Temporal Adjustments in the Evaluation of Events: The "Rosy View"

In a series of three investigations we examined people's anticipation of, actual experiences in, and subsequent recollection of meaningful life events: a trip to Europe, a Thanksgiving vacation, and a 3-week bicycle trip in California. The results of all three studies supported the hypothesis that people's expectations of personal events are more positive than their actual experience during the event itself, and their subsequent recollection of that event is more positive than the actual experience. The "rosy view" phenomenon is associated with an increase in the number of negative thoughts during the event which seem to be caused by distractions, disappointment, and a less positive view of the self. However, these effects are short-lived; within days after the event, people have much more positive evaluations of the event. We discuss alternative interpretations for our findings and implications for group and organizational settings.

Gregarina triboliorum (Eugregarinida: Gregarinidae) n. sp. from Tribolium confusum and resolution of the confused taxonomic history of Gregarina minuta Ishii, 1914

The septate gregarine parasites of flour beetles (Tribolium spp.) include Gregarina minuta Ishii, 1914, a relatively small species in which both primite and satellite possess an obvious protomerite, and a larger species that lacks the satellite protomerite. The latter species has been placed in the genera Didymophyes and Hirmocystis by various authors, but studies reported here demonstrate that this species, herein described as Gregarina triboliorum, exhibits early pairing and produces oocyst chains, both characteristics of the genus Gregarina. The oocysts of this new species are described for the first time. In addition, experimental infections using oocyst from single gametocysts reveal that oocyst chain number is variable but is typically 1, 2, or 4. Prior experiments involving a related beetle, Tenebrio molitor, demonstrated extreme host specificity within the 4 Gregarina species parasitizing larval and adult hosts. However, G. triboliorum is not limited either stadially or specially, infecting both adults and larvae of Tribolium confusum and Tribolium castaneum.

Effects of angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor antagonists in rats with heart failure. Role of kinins and angiotensin II type 2 receptors

Angiotensin-converting enzyme inhibitors (ACEi) improve cardiac function and remodeling and prolong survival in patients with heart failure (HF). Blockade of the renin-angiotensin system (RAS) with an angiotensin II type 1 receptor antagonist (AT1-ant) may have a similar beneficial effect. In addition to inhibition of the RAS, ACEi may also act by inhibiting kinin destruction, whereas AT1-ant may block the RAS at the level of the AT1 receptor and activate the angiotensin II type 2 (AT2) receptor. Using a model of HF induced by myocardial infarction (MI) in rats, we studied the role of kinins in the cardioprotective effect of ACEi. We also investigated whether an AT1-ant has a similar effect and whether these effects are partly due to activation of the AT2 receptor. Two months after MI, rats were treated for 2 mo with: (a) vehicle; (b) the ACEi ramipril, with and without the B2 receptor antagonist icatibant (B2-ant); or (c) an AT1-ant with and without an AT2-antagonist (AT2-ant) or B2-ant. Vehicle-treated rats had a significant increase in left ventricular end-diastolic (LVEDV) and end-systolic volume (LVESV) as well as interstitial collagen deposition and cardiomyocyte size, whereas ejection fraction was decreased. Left ventricular remodeling and cardiac function were improved by the ACEi and AT1-ant. The B2-ant blocked most of the cardioprotective effect of the ACEi, whereas the effect of the AT1-ant was blocked by the AT2-ant. The decreases in LVEDV and LVESV caused by the AT1-ant were also partially blocked by the B2-ant. We concluded that (a) in HF both ACEi and AT1-ant have a cardioprotective effect, which could be due to either a direct action on the heart or secondary to altered hemodynamics, or both; and (b) the effect of the ACEi is mediated in part by kinins, whereas that of the AT1-ant is triggered by activation of the AT2 receptor and is also mediated in part by kinins. We speculate that in HF, blockade of AT1 receptors increases both renin and angiotensins; these angiotensins stimulate the AT2 receptor, which in turn may play an important role in the therapeutic effect of the AT1-ant via kinins and other autacoids.

A prospective, randomized, controlled evaluation of peripheral nerve stimulation versus standard clinical dosing of neuromuscular blocking agents in critically ill patients

OBJECTIVES

To determine if vecuronium doses individualized by peripheral nerve stimulation are lower than those doses chosen by standard clinical techniques; and to determine whether patients monitored by peripheral nerve stimulation exhibit shorter recovery times and less prolonged neuromuscular blockade after discontinuation of vecuronium than control patients.

DESIGN

A prospective, randomized, controlled, single-blind trial.

SETTING

Two ten-bed medical intensive care units of a 937-bed tertiary care, not-for-profit, teaching hospital and health system.

PATIENTS

Mechanically ventilated patients requiring continuous neuromuscular blockade as part of their therapy.

INTERVENTIONS

After obtaining written, informed consent and baseline neurologic examinations, patients were randomized to treatment, where dosing was individualized by peripheral nerve stimulation or standard clinical assessment. Doses in the peripheral nerve stimulation group were adjusted to 90% blockade (Train-of-Four of 1/4). The standard clinical dosing group received doses individualized to clinical response by the medical team (blinded to Train-of-Four). Differences between groups were evaluated by Wilcoxon matched-pairs signed rank test.

MEASUREMENTS AND MAIN RESULTS

A total of 77 patients (35 standard clinical patients vs. 42 peripheral nerve stimulation patients) were enrolled in the study. Despite no difference in initial doses and time to reach 90% blockade or clinical response between groups, the peripheral nerve stimulation group used less drug than the standard clinical group (0.040 +/- 0.028 vs. 0.070 +/- 0.030 mg/kg/hr, respectively, p = .001). The total cumulative amount of vecuronium for the episode of paralysis was greater in the control group (285.8 +/- 246.6 vs. 137.1 +/- 106.4 mg, p = .001). The peripheral nerve stimulation group recovered neuromuscular function (relative risk of 1.85, with 95% confidence interval [CI] of 1.02-3.35, p = .039) and spontaneous ventilation (relative risk of 1.86, 95% CI 1.00-3.45, p = .047) faster than the control group. In patients, adjusting for renal dysfunction, the likelihood of a faster recovery in the peripheral nerve stimulation group increased for neuromuscular function (relative risk of 1.89, 95% CI of 1.07-3.32, p = .018) and spontaneous ventilation (relative risk of 2.27, 95% CI of 1.23-4.21, p = .019). Patients with combined renal and liver failure similarly demonstrated a faster recovery in the peripheral nerve stimulation group. The recovery was affected to a lesser extent by adjusting for concurrent aminoglycoside and corticosteroid administration.

CONCLUSIONS

Use of peripheral nerve stimulation for monitoring the degree of blockade and adjusting drug doses in continuously paralyzed critically ill medical patients results in lower doses of vecuronium to maintain a desired depth of paralysis, and allows a faster recovery of neuromuscular function and spontaneous ventilation.

Kinins and the events influenced by an angiotensin-converting enzyme inhibitor during neointima formation in the rat carotid artery

OBJECTIVE

In balloon-injured rat carotid arteries, angiotensin-converting enzyme inhibitors (ACEI) decrease neointima formation, and a kinin receptor antagonist partially reverses this inhibitory effect. We studied which of the events leading to neointima formation are involved in the effects of ACEI and kinins.

METHODS

We administered 5 mg/kg per day ramipril, either alone or combined with the kinin receptor antagonist icatibant (Hoe 140), on the days each wave occurred and studied the effects on neointima formation 14 days after balloon injury. Ramipril alone or combined with icatibant had no effect on neointima formation when administered from 2 days before to 3 or 5 days after balloon injury. In contrast, ramipril inhibited neointima formation when administered from day 7 to day 14. Treatment with icatibant had a small effect, which was sufficient to abolish the effects of ramipril (control 0.11 +/- 0.01 mm2, ramipril 0.08 +/- 0.01 mm2; P < 0.05; ramipril plus icatibant 0.09 +/- 0.01 mm2; NS, ramipril plus icatibant versus control). Thus ramipril was not effective when treatment was stopped after 3 or 5 days, but was mildly effective when treatment was administered during the second week. The effect on migration was studied by counting the number of neointimal cells in rats treated from 2 days before to 4 days after injury. Ramipril decreased the number of cells by 93% compared with controls (control 65.0 +/- 13.5 cells/slice, ramipril 4.7 +/- 2.0 cells/slice; P < 0.001), and this effect was blunted significantly by icatibant (19.5 +/- 5.7 cells/slice; P < 0.009, versus ramipril; P < 0.007, versus controls). The influence of treatment on the rate of proliferation (the 5'-bromo-2'-deoxyuridine index) was studied in the media 3 days, and in the neointima 7 and 10 days after balloon injury. Although proliferation peaked in the neointima after 7 days, there were no differences among the groups at any time. Thus neither ramipril nor icatibant affected the rate of proliferation at the times sampled. Ramipril increased cell density (cells/mm2) in the neointima, and this effect was abolished by cotreatment with icatibant (P < 0.05).

CONCLUSION

The ACEI needs to be present throughout the experimental period to be most effective. ACEI act on neointima formation in part by inhibiting migration; thus, because ramipril was mildly effective when administered from 7 to 10 days after injury, it is likely that vascular smooth muscle cell migration also occurs continuously. Kinins help mediate roughly 30% of the effect of ACEI on migration. In addition, ACEI, through kinins, affect a process that increases the density of the cells in the neointima, perhaps by decreasing extracellular matrix deposition.

Effect of neutral endopeptidase 24.11 inhibition on myocardial ischemia/reperfusion injury: the role of kinins

Angiotensin-converting enzyme inhibitors (ACEi) protect the heart against ischemia/reperfusion injury. Part of this cardioprotective effect may be mediated through kinins. Because kinins are also metabolized by neutral endopeptidase (NEP) 24.11 in vivo, we hypothesized that (a) inhibition of NEP-24.11 would afford cardioprotection similar to that of ACEi and potentiate the effect of ACEi; and (b) these effects are mediated by kinins or atrial natriuretic peptide (ANP) or both. In Lewis inbred rats, the left anterior descending coronary artery (LAD) was occluded for 30 min, followed by 120-min reperfusion. Immediately before reperfusion rats received vehicle, the ACEi ramiprilat, the NEP-24.11 inhibitor (NEPi) CGS24592, or both. To test whether the effect of NEPi could be suppressed by blocking kinins or ANP, the kinin-receptor antagonist icatibant or ANP antagonist HS-142-1 was administered before LAD occlusion. In controls, infarct size/risk area was 69 +/- 4%; NEPi reduced this to 24 +/- 4% (p < 0.001) and ramiprilat to 20 +/- 3% (P < 0.001). NEPi did not potentiate the effect of ramiprilat (infarct size/risk area, 18 +/- 4%). The protective effect of NEPi was blocked by icatibant; infarct size/risk area, 61 +/-4%, significantly larger than NEPi along (p < 0.001) but no different from controls. The effect of NEPi was slightly diminished by the ANP antagonist HS-142-1 (infarct size/risk area, 35 +/- 3%; NS vs. NEPi alone). Thus NEP-24.11 participates in catabolism of kinins in the heart; inhibition of NEP-24.11 may increases cardiac kinins, which are responsible for the cardioprotective effect of NEPi.

Chronic heart failure induced by coronary artery ligation in Lewis inbred rats

Rat models of heart failure (HF) secondary to myocardial infarction (MI) are useful in studying the progression of cardiac dysfunction and in testing therapeutic approaches. Sprague-Dawley rats are frequently used; however, this model is hampered by high mortality and a marked variability in infarct size and cardiac dysfunction, necessitating large numbers of rats and prolonged follow-up when studying the progression of dysfunction. In the present work, we developed a model of HF utilizing Lewis inbred rats. Ligation of the left anterior descending coronary artery in Lewis rats produced more uniform and larger infarcts (40 +/- 1.7 vs. 28 +/- 2.3%; P < 0.001) and lower mortality (16 vs. 36%; P < 0.001) than in Sprague-Dawley rats. Using this rat model, we further studied the course of left ventricular (LV) dysfunction and enlargement from 1 wk to 6 mo after MI with cineventriculography. LV end-systolic volume and end-diastolic volume were determined with the area-length method. LV ejection fraction ranged between 0.57 and 0.62 in control rats; after MI, it decreased significantly to 0.48 +/- 0.04 at 1 wk, 0.36 +/- 0.02 at 2 wk, 0.48 +/- 0.02 at 1 mo, 0.35 +/- 0.03 at 2 mo, 0.30 +/- 0.02 at 3 mo, 0.31 +/- 0.02 at 4 mo, and 0.24 +/- 0.02 at 6 mo (P < 0.001, MI vs. sham). LV end-diastolic volume in control rats ranged between 0.32 and 0.42 ml; it increased to 0.48 +/- 0.04 ml at 1 wk, 0.46 +/- 0.02 ml at 2 wk, and 0.46 +/- 0.03 ml at 1 mo. It markedly increased to 0.79 +/- 0.03, 0.79 +/- 0.06, 0.78 +/- 0.03, and 0.80 +/- 0.05 ml at 2, 3, 4, and 6 mo, respectively, after MI (P < 0.001 vs. sham). LV end-diastolic pressure was significantly elevated at all time points. Thus coronary ligation in Lewis inbred rats produces uniformly large infarcts with low mortality, progressive LV dysfunction, and increased LV chamber size. This model may be useful in studying chronic HF secondary to MI.

Serum and urinary interleukin-6 in systemic lupus erythematosus

Dysregulation of IL-6 production has been proposed as a pathogenic mechanism in SLE. We asked if serum or urine IL-6 levels could serve as indicators of systemic lupus erythematosus (SLE) disease activity. Using a sensitive enzyme-linked immunosorbent assay (ELISA), we measured serum and urine IL-6 in 56 SLE patients. Disease activity was assessed using a standard clinical index, the Systemic Lupus Activity Measure (SLAM). Only seven of 56 SLE patients had elevated serum IL-6 levels, compared with 1 of 32 controls (NS). SLE disease activity did not correlate with serum IL-6 levels. Sixteen of 50 SLE patients in whom urine IL-6 was measured exhibited elevated urine IL-6 levels, compared with 1 of 17 controls (p = < 0.05). Urine IL-6 levels correlated with overall disease activity and with the presence of active urinary sediment. Our results indicate that serum IL-6 is not a predictor of disease activity in SLE, but that urine IL-6 may be a marker of active nephritis.

Prevalence of possible undiagnosed asthma and associated morbidity among urban schoolchildren

OBJECTIVE

The extent to which urban children endure the symptoms and consequences of asthma without a physician diagnosis has not been well studied. Our objective was to obtain an estimate of the prevalence of possible undiagnosed asthma in a population of urban schoolchildren.

DESIGN AND METHODS

A population-based cross-sectional study was conducted in urban schoolchildren, grades 3 to 5. Undiagnosed asthma was defined as caretaker report of symptoms and/or bronchial hyperresponsiveness, defined as a 15% or greater drop in baseline forced expiratory volume in 1 second, after exercise challenge.

RESULTS

A total of 230 children (61% of those eligible) participated in the study. Forty children (17.4%; 95% Confidence interval (CI) = 12.5% to 22.3%) had reports of a physician diagnosis of asthma. Of these, 33 (14.3%; (95% CI = 9.8% to 18.9%) reported wheezing in the past 12 months. Among the remaining 189 eligible children, 11 (5.8%; 95% CI = 2.5% to 9.2%) met study criteria for undiagnosed asthma based on bronchial hyperresponsiveness (BHR). Another 16 (8.5%; 95% CI = 4.5% to 12.4%) met study criteria for undiagnosed asthma through modified American Thoracic Society symptom criteria. Overall, 27 children (27/189; 14.3%) fulfilled criteria for undiagnosed asthma. Children identified as having undiagnosed asthma were compared with children who had no BHR and no symptoms and who did not report a physician diagnosis of asthma (children without asthma). Children with BHR were more likely to have a report of allergies and eczema than children without asthma, odds ratios (OR) = 8.5 (95% CI = 2.4 to 30.7) and 6.4 (95% CI = 1.1 to 38.1), respectively. Children meeting symptom criteria were more likely to have a report of allergies, OR = 6.2 (95% CI = 2.0 to 19.1), and bronchitis, OR = 6.7 (95% CI = 2.0 to 22.4), and were also more likely to report sleep disruption, OR = 7.1 (95% CI = 2.3 to 21.8) and missed physical education classes, OR = 15.0 (95% CI = 4.8 to 46.7), compared with children without asthma.

CONCLUSIONS

We estimated a prevalence of 14.3% for possible undiagnosed asthma among urban schoolchildren, grades 3 to 5, through caretaker report of symptoms or BHR postexercise challenge. Children with undiagnosed asthma reported more atopic disease than children without asthma. In addition, children meeting symptom criteria for asthma reported more bronchitis, sleep disruption, and missed physical education classes than did those without asthma. These results suggest that rates of undiagnosed asthma may be high in this predominantly black school-age population.

Early clinical markers and CD4 percentage in subjects with human immunodeficiency virus infection

In a clinical trial involving asymptomatic, HIV-seropositive subjects treated with either the HIV-1 immunogen (an inactivated, gp120-depleted HIV-1 virus in incomplete Freund's adjuvant) or an adjuvant control, we examined the relationship between changes in the percentage of CD4 cells over time and early clinical markers of HIV disease progression. Subjects who had an early clinical event were more likely to have a greater decline in the percentage of CD4 cells than those subjects who did not have a clinical event (p = 0.054). The greatest decline in CD4 percentage occurred within 10 weeks prior to a clinical event (mean 11% decrease from baseline). Subjects from the quartile with the greatest decline in CD4 percentage had a fivefold greater risk of having a clinical event than subjects from the quartile with the second largest decline (p = 0.045). These results demonstrate a relationship between changes in the percentage of CD4 cells and early clinical events. Further validation of this association may be useful in clinical monitoring and in evaluating therapies to treat HIV infection.

Are smokers with alcohol disorders less likely to quit?

OBJECTIVES

This study examined the likelihood of smoking cessation in smokers with a prior history of alcoholism.

METHODS

Data came from an epidemiologic study of 1007 young adults, randomly selected from those insured in a large health maintenance organization (HMO) in southeast Michigan. Cox proportional hazards models with time-dependent covariates were used to estimate the hazards ratios of quitting in smokers with current and past alcoholism, with smokers with no history of alcoholism as a reference. Sex, race, and education were controlled.

RESULTS

Smokers with active alcoholism in the preceding year were 60% less likely to quit than were smokers with no history of alcoholism. In contrast, smokers whose alcoholism had remitted were at least as likely to quit as smokers with no history of alcoholism. Compared with persistent alcoholism, remission of alcoholism was associated with more than a threefold increase in the likelihood of subsequent smoking cessation.

CONCLUSIONS

The findings suggest that discontinuation of alcoholism might increase the potential for successful smoking cessation.

Health services research at United HealthCare Corporation: the role of the Center for Health Care Policy and Evaluation

This article describes collaborative health services research and performance evaluation activities at United HealthCare Corporation, a national health care management services company. We outline the development of a research capacity within our company, the principal data sources used, and the types of research conducted. The importance of health services research within a managed care system is illustrated using two projects as examples. finally, we discuss issues faced by organizations such as ours in defining appropriate research priorities, ensuring health plan participation, and disseminating research findings. Lessons learned should be of interest to health services researchers working in or collaborating with managed care organizations as well as others seeking to understand the dynamics of research in private-sector health care companies.

Linkage-disequilibrium of the senegal haplotype with the beta S gene in the republic of guinea

We have determined the beta gene cluster haplotype in 40 chromosomes carrying the beta S mutation from individuals of the major ethnic groups living in the Republic of Guinea. Thirty-one of these were either the typical (n = 29) or the atypical (n = 2) Senegal haplotype demonstrating that in this region of Atlantic West Africa, the sickle mutation is in linkage disequilibrium with this particular beta-gene cluster haplotype. Two individuals carrying one chromosome bearing the Benin haplotype were of Malinke ethnic origin. This is in keeping with the hypothesis that the Senegal beta-gene cluster haplotype is linked to the beta S gene in Atlantic West Africa.

Asymmetry of finger temperature and early behavior

Measures of the temperature of the fingertips of eighty-three 4-year-old children revealed an unexpected asymmetry in which the index finger of the left hand but the ring finger of the right hand were the coolest digits. In addition, a subset of 20 children who had the coolest right compared with the left ring finger were more fearful to unfamiliar events and also had a cooler right than left forehead at 21 months of age.

Sex differences in depression: a role for preexisting anxiety

The role of anxiety disorders in the development of sex differences in major depression is analyzed. Data come from a longitudinal epidemiologic study of young adults in the Detroit, Michigan area. The Diagnostic Interview Schedule, revised according to DSM-III-R, was used at baseline to measure lifetime psychiatric disorders and at follow-up to measure psychiatric disorders during the 3.5-year interval since baseline assessment. Consistent with previous reports, the lifetime prevalence of major depression was nearly two-fold higher in females than in males. The sex difference was primarily in major depression comorbid with anxiety disorders. Results from Cox-proportional hazards models, with time-dependent covariates, showed that prior anxiety disorder increased the risk for subsequent major depression in both sexes, with no evidence of an interaction. History of anxiety disorder, including number of prior anxiety disorders, accounted for a considerable part of the observed sex difference in major depression. Controlling for prior anxiety reduced by more than 50% the coefficient that estimates the association between gender and major depression. The results suggest that the higher occurrence of anxiety disorders in females than males beginning early in life might explain in large part the higher female risk for major depression. They emphasize the need for further research on sex differences in anxiety disorders.

The synthesis of glutamic acid in the absence of enzymes: implications for biogenesis

This paper reports on the non-enzymatic aqueous phase synthesis of amino acids from keto acids, ammonia and reducing agents. The facile synthesis of key metabolic intermediates, particularly in the glycolytic pathway, the citric acid cycle, and the first step of amino acid synthesis, lead to new ways of looking at the problem of biogenesis.

Effect of inhibiting renal kallikrein on prostaglandin E2, water, and sodium excretion

To test the hypothesis that renal kinins act as natriuretic and diuretic hormones, we examined the effect of inhibiting glandular kallikrein on renal function in normotensive unanesthetized rats during normal sodium intake. To inhibit kallikrein at both the luminal and basolateral sides of the distal nephron, we used Fab fragments of monoclonal antibodies to rat urinary kallikrein (Fab-kallikrein). Fab fragments have advantages over intact IgG: they are filtered through the glomerulus and reach the lumen of the distal nephron, where kallikrein is localized and urinary kinins are released. Furthermore, the Fab fragment-antigen complex does not activate the complement system, avoiding the side effects associated with intact antibodies. Fab-kallikrein effectively blocked generation of kinins in the nephron lumen, decreasing urinary kininogenase activity (kallikrein) by 74% to 85% and kinin excretion by 76% to 79%. Fab-kallikrein induced a 30% decrease in urine volume and a 20% to 40% decrease in urinary sodium excretion but did not alter blood pressure, glomerular filtration rate, or renal blood flow. Although urinary prostaglandin E2 excretion also tended to decrease, this change was slower and of lesser magnitude than those of kinin and kininogenase excretion and did not attain statistical significance after Bonferroni's correction. In controls injected with either vehicle or Fab fragments of monoclonal antibodies to ricin (a vegetable protein not present in mammals), none of these parameters decreased significantly. We conclude that renal kinins participate in the short-term regulation of water and sodium excretion in normotensive unanesthetized rats, acting as diuretic and natriuretic hormones.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of squalestatin 1 on the biosynthesis of the mevalonate pathway lipids

The effects of squalestatin 1 on rat brain and liver homogenates and on Chinese hamster ovary tissue culture cells have been investigated. This compound effectively inhibits squalene biosynthesis in a highly selective manner. Cytoplasmic farnesyl pyrophosphate and geranylgeranyl pyrophosphate synthases are not affected, which is also the case for microsomal cis-prenyltransferase. In tissue culture cells, squalestatin 1 inhibits cholesterol biosynthesis completely, but does not alter dolichol synthesis or protein isoprenylation to a great extent. Incorporation of [3H]mevalonate into ubiquinone-9 and -10 increases 3-4-fold, probably as a result of increased synthesis of this lipid. Squalestatin 1 appears not only to be an effective inhibitor of cholesterol biosynthesis, but also to be more specific than other inhibitors used earlier in various in vitro and in vivo systems.

Beta 2-microglobulin-deficient NOD mice do not develop insulitis or diabetes

The role of CD8+ T-cells in the development of diabetes in the nonobese diabetic (NOD) mouse remains controversial. Although it is widely agreed that class II-restricted CD4+ T-cells are essential for the development of diabetes in the NOD model, some studies have suggested that CD8+ T-cells are not required for beta-cell destruction. To assess the contribution of CD8+ T-cells to diabetes, we have developed a class of NOD mouse that lacks expression of beta 2-microglobulin (NOD-B2mnull). NOD-B2mnull mice, which lack both class I expression and CD8+ T-cells in the periphery, not only failed to develop diabetes but were completely devoid of insulitis. These results demonstrate an essential role for CD8+ T-cells in the initiation of the autoimmune response to beta-cells in the NOD mouse.

Immune responses elicited by recombinant vaccinia-human immunodeficiency virus (HIV) envelope and HIV envelope protein: analysis of the durability of responses and effect of repeated boosting

Previous studies indicate that immunization with recombinant (r) vaccinia-human immunodeficiency virus type 1 (HIV-1) gp160 and boosting with baculovirus-derived HIV-1 rgp160 results in stronger cellular and antibody responses than those following either vaccine alone. The durability of immunity over 1 year was evaluated in 12 recipients. Both cellular and binding antibody responses remained detectable but diminished, and neutralizing antibodies were absent. To boost immunity, rgp160 was given again 1 year after the initial boost. Reboosting elicited strong HIV-specific lymphoproliferative responses. Binding antibody levels also rose dramatically, and the magnitude of the peak responses was significantly greater following the 2-year than following the 1-year boost. However, neutralizing antibody titers were low (1:10-1:20) and detected in only 4 of 12 persons. Moreover, persistent CD8+ cytolytic responses were not induced. Thus, although repeated rgp160 boosting after vaccinia-envelope priming can augment selected immune components, an altered regimen may be necessary to achieve protective long-term immunity to HIV-1.

The Strecker synthesis as a source of amino acids in carbonaceous chondrites: deuterium retention during synthesis

Deuterium-enriched amino acids occur in the Murchison carbonaceous chondrite. Synthesis from D-enriched interstellar precursors by Strecker reactions during aqueous alteration of the parent body has been proposed. To test this hypothesis, we have measured the retention of deuterium in amino acids produced from HCN, NH3, and formaldehyde-D2, acetaldehyde-D4, and acetone-D6 in H2O. The isotopic label is 50% to 98% retained, with variations in retentivity depending on the amino acid and the reaction conditions. If amino acids, once formed on the parent body by the Strecker synthesis, lose no deuterium by subsequent exchange with water or H-bearing minerals, then the observed deuterium isotopic composition of Murchison amino acids represents as much as 50% or more of the enrichments inherited from their interstellar precursors. Imino diacids are prominent side products of the Strecker synthesis which have not been reported in carbonaceous chondrites. Under the conditions of the Strecker reaction using deuterium labeled aldehydes and ketones, unlabeled amino acids are also formed by an HCN polymerization route indicating multiple pathways for the synthesis of amino acids in meteorites.

Quantitative perceptual estimates: verbal versus nonverbal retrieval techniques

Examples of the inaccessibility of mental processes by means of verbal recall are described with particular reference to the accuracy of quantitative estimates of size, distance, and duration. Evidence is presented in support of the hypothesis that nonverbal retrieval techniques are more accurate than quantitative verbal estimates. Implications for the judicial process are considered.

A search for C60 in carbonaceous chondrites

Analysis of interior samples of the Murchison meteorite by two routes yielded an upper limit of 2 ppb for its C60 content, as compared to parts per million levels for individual polycyclic aromatic hydrocarbons (PAHs). Provided the samples contain an interstellar component, which is probable since Murchison hydrocarbons contain excess deuterium, this result argues against the ubiquitous presence of C60 in the interstellar medium. A possible explanation for the absence of C60 was found in experiments showing how PAHs replace fullerenes as stable end products when hydrogen is present during carbon condensation. As a secondary result we found high molecular weight PAHs in the Murchison and Allende meteorites. Coronene and its methyl derivatives are especially interesting since features in the coronene spectrum have been shown to match some of the unidentified interstellar infrared emission bands.