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Biomedical subjects

S Jepsen

Publications and source records attributed to S Jepsen.

116 records · Page 7Linked to original sources
PubMed1980

Antigens and antibodies in Plasmodium falciparum malaria studied by immunoelectrophoretic methods.

Soluble plasma antigens in 53 Liberian patients with P. falciparum malaria were analyzed in double diffusion using plasma from 27 immune adults. One immune plasma reacted with 17% of the plasma samples and was used in subsequent quantitative immunoelectrophoretic (IE) studies as antiserum. By fused rocket IE 2 antigens were found in samples with parasitaemia (P) above 0.6% and above 4.5% P the antigens had grossly increasing concentration. In 22 samples of 0.6% P or more, 7 antigens were demonstrated by crossed IE. Two electrophoretically heterogeneous antigens. Ag-1 and Ag-2, were found most frequently. Ag-1 was partly heat-stable and was in some samples amphiphilic as shown by charge shift crossed IE. Ag-1 and Ag-2 did not contain integral erythrocyte membrane proteins, and Ag-1 is suggested to be a structural protein of P. falciparum. Twenty-six immune plasma samples were screened for antibodies against 4 antigens in crossed IE with intermediate gel. It is suggested that an index for protective immunity may be obtained by summation of semiquantitative titers obtained by crossed IE with intermediate gel using an antigen pool representing e.g. 20--30 soluble antigens.

Animals↗
PubMed1979

Chloroquine-resistant Plasmodium falciparum malaria in Kenya.

A case of chloroquine-resistant Plasmodium falciparum malaria in a non-immune male is reported. Primary attack came 19 days after return to a non-malarious country from a visit to Kenya. Recrudescences occurred three times with intervals of 30 to 33 days after standard chloroquine treatment. The WHO extended field test for sensitivity of falciparum malaria to chloroquine was followed by recrudescence 31 days later. Treatment with Fansidar terminated the infection. If continuous treatment of the patient with lithium does not interfere with the schizontocidal action of chloroquine, this strain shows a resistance pattern of R I delayed recrudescence.

Adult↗
PubMedDate not supplied

Differential antibody response of Gambian donors to soluble Plasmodium falciparum antigens.

A seroepidemiological and clinical study was performed in an area of West Africa (The Gambia) where Plasmodium falciparum is endemic with seasonal transmission. Plasma samples were tested by intermediate gel immunoelectrophoresis for antibodies against 7 soluble P. falciparum antigens. There were marked differences in the age-related pattern of antibody response to the different antigens. Antibodies to 4 of the antigens were acquired slowly with a maximum prevalence reached after 25-35 years of age. Antibodies against the 3 remaining antigens, including the endotoxin-like antigen, Ag7, were acquired earlier with a plateau of maximum prevalence reached after 5-11 years, i.e. at the time when morbidity due to malaria decreased. Children who had not appeared to be infected with malaria during the preceding transmission season had lower levels of antibodies to soluble antigens than did children who had had a documented attack of clinical malaria or parasitaemia. There was no difference in antibody profiles to soluble antigens between children with sickle cell trait and children with normal haemoglobin.

Adolescent↗
PubMedDate not supplied

Seasonal changes in cell mediated immune responses to soluble Plasmodium falciparum antigens in children with haemoglobin AA and haemoglobin AS.

In this longitudinal study peripheral blood mononuclear cells (PBMC) were obtained before and during the malaria season from healthy HbAA and HbAS children. Cells were compared for proliferation in response to stimulation by soluble Plasmodium falciparum antigens (SPAg) or purified derivative of tuberculin (PPD). The lymphoproliferative responses to SPAg of the paired PBMC samples showed 2 distinct seasonal changes in relation to the haemoglobin phenotype. In HbAA children, the lymphoproliferative responses to SPAg were suppressed during the malaria season. In contrast, they were enhanced in HbAS children during the malaria season. No distinct seasonal change in the response to PPD was found in relation to the haemoglobin phenotype. The study points to the role of the sickle cell trait in modulating the cellular immune responses to falciparum malaria.

Adolescent↗
PubMedDate not supplied

The influence of the calibration mode of a laser fluorescence device on caries detection.

The aim of the present study was to assess the influence of the calibration mode of a laser fluorescence measurement device on caries detection. While positioning the probe on an occlusal carious lesion or stained fissure using a clamp, the occlusal surface of each of 62 teeth was covered with a light-body silicone impression material to facilitate a reproducible probe position. Then, measurements of the occlusal lesions were performed after standard and individual calibration at four non-carious areas on the buccal surface of each tooth. Mean laser fluorescence values of the occlusal reading point following standard calibration were about 4-5 units higher compared to values measured after individual calibration. After 1 week, readings after both standard and individual calibration were not different from baseline values (p > 0.05). During individual calibration, a mean range of about 2 units could be observed when comparing the readings of the occlusal reading point with respect to the four different areas of each buccal surface. The present study indicates that laser fluorescence readings are dependent on the mode of calibration. Moreover, for individual calibration, the probe position has to be recorded carefully. It is suggested that the same mode of calibration should always be used, when employing laser fluorescence measurements for longitudinal caries monitoring.

Calibration↗
PubMedDate not supplied

Evaluation of selective caries removal by a fluorescence feedback-controlled Er:YAG laser in vitro.

AIM: To establish a fluorescence threshold level that could guide a therapeutic Er:YAG laser through a caries lesion to determine a therapeutic endpoint of caries removal. MATERIALS AND METHODS: A total of 65 extracted human teeth, 35 with dentine caries and 30 healthy, were used for this study. An Er:YAG laser system that emitted at a wavelength of 2.94 microm was used. The laser was equipped with a laser fluorescence feedback system, excitation wavelength 655 nm, to control the irradiation by the Er:YAG laser. The evaluated threshold levels of the fluorescence feedback system were 3, 7, 8, 10, 12, 15 and 20. After treatment the teeth were prepared for histological staining according to the method of Brown and Brenn for the identification of bacteria. The specimens were subjected to a quantitative evaluation of residual bacteria on the treated dentine surface. In addition, the internal fluorescence of dentine and potential fluorescence changes of dentine after laser irradiation were evaluated. RESULTS: About 80% of the irradiated dentine surface showed residual bacteria with threshold levels of 20, 15, 12, and 10. Residual bacteria were not found with threshold levels of 7 and 3. The study revealed a significant increase in dentine fluorescence after laser irradiation. CONCLUSION: The results of the present in vitro study indicate that a fluorescence threshold level of 7 or 8 units can guide an Er:YAG laser to a complete removal of carious dentine.

Aluminum↗
PubMedDate not supplied

Longitudinal evaluation of aspartate aminotransferase in the crevicular fluid of implants with bone loss and signs of progressive disease.

Aspartate aminotransferase (AST) has been shown to be a promising host marker for periodontal disease progression. The aim of the present study was to analyze AST in the crevicular fluid (CF) of implants exhibiting peri-implantitis and to evaluate the association between AST levels and progressive attachment loss. Twenty patients who had received a total of 42 endosseous cylindric titanium implants were examined. Radiographic assessment of preexisting bone loss and clinical measurements, including electronic attachment of probing, presence or absence of plaque, bleeding on probing, and AST analysis in CF, were performed on 2 occasions 6 months apart. During this study period 13 of 168 sites in 7 patients experienced further loss of attachment greater than or equal to 1.0 mm (median 1.7 mm; interquartile range 0.4 mm). Evaluation of a positive AST test (> or = 300 microIU) in site-specific diagnosis revealed low positive (8%) and high negative predictive values (92%), with a sensitivity of 15% and a specificity of 83%. These results indicate that, in contrast to periodontal disease, the assessment of AST in peri-implant crevicular fluid may be of limited value as a diagnostic and prognostic marker for peri-implant disease.

Alveolar Bone Loss↗