulvic acid (FA) were chemically immobilized to a high performance liquid chromatography (HPLC) silica column material. The immobilization was performed by binding amino groups in HA/FA to the free aldehyde group in glutardialdehyde attached to the silica gel. The HPLC column materials were compared with a blank column material made by applying the same procedure but without immobilizing HA or FA. Also, a column was made by binding carbonyl groups in HA to amino groups attached to the silica gel. The humic substances were selected to secure appropriate variation of their structural features. The retention factors of 45 polycyclic aromatic compounds (PAC) to the four columns were determined by HPLC. The advantage of the technique is a large number of compounds can easily be studied. The binding procedure does not appear to cause a drastic selection between the HA molecules. The k' values obtained for the two Aldrich HA columns agree in general reasonably. The retention or sorption of the compounds increased with the size of the PAC and the number of lipophilic substituents, but decreased when polar substituents were present. The PAC retention was much stronger to the two HA columns than to the FA and blank column, both for hydrophobic polycyclic aromatic hydrocarbons (PAH) and the polar PAC. Other factors impacting the PAC binding may be specific interactions with HA and the ionic strength of the aqueous phase. The technique has been applied to do direct determinations of Koc.

Adsorption↗