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Biomedical subjects

L H Perrin

Publications and source records attributed to L H Perrin.

At least 19 recordsLinked to original sources
PubMed1998

A placebo-controlled trial of didanosine plus stavudine, with and without hydroxyurea, for HIV infection. The Swiss HIV Cohort Study.

OBJECTIVE: To explore the short-term effects on surrogate markers for HIV progression of didanosine (ddl) plus stavudine (d4T), with or without hydroxyurea. DESIGN: Randomized, double-blinded, prospective study. SETTING: Swiss HIV Cohort Study. PATIENTS: A total of 144 patients (75% antiretroviral-naive) were studied (mean baseline HIV-1 RNA, 4.53 log10 copies/ml; mean CD4 cell count, 370 x 10(6)/l). INTERVENTION: Patients received ddl (200 mg twice daily) plus d4T (40 mg twice daily), with additional hydroxyurea (500 mg twice daily) or placebo. MAIN OUTCOME MEASURES: The primary endpoint was a reduction of viraemia below 200 copies/ml after 12 weeks. At that time, patients who did not reach the primary endpoint were withdrawn in the hydroxyurea arm, whereas patients in the placebo group had the option of adding hydroxyurea to ddl and d4T. All patients were followed until week 24. RESULTS: After 12 weeks, 54% of the patients randomized to hydroxyurea had viraemia below 200 copies/ml, compared with 28% on placebo (P < 0.001). Using an ultrasensitive assay with a limit of detection of 20 copies/ml, 19% of patients receiving hydroxyurea had viraemia levels below 20 copies/ml, compared with 8% on placebo (P = 0.05). Mean decrease in HIV-1 RNA was 2.3 and 1.7 log10 copies/ml for hydroxyurea and placebo groups, respectively (P = 0.001). Hydroxyurea was found to induce lymphopenia (-124 x 10(6)/l). Increase in CD4 cell counts was +28 x 10(6)/l during hydroxyurea treatment compared with +107 x 10(6)/l on placebo (P = 0.001). CONCLUSIONS: Hydroxyurea improved the antiviral activity of d4T and ddl over a 12-week period, but was associated with a smaller increase in CD4 cell counts due to hydroxyurea-induced lymphopenia.

Adult↗
PubMed1998

Impact of treatment with human immunodeficiency virus (HIV) protease inhibitors on hepatitis C viremia in patients coinfected with HIV.

The impact of human immunodeficiency virus (HIV) protease inhibitors on hepatitis C (HCV) viremia was assessed in 19 patients infected with both HIV and HCV. HIV and HCV RNA levels were measured before and during treatment with protease inhibitors. Before treatment, mean levels of HCV RNA were 5.3 log for HCV RNA and 5.0 log for HIV RNA. CD4 lymphocyte counts were 63/mm3. After 6 weeks of treatment, a mean reduction of 2.1 log10 in HIV RNA (P < .001) and a mean (+/-SE) increase of 73 (+/-21) CD4 and 296 (+/-70) CD8 cells were observed (P < .05). In contrast, both HCV viremia (+0.4 log +/- 0.1) and alanine aminotransferase increased (P < .04). HCV RNA levels returned to baseline after 17 and 32 weeks of treatment. Thus, potent anti-HIV regimens with protease inhibitors may temporarily worsen HCV status despite improvement of HIV parameters.

Anti-HIV Agents↗
PubMed1995

Early and prolonged decrease of viremia in HIV-1-infected patients treated with didanosine.

Fourteen patients previously treated with zidovudine were monitored for laboratory parameters and clinical events during 1 year after introduction of didanosine (ddI) monotherapy. Proviral human immunodeficiency virus type 1 (HIV-1) copy numbers (cell-associated DNA) and concentration of free virions (viremia) were determined using a semiquantitative polymerase chain reaction (PCR). High levels of circulating virus were detected in all patients (range, 17 to 5,934 x 10(3)/ml of serum). Within 4 weeks of therapy, a decrease of viremia (60 to 98%) was observed in nine patients. After 1 year of treatment, eight of these nine patients still had decreased viremia when proviral HIV DNA was decreased or stable, and CD4+ lymphocytes were stable or higher in seven of these eight patients. Antiviral effect was more pronounced in the six patients with CD4+ > 100/mm3 at entry, five of them belonging to the subgroup of the seven responding patients as compared to two of eight patients with CD4+ < 100/mm3. Clinical events in this small group were not statistically correlated with virologic parameters; however, responding patients had a tendency to stabilize or gain weight. This study suggests that measurement of viremia deserves further study as a marker of antiviral efficacy and might predict, even at 4 weeks, the beneficial potential of ddI.

AIDS-Related Opportunistic Infections↗
PubMed1993

Human immunodeficiency virus type 1 nucleic acids detected before p24 antigenemia in a blood donor.

A blood donation from a 46-year-old homosexual man was discarded because of elevated alanine aminotransferase levels. Thirteen days later, the patient presented with symptomatic primary human immunodeficiency virus type 1 (HIV-1) infection. Virologic investigations were performed retrospectively on blood samples (including the donated blood) obtained before the symptoms. The HIV-1 genome was present, either integrated in mononuclear cell DNA or circulating in plasma, 39 days before the appearance of p24 antigen and 65 days before the appearance of HIV-1 or HIV type 2 antibody. It is concluded that p24 antigenemia is present during only a fraction of the seronegative "window" period. This case illustrates the risk of infection associated with blood transfusion in spite of HIV-1 antibody testing and stresses the need to improve nontechnical exclusion procedures as well as non-antibody-based diagnostic tests.

Base Sequence↗
PubMed1993

Symptomatic primary infection due to human immunodeficiency virus type 1: review of 31 cases.

In this series of 31 patients with acute infection due to human immunodeficiency virus (HIV) type 1, the male-to-female ratio was 3.4:1 and the mean age was 31.3 years. Sexual transmission accounted for 83.9% of cases; 45.2% of the patients were homosexual and 38.7% were heterosexual. The mean duration of symptoms and signs was 21 days (range, 5-60 days). Fever (87.1%) and skin rash (67.7%) were most commonly reported. Physical examination findings were abnormal for 96% of the patients; the oral cavity (76.7%) and the skin (73.3%) were the most frequently involved sites. Thirteen of 25 patients with sexually acquired infection had genital or oral ulcers, whereas five intravenous drug users had none (P = .052). Thrombocytopenia was the most common hematologic abnormality and was detected in 17 of 23 patients tested. P24 antigenemia, an initially negative screening test for HIV antibody, and a low CD4+ lymphocyte count were noted in 23 of 29, 23 of 30, and 14 of 21 tested patients, respectively.

Adult↗
PubMed1992

Plasmodium falciparum: identification and purification of the phosphoglycerate kinase of the malaria parasite.

Multiplication of the human malaria parasite Plasmodium falciparum within red blood cells is an energy-dependent process and glucose consumption increases dramatically in infected red blood cells (IRBC) versus normal red blood cells (NRBC). The major pathway for glucose metabolism in P. falciparum IRBC is anaerobic glycolysis. Phosphoglycerate kinase (PGK) is one of the key enzymes of this pathway as it generates ATP. We found that the PGK specific activity in P. falciparum IRBC is seven times higher than that in NRBC. The parasitic origin of the increase in PGK activity is confirmed by isoelectric focusing. Indeed, two P. falciparum isoenzymes with neutral isoelectric points were detected. P. falciparum PGK in purified form has a molecular mass of 48 kDa. Antiserum raised against purified P. falciparum PGK specifically recognizes the 48-kDa protein band in P. falciparum and also reacts with P. berghei and P. yoelii IRBC lysates but does not cross-react with PGK associated with NRBC.

Animals↗
PubMed1992

Identification and purification of glucose phosphate isomerase of Plasmodium falciparum.

The multiplication of malaria parasites within red blood cells is energy dependent. Since these parasites lack a functional tricarboxylic acid cycle, the energy needs of the parasite are met by anaerobic glycolysis of exogenous glucose. High levels of glycolytic enzymes such as fructose-1,6-diphosphate aldolase, phosphoglycerate kinase and pyruvate kinase have been detected in infected erythrocytes. Here we report a 4-9 times increase in glucose phosphate isomerase (GPI) activity of infected erythrocytes over that of normal erythrocytes. This increase is of parasitic origin, as additional enzyme bands were observed in lysates of infected erythrocytes. The expression of GPI parallels parasite maturation and reaches a maximum at the trophozoite/schizont stage. Two distinct but closely related activity patterns consisting of 3-4 GPI isoenzymes (not shown in normal erythrocytes) with neutral to weakly acidic isoelectric points were observed in 6 P. falciparum isolates tested by isoelectric focusing. The purified P. falciparum GPI has an apparent size of 66 kDa. No size variation was observed in the 6 P. falciparum isolates studied. Furthermore, antiserum raised against this protein in BALB/c mice specifically inhibits parasite encoded GPI activity while no effect was observed on host enzyme activity.

Animals↗
PubMed1992

Quantitation of human immunodeficiency virus provirus and circulating virus: relationship with immunologic parameters.

Virologic and seroimmunologic parameters were determined in 56 persons infected with human immunodeficiency virus (HIV). The provirus level varied from 10 to 100,000/10(6) CD4+ lymphocytes, and genomic HIV RNA was detectable in 39 of 56 patients at a relative concentration varying from 10 to greater than 250 copies/mL of serum. Provirus expressed as copies per 10(6) CD4+ lymphocytes and as circulating virus per milliliter of serum increased with disease progression and decrease of CD4+ cell concentration. The mean provirus concentration expressed per milliliter of blood varied little among categories of patients with various levels of CD4+ cells, but there was a progressive increase of circulating HIV genomic RNA. These virologic data suggest that during the course of HIV infection, an increasing proportion of the remaining CD4+ lymphocytes harbor the HIV genome and produce infectious virus. Finally, there was a marked correlation between increased provirus and genomic RNA concentration and three seroimmunologic markers: decrease in CD4+ cell count, p24 antigenemia, and disappearance of antibodies to HIV core antigen.

Base Sequence↗
PubMed1992

Frequencies of HIV-reactive B cells in seropositive and seronegative individuals.

Peripheral blood mononuclear cells (PBMC) from HIV-infected seropositive (HIV+) but not from normal, seronegative (HIV-) individuals are known to produce anti-HIV antibodies in vitro, in the absence or presence of pokeweed mitogen (PWM). Previous studies showed that up to 20-40% of spontaneously immunoglobulin-secreting B cells from HIV+ individuals are HIV-specific. To analyse the frequency of anti-HIV B cells among 'total' peripheral blood B cells in the present study, we used a limiting dilution assay in which EL-4 thymoma cells induce clones of immunoglobulin-secreting cells in activated as well as resting B cells. Anti-HIV B cells were detected not only in 11/12 HIV+ individuals (with frequencies from 1/910 to 1/21,500 B cells cultured; one negative test was from a person undergoing seroconversion), but also in 4/9 HIV- normal blood donors (1/16,200 to 1/49,000 B cells cultured) and in 3/6 newborns from HIV- mothers (1/11,800 to 1/26,600 B cells cultured). The mean frequency was nine times higher in the HIV+ individuals than in the normal donors. As in previous studies, only the cells from HIV+ individuals generated anti-HIV antibodies in PBMC bulk cultures with or without PWM. The relative proportion of specific anti-HIV antibody/total immunoglobulin in PBMC bulk cultures was 800 times higher by the mean than in EL-4 B cell cultures from HIV+ individuals (whereby the total immunoglobulin secretion for equal numbers of B cells cultured was 500 times lower for PBMC). These different results obtained with different assays suggest that in seropositives most anti-HIV B cells belong to an activated B compartment which is quite small, even in a disease with B cell hyperactivity. Therefore, the specific B cells are strongly diluted among the EL-4 cell-responsive, total B cells. On the other hand, the EL-4 assay can detect HIV-reactive B cells in the B cell repertoire of normal, non-infected individuals.

B-Lymphocytes↗
PubMed1991

Absence of chronic human immunodeficiency virus infection without seroconversion in intravenous drug users: a prospective and retrospective study.

It has been reported that human immunodeficiency virus type 1 (HIV-1) infection may exist in persons without specific antibodies for years. To measure the frequency of a silent carrier state, a study was conducted in a cohort of 124 intravenous drug users (IVDUs) without anti-HIV-1 antibodies. All the participants had engaged in high-risk behavior for HIV-1 transmission for a number of years until 1987 or later. Samples were analyzed at 6-month intervals for the presence of HIV-1 provirus using DNA amplification and for the appearance of anti-HIV-1 antibodies. HIV-1 provirus and antibodies were undetectable in 122 participants, whereas seroconversion was observed in 2. In one of these, both amplified HIV-1 pol gene segment and anti-HIV-1 antibodies were detected simultaneously, and in the other, provirus was detected 1 month before seroconversion. This study suggests that long-term HIV-1 infection without anti-HIV-1 antibodies is rare and that repeated antibody testing is sufficient to determine the HIV-1 status of a person no longer at high risk for HIV-1 infection.

Adult↗
PubMed1991

Comparative evaluation of an ELISA based on recombinant polypeptides and IFA for serology of malaria.

In the present investigation we compare the performance of a solid-phase assay based on three recombinant polypeptides corresponding to three asexual blood-stage antigens of P. falciparum (ELISA MIXT) with the reference method for the measurement of antimalaria antibodies: indirect immunofluorescence antibody assay (IFA). Sera collected from persons with various degrees of exposure to malaria were selected: sera from inhabitants of a malaria endemic area (Group I), European patients with acute malaria infection (Group II) and blood donors with clinical symptoms of sickness or fever during a stay in malaria endemic areas. 86% of the sera gave concording results by ELISA MIXT and IFA. The correlation was 100% for sera of Group I but discrepancies were observed for Groups II and III. The great majority of the differences were due to sera positive on ELISA MIXT but not by IFA. Most of the sera positive on ELISA MIXT reacted with parasite-derived components only on Western-blot. These results underline the potential of the ELISA MIXT for epidemiologic studies.

Adolescent↗
PubMed1990

Human immunodeficiency virus DNA amplification and serology in blood donors.

The significance of indeterminate screening antibody test for human immunodeficiency virus (HIV) serology is still difficult to evaluate, especially in low-risk populations. One hundred twenty-seven blood donors with an initially reactive screening test for HIV antibodies were enrolled in this study. The sera of 95 of these blood donors were reactive on repetition of the test, and none had detectable circulating p24 antigen. Western blot (WB) analysis of the repeatedly reactive sera was as follows: 9 positive, 31 indeterminate, and 55 negative. One of the blood donors with indeterminate WB later presented a seroconversion. On subsequent control 3 to 12 months later, the sera from donors with indeterminate or negative WB did not present any parameters that may indicate a seroconversion. DNA was purified from citrated blood collected from the 127 blood donors at the time of the initial antibody screening. Five micrograms of each DNA sample corresponding to 7 x 10(5) nucleated white blood cells was amplified by polymerase chain reaction (PCR) in the presence of oligonucleotides (primers) corresponding to a highly conserved segment of the pol gene. The detection of amplified DNA was achieved by dot blot and Southern blot using appropriate 32P-labeled oligonucleotides. Ten DNA samples were positive, 9 corresponded to blood donors with a positive HIV serology, and 1 to the blood donor who later presented a seroconversion. These results confirm the sensitivity of the PCR for the diagnosis of HIV infection; they also suggest that repetition of the serology at 3- to 12-month intervals is a valuable procedure for the control of HIV infection status in blood donors.

Base Sequence↗
PubMed1990

Specificity and inhibitory activity of antibodies to Plasmodium falciparum aldolase.

The multiplication of Plasmodium falciparum within RBC is energy-dependent and the glucose consumption of infected RBC is increased more than 50 times over the consumption of normal RBC. High levels of glycolytic enzymes such as fructose-1,6-diphosphate aldolase (p41) have been detected in infected RBC. Expression of the cloned aldolase gene of P. falciparum in Escherichia coli resulted in an enzymatically active polypeptide with a high sp. act. and the recombinant p41 aldolase was used for enzymatic and immunologic studies reported here. The presence of antibodies against p41 in the sera of human adults partially immune to malaria and immunization experiments in monkeys suggest that p41 is implicated in protective immune response against the parasite. Therefore, we analyzed the capacity of various antisera to inhibit P. falciparum aldolase activity. It was found that anti-p41 antibodies raised in mice, rabbits, and monkeys inhibited very efficiently aldolase activity in vitro up to dilutions higher than 10(-3). In contrast none of the human sera with high levels of anti-p41 antibodies were able to inhibit parasite aldolase activity even at a dilution of 1/2. The inability of human antisera to neutralize parasite aldolase is not related to antibody titers but is probably related to the specificity of the human antibodies. This finding is discussed in relation to homology of structure of P. falciparum and mammalian aldolase and to a possible mechanism of parasite adaptation and survival in its natural host.

Animals↗
PubMed1990

Structural diversity of Plasmodium falciparum gp200 is detected by T cells.

T lymphocyte clones (TLC) specific for P. falciparum gp200 (a glycoprotein precursor of the main merozoite surface component) were obtained from two individuals with past exposure to malaria. The 25 established TLC carried the CD4 antigen and proliferated in the presence of immunopurified gp200, crude lysate of the parasite and intact infected red blood cells. They were further tested in proliferation assays for their capacity to recognize the structural diversity displayed by gp200. The stimulating antigen used in these assays was either sonicated or viable preparations of schizonts from five P. falciparum isolates differing in their gp200. The majority of the TLC proliferated similarly in the presence of each of the isolates. One third of the TLC proliferated to a different extent depending on the isolate used for stimulation, while two clones gave isolate-specific responses. These results indicate that the majority of human TLC raised in vitro against gp200, is directed against common determinants. This also suggests that immunization with full length gp200 will not lead predominantly to T cell help restricted to isolate-specific determinant.

Animals↗
PubMed1990

Initiation of translation at a UAG stop codon in the aldolase gene of Plasmodium falciparum.

The gene coding for the key glycolytic enzyme fructose-1,6-diphosphate aldolase of the human malaria parasite Plasmodium falciparum lacks a functional AUG initiation codon for translation. Protein sequences of natural or in vitro translated aldolase include the candidate start methionine residue at internal positions. No additional AUG start codon is found in genomic DNA, cDNA or mRNA sequences. Instead, a UAG chain termination codon is recognized as the start signal of protein synthesis in vivo and in vitro.

Amino Acid Sequence↗