Science or marketing at WHO? A response to Williams.
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Delivery of Health Care↗
Biomedical subjects
O Adams
Publications and source records attributed to O Adams.
Natural variation in the amino acid sequence around the HIV type 1 glycoprotein 160 cleavage site and its effect on cleavability, subunit association, and membrane fusion.
To assess the natural variation of the structure of the cleavage site as well as the N-terminal region of gp41 for the cytopathogenicity of HIV-1, syncytium-inducing (SI) and non-syncytium-inducing (NSI) virus isolates were obtained from HIV-1-infected patients. In addition, the coreceptor usage of the isolates was determined by infection of primary macrophages and PM-1 cells. DNA sequences encoding the C-terminal 41 amino acid residues of gp120 and the 64 amino acid N-terminal residues of gp41 were amplified by the polymerase chain reaction and inserted into the Env expression vector pNLA1. When transfected into HeLa-T4(+) cells, all the recombinant plasmids, including those with inserts from NSI isolates, led to the formation of processed glycoprotein and to syncytium formation. One construct displayed significant lowered fusion capacity and had an amino acid exchange in the first position of the gp41 N terminus (gp41, 512A-->S) leading to a decreased association of the SU and TM subunits. Four constructs derived from two isolates of the same patient showed an unusual gp41 N terminus (gp41, 514G-->P) and a slightly diminished fusion capacity due to a decreased cleavability. This indicates that the major determinants for the SI and NSI phenotypes are not located around the gp160 cleavage site and that the N terminus of gp41 plays a minor role in the processing and fusion capacity of wild-type HIV-1 isolates.
Amino Acid Sequence↗
Mutations of the core promoter and response to interferon treatment in chronic replicative hepatitis B.
In chronic replicative hepatitis B the significance of mutations in the basic core promoter (BCP), core upstream regulatory sequences (CURS) and negative regulatory element (NRE) for response to interferon (IFN) is unknown. A sequence analysis of the NRE, CURS, BCP, and precore region was performed from sera of 96 patients with chronic replicative hepatitis B (64 hepatitis B e antigen [HBeAg]-positive patients and 32 HBeAg-negative patients) treated with alfa-IFN (IFN-alpha). The overall sustained response (SR) rate to IFN was 30% with no significant difference between HBeAg-positive and HBeAg-negative patients. IFN responsiveness correlated to hepatitis B virus (HBV)-DNA levels, hepatitis B surface antigen (HBsAg) levels, the number of mutations in the complete BCP, especially nucleotide (nt) region 1753 to 1766 and mutations at nt 1762 and 1764. In HBeAg-positive hepatitis, SR to IFN was associated with a high number of mutations in the BCP (P <.04) and nucleotide region 1753 to 1766 (P <.015) as well as mutations at nucleotide 1764 (P <.007). In HBeAg-negative hepatitis, SR to IFN correlated with a low number of mutations in the BCP (P <.04) and nucleotide region 1753 to 1766 (P <.02) and a wild-type sequence at nt 1764 (P <.003). Prediction of IFN response was possible on the basis of nt 1764 in 77% of HBeAg-positive patients and 78% of HBeAg-negative patients. IFN response did not correlate with the occurrence of the 1896 mutation, mutations in the CURS or NRE, disease duration, ethnic origin of the patient, alanine transaminase (ALT) levels and HBV genotype. Our data suggest that HBV genome mutations located within the BCP are determinants of a response to IFN therapy.
Adult↗
Clinical course and treatment of haemorrhagic cystitis associated with BK type of human polyomavirus in nine paediatric recipients of allogeneic bone marrow transplants.
UNLABELLED: Of a total of 117 bone marrow transplant (BMT) recipients in the period from August 1988 to November 1995, 9 (7.7%) developed haemorrhagic cystitis. This condition was characterized in all nine patients by late onset (day +24 to +50 post-BMT), long duration (1 to 7 weeks), and the excretion of BK virus in the urine, as confirmed by electron microscopy, DNA hybridization and PCR analysis. Adenovirus was not involved. The serological assessment of BK virus-specific IgM and IgG pre- and post-BMT is consistent with viral reactivation in all patients, although a primary infection cannot be absolutely excluded in a single patient. A significant correlation between the use of high-dose busulphan (16 mg/kg) in the preparative regimen and development of haemorrhagic cystitis (P = 0. 0003) was evident. The severe course of the disease in two patients resulted in bladder tamponade; bleeding could not be inhibited with coagulation and laser treatment. Deterioration was prevented by bladder irrigation via a suprapubic catheter. Remission occurred spontaneously in all patients. CONCLUSION: BK virus induced haemorrhagic cystitis in a paediatric bone marrow transplantation recipients is characterized by late onset, long duration, viral reactivation and correlates to high-dose busulphan. Severe bleeding could not be influenced by surgical intervention.
Adolescent↗
Fatal hepatitis B reinfection after orthotopic liver transplantation in an HBsAg negative patient following withdrawal of lamivudine.
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Antiviral Agents↗
Comparative evaluation of two branched-DNA human immunodeficiency virus type 1 RNA quantification assays with lower detection limits of 50 and 500 copies per milliliter.
We have comparatively evaluated Quantiplex version 3.0 and version 2. 0 on 133 plasma samples and a repetitive dilution series. Version 3. 0 yielded higher human immunodeficiency virus RNA values, and the ratio of version 3.0 results to version 2.0 results decreased from 3. 47 below 1,000 copies/ml to 1.97 above 50,000 copies/ml [linear regression, log (version 3.0) = 0.915 + 0.871 x log (version 2.0); r(2) = 0.952].
DNA Probes↗
Treatment-resistant expansion of CD8+CD28-cells in pediatric HIV infection.
There is a disease stage-dependent loss of CD28 expression on T cells in HIV-infected children. In this study, T cell recovery, in particular CD28 expression on T cells, was analyzed after initiation of highly active antiretroviral therapy in a group of eight mostly treatment-naive HIV-infected children. Plasma HIV-RNA levels were recorded, and numbers of CD4, CD8, CD4+CD28+, and CD8+CD28+ cells were determined by two-color flow cytometry. Values after 12 mo of therapy were compared with age-matched, seronegative control subjects. CD4 recovery to subnormal values was observed in all children. CD8+CD28+ cells recovered and were within the normal range after 12 mo of therapy (patients, 703 +/- 250 cells/microL; controls, 789 +/- 269 cells/microL), whereas CD8+CD28- cells (546 +/- 269 cells/microL) remained significantly expanded compared with age-matched controls (140 +/- 35 cells/microL). Expansions of CD8+CD28- cells persisted even in cases with long-term suppression of viral replication. Highly active antiretroviral therapy in HIV-infected children induces substantial but incomplete T cell recovery.
Adolescent↗
Prior cytomegalovirus infection and the risk of restenosis after percutaneous transluminal coronary balloon angioplasty.
BACKGROUND: Restenosis is a common problem after all revascularization procedures in atherosclerotic coronary arteries. Reactivated human cytomegalovirus (CMV) has been detected in tissues of restenotic vascular lesions and was hypothesized to be a contributing pathogenic factor. Recent data suggest an association of restenosis after optimal coronary atherectomy with CMV serostatus, and a possible role of antiviral therapy was discussed. We therefore tested the hypothesis that prior CMV infection might be a risk factor for restenosis after conventional coronary balloon angioplasty (PTCA). METHODS AND RESULTS: We analyzed 92 consecutive patients who had been admitted for control angiography after previous PTCA within a mean interval of 6 months. Anti-CMV antibodies were measured as an indicator of prior CMV infection and latency. The coronary angiograms before PTCA, directly after, and 6 months later were analyzed quantitatively. Sixty-five percent of the patients were CMV-positive. Before PTCA, the degree (mean+/-SD) of stenosis was 69+/-10% in CMV-positive and 68+/-8.3% in CMV-negative subjects. PTCA resulted in a residual stenosis of 39% in both groups. After 6 months, the late losses of luminal diameter in the CMV-positive and -negative groups were 11+/-13% and 12+/-15%, respectively (P=0.658). In an ANCOVA with 25 potential risk factors for restenosis, CMV serostatus was not significantly associated with restenosis development. CONCLUSIONS: Our data indicate that prior CMV infection, in contrast to optimal atherectomy, is not associated with chronic restenosis after conventional coronary balloon angioplasty. The results do not support a possible benefit from antiviral therapy.
Adult↗
Human immunodeficiency virus and hepatitis B virus co-infection in two siblings: viral loads markedly reduced by triple-therapy including lamivudine.
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Anti-HIV Agents↗
Herpes simplex virus (HSV-1) infection in a donor cornea.
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Aged↗
An evaluation of WHA resolution 45.5: health human resource implications.
The World Health Assembly approved resolution WHA45.5 in 1992. This paper reports the findings of an evaluation of the implementation of this resolution using a survey technique. A total of 150 WHO Member States responded, for a 79% response rate. Findings suggest that the greatest strides worldwide have been made in education. While the data show that progress has been made at the country level, far more action is needed to strengthen nursing and midwifery if these cost-effective resources are to play a decisive role in improving the extent and quality of services, especially as delivered to people in the greatest need.
Cross-Sectional Studies↗
Pilot study of zidovudine-lamivudine combination therapy in vertically HIV-infected antiretroviral-naive children.
OBJECTIVE: To examine tolerance and efficacy of a zidovudine plus lamivudine combination in HIV-infected children without previous exposure to antiretroviral drugs. METHODS: Thirteen vertically infected children (aged 4 months to 10 years) were treated with zidovudine (approximately 100 mg/m2 three times daily) and lamivudine (4 mg/kg twice daily). CD4 T-cell count, plasma HIV RNA concentration, complete blood count and blood chemistry profile were monitored before treatment and at months 1, 3 and 6. RESULTS: In general, treatment was well tolerated. One child developed slight neutropenia in the presence of antineutrophil antibodies. CD4 cell count increased from 851+/-621 x 10(6)/l at baseline to 1073+/-945 x 10(6)/l at month 3 (P < 0.05) and to 1133+/-728 x 10(6)/l at month 6 (P = 0.01). CD4+ cell count increased in 10 patients after 3 months and in 11 patients treated for 6 months. One child showed a continuous decrease of CD4 cells despite treatment. Before treatment the plasma HIV RNA concentration was elevated in nine children (> 4.0 log10 copies/ml) and decreased in all of them: by month 1, the mean reduction was -1.16 log10 copies/ml; by month 3, -1.38 log10 copies/ml; and by month 6, -1.53 log10 copies/ml compared with baseline. However, one child showed steadily increasing viral load from 2.7 log10 copies/ml to a maximum of 4.52 log10 copies/ml, surprisingly in association with increasing numbers of CD4 cells. This child was switched to a new combination regimen after 6 months of treatment. Plasma HIV RNA levels below limit of detection were reached in six patients: after 1 month of treatment in one patient, after 3 months in five patients, and after 6 months in six patients. There was a mean reduction of viral load from 4.56 log10+/-4.63 log10 copies/ml (n = 13) to 3.8 log10+/-3.9 log10 copies/ml (P < 0.05; n = 9) after 1 month, to 3.67 log10+/-3.88 log10 copies/ml (P < 0.01; n = 13) after 3 months, and to 3.64 log10+/-3.95 log10 copies/ml after 6 months of treatment (P < 0.001; n = 13). CONCLUSIONS: This pilot study demonstrates the feasibility of zidovudine-lamivudine combination in children not previously exposed to antiretroviral drugs. This promising combination should therefore be evaluated in larger trials.
Anti-HIV Agents↗
Congenital infections with human herpesvirus 6.
Cord blood DNA was tested for the presence of human herpesvirus 6 (HHV-6) DNA by the polymerase chain reaction. Specific DNA could be detected in the specimens of 5 (1.6%) of 305 babies born to ostensibly healthy mothers, indicating that intrauterine infection had occurred. These transmissions would not have been detected by serologic methods, because no specific IgM antibody could be found in the fetal sera. These results indicate that, in addition to infections acquired in early childhood, congenital infections may account for the HHV-6 seropositivity in children.
Antibodies, Viral↗
Combination therapy with ZDV + DDI versus ZDV + DDC in patients with progression of HIV-infection under treatment with ZDV.
HIV-seropositive patients (n = 67) who had tolerated zidovudine for at least 24 weeks and deteriorated clinically or immunologically within 12 weeks prior to study entry were allocated in an alternating manner to didanosine chewable tablets (400 mg/day) plus zidovudine (500 mg/day) or dideoxicytidine capsules (2.25 mg/day) plus zidovudine (500 mg/day). The combination of didanosine and zidovudine resulted in a more pronounced increase of CD4 cells over time compared to the combination of dideoxicytidine with zidovudine (p < 0.002). The increase of CD4 cells was almost exclusively due to patients with more than 100 CD4 cells/microliters. Clinical end points (death, AIDS-defining disease, CDC IV event) were less frequent under didanosine plus zidovudine but failed to reach statistical significance (p = 0.07). For didanosine plus zidovudine the median time on medication during study was shorter (63% vs. 100%, p < 0.05) and the number of patients discontinuing medication prematurely due to side effects was higher (59% vs. 30%, p < 0.02). The present study favors the combination of didanosine and zidovudine in patients deteriorating while receiving zidovudine for > 24 weeks in respect to the time course of the CD4 cells. In this small sized study, there seemed to be fewer clinical events in patients on the didanosine combination compared to the combination with dideoxicytidine; however, this trend failed to reach statistical significance and needs therefore to be substantiated by larger studies. However, the lower compliance of the patients may hamper the efficacy of didanosine.
Adult↗
Hematopoietic transplant potential of unrelated cord blood: critical issues.
To date, hematopoietic stem and progenitor cells from human umbilical cord blood (CB) have been employed in approximately 90 allogeneic (56 sibling and 34 unrelated) matched and mismatched transplantations worldwide with easy and successful restoration of hematopoiesis. Requests for stem cell preparations from CB will continue to increase. Thus, as a pilot study, the examination and standardization of unrelated cord blood-derived stem cell preparations and banking as well as their biologic characterization were initiated. Up to October 1995, a total of 574 samples [mean volume 79 +/- 26 ml, total nucleated cells (NC) 8.5 +/- 5 x 10(8), BFU-E 9.5 +/- 8.6 x 10(5), CFU-GM 5.7 +/- 6.3 x 10(5), CFU-GEMM 1.6 +/- 1.9 x 10(5)] from cord-derived or placental-derived residual blood have been defined by hematologic, immunologic, and microbiologic criteria. These CB samples were collected from the umbilical cord vein immediately after vaginal full-term delivery (n = 450) or cesarean section (n = 124) and stored frozen in liquid nitrogen. Seven percent of all samples collected could not be considered for potential transplants because of volumes < 40 ml. Only 5.0 ml of a CB sample is required for routine laboratory testing, consisting of HLA class I typing, HLA class II typing by sequence-specific oligonucleotide probes (PCR-SSOP), ABO typing, sterility control, assessment of progenitor and stem cells by colony-forming and LTC-IC assays, and CD34+ status. To assess the potential problem of contaminating maternal cells, a PCR was performed on 7 representative samples. During the initial 6 months of the unrelated CB collection program, a median bacterial contamination rate of 18% (20% skin flora species, 80% perineal flora species) was encountered, which has since been reduced to < 1% through practical experience. With regard to viral infections, maternal sera was tested for HBsAg (0.6% positive), anti-HCV (0%), anti-HAV (IgG 18%, IgM 0%), anti-HIV-1-2 (0%), anti-EBV (IgG 98%, IgM 0%), anti-HTLVI-II (0%), anti-CMV (IgG 43%, IgM 0.4%), toxoplasmosis (46%) and syphilis (0%). In addition, all cord blood samples were tested by PCR for CMV infection. With regard to its clinical relevance, it is important that only 0.3% of all the samples were positive for CMV by this sensitive method. This may represent a critical advantage of CB grafts over bone marrow (BM) since, in contrast, > 40% of the unrelated BM donors have been identified to be positive for CMV. An additional advantage of CB is that since 20% of CB samples were collected from ethnic minorities, it appears possible to balance common HLA types and uncommon HLA types represented in this group. In summary, with the extensive practical experience of the obstetric collection team as well as the stem cell-processing laboratory, it appears feasible to obtain a 90% yield of unrelated CB-derived stem cell preparations for banking, which clearly should meet the medical and regulatory qualification criteria required for clinical transplantation. To test the feasibility of hematopoietic transplant potential of unrelated CB for adult patients, ex vivo expansion of CD34+-enriched stem/progenitor cell populations isolated from fresh or frozen CB was attempted in the presence of rh-IL-3, rh-IL-6, rh-EPO, rh-GM-CSF, and rh-SCF with or without fit 3. At varying time points (days 0, 2, 4, 7, 14, 21), the contents of these cultures were analyzed for the numbers of cells, CFC (BFU-E, CFU-GM, CFU-GEMM), and LTC-IC. In this setting, the increase of cells was 200-fold, that of CFC 70-fold, and most importantly that of LTC-IC was 4.5-fold after 7 days in culture in the presence of flt3. In conclusion, LTC-IC derived from CB can be maintained and considerably expanded ex vivo from highly enriched CD34 + CB cell populations from fresh or frozen CB samples.
ABO Blood-Group System↗
Requirement of N-terminal amino acid residues of gp41 for human immunodeficiency virus type 1-mediated cell fusion.
An expression vector was designed to test the structural requirements of the gp41 N terminus for human immunodeficiency virus type 1-induced membrane fusion. Mutations in the region coding for the N terminus of gp41 were found to disrupt glycoprotein expression because of deleterious effects on the Rev-responsive element (RRE). Insertion of an additional RRE in the 3'-noncoding sequence of env made possible efficient glycoprotein expression, irrespective of the mutations introduced into the RRE in the natural location. This permitted the insertion of the unique restriction site SpeI within the N-terminal sequences of gp41, allowing convenient and efficient mutation of the gp41 N terminus by using double-stranded synthetic oligonucleotides. Mutants with deletions of 1 to 7 amino acids of the N terminus were constructed. Expression and cleavage of all mutants were confirmed by Western immunoblot analysis with anti-gp41 antibodies. The capability of mutants to induce membrane fusion was monitored following transfection of HeLa-T4+ cell lines with wild-type and mutant expression vectors by electroporation and microinjection. The efficiency of cell-fusing activity decreased drastically with deletion of 3 and 4 amino acids and was completely lost with deletion of 5 amino acids. Cotransfection of the parent and mutant expression vectors resulted in reduced cell-fusing activity. The extent of this dominant interference by mutant glycoprotein paralleled the decrease in cell-fusing activity of the mutants alone. This suggests the existence of a specific N-terminal structure required for fusing activity. However, there does not appear to be a stringent requirement for the precise length of the N terminus. This finding is supported by the length variation of this region among natural human immunodeficiency virus type 1 isolates and is in contrast to the apparent stringency in the length of analogous N-terminal structures of influenza A virus and paramyxovirus fusion glycoproteins.
Amino Acid Sequence↗
The use of intravenous immunoglobulins in symptomatic HIV infection. Results of a randomized study.
To study the efficacy of intravenous immunoglobulin in symptomatic infection with human immunodeficiency virus (HIV) we enrolled 35 patients with CD4 lymphocyte counts below 300/microliter in a randomized three-arm study. In addition to standard HIV treatment (e.g., zidovudine, aerosolized pentamidine), 13 patients were treated with 7.5 g and 11 with 40 g of a 7 S intravenous IgG preparation every 4 weeks over a period of 1 year. A control group of 11 patients remained on standard treatment. Clinical and laboratory parameters, including lymphocyte proliferation and in vitro immunoglobulin synthesis were evaluated prior to intravenous IgG administration. HIV-specific immunological abnormalities such as increased B-cell activation and B-cell immaturity were observed in all three study groups at the beginning of the study. Mitogen-induced lymphocyte proliferation was diminished. These disturbances were not influenced by intravenous IgG treatment. Further laboratory data and the course of the HIV infection (fever, antibiotic treatment, hospitalization, Candida and herpes simplex or cytomegalovirus infection) remained unchanged. Thus, our data with an observation period of 12 months do not support the use of intravenous IgG treatment in adult symptomatic HIV-infected patients with CD4 counts lower than 300/microliter.
AIDS-Related Opportunistic Infections↗