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Biomedical subjects

S Lindbäck

Publications and source records attributed to S Lindbäck.

At least 19 recordsLinked to original sources
PubMed2006

Adherence to treatment in Swedish HIV-infected patients.

OBJECTIVES: The objectives were to assess the prevalence of adherence to antiretroviral treatment in Swedish human immunodeficiency virus (HIV)-infected patients and to evaluate factors associated with adherence. METHODS: All HIV-treated patients, who attended one of 30 (of a total of 32) Swedish infectious diseases clinics, during 7 months, were asked to complete an anonymous questionnaire containing the 9-item Morisky Medication Adherence Scale (MMAS) and questions about other factors potentially affecting adherence. The summary score of MMAS ranges from 1 to 13, where 13 indicates perfect adherence; patients scoring 11 or above (corresponding to 95% adherence level) were classified as 'adherent'. RESULTS AND DISCUSSION: In total 946 patients participated (response rate 97.5%). The proportion of patients who reported not missing a dose during the day prior to the completion of the questionnaire was 97% and the proportion classified as 'adherent' was 63%. 'Adherent' patients were more likely to have a good relationship with their health care professionals (P < 0.05) and not have problems with drugs or alcohol (P < 0.01). Being older (P < 0.01) and having a shorter time on current treatment (P < 0.01) and on treatment in total (P < 0.05) were factors also associated with good adherence. CONCLUSION: Factors modifiable for interventions by health care professionals are patient-provider relationship, drug or alcohol problems and patients with long treatment periods.

Adult↗
PubMed2001

Recent origin of human immunodeficiency virus type 1 variants in resting CD4+ T lymphocytes in untreated and suboptimally treated subjects.

Resting CD4(+) T lymphocytes are an important reservoir for human immunodeficiency virus type 1 (HIV-1) in treated patients with undetectable viremia. The knowledge of viral persistence in these cells is limited, however, for patients without treatment or patients for whom treatment is failing; therefore, this reservoir in such patients was characterized. Virus variants were characterized in 3 subjects who were followed-up from primary HIV-1 infection and 5 treatment-experienced subjects. No founder viral sequences and only a minority of the earlier identified drug-induced mutations were found in the resting T lymphocytes. Instead, the viral sequences were closely related to those detected simultaneously in plasma, except in 2 treatment-experienced subjects. Thus, a turnover and replenishment of this virus reservoir in peripheral blood is likely to occur in most persons with detectable viremia. However, infrequently the virus variants in plasma and resting T cells seem to be derived from independent sources.

Anti-HIV Agents↗
PubMed2001

Initiation of therapy during primary HIV type 1 infection results in a continuous decay of proviral DNA and a highly restricted viral evolution.

A latent pool of HIV-1 is established early in memory CD4+ T lymphocytes and persists during antiretroviral therapy. Also, viral replication may continue in subjects despite undetectable viremia. However, it remains unclear whether this residual replication results in any significant sequence evolution. We were therefore interested in studying the viral evolution and HIV-1 DNA dynamics in subjects with primary infection receiving or not receiving early potent antiretroviral therapy. In 16 subjects, HIV-1 DNA load was monitored from 1 to 23 days, up to 1253 days, after onset of symptoms. Extensive sequential cloning and sequence analysis of the V3 region was performed in four subjects. In the treated subjects a continuous decline in the proviral load was found, corresponding to a half-life of about 6 months. As expected in newly infected individuals the founder virus populations showed high intrasubject sequence similarity. Also, a limited increase in the viral divergence was detected during the first 6 months in three treated subjects. Thereafter, no significant sequence changes were found despite analysis of a large number of clones. Our data thus suggest that early and successful therapy in compliant subjects with primary HIV-1 infection results in a highly restricted viral evolution and a decline in the proviral load close to the decay rate of human memory T lymphocytes.

DNA, Viral↗
PubMed2000

Viral dynamics in primary HIV-1 infection. Karolinska Institutet Primary HIV Infection Study Group.

OBJECTIVES: To study the natural course of viremia during primary HIV infection (PHI). METHOD: Eight patients were followed from a median of 5 days from the onset of PHI illness. Plasma HIV-1 RNA levels were measured frequently and the results were fitted to mathematical models. HIV-1 RNA levels were also monitored in nine patients given two reverse transcriptase inhibitors and a protease inhibitor after a median of 7 days from the onset of PHI illness. RESULTS: HIV-1 RNA appeared in the blood during the week preceding onset of PHI illness and increased rapidly during the first viremic phase, reaching a peak at a mean of 7 days after onset of illness. This was followed by a phase of rapidly decreasing levels of HIV-1 RNA to an average of 21 days after onset. Viral density continued to decline thereafter but at a 5- to 50-fold lower rate; a steady-state level was reached at a median of 2 months after onset of PHI. Peak viral density levels correlated significantly with levels measured between days 50 and 600. Initiation of antiretroviral treatment during PHI resulted in rapidly declining levels to below 50 copies/mL. CONCLUSIONS: This study demonstrates the kinetic phases of viremia during PHI and indicates two new contributions to the natural history of HIV-1 infection: PHI peak levels correlate with steady-state levels and HIV-1 RNA declines biphasically; an initial rapid decay is usually followed by a slow decay, which is similar to the initial changes seen with antiviral treatment.

Antiretroviral Therapy, Highly Active↗
PubMed2000

Diagnosis of primary HIV-1 infection and duration of follow-up after HIV exposure. Karolinska Institute Primary HIV Infection Study Group.

OBJECTIVE: To determine the sensitivity of 33 currently available and seven earlier tests for the detection of HIV or HIV antibody in primary HIV-1 infection, to estimate the duration of the 'window period' and the influence of early initiated antiretroviral treatment (ART). DESIGN: A prospective cohort study of 38 patients with primary HIV-1 infection. ART was initiated at a median time of 13 (range 0-23) days after the onset of symptoms in 10 patients. MAIN OUTCOME MEASURES: The time from infection to onset of symptoms and from onset of symptoms to the appearance of HIV antibody as measured by 36 different tests, and the start and duration of viraemia, as detected by four different tests. RESULTS: The illness appeared 13-15 days after infection in 12 of 15 determinable cases, and seroconversion was detected within 1-2 weeks after the onset of illness by 27 of 30 currently available tests for HIV antibody, in contrast to the 2-7 weeks or more needed by the old tests. HIV RNA appeared during the week preceding the onset of illness and was detected in all subsequent samples, except when ART had been initiated, which also induced a delay of the antibody response. CONCLUSION: Many tests for HIV or HIV antibody can now be employed for an early confirmation of primary HIV infection (PHI). Currently available screening tests proved much more sensitive than older tests, and seroconversion was usually detected within one month after infection. Consequently, in Sweden we now recommend only 3 months of follow-up after most cases of HIV exposure.

Follow-Up Studies↗
PubMed1999

Long-term prognosis following zidovudine monotherapy in primary human immunodeficiency virus type 1 infection.

Eighty-five subjects with symptomatic primary (P) human immunodeficiency virus (HIV) type 1 infection were analyzed in a retrospective cohort study to investigate the long-term clinical benefit of antiretroviral treatment during PHIV infection. Zidovudine treatment was initiated (PHIV treatment group) in 21 persons a median of 9 days after onset of PHIV symptoms and continued for a median of 55 days (range, 21-99). Sixty-four subjects did not receive early antiretroviral treatment (PHIV nontreatment group). After follow-up for 3-10 years, 33 subjects had developed AIDS and 22 subjects had died of AIDS. The median times for progression to AIDS and death were 6.4 and 9.1 years, respectively. Progression rates did not differ between the PHIV treatment and nontreatment groups. Zidovudine treatment initiated during PHIV infection did not improve long-term outcome after symptomatic PHIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Reappearance of founder virus sequence in human immunodeficiency virus type 1-infected patients.

Different patterns of temporal evolution in human immunodeficiency virus type 1 V3 and p17 regions are described for eight patients studied during the first years following primary infection. In samples from three patients, a rapid replacement of the major sequence occurred but the original sequence reappeared later simultaneously with clinical deterioration and increased plasma viral load.

Base Sequence↗
PubMed1998

Characterization of the viral population during primary HIV-1 infection.

OBJECTIVE: To study viral heterogeneity at a very early phase of primary HIV-1 infection. DESIGN: Samples were drawn very early during primary HIV-1 infection. A virus population-based approach was used to study the viral heterogeneity in the C2-V3 and p17 regions. METHODS: Plasma samples (n = 33) were obtained before or shortly after onset of acute symptoms in 15 patients. In all subjects, the first sample was drawn within 10 days after onset of symptoms. Peripheral blood mononuclear cells (PBMC) were available in two patients. The number of polymorphic sites in the C2-V3 (15 patients) and p17 regions (eight patients) were determined by direct sequencing. RESULTS: The sequence heterogeneity was restricted in most patients, although only two out of 15 patients had a completely homogeneous C2-V3 sequence. However, pronounced individual differences were seen. Rapid sequence changes occurred during the first month in two patients. In one patient, the major DNA species at day 12 later became the major species in plasma. CONCLUSIONS: The viral population is seldom completely homogeneous during primary HIV-1 infection, although the heterogeneity is restricted in most, but not all, patients. These individual differences do not seem to be due to sex or viral subtype. Rapid changes of the virus population may occur during primary HIV-1 infection. The DNA species detected in PBMC do not only represent earlier viral quasispecies but are also a potential source of future viral RNA species.

Base Sequence↗
PubMed1998

Evaluation of 14 commercial HIV-1/HIV-2 antibody assays using serum panels of different geographical origin and clinical stage including a unique seroconversion panel.

The performance of 14 commercially available HIV-1/2 antibody assays were compared using well-characterized serum panels containing in total 1500 1800 sera. The panels included consecutive HIV-negative blood donor sera from Sweden, unselected blood donor and patient sera from Tanzania and unselected sera from outpatient clinics in Guinea-Bissau. Furthermore selected HIV-1 antibody positive sera from Sweden and Tanzania and HIV-2 antibody positive sera from Guinea-Bissau were included in the panels. The HIV-1 antibody positive sera were from individuals at various stages of HIV infection, from primary infection, to asymptomatic phase and late stage disease. 12 of the 14 assays identified correctly all HIV-1 and HIV-2 antibody positive sera. One Tanzanian HIV-1 antibody positive sample with complete banding pattern on Western blot was not detected by two of the ELISAs employing synthetic peptides. There were small differences in sensitivity between the assays when used for analysis of seroconversion panels. The most sensitive assay, Abbott IMx HIV-1/HIV-2 III Plus detected antibodies in all nine samples collected from four individuals during the first week after onset of symptoms of primary HIV-1 infection. Most of the assays became reactive during the second week after onset of symptoms and the least sensitive assays were reactive from the third week. The assays showed a high specificity ranging from 99.2 to 100% when used for analysis of Swedish blood donor sera, while most of the assays showed a significantly lower specificity, 91.9-99.6%, when used for testing African specimens.

AIDS Serodiagnosis↗
PubMed1998

Low relative frequencies of CD26(+) CD4(+) cells in long-term nonprogressing human immunodeficiency virus type 1-infected subjects.

A broad antibody panel was used for immunophenotyping of human immunodeficiency virus type 1 (HIV-1)-infected patients who were long-term nonprogressors (LTNP). The LTNP were compared with patients in the early phase of infection and patients who had progressed to advanced immunodeficiency. Changes in CD8(+) subset distribution were observed mainly at acquisition of HIV-1 infection, whereas CD4(+) subset changes appeared during progression of HIV-1 infection. The decreasing levels of CD4(+) cells were characterized by an increasing frequency of cells expressing the activation markers HLA-Dr and CD45RO but not the CD28 surface antigen. The LTNP exhibited significant changes compared to HIV-negative patients in almost all markers. Compared to patients in the early phase of infection, the only difference was a relatively lower frequency of CD4(+) cells expressing CD26 among the LTNP. The results show that HIV-1-infected persons who have no signs of immunodeficiency despite many years of infection have an immunophenotypic pattern that is substantially different from that of noninfected persons. Despite the long duration of infection, the LTNP exhibit a pattern similar to that of newly infected persons, with the exception of lower expression of CD26 on CD4(+) cells.

Adult↗
PubMed1997

Longer survival after HIV infection for injecting drug users than for homosexual men: implications for immunology.

BACKGROUND: Comparisons of progression in HIV-1 infection between injecting drug users (IDU) and homosexual men have been inconclusive due to the short follow-up periods, often with less well-defined starting points and endpoints. In addition, comparisons of survival after injection have been to some extent obscured by higher non-AIDS mortality in IDU. METHOD: In a retrospective cohort study, homo-/bisexual men and IDU were followed, with dates of seroconversion defined within +/- 1 year by a previously negative HIV antibody test. Endpoints were CD4 cell count below 200 x 10(6)/l, AIDS and death from AIDS. RESULTS: Sixty-three homo-/bisexual men and 125 IDU fulfilled the entry criteria, with no significant differences in age at or date for seroconversion. Mean follow-up times were 6.7 and 7.0 years, respectively. The homo-/bisexual group had a significantly accelerated progression rate to all three endpoints: time to CD4 cell count below 200 x 10(6)/l (P = 0.002), to AIDS (P = 0.0003), and to death from AIDS (P < 0.0001). Adjusting for age and sex only made marginal alterations. Ten years after infection, 54% of homosexual men had developed an AIDS-defining condition and 51% had died from AIDS, whereas the corresponding precentages in the IDU group were 26 and 15, respectively. There was, however, no difference in overall mortality due to almost constant, non HIV-related, yearly mortality of some 4% in IDU. CONCLUSIONS: In our cohort there was a highly significant difference in disease progression and death from AIDS between homo-/bisexual men and IDU. This difference was proposed to be due to the transmission route determining the initial immune response and suggested that this route may have played a more important role than virus variability of the subsequent prognosis.

Adult↗
PubMed1996

Mucocutaneous manifestations in 22 consecutive cases of primary HIV-1 infection.

Twenty-two consecutive patients presenting with symptomatic human immunodeficiency virus 1 (HIV-1) seroconversion were studied. Most of the patients had a glandular fever-like illness. All patients had fever and pharyngitis, and eight of them also suffered from ulcers of the oral, genital or anal mucosa. Uniform skin eruptions were observed in 17 of the 22 patients. The exanthem consisted of varying numbers of macular or maculopapular lesions that were oval or rounded in shape, ranging from a few millimetres to 1 cm in diameter. The lesions were distributed on the upper thorax in all cases, and were particularly profuse in the collar region. The face, forehead and scalp were involved in most cases, but the eruption was sparse or absent at the periphery of the extremities. In the majority of patients, the exanthem appeared after 2 or 3 days of fever. The exanthem developed during the first day, persisted for 5-8 days, and then cleared concurrently with the general recovery of the patients. Histopathological studies of skin punch biopsy specimens from four patients showed a sparse lymphocytic cell infiltrate distributed around vessels of the dermal superficial plexus. The infiltrates predominantly consisted of equally represented T-helper/inducer and T-suppressor/cytotoxic cells. A vacuolar aberration of basal layer cells was found in two of the four cases studied histologically. The microscopic findings correspond to the histopathological patterns seen in toxicodermia and in the interface dermatitis of morbilliform viral exanthems. The exanthem is a frequent and characteristic sign of primary HIV infection, which is further indicated if mucosal ulcers are present.

Adolescent↗
PubMed1994

Does symptomatic primary HIV-1 infection accelerate progression to CDC stage IV disease, CD4 count below 200 x 10(6)/l, AIDS, and death from AIDS?

OBJECTIVE: To investigate the prognostic significance of symptomatic primary HIV-1 infection. DESIGN: Prospective study of homosexual men seroconverting to HIV in 1985 and 1986. Patients were followed up at least three times yearly with clinical examinations and T cell subset determinations for an average of 7.2 years. SETTING: Research project centred on attenders for treatment and screening for HIV at the Karolinska Institute, Stockholm. SUBJECTS: 19 patients presenting with a glandular-fever-like illness associated with seroconversion to HIV and 29 asymptomatic seroconverters. MAIN OUTCOME MEASURES: Progression to Centers for Disease Control and Prevention stage IV disease, CD4 cell count below 200 x 10(6)/l, AIDS, and death from AIDS. RESULTS: Symptomatic seroconverters were significantly more likely to develop Centers for Disease Control and Prevention stage IV disease (95% v 66%), CD4 cell counts below 200 x 10(6)/l (84% v 55%), and AIDS (58% v 28%) and die of AIDS (53% v 7%). CONCLUSION: A glandular-fever-like illness associated with seroconversion to HIV-1 predicts accelerated progression to AIDS and other HIV related diseases.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Aerosolized pentamidine as primary prophylaxis for Pneumocystis carinii pneumonia: efficacy, mortality and morbidity.

OBJECTIVE: Primary prophylaxis against Pneumocystis carinii pneumonia (PCP) for patients with HIV infection has been recommended by the Centers for Disease Control and Prevention. We evaluated alternatives to routine primary PCP prophylaxis with aerosolized pentamidine. METHODS: A total of 121 HIV-infected patients with CD4+ cell counts < or = 200 x 10(6)/l or an AIDS diagnosis were enrolled in a controlled study of aerosolized pentamidine as primary PCP prophylaxis. Patients were randomly assigned to treatment (n = 61) with aerosolized pentamidine once every month or to no treatment (n = 60). Patients were evaluated for PCP, mortality, morbidity and progression of HIV disease. Morbidity was estimated from the number of days patients were unable to work due to illness, number of days hospitalized and AIDS events. RESULTS: Baseline characteristics were similar in the treatment and control groups and mean CD4+ cell counts were 116 and 107 x 10(6)/l, respectively. Eight incidents of PCP and 19 deaths were observed in the treatment group during a median follow-up of 16.4 months (range, 2.3-32.4 months). Nineteen incidents of PCP and 13 deaths, of which one was related to an acute episode of PCP, were noted in the control group. Median follow-up of controls was 18.5 months (range, 3.1-32.9 months). Patients in the treatment group were unable to work 19% of the observation time and were hospitalized for 4.3% of that time. Corresponding figures were 20 and 3.0%, respectively, in the control group. CONCLUSIONS: Aerosolized pentamidine had significant prophylactic efficacy, but we could not detect any major effect on mortality and morbidity. The overall mortality and morbidity were not markedly influenced by PCP. Clinical check-ups and treatment of acute PCP could be a justifiable alternative to drug prophylaxis with aerosolized pentamidine in selected patients.

AIDS-Related Opportunistic Infections↗
PubMed1992

CD4+ cells and CD4+ percent as risk markers for Pneumocystis carinii pneumonia (PCP): implications for primary PCP prophylaxis.

The incidence of Pneumocystis carinii pneumonia (PCP) during 2 years in HIV-infected patients with less than or equal to 100 x 10(6)/l CD4+ cells, less than or equal to 200 x 10(6)/l CD4+ cells and less than 20% CD4+ cells of total T lymphocytes were compared. The relative PCP risk in 57 patients with less than or equal to 100 CD4+ cells was more than twice higher than in 120 patients with less than or equal to 200 CD4+ cells. The latter had almost twice higher relative PCP risk than 271 patients with less than or equal to 20% CD4+ cells. Only 3/56 patients who acquired PCP had greater than 200 CD4+ cells and 15/56 patients had greater than 100 CD4+ cells. Centers for Disease Control (CDC) recommends primary PCP prophylaxis in HIV-infected patients when the number of CD4+ cells is less than 200 x 10(6)/l or when the CD4+ is less than 20. On the basis of the presented data we suggest that primary prophylaxis is considered only when CD4+ cells fall below 200 x 10(6)/l.

Adult↗
PubMed1989

The value of C-reactive protein as a marker of bacterial infection in patients with septicaemia/endocarditis and influenza.

In order to evaluate the capacity of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell count (WBC) and polymorphonuclear neutrophils (PMNs) to differentiate between bacterial and viral infection we studied 176 patients with septicaemia/endocarditis (SE), 59 patients with uncomplicated influenza (UI) and 22 patients with complicated influenza (CI) retrospectively. All 4 parameters were significantly more elevated in SE and CI than in UI. Among patients with SE 10 176 had a CRP value less than 50 mg/l and in patients with UI 5/56 had a CRP value greater than 100 mg/l. Patients with SE caused by pneumococci had the highest CRP levels and patients with alfa-haemolytic streptococci the lowest. The sensitivity and specificity favours the use of CRP as an indicator of bacterial superinfection in influenza.

Adolescent↗
PubMed1983

Neutron beam characteristics from 50 MeV protons on beryllium using a continuously variable multi-leaf collimator.

The dose distributional properties of a p(50) Be neutron beam using a continuously variable multi-leaf collimator are presented and compared with a 6 MV photon beam. The differences in physical dose delivery between these two radiation modalities are generally insignificant for radiation therapy, and stringent comparisons of neutron and photon treatments should therefore be possible. The flexibility in field shaping with the multi-leaf collimator opens new possibilities in the treatment of complex irregular target volumes. The collimator consists of 40 wedge-shaped leaves that are independently moved under computer control with their collimating surfaces always aligned with the effective radiation source to minimize the penumbra. The leaf collimator eliminates the need for handling of heavy insert collimators and beam blocks at the same time that it allows dynamic conformation therapy with neutrons.

Beryllium↗