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A M Hill

Publications and source records attributed to A M Hill.

At least 19 recordsLinked to original sources
PubMed2000

M-1/M-2 macrophages and the Th1/Th2 paradigm.

Evidence is provided that macrophages can make M-1 or M-2 responses. The concept of M-1/M-2 fomented from observations that macrophages from prototypical Th1 strains (C57BL/6, B10D2) are more easily activated to produce NO with either IFN-gamma or LPS than macrophages from Th2 strains (BALB/c, DBA/2). In marked contrast, LPS stimulates Th2, but not Th1, macrophages to increase arginine metabolism to ornithine. Thus, M-1/M-2 does not simply describe activated or unactivated macrophages, but cells expressing distinct metabolic programs. Because NO inhibits cell division, while ornithine can stimulate cell division (via polyamines), these results also indicate that M-1 and M-2 responses can influence inflammatory reactions in opposite ways. Macrophage TGF-beta1, which inhibits inducible NO synthase and stimulates arginase, appears to play an important role in regulating the balance between M-1 and M-2. M-1/M-2 phenotypes are independent of T or B lymphocytes because C57BL/6 and BALB/c NUDE or SCID macrophages also exhibit M-1/M-2. Indeed, M-1/M-2 proclivities are magnified in NUDE and SCID mice. Finally, C57BL/6 SCID macrophages cause CB6F1 lymphocytes to increase IFN-gamma production, while BALB/c SCID macrophages increase TGF-beta production. Together, the results indicate that M-1- or M-2-dominant macrophage responses can influence whether Th1/Th2 or other types of inflammatory responses occur.

Animals↗
PubMed1999

Increased vibrissa growth in transgenic mice expressing insulin-like growth factor 1.

Insulin-like growth factor 1 (IGF-1) mediates many of the actions of growth hormone. Overexpression of IGF-1 has been reported to have endocrine and paracrine/autocrine effects on somatic growth in transgenic mice. To study the paracrine/autocrine effects of IGF-1 in hair follicles, transgenic mice were produced by pronuclear microinjection of a construct containing a mouse ultra-high sulfur keratin (UHS-KER) promoter linked to an ovine IGF-1 cDNA. This UHS-KER promoter has previously been shown to direct expression of a reporter gene to the hair follicles of transgenic mice. Four transgenic mouse lines were established as a result of microinjection of 435 embryos. Transgene expression was found in skin at day 8 and day 15 of age in three of the lines. Progeny tests were carried out by mating two of the transgenic expressing males to nontransgenic females. Mice from one line were all nonexpressors while four of the 12 mice from the other showed integration of the transgene and three expressed transgene IGF-1 mRNA in the skin. Vibrissa growth at 11-21 d of age was significantly greater in transgenic expressors than in their nontransgenic littermates. Specifically, the increase in vibrissa length for transgenics at days 11-16 (20.5%) is approximately 2-fold compared with days 16-21 (11.9%). These results demonstrate that local overexpression of IGF-1 in transgenic mice is capable of stimulating vibrissa growth during the first neonatal hair cycle.

Animals↗
PubMed1998

HIV-1 RNA, CD4 cell count and the risk of progression to AIDS and death during treatment with HIV-1 reverse transcriptase inhibitors.

CONTEXT: There is little information available on the correlation between HIV-1 RNA level, CD4 cell count and the risk of progression to AIDS or death during treatment with reverse transcriptase inhibitors. OBJECTIVES: To define the correlation between HIV-1 RNA level, CD4 cell count and the 1 year risk of progression to AIDS or death. DESIGN: Pooled analysis of six randomized clinical trials of zidovudine/lamivudine versus control treatments. SETTING: Investigational sites in Europe, North America, Australia and South Africa. PATIENTS: The trials recruited 1488 adult HIV-1-infected male and female patients aged > or = 18 years, with inclusion CD4 cell count between 25 and 500 x 10(6) cells/l. Patients were either nucleoside analogue-naive or pre-treated, and at all stages of HIV-1 disease. MAIN OUTCOME MEASURES: : Progression (defined as all new and recurrent AIDS-defining events or death) was correlated with the HIV-1 RNA level and CD4 cell count during the first 8 to 52 weeks of treatment. RESULTS: During a median 1 year follow up, progression was largely restricted to patients with both low CD4 cell count (< or = 200 x 10(6) cells/l) and high HIV-1 RNA level (> 5000 copies/ml). There was an increase in the incidence of progression events with rises in HIV-1 RNA level > 5000 copies/ml and reductions in CD4 cell count under 200 x 10(6) cells/l. The events occurring with HIV-1 RNA < 5000 copies/ml were generally atypical. CONCLUSIONS: Progression to AIDS or death is rare for patients with HIV-1 RNA < or = 5000 copies/ml, particularly when CD4 cell count is more than 200 x 10(6) cells/l.

AIDS-Related Opportunistic Infections↗
PubMed1998

The effects of lamivudine treatment on HIV-1 disease progression are highly correlated with plasma HIV-1 RNA and CD4 cell count.

OBJECTIVE: To determine the value of plasma HIV-1 RNA and CD4 cell count as predictors of the clinical benefit of antiretroviral treatment. DESIGN AND SETTING: The CAESAR (Canada, Australia, Europe, South Africa) trial randomized 1840 patients [inclusion CD4 cell count, 25-250 x 10(6)/l] to add either placebo, lamivudine (3TC) or 3TC plus loviride in a double-blinded fashion to baseline treatments (zidovudine, zidovudine-didanosine or zidovudine-zalcitabine) for 1 year. PATIENTS: This analysis included 487 patients with data on CD4 cell count and HIV-1 RNA after 12-20 weeks of treatment and subsequent follow-up for clinical progression. MAIN OUTCOME MEASURES: The correlation between 12-20-week change in CD4 cell count, HIV-1 RNA and progression to AIDS or death in the placebo group was used to predict the clinical benefit of the 3TC-containing arms of the trial, given their effects on CD4 cell count and HIV-1 RNA. RESULTS: After 12-20 weeks of treatment, HIV-1 RNA fell by 0.37 log10 copies/ml in the 3TC arms versus a rise of 0.05 log10 copies/ml in the placebo arm. The 12-20-week CD4 cell count rose by 35 x 10(6)/l in the 3TC arm versus a fall of 8 x 10(6)/l in the placebo arm. After 12-20 weeks of treatment, a reduction in HIV-1 RNA of 1 log10 at 12-20 weeks predicted a 49% reduction in progression [hazard ratio (HR), 0.51; 95% confidence interval (CI), 0.30-0.87] and a rise in CD4 cell count of 50 x 10(6)/l predicted a 51% reduction in progression (HR, 0.49; 95% CI, 0.33-0.73). Using the model from the placebo arm, the rises in CD4 cell count and reductions in HIV-1 RNA during 3TC treatment predicted a 59% reduction in progression to AIDS or death. The observed clinical benefit was a 57% reduction in progression for the 3TC arms versus placebo (HR, 0.43; 95% CI, 0.26-0.71). CONCLUSIONS: Rises in CD4 cell count and reductions in HIV-1 RNA were reliable in predicting the clinical benefit of 3TC in the CAESAR trial.

Acetamides↗
PubMed1998

Inhibition of major histocompatibility complex class I antigen presentation in pig and primate cells by herpes simplex virus type 1 and 2 ICP47.

Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) express an immediate-early protein, ICP47, that effectively inhibits the human transporter associated with antigen presentation (TAP), blocking major histocompatibility complex (MHC) class I antigen presentation to CD8+ T cells. Previous work indicated that the mouse TAP is relatively resistant to inhibition by the HSV-1 and HSV-2 ICP47 proteins (ICP47-1 and ICP47-2) and that mouse cells infected with HSV-1 are lysed by anti-HSV CD8+ cytotoxic T lymphocytes (CTL). Therefore, mice are apparently not suitable animals in which to study the in vivo effects of ICP47. In order to find an animal model, we introduced ICP47-1 and ICP47-2 into cells from various animal species-mice, rats, guinea pigs, rabbits, dogs, pigs, cows, monkeys, and humans-and measured TAP activity in the cells. Both proteins were unable to inhibit TAP in mouse, rat, guinea pig, and rabbit cells. In contrast, ICP47-1 and ICP47-2 inhibited TAP in pig, dog, cow, and monkey cells, and the TAP in pig and dog fibroblasts was often more sensitive to both proteins than TAP in human fibroblasts. These results were extended by measuring CD8+-T-cell recognition (CTL lysis) of cells from various species. Cells were infected with recombinant HSV-1 constructed to express murine MHC class I proteins so that the cells would be recognized and lysed by well-characterized murine anti-HSV CTL unless antigen presentation was blocked by ICP47. Anti-HSV CD8+ CTL effectively lysed pig and primate cells infected with a recombinant HSV-1 ICP47- mutant but were unable to lyse pig or primate cells infected with a recombinant HSV-1 that expressed ICP47. Therefore, pigs, dogs, and monkeys may be useful animal models in which to test the effects of ICP47 on HSV pathogenesis or the use of ICP47 as a selective immunosuppressive agent.

Animals↗
PubMed1998

Meta-analysis of antiretroviral effects on HIV-1 RNA, CD4 cell count and progression to AIDS or death.

There is uncertainty as to how the effects of antiretroviral treatments on human immunodeficiency virus type 1 (HIV-1) RNA levels and CD4 cell counts can predict reductions in clinical progression to AIDS or death. A meta-analysis was conducted for 27 pairwise comparisons of antiretroviral treatments in 15 randomized trials of antiretroviral treatments. For each trial, three measures of treatment effect were used: (i) 16 week change from baseline in HIV-1 RNA; (ii) 16 week change from baseline in CD4 cell count; and (iii) rate of clinical progression. Treatments which caused greater increases in CD4 cell count and greater reductions in HIV-1 RNA were more effective at reducing the rate of clinical progression (P < 0.05 for each comparison). However, there was variability in the consistency of this correlation between different trials and treatments. The results support the use of both CD4 count and HIV-1 RNA levels as the primary markers of the efficacy of antiretroviral treatment.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Prediction of HIV-1 RNA suppression and its durability during treatment with zidovudine/lamivudine.

To predict the probability of long-term viral suppression during treatment with zidovudine and lamivudine, human immunodeficiency virus type 1 (HIV-1) RNA values were retrospectively pooled for 1083 patients from six randomized, double-blind clinical trials. All analyses of HIV-1 RNA were obtained using the Roche Amplicor assay or its earlier prototype. Time to loss of response was evaluated by Kaplan-Meier analysis; Cox proportional hazards models were used to assess the influence of baseline variables. Among 523 patients with < or = 6 months of prior zidovudine treatment, the probability of HIV-1 RNA suppression below 400 copies/ml at 48 weeks was 71% in those with baseline HIV-1 RNA < 5000 copies/ml, but only 14% in those with HIV-1 RNA between 50,000 and 200,000 copies/ml. Among 560 patients with > 6 months of prior zidovudine treatment, the rates of sustained viral suppression were lower, but also significantly associated with the baseline HIV-1 RNA. Multivariate analyses showed no independent effect of CD4 cell count, age, sex, race, or CDC disease stage on the probability of sustained HIV-1 RNA suppression. When patients with < or = 6 months of prior therapy were stratified based on the magnitude of HIV-1 RNA nadir achieved during treatment, those who reached a nadir of < 400 copies/ml retained this response for significantly longer time periods than the ones who only achieved partial viral suppression. In conclusion, baseline HIV-1 RNA levels and the duration of prior zidovudine therapy strongly predict the antiretroviral efficacy of zidovudine/lamivudine. The baseline parameters should influence the choice of the antiretroviral regimen.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Reductions in HIV-1 disease progression for zidovudine/lamivudine relative to control treatments: a meta-analysis of controlled trials.

OBJECTIVES: Four randomized double-blind trials have demonstrated that zidovudine/lamivudine (ZDV/3TC) reduces HIV RNA and raises CD4 counts relative to control treatments (ZDV or ZDV/zalcitabine (ddC)]. A meta-analysis of the clinical events in these trails was conducted to determine whether treatment with ZDV/3TC was also associated with a clinical benefit. DESIGN: The four trials, ZDV/3TC versus ZDV (NUCA3001, NUCB3001, NUCB3002) or versus ZDV/ddC (NUCA3002), were run concurrently, using the same doses of ZDV and 3TC. SETTING: Investigational sites in Europe and North America. PATIENTS: The trials recruited 972 HIV-1-positive, male and female patients aged > or = 18 years, with CD4 counts of 100-500 cells x 10(6)I. Two trials were for ZDV-naive patients and two were for ZDV pre-treated patients. MAIN OUTCOME MEASURES: Progression to first new Centers for Disease Control and Prevention (CDC) B or C event was compared between all ZDV/3TC arms and all control (ZDV, ZDV/ddC) arms. RESULTS: A total of 118 patients progressed to a first new CDC B/C event during the four trials, while 28 progressed to a new CDC event. Meta-analysis of the trials showed a 49% reduction in progression to new CDC B/C events (relative risk, 0.509; 95% confidence interval, 0.365-0.710; P < 0.0001) and a 66% reduction in progression to new CDC C events (relative risk, 0.344; 95% confidence interval, 0.169-0.700; P = 0.003) for the ZDV/3TC patients relative to the control patients. Reductions in progression to CDC B/C disease were seen in subgroups of naive and pre-treated patients, those with high and low CD4 counts and symptomatic and asymptomatic patients. CONCLUSIONS: ZDV/3TC combination treatment delays the progression of CDC B/C disease compared with control treatments. In view of the low incidence of CDC C events, the results for progression to CDC C disease should be interpreted with caution.

Adolescent↗
PubMed1997

Correspondence between the effect of zidovudine plus lamivudine on plasma HIV level/CD4 lymphocyte count and the incidence of clinical disease in infected individuals. North American Lamivudine HIV Working Group.

OBJECTIVES: To investigate whether apparently beneficial changes in plasma HIV RNA level and CD4 lymphocyte count that are induced by antiretroviral therapy are associated with a corresponding clinical benefit. METHODS: For 620 patients in two randomized, double-blind trials of lamivudine (3TC) and zidovudine (ZDV) plasma HIV RNA and CD4 lymphocyte count changes were compared in patients randomized to 3TC plus ZDV and patients randomized to other treatment arms. The effect of therapy on the HIV RNA level and CD4 count was compared with the effect of therapy on clinical endpoints over the same time period. RESULTS: Median baseline values for all subjects were 42 420 copies/ml for HIV RNA and 277 x 10(6)/l for CD4 count. During the trial a significantly lower HIV RNA level and higher CD4 count was sustained in the ZDV/3TC group compared with the other group, with a difference in the median area under the curve from baseline per month of follow-up of 0.38 log10 copies/ml HIV RNA and 0.18 log2 x 10(6)/l CD4 cells (P < 0.001 in each case). For patients who were initially asymptomatic or in CDC stage B, the adjusted relative hazard (RH) of AIDS for a twofold lower CD4 count was 3.14 [95% confidence interval (CI), 1.44-6.83] and for a 10-fold higher HIV RNA level was 3.22 (1.20-8.59). The RH progression to AIDS expected with ZDV/3TC compared with the control treatments, given the observed effects of treatment on CD4 cell counts and HIV RNA levels, is 0.52, whereas the observed value was 0.16 (0.03-0.74). After adjustment for HIV RNA and CD4 changes over time the observed RH of progression to AIDS for ZDV/3TC treatment compared with controls was increased to 0.36 and was no longer significant (95% CI, 0.07-1.85). CONCLUSION: In this analysis of two trials, the effects of ZDV/3TC in reducing plasma HIV RNA and raising peripheral blood CD4 counts were associated with concurrent clinical benefits and the effect of treatment on these markers could account for at least part of the clinical benefits of therapy that were observed.

Anti-HIV Agents↗
PubMed1997

Modelling the cost effectiveness of lamivudine/zidovudine combination therapy in HIV infection.

The use of combination antiretroviral therapy is supported by clinical evidence for its superiority over monotherapy. Lamivudine (3TC) has been studied in combination with zidovudine (ZDV) and is recommended for use specifically in combination therapy. With the associated increase in drug acquisition cost, the economics of combination therapy versus monotherapy warrant study. An economic evaluation was undertaken to compare 3TC/ZDV combination therapy with ZDV monotherapy, taking a UK public finance perspective. The cost effectiveness of each of the 2 treatments was estimated using a Markov model of progression through 3 HIV-positive disease states: (i) CD4 cells > 200 and < 500 cells/mm3; (ii) CD4 < 200 cells/mm3, non-AIDS; and (iii) AIDS to eventual death. Progression probabilities and life expectancy were derived from a cohort treated at Chelsea and Westminster Hospital in London, using data for 1987 to 1995, along with cost data for a ZDV intent-to-treat population for 1994 and 1995. The relative risk of progression for 3TC/ZDV compared with ZDV monotherapy was estimated from meta-analysis of 4 completed comparative trials. To predict the effect of 3TC/ZDV on life expectancy and lifetime costs, progression probabilities were adjusted by the relative risk statistic for the duration of treatment with 3TC/ZDV. On the basis of an estimated relative risk of progression of 0.509 (95% CI 0.365 to 0.710), treatment with 3TC/ZDV is predicted to yield an incremental cost-effectiveness ratio of Pounds 6276 (95% CI Pounds 5337 to Pounds 9075) per life year saved (discounted at 6% per year). Extensive sensitivity analyses were performed to test the effects of varying values of input parameters on the model results. Under reasonable assumptions, the predicted cost effectiveness of 3TC/ZDV combination therapy compares favourably with previously reported economic analyses of various HIV treatments.

Adult↗
PubMed1996

High level expression of Ricinus communis casbene synthase in Escherichia coli and characterization of the recombinant enzyme.

Casbene synthase catalyzes the cyclization of geranylgeranyl diphosphate (2) to casbene (1), a diterpene phytoalexin with antibacterial and antifungal activity that is produced by seedlings of castor bean (Ricinus communis L.) in response to fungal attack. We report the high-level expression of casbene synthase cDNA in Escherichia coli as insoluble inclusion bodies, the solubilization and refolding of active casbene synthase, and the kinetic and product analysis of the recombinant enzyme. To overcome problems apparently associated with the presence in the casbene synthase gene of rare Arg codons, as well as the intrinsic antibacterial activity of casbene itself, the casbene synthase gene was expressed in an E. coli host harboring the pSM102 vector that encodes the dnaY gene for tArg(AGA/G), using an expression vector, pET-21d(+), carrying the tightly controlled T7lac promoter.

Ricinus communis↗
PubMed1996

Safety and efficacy of lamivudine-zidovudine combination therapy in zidovudine-experienced patients. A randomized controlled comparison with zidovudine monotherapy. Lamivudine European HIV Working Group.

OBJECTIVE: To compare the safety and efficacy of 2 doses of lamivudine given in combination with zidovudine with continued zidovudine monotherapy. DESIGN: Double-blind, randomized, multicenter, comparative trial of 223 patients treated for 24 weeks. SETTING: Patients from 32 hospitals in Europe were enrolled throughout a 1-year period. PATIENTS: Adult human immunodeficiency virus type 1 (HIV-1)-positive, zidovudine-experienced ( > or = 24 weeks prior zidovudine) patients with CD4+ cell counts between 0.10 and 0.40 x 10(9)/L (100-400 cells/microL). INTERVENTION: Patients received either 200 mg of zidovudine every 8 hours, 150 mg of lamivudine every 12 hours plus zidovudine, or 300 mg of lamivudine every 12 hours plus zidovudine for 24 weeks. All patients were then allowed to receive zidovudine and open-label lamivudine combination therapy. Twelve patients withdrew because of adverse events during the 24-week treatment period. MAIN OUTCOME MEASURES: Efficacy was measured by evaluating immunological and viral load changes, and safety was assessed by evaluating clinical manifestations and laboratory indexes of toxic effects. RESULTS: Patients receiving low- or high-dose combination therapy had greater treatment effects compared with patients receiving continued zidovudine monotherapy during the first 24 weeks as documented by changes in CD4+ cell counts (+0.04 vs +0.03 vs -0.02 x 10(9)/L, respectively; P < .001); log10 HIV-1 RNA as measured by the Roche assay (-0.96 vs -0.77 vs +0.07 copies/mL, respectively; P < .001) or log10 HIV-1 RNA measured by the quantitative nucleic acid sequence-based amplification assay (-0.59 vs -1.06 vs -0.02 copies/mL, respectively; P < .011); and immune-complex dissociated (ICD) p24 antigen (-74% vs -68% vs +27%, respectively; P < .001). There were no statistically significant differences in viral measurements, in CD4+ cell counts, or in safety profile between the groups receiving 2 doses of lamivudine in combination with zidovudine. The effects on CD4+ cell counts and ICD p24 antigen were sustained throughout 48 weeks for patients continuing combination therapy. Patients switching to combination therapy at week 24 showed improvement. CONCLUSION: In zidovudine-experienced HIV-1-infected patients, combination treatment with lamivudine and zidovudine is well tolerated and provides greater and more sustained increases in CD4+ cell counts and decreases in viral load than continued zidovudine monotherapy.

Adult↗
PubMed1996

Safety and efficacy of lamivudine-zidovudine combination therapy in antiretroviral-naive patients. A randomized controlled comparison with zidovudine monotherapy. Lamivudine European HIV Working Group.

OBJECTIVE: To compare safety and efficacy of lamivudine-zidovudine combination therapy with zidovudine monotherapy in treating human immunodeficiency virus type 1 (HIV-1)-infected, antiretroviral therapy-naive patients. DESIGN: Double-blind, randomized, multicenter, comparative trial of 129 patients throughout 24 weeks followed by 24 weeks of open-label lamivudine in combination with zidovudine. SETTING: Outpatients from 14 hospitals in Belgium, France, Germany, Spain, and the United Kingdom were enrolled within 6 months. PATIENTS: HIV-1-positive, antiretroviral-naive ( < or = 4 weeks prior zidovudine use) patients aged atleast 18 years with CD4+ cell counts between 0.10 x 10(9)/L and 0.40 x 10(9)/L (100-400/microL). INTERVENTION: Patients received either 300 mg of lamivudine every 12 hours in combination with 200 mg of zidovudine every 8 hours for 24 weeks or zidovudine monotherapy for 24 weeks. All patients were then allowed to receive zidovudine in combination with open-label lamivudine (300 mg every 12 hours). MAIN OUTCOME MEASURES: Efficacy was assessed by changes in CD4+ cell counts beta 2-microglobulin, neopterin, HIV-1 immune-complex dissociated (ICD) p24 antigenemia, and HIV-1 viral load. Safety was assessed by incidence of adverse clinical events and defined laboratory-measured toxic effects. RESULTS: Combination therapy showed superior treatment effects compared with monotherapy during the first 24 weeks as documented by changes in CD4+ cell counts (increase of 0.08 x 10(9)/L vs 0.02 x 10(9)/L; P < .001), ICDp24 (-88% vs -49%; P = .04), cellular viremia (-1.27 vs -0.20 log10 median tissue-culture infected dose [TCID50] per 10(6) peripheral blood mononuclear cells; P = .001), and viral load measured by HIV-1 RNA polymerase chain reaction using a Roche method (-1.33 vs -0.57 log10 copies/mL; P = .001) or an immune-capture method (-0.6 vs -0.14log10 copies/mL; P = .008). Observed changes were sustained to 48 weeks for patients continuing to receive combination therapy. Patients switching to receive combination therapy at week 24 showed improvements in CD4+ cell count and viral load to week 48. Mutation results suggested that mutations associated with zidovudine resistance may have developed more slowly over the first 24 weeks in patients receiving combination therapy. In contrast, mutations associated with lamivudine resistance appeared to develop rapidly, despite sustained antiviral treatment effect. However, the number of patients evaluated for genotypic changes was small, and confirmation of these results is needed in larger studies. No statistically significant differences in incidence or severity of clinically manifested or laboratory-measured toxic effects were noted between treatment groups. CONCLUSIONS: The combination of lamivudine and zidovudine results in a potent and sustained antiviral effect in antiretroviral-naive patients that is superior to that observed with zidovudine monotherapy.

Adult↗
PubMed1996

Viral dynamics in hepatitis B virus infection.

Treatment of chronic hepatitis B virus (HBV) infections with the reverse transcriptase inhibitor lamivudine leads to a rapid decline in plasma viremia and provides estimates for crucial kinetic constants of HBV replication. We find that in persistently infected patients, HBV particles are cleared from the plasma with a half-life of approximately 1.0 day, which implies a 50% daily turnover of the free virus population. Total viral release into the periphery is approximately 10(11) virus particles per day. Although we have no direct measurement of the infected cell mass, we can estimate the turnover rate of these cells in two ways: (i) by comparing the rate of viral production before and after therapy or (ii) from the decline of hepatitis B antigen during treatment. These two independent methods give equivalent results: we find a wide distribution of half-lives for virus-producing cells, ranging from 10 to 100 days in different patients, which may reflect differences in rates of lysis of infected cells by immune responses. Our analysis provides a quantitative understanding of HBV replication dynamics in vivo and has implications for the optimal timing of drug treatment and immunotherapy in chronic HBV infection. This study also represents a comparison for recent findings on the dynamics of human immunodeficiency virus (HIV) infection. The total daily production of plasma virus is, on average, higher in chronic HBV carriers than in HIV-infected patients, but the half-life of virus-producing cells is much shorter in HIV. Most strikingly, there is no indication of drug resistance in HBV-infected patients treated for up to 24 weeks.

Alanine Transaminase↗
PubMed1996

Intracellular calcium stores and inositol 1,4,5-trisphosphate receptor in rat liver cells.

The D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] receptor was localized by immunofluorescence experiments in situ in liver cryosections. Two anti-Ins(1,4,5)P3 receptor antibodies (against the 14 C-terminal residues of the type 1 receptor or against the entire cerebellar receptor) weakly decorated the whole cytoplasm, and a more intense labelling was observed at the periphery of the hepatocytes, particularly beneath the canalicular and the sinusoidal domains of the plasma membrane (PM). Antibodies against calreticulin, the Ca2+ pump (SERCA2b) or endoplasmic reticulum (ER) membranes homogeneously labelled the cytoplasm and the subplasmalemmal area. These data indicate that the ER can be divided into at least two specialized subregions: one is located throughout most of the cytoplasm and contains markers of the rough ER (RER), calreticulin, SERCA2b and a low density of Ins(1,4,5)P3 receptor, and the other is confined to the periphery of the cells and contains calreticulin, Ca2+ pump, RER markers and a high density of Ins(1,4,5)P3 receptor. A membrane fraction enriched in Ins(1,4,5)P3 receptor and in markers of the PM was immuno-adsorbed with the antibody against the C-terminal end of the Ins(1,4,5)P3 receptor and pelleted with Sepharose protein A. The immuno-isolated material was enriched in Ins(1,4,5)P3 receptor, but none of the markers of the ER or of the PM could be detected. This suggests that the Ins(1,4,5)P3 receptor is localized on discrete domains of the ER membrane beneath the canalicular and the sinusoidal membranes, where it was found at higher densities than the other markers.

Animals↗
PubMed1996

HIV-1 RNA levels and the development of clinical disease. North American Lamivudine HIV Working Group.

OBJECTIVE: To assess the prognostic value of HIV RNA levels for predicting clinical disease independently of the CD4 lymphocyte count in patients on antiretroviral therapy. DESIGN: Cohort of HIV-infected patients from two trials of lamivudine therapy. PATIENTS: For 620 patients randomized in the North American NUCA3001 and NUCA3002 trials of lamivudine, HIV RNA levels were measured (median, seven measures per patient) and CD4 counts were assessed at a central laboratory (median, 13 counts per patient). Patients were in the 1993 Centers for Disease Control and Prevention (CDC) stages A (n = 439), B (n = 135) or C (n = 46) at baseline. OUTCOME MEASURES: For patients who were in CDC stage A at baseline we considered the ability of HIV RNA levels and CD4 counts to predict the development of CDC stage B or C disease. A Cox proportional hazards model was used. In a second analysis, patients who were AIDS-free at baseline were considered, and the endpoint was AIDS (CDC stage C). RESULTS: Patients' initial CD4 counts ranged (5-95% centiles) from 104 to 529 x 10(6)/l (median, 274 x 10(6)/l) and HIV RNA levels from 1900 to 339680 copies/ml (median, 44240 copies/ml). For the first analysis, with CDC stage B or C disease as endpoint, both the most recent HIV RNA level and CD4 count predicted the development of clinical disease [relative hazard (RH) for HIV RNA, 1.96 per 10-fold difference in HIV RNA; 95% confidence interval (CI), 1.41-2.73; P = 0.0001; and RH for CD4 count, 1.82 per twofold difference in CD4 count; 95% CI, 1.27-2.56; P = 0.0009]. When both HIV RNA and CD4 count were included in a multiple regression model, both markers provided information additional to that given by the other (RH for HIV RNA, 1.75; 95% CI, 1.23-2.50; P = 0.002; and RH for CD4 count, 1.40; 95% CI, 0.95-2.07; P = 0.09). In the second analysis, with AIDS as endpoint, both HIV RNA level (P = 0.02) and CD4 count (P = 0.004) were independently associated with clinical progression. These results were essentially unchanged after adjustment for treatment arm (zidovudine/lamivudine versus control arms). CONCLUSION: The HIV RNA level shows ability to predict the development of clinical disease and may thus be of importance in addition to the CD4 count in patient monitoring.

Adult↗