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Biomedical subjects

K Hansen

Publications and source records attributed to K Hansen.

At least 181 records · Page 10Linked to original sources
PubMed1991

Fertility of workers chronically exposed to chemically contaminated sewer wastes.

Few studies have investigated the reproductive effects of exposure to chemical mixtures. The purpose of this study was to assess fertility in males exposed to mixed industrial and domestic wastes. A detailed reproductive history was obtained from the wives of 231 employees in order to evaluate fertility. Daily work records were used to define exposure status. To ascertain problems of infertility, the ratios of observed live births to expected live births (generated from U.S. birth probabilities) for exposed and nonexposed groups were calculated, and the ratios of these Standardized Fertility ratios (SRFs) were compared. Other analyses considered the couples' contraceptive history and preexposure versus postexposure experience. Though multiple statistical approaches were used to examine the data, the conclusion of this study was that exposure to chemical mixtures was not associated with a decrease in the couples' fertility.

Air Pollutants, Occupational↗
PubMed1991

[A 3-dimensional reconstructive procedure in lumbar computed tomography].

In this study, 50 patients were examined by a Siemens' "Somatom Plus"; continuous 2 mm sections between the third lumbar and first sacral vertebra were obtained. The accuracy of the 3-D reconstruction software programme was checked by measuring a polyethylene phantom of a second lumbar vertebra. Reconstruction was carried out with a threshold definition of 150 Hu. In each case, four standard projections and medio-sagittal, medio-lateral and coronary sections were reconstructed, photographed and compared with axial CT sections and conventional radiographs. All these imaging procedures were suitable for the diagnosis of osteochondrosis and chondrosis. Spondylosis was diagnosed more frequently on 3-D CT. Spondylarthrosis, with narrowing of the intervertebral foramina and root canals is shown particularly well by 3-D CT, since the entire extent of these structures can be seen. 3-D surface reconstruction of the lumbar spine is useful in the diagnosis of lumbar spondylarthrosis with narrowing of the root canals and of the spinal canal. This method of axial Ct is superior to conventional radiography of the lumbar spine in the usual two planes.

Adult↗
PubMed1991

Long-term effects of the Herbst appliance in relation to the treatment growth period: a cephalometric study.

The aim of this study was to analyse the long-term effects of Herbst treatment on the dentofacial complex with special reference to the growth period in which the patients were treated. The sample consisted of 40 male subjects with a Class II, division 1 malocclusion treated successfully with the Herbst appliance for an average period of 7 months. The patients were reinvestigated at the end of the growth period, on average 6.6 years (SD = 1.0 years) after therapy. Nineteen patients were treated before the maximum of pubertal growth (prepeak), 15 at the maximum (peak) and 6 after the pubertal growth maximum (post-peak). Sagittal skeletal and dental changes occurring during and after Herbst treatment were evaluated on lateral radiographs in centric occlusion. At the time of follow-up examination no group differences were seen in sagittal dental arch relationships. During the follow-up period after Herbst treatment maxillary and mandibular growth development were favourable and comparable in all three groups: mandibular growth exceeding maxillary growth by an average of 4.3 mm (SD = 2.4 mm). For natural reasons, however, the amount of jaw growth during the follow-up period was larger in the subjects treated before the maximum of pubertal growth than in the subjects treated at the later stages. The conclusion of this study was that the growth period in which Herbst treatment was performed did not seem to have any conclusive effect on the long-term results. However, in order to favour occlusal stability after treatment and to reduce the time of post-treatment retention, Herbst therapy in the permanent dentition at or just after peak height velocity of growth is recommended.

Activator Appliances↗
PubMed1991

Lyme arthritis: oligoclonal anti-Borrelia burgdorferi IgG antibodies occur in joint fluid and serum.

The antibody response to Borrelia (B.) burgdorferi, and to measles virus as control antigen, was analysed by agarose isoelectric focusing (AIF) and immunoblot of joint fluid and serum from 10 patients with Lyme arthritis and 10 controls with rheumatoid arthritis. Among the Lyme arthritis patients, six had oligoclonal anti-B. burgdorferi IgG antibody bands in joint fluid and corresponding serum, one patient had oligoclonal antibody bands in joint fluid only and also an elevated B. burgdorferi-specific joint fluid to serum antibody ratio as evidence of intra-joint production of specific antibodies, and the remaining three patients were negative for oligoclonal-specific antibody bands. Absorption with B. burgdorferi antigen confirmed the specificity of the oligoclonal antibody bands. They comigrated only partially on AIF with oligoclonal bands of total IgG, and the specificity of most oligoclonal IgG in joint fluid and serum in Lyme arthritis remains undefined. Among the controls, no anti-B, burgdorferi IgG antibodies were detected by AIF and immunoblot. Instead, 9 of the 10 rheumatoid arthritis patients had oligoclonal anti-measles IgG antibody bands which were restricted to the joint fluid in three of them, indicating local production. We conclude that Lyme arthritis is often accompanied by an oligoclonal specific antibody response in joint fluid and serum simultaneously, and occasionally by intrasynovial synthesis of oligoclonal-specific antibodies.

Adolescent↗
PubMed1991

Anti-Borrelia burgdorferi antibody response over the course of Lyme neuroborreliosis.

Characteristic findings on examination of cerebrospinal fluid (CSF) in Lyme neuroborreliosis include mononuclear pleocytosis, oligoclonal immunoglobulin G (IgG) bands, and evidence for local production of specific antibodies. We utilized an immunospot assay to detect cells secreting anti-Borrelia burgdorferi antibodies of different isotypes over the course of disease. Such cells were detected in CSF from 13 consecutive patients with neuroborreliosis examined before treatment. IgG antibody-secreting cells were present in high numbers (mean, 32 cells per 10(4) CSF cells), whereas IgA and IgM antibody-secreting cells were found less frequently and at lower numbers (mean, 5 and 6 cells per 10(4) CSF cells, respectively). Clinical improvement after penicillin treatment was paralleled by a rapid decline of antibody-secreting cells in CSF, but they were still detected, although at lower numbers, in 5 of 10 patients examined more than 6 months after treatment. This specific B-cell response persisted despite clinical improvement. Whether it reflects persistence of antigen is unsettled.

Adult↗
PubMed1991

Improved immunoglobulin M serodiagnosis in Lyme borreliosis by using a mu-capture enzyme-linked immunosorbent assay with biotinylated Borrelia burgdorferi flagella.

A mu-capture enzyme-linked immunosorbent assay (ELISA) for detection of serum immunoglobulin M (IgM) antibodies to Borrelia burgdorferi by using biotinylated purified B. burgdorferi flagella was developed. The diagnostic performance of the mu-capture ELISA was compared with that of a conventional indirect ELISA. Sera from untreated patients with erythema migrans (n = 50), neuroborreliosis (n = 100), and acrodermatitis chronica atrophicans (ACA; n = 48) were investigated. The cutoff of the ELISAs was adjusted to a diagnostic specificity of 98% on the basis of examination of 200 serum specimens from healthy controls. The mu-capture ELISA increased the diagnostic sensitivity in patients with erythema migrans from 32 to 48% (P less than 0.01) and in patients with neuroborreliosis from 37 to 57% (P less than 0.001). Because of an increased signal/noise ratio, the mu-capture ELISA yielded a significantly better quantitative discrimination of individual positive measurements from the cutoff (P less than 0.001). The increased signal/noise ratio was most likely a consequence of the elimination of IgG competition for the test antigen. This may also explain why 12% of patients with ACA showed significantly increased specific IgM levels only by the mu-capture ELISA. Of patients with ACA, 27% had IgM rheumatoid factor. The mu-capture principle with a directly labeled antigen showed no interference with IgM rheumatoid factor, in contrast to the indirect ELISA. The high diagnostic performance and ease of this three-step mu-capture ELISA make it suitable for routine anti-B. burgdorferi IgM serodiagnosis.

Adolescent↗
PubMed1991

Comparison of in vitro culture and polymerase chain reaction for detection of Borrelia burgdorferi in tissue from experimentally infected animals.

A polymerase chain reaction (PCR) was developed for identification of Borrelia burgdorferi in biological specimens. The diagnostic efficiency was compared with that of in vitro culture. A primer set specifying a 791-bp DNA fragment of the B. burgdorferi B31 flagellin gene was used. Amplified DNA sequences were analyzed by agarose gel electrophoresis, and the identity of amplified DNA was confirmed by restriction enzyme cleavage and Southern blot hybridization with a 32P-labeled probe. By using purified B. burgdorferi DNA, the detection limit of the assay was approximately 0.002 pg of DNA, corresponding to one copy of the B. burgdorferi genome. By using in vitro-cultivated B. burgdorferi without prior DNA purification as the template DNA, 2 to 20 organisms could be detected. A 791-bp DNA fragment was amplified from all of 18 different B. burgdorferi strains tested, as well as from Borrelia hermsii and Borrelia anserina but not from Treponema pallidum. The efficacy of the PCR assay was evaluated on spleen, renal, and urinary bladder tissue specimens from eight experimentally infected gerbils. Specimens from the same organs were cultured in BSK medium in parallel. Of 24 organs, 21 (88%) were PCR positive and 17 (71%) were culture positive. All culture-positive specimens were also PCR positive. Compared with B. burgdorferi cultivation, PCR had at least a comparable diagnostic sensitivity, it was less laborious, and results were available within 1 to 2 days.

Animals↗
PubMed1991

Statistical issues in risk assessment of reproductive outcomes with chemical mixtures.

Establishing the relationship between a given chemical exposure and human reproductive health risk is complicated by exposures or other concomitant factors that may vary from pregnancy to pregnancy. Moreover, when exposures are to complex mixtures of chemicals, varying with time in number of components, doses of individual components, and constancy of exposure, the picture becomes even more complicated. A pilot study of risk of adverse reproductive outcomes among male wastewater treatment workers and their wives is described here. The wives of 231 workers were interviewed to evaluate retrospectively the outcomes of spontaneous early fetal loss and infertility. In addition, 87 workers participated in a cross-sectional evaluation of sperm/semen parameters. Due to the ever-changing nature of the exposure and the lack of quantification of specific exposures, six dichotomous variables were used for each specific job description to give a surrogate measure of exposure. Hence, no quantitative exposure-response relationships could be modeled. These six variables were independently assigned by two environmental hygienists, and their interrater reliability was assessed. Results are presented and further innovations in statistical methodology are proposed for further applications.

Data Interpretation, Statistical↗
PubMed1991

Tibial periosteal reactions in soldiers. A scintigraphic study of 29 cases of lower leg pain.

Twenty-two soldiers with tibial pain along the posteromedial tibial border (29 painful tibias) entered the study. The tibias were evaluated using radiographs and scintigraphs. Follow-up scintigraphs of 12 tibias were performed. The scintigraphic lesions were classified as Stages 0-V depending on the percentage of bone thickness involved. No attempts were made to differentiate between shin splints and stress fractures. Twenty-four symptomatic lesions and five asymptomatic lesions were found by scintigraphy. Radiographic changes were found in all the lesions classified as Stage III or higher, in some Stage II lesions, but never in Stages 0 and I lesions. Because intense scintigraphic uptake is seen in bone tumors, radiographs are needed to exclude this diagnosis. Radiographs were, however, not as sensitive as scintigraphs for differentiating the periosteal injuries seen in this study. The initial scintigraphs can be used to classify the lesions. Follow-up scintigraphs are not useful because they take months to return to normal. Consequently, the clinical symptoms and the level of pain should be the guidelines for treatment.

Adult↗
PubMed1991

Gynecologic surgery after repair of gastroschisis or omphalocele. A report of two cases.

Anterior abdominal wall defects, omphalocele and gastroschisis are rare fetal anomalies. Prenatal diagnosis of these conditions has improved with the widespread use of ultrasound and serum alpha-fetoprotein and amniotic fluid cholinesterase levels. Improvements in prenatal diagnosis have allowed appropriate and timely intensive care and surgical intervention, reducing morbidity and mortality. As more of these infants survive, gynecologists will more frequently encounter them as adults with a condition requiring surgical correction. Two cases demonstrate that well-planned surgery can maximize the outcome for these patients.

Abdominal Muscles↗
PubMed1991

Antibiotic susceptibility of Borrelia burgdorferi in vitro and in animal models.

The development of a rational antibiotic therapy for Lyme borreliosis has been hampered by the lack of reliable microbiologic or serologic criteria for diagnosis or cure. In studies of the treatment, the clinical response, has been used as the primary indicator of efficacy. Studies often differ in their criteria for a successful outcome, and it is not clear whether persistent symptoms are due to incomplete eradication of the pathogen, to a post-infectious syndrome, or to erroneous diagnosis in the first place. Thus, laboratory experiments are needed as a complement to clinical trials.

Animals↗
PubMed1990

[Hospital employees' knowledge about HIV disease. A study from 2 provincial hospitals].

The knowledge of and attitudes to HIV infection were investigated by means of questionnaires during the period 1.10.1988 to 30.4.1989 in two small Danish Hospitals. Two hundred and thirty two nurses, 147 nursing aids, 44 doctors, 25 laboratory workers and 22 midwives took part in the investigation. The overall response was 99% of the staff contacted. The questionnaires were anonymous and were completed immediately and without use of any sources of information. Poor knowledge was revealed concerning symptoms, sources of infection, precautions to avoid infection, high-risk groups and patients duty to provide information. In fact, none of the groups exceeded 66% correct answers on these subjects. A total of 70% of the whole group had been in contact with patients, whom they suspected to be HIV-positive. Every third individual had felt insecure regarding HIV at work. Incidents at work had caused 18 employees to be tested for HIV. Only about half had been instructed about HIV. A total of 73% expressed needs for further instruction about the disease. The investigation shows difference between the staff opinion of possible claims on the patients about tests and to the policy of the Danish Department of Health concerning voluntary testing.

Denmark↗
PubMed1990

[Young men's knowledge of AIDS. Development from June 1987 to January 1989].

The changes in young men's knowledge about AIDS were investigated in January 1989 by means of questionnaires, and compared with a similar investigation in June 1987. The answers to the questionnaires were voluntary and anonymous. Three hundred and six persons took part in the 1989-investigation. The investigation shows improved knowledge of AIDS and improved knowledge of the symptoms of AIDS. A greater percentage had received information about AIDS in school. 71% had attempted to use a condom compared to 45% in 1987. Furthermore, 96% knew that condoms provide protection from AIDS.

Acquired Immunodeficiency Syndrome↗