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Biomedical subjects

M Bakker

Publications and source records attributed to M Bakker.

At least 73 records · Page 4Linked to original sources
PubMed1988

Serodiagnostic profiles of HIV and HIV pathogenesis in vivo.

Different stages of HIV infection are marked by expression of HIV genes, production of HIV antibodies, formation of antigen/antibody complexes and clearance of such complexes. Transient HIV antigenemia appearing generally 6-8 weeks prior to HIV antibody (HIV-Ab) seroconversion and lasting 3-4 months is generally seen in acute infection. If IgG antibodies to both envelope and core protein persist in the absence of HIV-Ag the short-term prognosis is relatively good. However, HIV-Ag seroconversion may appear at any time after HIV-Ab seroconversion. Progression to AIDS is strongly associated with declining or absent levels of IgG antibodies to p24. Titers of antibodies to HIV p24 below 64 are strongly associated with the presence of HIV antigen and a poor clinical outcome. HIV antigen may be less efficiently detected with the present assays in sera from regions where the prototype strains of HIV (HTLV-III and LAV) are less prevalent, like Central Africa. Levels of HIV-Ag in serum, and possibly in CSF, can be decreased by nucleoside analogues, like AZT. This indicates HIV-Ag and possibly antibody to HIV core protein p24 as suitable markers for selecting individuals for antiviral therapy as well as monitoring the efficacy of such therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Influenza-like syndrome in homosexual men: a prospective diagnostic study.

In the course of a prospective study of the prevalence and incidence of infection with the human immunodeficiency virus (HIV) and risk factors for the acquired immune deficiency syndrome among 961 homosexual men, 97 initially HIV antibody seronegative men reported a febrile period lasting at least three days. In 60 of these men serological evidence for an infection was found: influenza A or B virus (17 men), HIV (14), Epstein-Barr virus (seven), parainfluenza virus type I, 11 or Ill (five), hepatitis A virus (three), cytomegalovirus (three), adenovirus (two), respiratory syncytial virus (two), hepatitis B virus (one) and Toxoplasma gondii (one). Combined infections were found in five men. A total of 17 men seroconverted for HIV antibody. The clinical symptoms of acute HIV infection closely resembled those of influenza A or B infection. Skin rashes also occurred frequently in men with HIV infection. HIV antibody seroconversion gives rise to a number of different symptoms and primary HIV infection should be included in the differential diagnosis of prolonged febrile illness in those at risk of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Spread of human T-cell leukemia virus (HTLV-I) in the Dutch homosexual community.

Sequential sera of 697 homosexual men, participating in a prospective study (1984-1986) of the risk to acquire human immunodeficiency virus (HIV) or AIDS, were tested for antibodies to human T-cell leukaemia virus (HTLV-I) by particle agglutination and immunoblotting. No intravenous drug users were included in this trial. Three men (0.4%) were HTLV-I antibody positive at intake and an additional 2 at the end of the observation period, resulting in an attack rate of approximately 0.3%. One of the 3 men with HTLV-I antibodies at intake was a Brazilian. One man had an acute HTLV-I infection after sexual intercourse with a Brazilian during holiday in Brazil. No serological cross-reactivity with HIV was observed nor a relationship with other sexually transmissible viral or bacterial infections. In contrast to HIV no relationship with anogenital intercourse was noted; both primary HTLV-I infected men practiced only orogenital intercourse. This suggests that HTLV-I was imported in the Dutch homosexual community after HIV was introduced in the Netherlands. HTLV-I appears to spread slower within the homosexual community than HIV and possibly by other routes.

Adult↗
PubMed1987

Pathogenesis of HIV and its implications for serodiagnosis and monitoring of antiviral therapy.

Human immunodeficiency virus (HIV) is lymphotropic and neurotropic. In vivo clinical and immunological abnormalities develop in a large proportion of long-term HIV antibody seropositive persons. Different stages of HIV infection are marked by expression of HIV genes, production of HIV antibodies, formation of antigen/antibody complexes and clearance of such complexes. Transient HIV antigenemia appearing generally 6-8 wk prior to HIV antibody (HIV-Ab) seroconversion and lasting 3-4 mth is generally seen in acute infection. IgM antibodies predominantly to core proteins may occasionally be detectable when, or just before, IgG antibodies appear. If IgG antibodies to both envelope and core proteins persist in the absence of HIV-Ag the short-term prognosis is relatively good. However, HIV-Ag seroconversion may appear at any time after HIV-Ab seroconversion. Progression to AIDS is strongly associated with declining or absent levels of IgG antibodies to p24. IgG2 and IgG4 antibodies to HIV, which are mainly directed to p24, disappear most dramatically. Titers of antibodies to HIV p24 below 64 are strongly associated with the presence of HIV antigen and a poor clinical outcome. HIV antigen was detected frequently in sera from children in all stages of infection in contrast to adults whose sera were generally HIV-Ag negative when asymptomatic and positive when AIDS was apparent. HIV antigen may be less efficiently detected with the present assays in sera from regions where the prototype strains of HIV (HTLV-III and LAV) are less prevalent, like Central Africa. Persistence of HIV-Ag in cerebrospinal fluid (CSF) appears to be pathognomonic for progressive encephalopathy, particularly in children. Levels of HIV-Ag in serum, and possibly in CSF, can be decreased by nucleoside analogues, such as AZT. This indicates HIV-Ag and possibly antibody to HIV core protein p24 as suitable markers for selecting individuals for antiviral therapy as well as monitoring the efficacy of such therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Intrathecal synthesis of antibodies to HTLV-III in patients without AIDS or AIDS related complex.

De novo synthesis in the central nervous system of IgG antibodies to human T cell lymphotropic virus type III (HTLV-III) (lymphadenopathy associated virus) was shown in seven of 10 seropositive men who had syphilis but not the acquired immune deficiency syndrome (AIDS) or AIDS related complex. None of these men showed neurological symptoms when the serum and cerebrospinal fluid were collected. Pleocytosis was present in all 10. Of the seven men who showed evidence of intrathecal synthesis of antibodies, five had increased total concentrations of IgG and four had oligoclonal IgG bands in their cerebrospinal fluid. Oligoclonal bands were also present in one man who did not have any antibodies. Longitudinal study of one man showed that seroconversion preceded intrathecal synthesis of antibody specific to HTLV-III. The appearance of antibody in the cerebrospinal fluid was accompanied by a transient rise in mononuclear cell count and the appearance of oligoclonal bands. The presence of clones of B cells specific to HTLV-III in the central nervous system of these patients without persisting neurological symptoms suggests that HTLV-III enters the central nervous system in the early stages of infection.

Acquired Immunodeficiency Syndrome↗
PubMed1986

HLA-antigens in the human uvea.

With the use of monoclonal antibodies in an indirect immunofluorescence technique we studied the distribution of Class I (HLA-ABC and B27) and Class II (HLA-DR) antigens in the human uvea. W6/32, directed against the core of HLA-ABC antigens, was used to study the distribution of Class I antigens. The anterior border layer of the iris, the non-pigmented and pigmented epithelium and the external basement membrane of the ciliary body and the vascular endothelium in the uvea showed a positive staining for Class I antigens. B27/M1, directed against an epitope of the HLA-B27 antigen, and the control antibody A11/Aw24, which was directed against an epitope of HLA-A11, revealed the same distribution pattern in respectively HLA-B27 and HLA-A11 positive donor eyes. The intensity of their staining was much weaker than the staining with W6/32. Class II antigens were studied with OkIa1, an antibody directed against the core of HLA-DR antigens. HLA-DR antigens were detectable on single cells scattered throughout the entire uvea. These cells did not seem to relate to any anatomical entity. No staining for Class II antigens was seen in the uveal blood vessel endothelium. The expression of HLA-antigens in the uvea is compatible with the distribution in other tissues. These findings suggest that the expression of HLA-B27 in the human uvea does not explain why the eye is one of the target tissues in HLA-B27 associated disease.

Adolescent↗
PubMed1986

The use of HLA-B27 as a diagnostic and prognostic aid in acute anterior uveitis (AAU) in The Netherlands.

Acute anterior uveitis (AAU) may be considered to be one manifestation of the seronegative spondylarthropathies of which ankylosing spondylitis (AS) is the prototype, especially when the patient is HLA-B27 positive. However, it is not yet clear under which circumstances a patient with AAU should be referred to the rheumatologist. In a retrospective study we evaluated the management of 68 consecutive HLA-B27+ AAU patients from a rheumatologic point of view. Although the majority (73%) showed rheumatic problems, only half (52%) of the patients was referred to a rheumatologist, due to problems in evaluation of clinical history and of x-ray reading of the sacroiliac (SI) joints. Because HLA-B27 typing will determine whether the AAU patients "at risk" have AS or a related arthropathy, we suggest using HLA-B27 typing in AAU patients as a diagnostic and prognostic aid. When the AAU patient is found to be HLA-B27 positive, the rheumatologist will be able to "split" these patients into those with AS and those without. Early diagnosis of AS in AAU patients is important as an early start of drug therapy and physiotherapy may prevent deformities and improve final rheumatologic outcome.

Back Pain↗
PubMed1986

[Not Available].

Explore the source record for details and available documents.

Academies and Institutes↗
PubMed1985

Immune response after vaccination with recombinant hepatitis B vaccine as compared to that after plasma-derived vaccine.

Thirty-one individuals (health care workers) were vaccinated with recombinant hepatitis B vaccine (10 microgram dose) and their immune response (anti-HBs) was compared to that of twenty-five health care workers after vaccination with plasma-derived vaccine (20 microgram dose). Although the seroconversion rate and the percentage of anti-HBs/a antibodies at month 7 were comparable, the geometric mean titre of anti-HBs at month 7 was considerably lower for the recombinant vaccine group (857.4 vs. 6736.5 IU/l). However, vaccinees from the two groups showing seroconversion at month 1 had comparable titres at month 7. Raising the dose of HBsAg in the recombinant vaccine may favourably influence the seroconversion rate at month 1 and thereby the immune response after three injections.

Adult↗
PubMed1985

The expression of HLA-antigens in the human anterior uvea.

The expression of MHC Class I and Class II antigens was investigated in the human uvea using monoclonal antibodies in an indirect immunofluorescence technique. The anterior border layer of the iris, the non-pigmented and pigmented epithelium of the ciliary body, the external basement membrane of the ciliary body and the vascular endothelium in the uvea showed a positive staining for Class I antigens. The endothelium lining the bloodvessels in the uvea expressed the highest density of Class I antigens. Class II antigens were found only on single cells spread throughout the entire uvea. These cells did not seem to relate to any anatomical entity. No staining for Class II antigens was detected in the uveal blood vessel endothelium. The expression of HLA-antigens in the uvea may provide insight in the pathogenesis of certain HLA associated uveitis entities.

Adolescent↗
PubMed1983

Effect of antibiotics on the human intestinal flora in mice.

Antibiotics used during selective decontamination were studied for their effect on the human intestinal flora in mice. Polymyxin B and neomycin were found to eliminate Escherichia coli from the gastrointestinal tract but did not alter total numbers of obligate anaerobes. Neomycin induced an increase of the percentage of gram-negative obligate anaerobes. Cephradine did not affect the numbers of obligate and facultative anaerobes but increased the percentage of gram-negative obligately anaerobic rods in the flora. The selective effect of polymyxin B and neomycin on the flora is accounted for by a relative insusceptibility of the anaerobic flora as compared with E. coli. Low concentrations of polymyxin B and neomycin were detected in caecal supernatants. This was found to be due to strong binding of both antibiotics to the solid fraction of intestinal contents.

Ampicillin↗
PubMed1983

Binding to faeces and influence on human anaerobes of antimicrobial agents used for selective decontamination.

The degree of binding of ampicillin, cephradine, co-trimoxazole, gentamicin, nalidixic acid, neomycin, polymyxin B and tobramycin by faecal substance as well as the influence of these antibiotics on human intestinal obligate anaerobes was investigated. In contrast to ampicillin, cephradine, co-trimoxazole and nalidixic acid, the nonabsorbable antibiotics polymyxin B and neomycin were bound to a considerable degree by human faeces. The binding of tobramycin and gentamicin to the solid part of faeces was less effective. The inhibitory effect of co-trimoxazole, gentamicin, nalidixic acid, neomycin, polymyxin B and tobramycin on the human obligate anaerobes was weak as compared with ampicillin and cephradine. Drugs which effectively eliminate Enterobacteriaceae from the gastrointestinal tract and which have a moderate effect on obligate anaerobes, like polymyxin B, are particularly suitable for selective decontamination of the gastrointestinal tract. The strong inactivating binding of aminoglycosides and polymyxin B to faeces accounts for the relatively high oral dose needed for a suitable faecal concentration.

Ampicillin↗
PubMedDate not supplied

Low levels of specific T cell activation marker CD27 accompanied by elevated levels of markers for non-specific immune activation in the cerebrospinal fluid of patients with AIDS dementia complex.

Concentrations of soluble receptors for tumor necrosis factor (sTNFR-p55 and sTNFR-p75) and soluble T cell antigens CD25 and CD27 (sCD25 and sCD27) were measured in paired serum/cerebrospinal fluid (CSF) samples of 15 patients with AIDS dementia complex (ADC) and 15 HIV-infected control subjects (11 with other central nervous system (CNS) infections and four without CNS infection). In this study levels of sTNFR-p55, sTNFR-p75 and sCD25 were elevated in the CSF of ADC patients and of the 11 patients with other CNS infections, whereas CSF-levels of the specific T cell marker sCD27 were lower in patients with ADC as compared to the control subjects with and without other CNS infections. This pattern suggests a relative failure of eliciting a T cell-mediated immune response intrathecally in patients with ADC.

AIDS Dementia Complex↗
PubMedDate not supplied

Subtypes within a sample of precontemplating smokers: a preliminary extension of the stages of change.

Precontemplating smokers are not planning to quit within the next 6 months. There are indications that this group is not homogeneous. The present investigation aimed at identifying relevant subgroups within this large group of smokers in order to refine stage-matched interventions. Precontemplators were asked whether they were planning to quit (1) within the next year. (2) within the next 5 years, (3) not within the next 5 years but sometime, (4) never, or (5) none of the above. Smokers who were planning to quit within 5 years (redefined precontemplators) differed from smokers who were not planning to quit within the next 5 years (immotives) on the pros of quitting but not on self-efficacy scores. Compared to smokers in the other groups, immotives scored significantly lower on specific factors within the pros of quitting.

Adult↗