Maintained intentional weight loss reduces cardiovascular outcomes: results from the Sibutramine Cardiovascular OUTcomes (SCOUT) trial.

AIM: The Sibutramine Cardiovascular OUTcomes trial showed that sibutramine produced greater mean weight loss than placebo but increased cardiovascular morbidity but not mortality. The relationship between 12-month weight loss and subsequent cardiovascular outcomes is explored. METHODS: Overweight/obese subjects (N = 10 744), ≥55 years with cardiovascular disease and/or type 2 diabetes mellitus, received sibutramine plus weight management during a 6-week Lead-in Period before randomization to continue sibutramine (N = 4906) or to receive placebo (N = 4898). The primary endpoint was the time from randomization to first occurrence of a primary outcome event (non-fatal myocardial infarction, non-fatal stroke, resuscitated cardiac arrest or cardiovascular death). RESULTS: For the total population, mean weight change during Lead-in Period (sibutramine) was -2.54 kg. Post-randomization, mean total weight change to Month 12 was -4.18 kg (sibutramine) or -1.87 kg (placebo). Degree of weight loss during Lead-in Period or through Month 12 was associated with a progressive reduction in risk for the total population in primary outcome events and cardiovascular mortality over the 5-year assessment. Although more events occurred in the randomized sibutramine group, on an average, a modest weight loss of approximately 3 kg achieved in the Lead-in Period appeared to offset this increased event rate. Moderate weight loss (3-10 kg) reduced cardiovascular deaths in those with severe, moderate or mild cardiovascular disease. CONCLUSIONS: Modest weight loss over short-term (6 weeks) and longer-term (6-12 months) periods is associated with reduction in subsequent cardiovascular mortality for the following 4-5 years even in those with pre-existing cardiovascular disease. While the sibutramine group experienced more primary outcome events than the placebo group, greater weight loss reduced overall risk of these occurring in both groups.

Regulation of proto-oncogene expression in adult and developing lungs.

Activation of immediate-early gene expression has been associated with mitogenesis, differentiation, nerve cell depolarization, and recently, terminal differentiation processes and programmed cell death. Previous evidence also suggested that immediate-early genes play a role in the physiology of the lungs (J. I. Morgan, D. R. Cohen, J. L. Hempstead, and T. Curran, Science 237:192-197, 1987). Therefore, we analyzed c-fos expression in adult and developing lung tissues. Seizures elicited by chemoconvulsants induced expression of mRNA for c-fos, c-jun, and junB and Fos-like immunoreactivity in lung tissue. The use of pharmacological antagonists and adrenalectomy indicated that this increased expression was neurogenic. Interestingly, by using a fos-lacZ transgenic mouse, it was shown that Fos-LacZ expression in response to seizure occurred preferentially in clusters of epithelial cells at the poles of the bronchioles. This was the same location of Fos-LacZ expression detected during early lung development. These data imply that pharmacological induction of immediate-early gene expression in adult mice recapitulates an embryological program of gene expression.

Adherence to antiretroviral therapy and its impact on clinical outcome in HIV-infected patients.

We analyse data on patient adherence to prescribed regimens and surrogate markers of clinical outcome for 168 human immunodeficiency virus infected patients treated with antiretroviral therapy. Data on patient adherence consisted of dose-timing measurements collected for an average of 12 months per patient via electronic monitoring of bottle opening events. We first discuss how such data can be presented to highlight suboptimal adherence patterns and between-patient differences, before introducing two novel methods by which such data can be statistically modelled. Correlations between adherence and subsequent measures of viral load and CD4+T-cell counts are then evaluated. We show that summary measures of short-term adherence, which incorporate pharmacokinetic and pharmacodynamic data on the monitored regimen, predict suboptimal trends in viral load and CD4+T-cell counts better than measures based on adherence data alone.

The active site of human C4a anaphylatoxin.

The human C4 activation peptide C4a has recently been shown to be biologically active and to share common tissue receptors with human C3a anaphylatoxin. Human C3a and C4a each induce contraction and cause cross-desensitization of isolated guinea-pig ileal strips. The essential active site of C3a is comprised in the model peptide containing the five COOH-terminal residues, Leu-Gly-Leu-Ala-Arg. The anaphylatoxic activities of the corresponding C4a pentapeptide, Ala-Gly-Leu-Gln-Arg, and several other synthetic peptides related to the COOH-terminal sequence of human C4a were examined. The C4a pentapeptide induced contraction of guinea-pig ileum at 1 X 10(-3) M and produced a wheal and flare reaction in human or guinea-pig skin when 2-5 mumols were injected intradermally. The corresponding C3a pentapeptide is 500-fold more active, since it induces contraction of guinea-pig ileum at 3-4 X 10(-6) M and only 4-10 nmole induce a visible skin reaction. Although the C4a pentapeptide is relatively inactive compared to the C3a pentapeptide, two analogs of these peptides, Leu-Gly-Leu-Gln-Arg and Ala-Gly-Leu-Ala-Arg, each exhibited significantly greater activity than Ala-Gly-Leu-Gln-Arg and each analog desensitized ileal smooth muscle towards contraction by either C3a or C4a. Thus it is a combination of two amino acid substitutions, the Ala for Leu-73 and Gln for Ala-76, in the COOH-terminal pentapeptide of C3a that accounts for the markedly reduced activity of C4a. The contribution of the COOH-terminal portion of C4a on its activity was further documented by examining the C4a octapeptide, Lys-Gly-Gln-Ala-Gly-Leu-Gln-Arg and a trialanyl analog, Ala-Ala-Ala-Ala-Gly-Leu-Gln-Arg. The C4a octapeptide, C4a (70-77), exhibited 5-fold greater biologic activity than the C4a pentapeptide, while the trialanyl analog was 40-fold more active. Anaphylatoxic activities of the C4a-(73-77) pentapeptide, C4a-(70-77) octapeptide, and the trialanyl octapeptide analog and their ability to specifically block the action of C3a and C4a on smooth muscle tissue support the conclusion that, as in C3a, the essential active site of C4a resides at its COOH terminus. Since C4a functions as an anaphylatoxin and significant quantities of this mediator may be generated in individuals with hereditary angioneurotic edema (HANE), the hypotheses that the kinin-like activity promoting edema in HANE patients is derived solely from component C2 and/or kininogens should be reappraised. The activities previously assigned to C4a and now confirmed by synthetic C4a analog peptides suggest that the kinin-like activity generated in HANE plasma may be derived in part from C4a.

The duration of viral suppression during protease inhibitor therapy for HIV-1 infection is predicted by plasma HIV-1 RNA at the nadir.

OBJECTIVE: To determine markers that are associated with the durability of virologic response to therapy with HIV protease inhibitors in HIV-infected individuals. DESIGN: This study encompassed two retrospective analyses of the duration of virologic response to protease inhibitor therapy. The first analysis included 29 patients receiving either monotherapy or combination therapy with the protease inhibitor ritonavir whose plasma HIV RNA levels rebounded from the point of greatest decline with mutations associated with resistance to ritonavir. The second analysis included a cohort of 102 patients who initially responded to randomized treatment with either monotherapy with ritonavir or combination therapy with ritonavir and zidovudine. METHODS: Durability of response was defined as the time from the initiation of therapy to the point at which plasma HIV RNA displayed a sustained increase of at least 0.6 log10 copies/ml from the nadir value. In the first analysis, durability of response was analyzed with respect to baseline HIV RNA, HIV RNA at the nadir, and the drop in HIV RNA from baseline to the nadir. In the second analysis, time to rebound was examined using Kaplan-Meier analysis, stratifying by either baseline HIV RNA or HIV RNA at the nadir. RESULTS: In both analyses, the durability of response was not highly associated with either baseline RNA or the magnitude of RNA decline from baseline. Instead, a strong relationship was observed between the durability of response and the nadir plasma HIV-1 RNA value (P < 0.01). The nadir in viral load was generally reached after 12 weeks of randomized therapy. CONCLUSIONS: Viral RNA determinations at intermediate timepoints may be prognostic of impending virologic failure of protease inhibitor therapy. Therapeutic strategies that allow intensification of initial antiretroviral regimens in the subset of patients with incomplete virological response before the emergence of high level resistance should be investigated.

Ritonavir and saquinavir combination therapy for the treatment of HIV infection.

OBJECTIVE: To evaluate the safety and antiretroviral activity of ritonavir (Norvir) and saquinavir (Invirase) combination therapy in patients with HIV infection. DESIGN: A multicenter, randomized, open-label clinical trial. SETTING: Seven HIV research units in the USA and Canada. PATIENTS: A group of 141 adults with HIV infection, CD4 T lymphocyte counts of 100-500 x 10(6) cells/l, whether treated previously or not with reverse transcriptase inhibitor therapy, but without previous HIV protease inhibitor drug therapy. INTERVENTIONS: After discontinuation of prior therapy for 2 weeks, group I patients were randomized to receive either combination (A) ritonavir 400 mg and saquinavir 400 mg twice daily or (B) ritonavir 600 mg and saquinavir 400 mg twice daily. After an initial safety assessment of group I patients, group II patients were randomized to receive either (C) ritonavir 400 mg and saquinavir 400 mg three times daily or (D) ritonavir 600 mg and saquinavir 600 mg twice daily. Investigators were allowed to add up to two reverse transcriptase inhibitors (including at least one with which the patient had not been previously treated) to a patient's regimen after week 12 for failure to achieve or maintain an HIV RNA level < or = 200 copies/ml documented on two consecutive occasions. MEASUREMENTS: Plasma HIV RNA levels and CD4+ T-lymphocyte counts were measured at baseline, every 2 weeks for 2 months, and monthly thereafter. Safety was assessed through the reporting of adverse events, physical examinations, and the monitoring of routine laboratory tests. RESULTS: The 48 weeks of study treatment was completed by 75% (106/141) of the patients. Over 80% of the patients on treatment at week 48 had an HIV RNA level < or = 200 copies/ml. In addition, intent-to-treat and on-treatment analyses revealed comparable results. Suppression of plasma HIV RNA levels was similar for all treatment arms (mean areas under the curve minus baseline through 48 weeks were-1.9, -2.0, -1.6, -1.8 log10 copies/ml in ritonavir-saquinavir 400-400 mg twice daily, 600-400 mg twice daily, 400-400 mg three times daily, and 600-600 mg twice daily, respectively). Median CD4 T-lymphocyte count rose by 128 x 10(6) cells/l from baseline, with an interquartile range (IQR) of 82-221 x 10(6) cells/l. The most common adverse events were diarrhea, circumoral paresthesia, asthenia, and nausea. Reversible elevation of serum transaminases (> 5 x upper limit of normal) occurred in 10% (14/141) of the patients enrolled in this study and was associated with baseline abnormalities in liver function tests, baseline hepatitis B surface antigen positivity, or hepatitis C antibody positivity (relative risk, 5.0; 95% confidence interval 1.5-16.9). Most moderate or severe elevations in liver function tests occurred in patients treated with ritonavir-saquinavir 600-600 mg twice daily. CONCLUSIONS: Ritonavir 400 mg combined with saquinavir 400 mg twice daily with the selective addition of reverse transcriptase inhibitors was the best-tolerated regimen of four dose-ranging regimens and was equally as active as the higher dose combinations in HIV-positive patients without previous protease inhibitor treatment.

Reductions in viral load and increases in T lymphocyte numbers in treatment-naive patients with advanced HIV-1 infection treated with ritonavir, zidovudine and zalcitabine triple therapy.

In order to test the hypothesis that a combination of protease inhibitors with nucleoside analogues-agents known to inhibit different steps of the human immunodeficiency virus (HIV) life cycle--is likely to prove more effective in reducing viral loads than either of those modalities alone, we performed a 60 week, open-label trial in 32 HIV-positive patients with depressed CD4 T lymphocyte cell counts but no active AIDS-defining illnesses. For the first 2 weeks, patients received 600 mg twice daily of liquid ritonavir, a protease inhibitor; then zidovudine 200 mg three times daily and zalcitabine 0.75 mg three times daily were added to the treatment regimen. Mononuclear blood cell fractions were analysed for infected cell levels, using a co-culture system. HIV-1 RNA in plasma was measured both by reverse transcriptase-polymerase chain reaction (RT-PCR) and reverse transcriptase quantitative PCR (QcRT-PCR); lymphocyte counts were determined by standard laboratory methods. In the 2 weeks of ritonavir therapy, both the mean count of infectious blood cells and plasma HIV RNA levels decreased dramatically. Mean CD4 cell counts increased from 173 cells/mm3 at baseline to 286 cells/mm3; CD8 cell counts rose from 951 cells/mm3 to 1,141 cells/mm3. With the introduction of the nucleoside analogues, infectious cell counts and plasma virus dropped another log unit to a nadir at 8 weeks, while CD4 T lymphocyte counts continued to rise slowly. By week 28, 12 patients had withdrawn due to adverse events, none of which were life-threatening. At week 36, infectious material could not be detected in the cells of 10 of the 17 remaining patients; by week 60, four of the seven patients with residual viraemia at week 24 had undergone viral relapse. After the introduction of a more palatable capsule formulation of ritonavir at week 52, infectious cells and plasma virus were undetectable in 50-60% of patients. The combination of protease inhibitors and nucleoside analogues significantly reduces HIV load, and in some patients may suppress viral activity for sustained periods.

Efficacy, complications, and cost of a comprehensive blood conservation program for cardiac operations.

We reviewed blood use in 118 consecutive patients who underwent primary, elective cardiac operations in 1989. In June 1989 we initiated a blood conservation program that included attempts to limit preoperative aspirin use, intraoperative phlebotomy and hemodilution, use of a cell conservation device (Electromedics, Inc., Englewood, Colo.) to concentrate residual oxygenator contents, reinfusion of chest drainage, and acceptance of a minimum hemoglobin level of 8.0 gm/dl in stable patients. Patient characteristics were similar for patients operated on both before (n = 58) and after (n = 60) initiation of the blood conservation program, except for age and preoperative aspirin use (both greater in postconservation patients). Fewer blood products were transfused (5.8 +/- 5.7 units per patient before conservation versus 4.0 +/- 7.4 units per patient after conservation; p = 0.005). More complete data were available for 82 patients (40 patients before conservation and 42 after conservation). In the postconservation patients, 20 of 42 had 575 +/- 140 ml of blood withdrawn before cardiopulmonary bypass and reinfused afterward, 26 of 42 had 806 +/- 376 ml of blood processed with the cell conservation device returned, and 21 of 42 patients had an average of 287 +/- 127 ml of chest drainage reinfused. Chest tube drainage, postoperative hematologic parameters, and the prevalence of complications were not significantly different between groups. Stepwise linear regression analysis identified intraoperative withdrawal of blood before cardiopulmonary bypass, bypass duration, and preoperative hematocrit value as predictors of blood use. Intraoperative withdrawal of blood before cardiopulmonary bypass is an important conservation measure, and its use should be expanded.

The effect of pituitary suppression and the women's age on embryo viability and uterine receptivity.

OBJECTIVE: To examine the effect of pituitary suppression and the women's age on embryo viability and uterine receptivity. DESIGN: Retrospective analysis of 394 embryo transfers (ET) after in vitro fertilization (IVF). SETTING: Community hospital IVF program from 1986 to 1990. PATIENTS: Three groups were studied: women less than 40 years with pituitary suppression (group 1) and without pituitary suppression (group 2); women 40 years of age and older with pituitary suppression (group 3). INTERVENTIONS: Pituitary suppression was achieved in groups 1 and 3 with daily leuprolide acetate starting in the luteal phase; human menopausal gonadotropin and progesterone were given intramuscularly. MAIN OUTCOME MEASURES: Ongoing and multiple ongoing pregnancy rates (PRs) were compared in the three groups. A mathematical model of implantation was used to estimate embryo viability and uterine receptivity. RESULTS: Ongoing and multiple ongoing PRs per ET in group 1 (28.6% and 12.3%) were significantly higher than the corresponding rates in group 2 (16.9% and 2.4%) and in group 3 (16.9% and 3.4%). Implantation analysis revealed higher embryo viability without change in uterine receptivity with pituitary suppression (group 1 versus 2). Decrease in both embryo viability and uterine receptivity was noted in women greater than 40 (group 1 versus 3). CONCLUSIONS: (1) Pituitary suppression improved implantation outcome by increasing embryo viability with no change in uterine receptivity and was associated with a high multiple PR in women less than 40; (2) in women greater than 40 both embryo viability and, to a lesser extent, uterine receptivity were decreased; (3) transfer of a larger number of embryos in older patients may improve IVF outcome without excessive risk of multiple pregnancy.

The safety and efficacy of indinavir and ritonavir (400/400 mg BID) in HIV-1-infected individuals from an inner-city minority population: a pilot study.

We evaluated the safety and efficacy of indinavir 400 mg and ritonavir 400 mg twice daily (RIT/IND 400/400) in HIV-1-infected individuals, using an open label, proof of concept study. All patients received indinavir 400 mg and ritonavir 400 mg twice daily. Patients were followed up to 48 weeks. Nineteen subjects were enrolled, 11 (58%) men and eight (42%) women. The majority were American Black (nine; 47%) or Haitian (eight; 42%). The median baseline plasma HIV-1 viral load (VL) was 5.13 log10 copies/mL and the median CD4 cell count was 112 cells/mm(3). The proportion of compliant patients with VL <400 copies/mL at week 24 was 60% compared with 0% for non-compliant patients (P=0.011 [intent-to-treat] or P=0.085 [on-treatment]). VL at week 4 predicted week 24 VL response. Compliant patients had a median average CD4 cell count increase of 83.2 cells/mm(3) compared with 42.0 cells/mm(3) for non-compliant patients (P=0.010). The median average changes in triglycerides and cholesterol were significantly higher in compliant patients. This is a potent, safe combination for the treatment of HIV-1. VL at week 4 is predictive of viral outcome at week 24. Fasting serum cholesterol and triglycerides were significantly elevated during the study.

[Coronary angiography in a county hospital]. / Koronarangiografi ved et sentralsykehus.

BACKGROUND: At a county hospital in northern Norway, coronary angiographies have been performed for more than 25 years. We wanted to compare our complication rates with results from larger hospitals. MATERIAL AND METHODS: Data concerning indication for angiography, findings and complications were collected retrospectively from the files of 837 patients who underwent coronary angiography at our hospital during the last ten years. The number of procedures per year has varied from 30 to 125. RESULTS: 50% of the patients had three-vessel and/or left main coronary artery stenosis. Less than 10% of the patients had no significant coronary stenosis or valvular disease at angiography. The total complication rate was 4.8%. Nine patients (1.1%) had myocardial infarction or stroke with sequelae; three patients died (0.4%). INTERPRETATION: Our complication rates are higher than those from other larger hospitals in Norway and internationally, but they have decreased over time. The high percentage of serious coronary pathology among our patients may have contributed significantly to the complication rate. In addition, the annual number of exams may have been too low to give sufficient operator training. The results require a continuing evaluation of our practice.

Gender difference in HIV-1 RNA viral loads.

OBJECTIVES: To test and characterize the dependence of viral load on gender in different countries and racial groups as a function of CD4 T-cell count. METHODS: Plasma viral load data were analysed for > 30,000 HIV-infected patients attending clinics in the USA [HIV Insight (Cerner Corporation, Vienna, VA, USA) and Plum Data Mining LLC (East Meadow, NY, USA) databases] and the Netherlands (Athena database; HIV Monitoring Foundation, Amsterdam, Netherlands). Log-normal regression models were used to test for an effect of gender on viral load while adjusting for covariates and allowing the effect to depend on CD4 T-cell count. Sensitivity analyses were performed to test the robustness of conclusions to assumptions regarding viral loads below the lower limit of quantification (LLOQ). RESULTS: After adjusting for covariates, women had (nonsignificantly) lower viral loads than men (HIV Insight: -0.053 log(10) HIV-1 RNA copies/mL, P = 0.202; Athena: -0.005 log(10) copies/mL, P = 0.667; Plum: -0.072 log(10) copies/mL, P = 0.273). However, further investigation revealed that the gender effect depended on CD4 T-cell count. Women had consistently higher viral loads than men when CD4 T-cell counts were at most 50 cells/microL, and consistently lower viral loads than men when CD4 T-cell counts were greater than 350 cells/microL. These effects were remarkably consistent when estimated independently for the racial groups with sufficient data available in the HIV Insight and Plum databases. CONCLUSIONS: The consistent relationship between gender-related differences in viral load and CD4 T-cell count demonstrated here explains the diverse findings previously published.

Amino acids and N-acetyl-aspartyl-glutamate as neurotransmitter candidates in the monkey retinogeniculate pathways.

The identity of the neurotransmitter(s) in the mammalian retinogeniculate pathway is unclear. To investigate the possibility that some amino acids and certain dipeptides, such as N-acetyl-aspartyl-glutamate (NAAG), fulfill this function, changes in their concentration were measured in the optic tract, and the parvocellular and magnocellular segments of the LGNd of six monkeys (Macaca fascicularis), seven days after right optic tractotomy. The LGNd was studied also in two additional macaques, three months after occipital lobectomy. Tissue was frozen within five minutes of death, regions were dissected with the micropunch technique, and substances were analyzed by HPLC. Optic tractotomy induced significant, large reductions in NAAG, glutamate and aspartate in the optic tract distal to the lesion. Significant decreases in NAAG were also measured in the LGNd, and these changes were apparent in both the parvocellular and magnocellular segments. A small reduction in glutamate reached significance in the parvocellular laminae, and that of aspartate only approached significance in the magnocellular division. Occipital lobectomy produced large declines in aspartate and glutamate in the LGNd. The results of optic tractotomy support the role of NAAG as a neurotransmitter candidate in the monkey retinogeniculate pathways; its significant decrease in both geniculate segments suggests that both P- and M- retinal axons utilize this substance. Although at times the reductions in glutamate or aspartate failed to reach significance, their role cannot be excluded. The findings after occipital lobectomy strongly favor these latter substances as corticogeniculate and/or geniculocortical transmitters.

[Coronary angiography in a county hospital]. / Koronarangiografi ved et sentralsykehus.

BACKGROUND: At a county hospital in northern Norway, coronary angiographies have been performed for more than 25 years. We wanted to compare our complication rates with results from larger hospitals. MATERIAL AND METHODS: Data concerning indication for angiography, findings and complications were collected retrospectively from the files of 837 patients who underwent coronary angiography at our hospital during the last ten years. The number of procedures per year has varied from 30 to 125. RESULTS: 50% of the patients had three-vessel and/or left main coronary artery stenosis. Less than 10% of the patients had no significant coronary stenosis or valvular disease at angiography. The total complication rate was 4.8%. Nine patients (1.1%) had myocardial infarction or stroke with sequelae; three patients died (0.4%). INTERPRETATION: Our complication rates are higher than those from other larger hospitals in Norway and internationally, but they have decreased over time. The high percentage of serious coronary pathology among our patients may have contributed significantly to the complication rate. In addition, the annual number of exams may have been too low to give sufficient operator training. The results require a continuing evaluation of our practice.

[Prolonged action nitrates in stable angina pectoris]. / Langtidsvirkende nitrater ved stabil angina pectoris.

A randomized double blind comparison of transdermal nitroglycerin and isosorbide dinitrate tablets was conducted in 100 men with stable angina pectoris. Subjective and objective effects were virtually identical for both regimens (number of angina attacks/nitroglycerin consumption and exercise ECG test variables). The pattern of side effects was also similar for both drugs. A considerable dissociation was observed between subjective effects and effects measured by ergometer test in the individual patient. Lack of both subjective and objective effects--i.e. nitrate tolerance--was observed in approximately one fourth of the patients, and was not prevented by a twelve-hour dosing interval on isosorbide dinitrate nor a six hour transdermal nitroglycerin-free interval. Our data lends credence to the notion that the effects of long-acting nitrates in daily life and the effects measured during stress testing may involve different mechanisms.

Regression analysis, proposed interpretative zone size standards, and quality control guidelines for a new macrolide antimicrobial agent, A-56268 (TE-031).

A-56268 is a 6-O-methyl derivative of erythromycin A which has a spectrum of activity similar to that of erythromycin and is 1 log2 dilution more potent than erythromycin against most organisms that have been tested. The correlation of zone size diameters and MICs of A-56268 for 461 strains of bacteria isolated from clinical specimens was investigated. Based on anticipated levels in human serum of 2 micrograms/ml, 15-microgram disks have been recommended with zone size standards of greater than or equal to 15 mm for susceptibility (MIC correlate, less than or equal to 2.0 micrograms/ml) and less than or equal to 11 mm for resistance (MIC correlate, greater than or equal to 8 micrograms/ml). Selection of these tentative breakpoints resulted in no very major errors (false susceptible), a major error (false resistant) rate of 0.22%, and an acceptable minor error (intermediate) rate of 2.82%. MIC ranges and zone diameter limits for quality control organisms used in the standardized agar dilution and disk diffusion susceptibility tests with A-56268 are given.

Bioassay for A-56268 (TE-031) and identification of its major metabolite, 14-hydroxy-6-O-methyl erythromycin.

A-56268 is a new macrolide which is generally two-fold more potent than erythromycin. A new bioassay is described in which plasma samples are extracted with acetonitrile prior to bioassay. The concentration range for the assay is between 0.05-4.0 micrograms/ml, and the concentrations measured are within 6% of those measured by high-power liquid chromatography. An active metabolite which is as active as erythromycin was identified in the plasma. The plasma half-life and area under the plasma curve values of A-56268, as determined by bioassay, were significantly greater than those of erythromycin.

Ascending aorta to right pulmonary artery interposition shunt in critically ill infants.

In spite of a trend toward earlier complete repair, some neonates and infants with complex cyanotic heart disease continue to require interim palliation with systemic-to-pulmonary artery shunts. A variety of shunt procedures have been proposed, each with inherent advantages and disadvantages. We have found a prosthetic interposition shunt between the ascending aorta and right pulmonary artery (AA-RPA) to be effective in very young infants with small vessels. Over a 15-year period, 51 patients, mean weight 3.33 kg and mean age 59 days, underwent this procedure with a 13% perioperative mortality and a 78% 2-year overall shunt patency rate. We conclude that the AA-RPA interposition shunt is a safe, effective procedure in these infants.

Enhancement of the in vitro and in vivo activities of clarithromycin against Haemophilus influenzae by 14-hydroxy-clarithromycin, its major metabolite in humans.

MICs of clarithromycin and its major human metabolite, 14-hydroxy-clarithromycin, for Haemophilus influenzae in combination were reduced two- to fourfold compared with the MICs of each compound alone. Serum reduced the MICs of the parent compound and metabolite two- to fourfold compared with the MICs in medium without serum. In serum spiked with clinically relevant concentrations of clarithromycin and 14-hydroxy-clarithromycin at a fixed ratio of 4:1, 15 of 16 strains (94%) were inhibited and killed by combinations containing 1.2 and 0.3 micrograms/ml, respectively. In time kill experiments, the combination of parent compound and metabolite at one-fourth and one-half of their individual MICs, respectively, reduced bacterial counts by greater than 5 log CFU. The postantibiotic effect of clarithromycin combined with 14-hydroxy-clarithromycin was twice that of clarithromycin when tested alone. When orally administered to gerbils with H. influenzae otitis media, the 14-hydroxy metabolite was significantly more active than clarithromycin in reducing bacterial counts from the middle ear. The in vivo activity of the two compounds in combination was synergistic or additive, depending on the level of H. influenzae present at the time treatment was initiated. Significant reductions in bacterial counts and increases in cure rates were observed when clarithromycin at 50 or 100 mg/kg of body weight was combined with 14-hydroxy-clarithromycin at 12 mg/kg or higher. Results from in vitro and in vivo combinations suggest that routine susceptibility tests and animal efficacy studies with clarithromycin alone may underestimate its potential efficacy against H. influenzae.

Randomised placebo-controlled trial of ritonavir in advanced HIV-1 disease. The Advanced HIV Disease Ritonavir Study Group.

BACKGROUND: Ritonavir is a potent, orally bioavailable inhibitor of HIV-1 protease. We undertook an international, multicentre, randomised, double-blind, placebo-controlled trial of ritonavir in patients with HIV-1 infection and CD4-lymphocyte counts of 100 cells/microL or less, who had previously been treated with antiretroviral drugs. METHODS: 1090 patients were randomly assigned twice-daily liquid oral ritonavir 600 mg (n = 543) or placebo (n = 547) while continuing treatment with up to two licensed nucleoside agents. The primary study outcome was any first new, or specified recurrent, AIDS-defining event or death. Open-label ritonavir was provided after 16 weeks in the study to any patient who had an AIDS defining event. FINDINGS: The baseline median CD4-lymphocyte count was 18 (IQR 10-43)/microL in the ritonavir group and 22 (10-47)/microL in the placebo group. Study medication was discontinued in 114 (21.1%) ritonavir-group patients and 45 (8.3%) placebo-group patients mainly because of initial adverse symptoms. Outcomes of AIDS-defining illness or death occurred in 119 (21.9%) ritonavir-group patients and 205 (37.5%) placebo-group patients (hazard ratio 0.53 [95% CI 0.42-0.66]; log-rank p < 0.0001) during median follow-up of 28.9 weeks, with loss to follow-up of 15 (1.4%) patients. Ritonavir was then offered to all patients; at median follow-up of 51 weeks, 87 (16%) ritonavir-group patients had died of any cause versus 126 (23%) placebo-group patients (hazard ratio 0.69 [95% CI 0.52-0.91], log-rank p = 0.0072). INTERPRETATION: Although earlier intervention with combination therapy may provide much more effective treatment, ritonavir in patients with advanced disease and extensive previous antiretroviral use is safe and effective, lowers the risk of AIDS complications, and prolongs survival.