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Biomedical subjects

I Bygbjerg

Publications and source records attributed to I Bygbjerg.

18 recordsLinked to original sources
PubMed1999

IgG reactivities against recombinant Rhoptry-Associated Protein-1 (rRAP-1) are associated with mixed Plasmodium infections and protection against disease in Tanzanian children.

A cross-sectional sero-epidemiological study was performed in Magoda, Tanzania, an area where malaria is holoendemic. Blood samples were collected from children (1-4 years) and tested for IgG antibody reactivity against 2 recombinant protein fragments of Plasmodium falciparum Rhoptry-Associated Protein-1 (rRAP-1). The data were related to the prevalence of malarial disease and single P. falciparum or mixed Plasmodium infections. Fever (> or = 37.5 degrees C) in combination with parasite densities > 5000/microliter were used to distinguish between children with asymptomatic malaria infections and those with acute clinical disease. Furthermore, C-reactive protein (CRP) was applied as a surrogate marker of malaria morbidity. The prevalence of Plasmodium infections was 96.0%. Eleven children were defined as clinical malaria cases, all with single P. falciparum infections. The density of P. falciparum was significantly lower in children with mixed Plasmodium infections compared to those with single P. falciparum infections. Children with asymptomatic P. falciparum infections had higher IgG reactivities to rRAP-1, compared to IgG reactivities of children with malarial disease. Children with mixed Plasmodium infections generally showed elevated IgG reactivity to rRAP-1, when compared to children with single P. falciparum infections. The possible relationship between mixed species infections, clinical outcome of the disease and antibody responses to RAP-1 is discussed.

Age Factors↗
PubMed1994

Hepatitis A vaccine. A new convenient single-dose schedule with booster when long-term immunization is warranted.

A total of 162 anti-HAV-negative healthy adults were immunized with a single high dose (1440 ELISA units = 1 ml) of inactivated hepatitis A vaccine and a booster was given at month 6. Antibodies were measured after modification of a commercial ELISA kit, enabling quantification of titres down to 6 mIU ml-1. After 14 days, 96% of vaccinees had positive anti-HAV titres (> 20 mIU ml-1), and after 30 days all vaccinees had seroconverted. The geometric mean titres were 150 mIU ml-1 and 380 mIU ml-1 respectively. The booster dose at month 6 elicited a dramatic (25-fold) increase in antibody titres from 125 to 3090 mIU ml-1. Thus a single dose may be a convenient alternative to immunoglobulin for inducing rapid seroprotection, with a booster dose at month 6 ensuring long-lasting protection.

Adolescent↗
PubMed1993

Influence of in vivo hypobaric hypoxia on function of lymphocytes, neutrocytes, natural killer cells, and cytokines.

We have investigated the effects of short-term hypoxia in vivo on the human cellular immune system. Seven young healthy volunteers were placed in a decompression chamber (380 Torr) for 20 min with or without supplemental O2. The leukocyte concentration increased during hypobaric conditions because of an increased concentration of lymphocytes. The absolute and relative concentration of CD16+ natural killer (NK) cells increased markedly during hypoxia and returned to pretest values after 2 h of recovery. The NK cell activity of blood mononuclear cells (BMNC, %lysis/fixed no. of BMNC) boosted with interferon-alpha, interleukin-2 (IL-2), and indomethacin rose in parallel with unboosted NK cell activity during hypoxia. The percentage of CD4+ and CD8+ cells declined during hypoxia, whereas the absolute concentration of both CD8+ cells and CD14+ monocytes increased. Although the BMNC composition varied, the proliferative responses of BMNC after stimulation with phytohemagglutinin, purified derivative of tuberculin, and IL-2 did not change significantly. The in vitro production of interleukin-1 beta and IL-2 in supernatants obtained after stimulation of BMNC with phytohemagglutinin or lipopolysaccharide was not affected. The chemiluminescence response of neutrocytes increased 2 h after hypoxia. It was concluded that acute hypoxia induced marked alterations in the immune system and that the NK cells are especially sensitive to the hypoxic stimulus.

Adult↗
PubMed1991

The effect of prophylaxis with chloroquine and proguanil on delayed-type hypersensitivity and antibody production following vaccination with diphtheria, tetanus, polio, and pneumococcal vaccines.

In vitro studies have shown that anti-malarial drugs suppress immunity. In this study, the effects of chloroquine and proguanil (Paludrine) on the cellular and humoral immune system were measured by two in vivo methods: 1) cell-mediated immunity (delayed cutaneous hypersensitivity) i.e., skin tests with seven delayed-type common antigens (Multitest) and 2) humoral immunity by measurement of specific antibody response to vaccination. Sixty healthy young individuals were randomized into four groups and given 1) no treatment (controls), 2) chloroquine diphosphate (500 mg/week), 3) chloroquine diphosphate (1,000 mg/week), or 4) proguanil hydrochloride (200 mg/day) for six weeks. Skin testing was performed on days 0 and 28. Vaccinations with diphtheria, tetanus, polio, and pneumococcal polysaccharide antigen vaccines were performed on day 28, and the presence of specific antibodies was determined on days 0, 28, and 42. The skin tests induced a significant increase in skin reactive areas from day 0 to day 28 in all groups. Furthermore, the skin test induced an increase in the level of specific IgG for diphtheria and tetanus, but had no effect on antibodies to antigens not included in the skin test. The results showed that there were no significant differences among the four groups regarding skin test areas and increases in antibody titers following vaccination. Therefore, it is concluded that in healthy persons, six weeks intake of chloroquine, even in double doses, or proguanil in chemoprophylactic dosages, does not induce any detectable suppression of delayed-type hypersensitivity or vaccination responses to diphtheria, tetanus, polio, or pneumococcal polysaccharide antigens.

Adult↗
PubMed1990

Evaluation of simple tests for detection of HIV antibodies: analysis of interobserver variation in Tanzania.

200 sera were tested for HIV antibodies with different tests in Tanzania. The results were interpreted by 5 different observers with different laboratory experience. There was considerable variation between observers and between testing methods. HIV-Chek was easiest to perform with little interobserver variation, but a few probably false negative readings were seen. Serodia gave many false positives. Western Blots gave more diverging results due to indeterminate sera and lack of training. HIV-Chek seems best when time, facilities, and training are limited and if combined with Serodia false negative results can be excluded.

Blotting, Western↗
PubMed1989

Prognostic value of immunologic abnormalities and HIV antigenemia in asymptomatic HIV-infected individuals: proposal of immunologic staging.

The prognostic value of various immunologic tests was investigated in 150 HIV-seropositive homosexual men, who were initially without HIV-related symptoms or AIDS and who were followed for a median of 12 months (range 3-28 months). The laboratory investigations included HIV antigen in serum, total lymphocyte count, T-helper (CD4) and T-cytotoxic/suppressor (CD8) counts, and lymphocyte transformation responses to the mitogens phytohemagglutinin (PHA) and pokeweed mitogen (PWM), and to antigenic extracts from Candida albicans and cytomegalovirus. 24 individuals developed HIV-related symptoms or AIDS (11 cases). All parameters except the CD8 count were of prognostic value, but a multivariate analysis of symptom-free survival showed that HIV antigenemia, a CD4 count less than 0.5 x 10(9)/l, and relative response to PWM below 25% of controls contained all the prognostic information. Individuals abnormal at entry for these 3 variables had a theoretical 36 times as high hazard of developing symptoms within the observation period as had individuals with normal parameters. There was no significant covariation between HIV antigenemia on the one hand and CD4 count and response to PWM on the other. Although, the latter 2 variables covaried, each of them provided independent information, and both were used to classify the degree of the immunodeficiency in 3 stages: Im-0 with normal values, Im-1 with one, and Im-2 with both tests abnormal. Individuals in stage Im-2 had a 10 times increased risk of developing symptoms. The immunologic staging correlated significantly with the clinical grouping (CDC criteria). This staging improved in only 1, but deteriorated in half of 36 individuals observed for at least 18 months. Thus, the staging is likely to prove useful when attempts to arrest the immunodeficiency of HIV-infected individuals has to be monitored.

Biomarkers↗
PubMed1987

Human pharmacokinetics of proguanil and its metabolites.

The pharmacokinetics of proguanil and its metabolites cycloguanil and p-chlorophenylbiguanide were studied in five healthy volunteers taking 200 mg orally for 14 days. A highly sensitive and specific high-performance liquid chromatographic assay was applied, clearly identifying all three compounds in plasma extracts as separate peaks. In four subjects peak plasma concentrations of proguanil (500 to 600 nmol/l) were reached after two to three hours, while cycloguanil and p-chlorophenylbiguanide showed a plateau after three and six hours, respectively. In the fifth subject peak concentrations of proguanil and cycloguanil appeared after seven hours. Trough concentrations (pre-dose in the morning) of proguanil and cycloguanil were about 200 and 100 nmol/l, respectively. Mean half-life of proguanil was estimated to approximately 20 h. The active metabolite cycloguanil constituted 30% of the total plasma drug concentration. The concentration of proguanil was higher in erythrocytes than in plasma, while that of cycloguanil was lower. Relevant clinical studies correlating plasma concentrations to the suppressive activity against malaria will be possible to perform based on the applied method and presented kinetic data.

Adult↗
PubMed1982

Severe acquired immunodeficiency in European homosexual men.

Four previously healthy Danish homosexual men developed Kaposi's sarcoma or opportunistic infections with fever of unknown origin and lymphadenopathy. One patient died of a Pneumocystis carinii pneumonia. Three patients had defective cell-mediated immunity with absent leucocyte interferon production and decreased proliferative response to mitogens and antigens. T lymphocyte helper subsets and natural killer cell activity were reduced. Unstimulated mononuclear cells produced leucocyte migration inhibitor factor. Two patients were sexual partners and three had never been to the USA, where cases of severe acquired immunodeficiency have been reported. Thus, the syndrome must also be suspected in European homosexual men who present with fever of unknown origin, opportunistic infections, or Kaposi's sarcoma.

Adult↗
PubMed1982

Microbiological and immunological studies in a case of human melioidosis diagnosed in Denmark.

The first case of melioidosis reported in Denmark was in a 64-year-old man 2 weeks after his return from a 3-week visit to Kenya. The clinical course was characterized by septicaemia and Pseudomonas pseudomallei was isolated from repeated blood cultures, urine and sputum. Transient impairment of cellular immunity was observed. During the convalescence a cell-mediated immune response against the pathogen was detected by the lymphocyte blast transformation test. Two precipitins against P. pseudomallei were detected by crossed immunoelectrophoresis; the most pronounced was directed against the common antigen of P. aeruginosa. The patient was treated with a combination of oxytetracycline, sulfamethoxazole and trimethoprim for one month, followed by sulfamethoxazole and trimethoprim for another month. The clinical response to the treatment was good. The patient had previously had recurrent pulmonary tuberculosis. The relationship of melioidosis to tuberculosis is briefly discussed.

Animals↗
PubMed1981

Fansidar resistant falciparum malaria acquired in South East Asia.

A case of Plasmodium falciparum malaria resistant to Fansidar (sulphadoxine plus pyrimethamine) at a level corresponding to R III and resistant to chloroquine is reported. The infection was most certainly acquired in Malaysia, but diagnosed and treated in a non-malarious area. Normal resorption and elimination rates of the Fansidar components excludes cure failure due to abnormal drug fate in the host. P. falciparum parasites from the patient have been maintained in vitro cultures. The patient was permanently cured with mefloquine.

Adult↗
PubMedDate not supplied

Reported side effects to chloroquine, chloroquine plus proguanil, and mefloquine as chemoprophylaxis against malaria in Danish travelers.

BACKGROUND: The aim of the study was to provide data on the relative frequency of reported symptoms in travelers using chloroquine, chloroquine plus proguanil, and mefloquine. METHOD: The study was an open, nonrandomized study recording self-reported events in travelers recruited consecutively from two travel clinics in Copenhagen, Denmark. The main outcome measures were the relative proportion of travelers reporting particular symptoms in the three prophylaxis groups, compliance, hospitalization and premature termination of the travel. RESULTS: From May 1996 to April 1998 5, 446 travelers were included and 4,158 questionnaires (76.3%) returned. Compliance was significantly better in mefloquine users with 83.3% of short term travelers compared to 76.3% in chloroquine plus proguanil users. Also, 84.8%, 59.3% and 69.5% using chloroquine, chloroquine plus proguanil, and mefloquine respectively reported no symptoms and 0.6%, 1.1% and 2.8% reported "unacceptable" symptoms. Compared to chloroquine, mefloquine users had a significantly higher risk of reporting depression, RR 5.06 (95% CI 2.71 - 9.45), "strange thoughts," RR 6.36 (95% CI 2.52 - 16.05) and altered spatial perception, RR 3.00 (95% CI 1.41 - 6.41). CONCLUSION: Overall mefloquine is tolerated at least as well as chloroquine plus proguanil and shows better compliance, however, symptoms related to the central nervous system are more prevalent in mefloquine users and when symptoms develop, they are perceived as more severe.

Antimalarials↗