Sensitivity of the Preclinical Alzheimer's Cognitive Composite (PACC), PACC5, and Repeatable Battery for Neuropsychological Status (RBANS) to Amyloid Status in Preclinical Alzheimer's Disease -Atabecestat Phase 2b/3 EARLY Clinical Trial

BACKGROUND

Cognitive composites commonly serve as primary outcomes in Alzheimer's disease (AD) secondary prevention trials.

OBJECTIVE

To evaluate the association between amyloid (Aβ) burden level (+/-) and performance on three separate composite endpoints: Preclinical Alzheimer's Cognitive Composite (PACC), PACC+Semantic Fluency (PACC5), and Repeatable Battery for Neuropsychological Status (RBANS).

DESIGN

Screening data from the randomized, double-blind, placebo-controlled, phase 2b/3 atabecestat EARLY study in preclinical AD participants were used in this analysis.

SETTING

The EARLY study was conducted at 143 centers across 14 countries.

PARTICIPANTS

3,569 cognitively unimpaired older adults (Clinical Dementia Rating of 0; aged 60-85 years) screened for inclusion in the EARLY study with Aβ status and at least PACC or RBANS at screening were included. Participants were categorized as those with non-pathological Aβ levels (Aβ-, n=2,824) and those with pathological Aβ levels (Aβ+, n=745) based on florbetapir uptake or levels of cerebrospinal fluid Aβ1-42.

MEASUREMENTS

Analysis of Covariance models controlling for age, sex, and education were used to examine the difference in PACC, PACC5, and RBANS between Aβ groups. Nonparametric bootstrap was used to compare sensitivity of composites to differentiate between Aβ status.

RESULTS

Of 3,569 participants, 2,116 were women (59%); 3,006 were Caucasian (84%); mean (SD) age was 68.98 (5.28) years. Aβ+ participants performed worse versus Aβ- participants on all cognitive composites though the magnitude of the Aβ effect was generally small. The Aβ+/- effect size for the PACC (Cohen's d=-0.15) was significantly greater than the RBANS (d=-0.097) while the PACC5 effect size (d=-0.139) was numerically larger than the RBANS. When examining subscores from the composites, memory tests (i.e., Free and Cued Selective Reminding Test, Figure Recall) and speed of processing (i.e., Digit-Symbol/Coding on the PACC/RBANS) exhibited the largest Aβ+/- effect sizes.

CONCLUSIONS

Cross-sectional relationships between Aβ and cognition among clinically unimpaired older adults are detectable on multi-domain cognitive composites but are relatively small in magnitude. The Aβ+/- group effect was statistically larger for PACC and marginally larger for PACC5 versus RBANS. However, interpretation of composite sensitivity to Aβ status cross-sectionally cannot be generalized to sensitivity to change over time.

Randomized, Placebo-Controlled Six-Month Intervention Study of Soy Protein Isolate in Men with Biochemical Recurrence after Radical Prostatectomy: A Pilot Study

There is evidence to suggest that soy may be beneficial for prostate cancer patients, but few randomized trials have addressed this. We examined the effect of 6-8 mo soy protein supplementation on prostate specific antigen (PSA) serum levels in men who recurred (PSA > 0.1 ng/ml) within three years of prostatectomy. Sixteen men were randomized to 20 g soy protein (∼24-26/day genistein; ∼40-43/day total isoflavones) or casein placebo. PSA was measured at base line and at 1, 2, 4, and 6-8 mo. Serum genistein levels greatly increased from baseline and cholesterol decreased in the soy group. In both treatment arms PSA increased similarly and PSA doubling times were not different over the 6-8 mo study duration. Two subjects in each group had stable PSA. A literature search for clinical studies of soy, isoflavones, and PSA revealed that supplementation with soy or isoflavones did not affect PSA in virtually all clinical studies identified. Although this study is too small to draw a definitive conclusion on the effect of soy protein on PSA in men with biochemical failure, the null finding in this study is consistent with the results of virtually all reports of soy and soy isoflavones in the literature.

Soy protein supplementation in men following radical prostatectomy: a 2-year randomized, placebo-controlled clinical trial

BACKGROUND

Many studies have addressed effects of dietary supplementation with soy protein, but most have been inconsistent and few have been long-term studies in men.

OBJECTIVES

This study was a secondary analysis of body weight, blood pressure, thyroid hormones, iron status, and clinical chemistry in a 2-y trial of soy protein supplementation in middle-aged to older men.

METHODS

Data were analyzed as secondary outcomes of a randomized controlled trial of dietary supplementation with 20 g/d soy protein isolate, providing 41 mg/d total isoflavones and 23 mg/d genistein, in 44- to 75-y-old men who were at risk of cancer recurrence following prostatectomy randomized to soy (n = 50) or a casein-based placebo (n  = 43). Weight, blood pressure, and blood samples were collected at baseline, every 2 mo in year 1, and every 3 mo in year 2.

RESULTS

Compared with casein, soy supplementation did not affect body weight, blood pressure, serum total cholesterol, calcium, phosphorus, and thyroid hormones. Serum ferritin concentrations doubled over 2 y in both groups (117-129%), whereas hemoglobin and hematocrit increased slightly. In an exploratory subgroup analysis of soy group data, weight increased in subjects producing equol but not in nonproducers. Blood pressure was reduced in nonequol producers but not in producers. Other endpoints were not affected by equol production status.

CONCLUSIONS

Soy protein supplementation for 2 y compared with a casein-based placebo did not affect body weight, blood pressure, serum total cholesterol, iron status parameters, calcium, phosphorus, and thyroid hormones. Exploratory analysis suggests that equol production status of subjects on soy may modify effects of soy on body weight and possibly blood pressure. This trial was registered at clinicaltrials.gov as NCT00765479.

Changes in cerebral glucose metabolism with normal aging

The pattern of changes in cerebral glucose metabolism occurring with normal aging has been unclear. Advances in imaging technology, such as improved resolution and anatomical referencing, allow for more precise regional measurement than previously possible. This study explored cerebral glucose metabolism in 17 normal controls ranging in age from 20 to 74 years. High resolution PET scanning, with MRI-based regions of interest correcting for partial volume and atrophy effects, revealed a linear association between advancing age and declining cerebral glucose metabolism. The decline averaged 8% per decade for the whole brain. Changes were most pronounced in limbic structures, and could be implicated in age-associated memory loss.

Effect of soy protein isolate supplementation on biochemical recurrence of prostate cancer after radical prostatectomy: a randomized trial

IMPORTANCE

Soy consumption has been suggested to reduce risk or recurrence of prostate cancer, but this has not been tested in a randomized trial with prostate cancer as the end point.

OBJECTIVE

To determine whether daily consumption of a soy protein isolate supplement for 2 years reduces the rate of biochemical recurrence of prostate cancer after radical prostatectomy or delays such recurrence.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, double-blind trial conducted from July 1997 to May 2010 at 7 US centers comparing daily consumption of a soy protein supplement vs placebo in 177 men at high risk of recurrence after radical prostatectomy for prostate cancer. Supplement intervention was started within 4 months after surgery and continued for up to 2 years, with prostate-specific antigen (PSA) measurements made at 2-month intervals in the first year and every 3 months thereafter.

INTERVENTION

Participants were randomized to receive a daily serving of a beverage powder containing 20 g of protein in the form of either soy protein isolate (n=87) or, as placebo, calcium caseinate (n=90).

MAIN OUTCOMES AND MEASURES

Biochemical recurrence rate of prostate cancer (defined as development of a PSA level of ≥0.07 ng/mL) over the first 2 years following randomization and time to recurrence.

RESULTS

The trial was stopped early for lack of treatment effects at a planned interim analysis with 81 evaluable participants in the intervention group and 78 in the placebo group. Overall, 28.3% of participants developed biochemical recurrence within 2 years of entering the trial (close to the a priori predicted recurrence rate of 30%). Among these, 22 (27.2%) occurred in the intervention group and 23 (29.5%) in the placebo group. The resulting hazard ratio for active treatment was 0.96 (95% CI, 0.53-1.72; log-rank P = .89). Adherence was greater than 90% and there were no apparent adverse events related to supplementation.

CONCLUSION AND RELEVANCE

Daily consumption of a beverage powder supplement containing soy protein isolate for 2 years following radical prostatectomy did not reduce biochemical recurrence of prostate cancer in men at high risk of PSA failure.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00765479.

Differential effects of selenium on benign and malignant prostate epithelial cells: stimulation of LNCaP cell growth by noncytotoxic, low selenite concentrations

We examined the hypothesis that nontoxic concentrations of selenium induce apoptosis and growth inhibition selectively in prostate cancer cells but not in benign prostate cells. Nontumorigenic BPH-1 prostate epithelial cells, androgen-sensitive LNCaP, and androgen-independent PC-3 prostate cancer cells were exposed to sodium selenite at 1 to 10 micromol/l for 24 to 72 h. Cell proliferation, viability, and apoptosis were assessed by MTT assay, trypan blue exclusion, flow cytometry, DNA laddering, and caspase activation. BPH-1 cells were more sensitive for cytotoxic selenium effects than malignant prostate cells, whereas LNCaP cells were more sensitive than PC-3 cells. At noncytotoxic selenium concentrations, there was no apoptosis in BPH-1 and PC-3 cells and no growth inhibition of LNCaP and BPH-1 cells. PC-3 cells were refractory to apoptosis induction but were growth inhibited at noncytotoxic concentrations. LNCaP cells were growth stimulated at 1 micromol/l and sensitive to apoptosis induction at higher noncytotoxic concentrations. Thus, noncytotoxic selenite concentrations did not induce growth inhibition or apoptosis selectively in prostate cancer cells. Growth stimulation of LNCaP cells by low concentrations suggests the possibility of adverse effects of selenium supplementation on hormone sensitive prostate cancer, whereas inhibition of PC-3 cell proliferation at noncytotoxic concentrations suggests potential benefit of selenium in advanced prostate cancer.

Liposome encapsulation of curcumin and resveratrol in combination reduces prostate cancer incidence in PTEN knockout mice

Increasing interest in the use of phytochemicals to reduce prostate cancer led us to investigate 2 potential agents, curcumin and resveratrol as preventive agents. However, there is concern about the bioavailability of these agents pertinent to the poor absorption and thereby limiting its clinical use. With the view to improve their bioavailability, we used the liposome encapsulated curcumin, and resveratrol individually and in combination in male B6C3F1/J mice. Further, we examined the chemopreventive effect of liposome encapsulated curcumin and resveratrol in combination in prostate-specific PTEN knockout mice. In vitro assays using PTEN-CaP8 cancer cells were performed to investigate the combined effects curcumin with resveratrol on (i) cell growth, apoptosis and cell cycle (ii) impact on activated p-Akt, cyclin D1, m-TOR and androgen receptor (AR) proteins involved in tumor progression. HPLC analysis of serum and prostate tissues showed a significant increase in curcumin level when liposome encapsulated curcumin coadministered with liposomal resveratrol (p < 0.001). Combination of liposomal forms of curcumin and resveratrol significantly decreased prostatic adenocarcinoma in vivo (p < 0.001). In vitro studies revealed that curcumin plus resveratrol effectively inhibit cell growth and induced apoptosis. Molecular targets activated due to the loss of phosphatase and tensin homolog (PTEN) including p-Akt, cyclin D1, mammalian target of rapamycin and AR were downregulated by these agents in combination. Findings from this study for the first time provide evidence on phytochemicals in combination to enhance chemopreventive efficacy in prostate cancer. These findings clearly suggest that phytochemicals in combination may reduce prostate cancer incidence due to the loss of the tumor suppressor gene PTEN.

Exisulind in combination with celecoxib modulates epidermal growth factor receptor, cyclooxygenase-2, and cyclin D1 against prostate carcinogenesis: in vivo evidence

PURPOSE

Nonsteroidal anti-inflammatory drugs mediate anticancer effects by modulating cyclooxygenase-2 (COX-2)-dependent and/or COX-2-independent mechanism(s); however, the toxicity issue is a concern with single agents at higher doses. In this study, we determined the combined effect of celecoxib, a COX-2 inhibitor, along with exisulind (sulindac sulfone/Aptosyn) at low doses in prostate cancer.

EXPERIMENTAL DESIGN

We used a sequential regimen of N-methyl-N-nitrosourea + testosterone to induce prostate cancer in Wistar-Unilever rats. Following carcinogen treatment, celecoxib and exisulind individually and their combination at low doses were given in NIH-07 diet for 52 weeks. We determined the incidence of prostatic intraepithelial neoplasia, adenocarcinomas, rate of tumor cell proliferation, and apoptosis. Immunohistochemical and Western blot analysis were done to determine COX-2, epidermal growth factor receptor (EGFR), Akt, androgen receptor, and cyclin D1 expression. Serum prostaglandin E2 and tumor necrosis factor-alpha levels were determined using enzyme immunoassay/ELISA assays.

RESULTS

The rats that received celecoxib in combination with exisulind at low doses showed a significant decrease in prostatic intraepithelial neoplasia and adenocarcinomas as well as an enhanced rate of apoptosis. An overall decrease in COX-2, EGFR, Akt, androgen receptor, and cyclin D1 expression was found associated with tumor growth inhibition. Reduced serum levels of COX-2 protein, prostaglandin E2, and tumor necrosis factor-alpha indicated anti-inflammatory effects. A strong inhibition of total and phosphorylated form of EGFR (Tyr(992) and Tyr(845)) and Akt (Ser(473)) was significant in rats given with these agents in combination.

CONCLUSIONS

In this study, we show for the first time that the combination of celecoxib with exisulind at low doses could prevent prostate carcinogenesis by altering key molecular events.

Determinants of confrontation naming performance

Confrontation naming tests are commonly employed in neuropsychological assessment. Surprisingly little work has been done, however, to determine how various demographic, linguistic, and disease status variables influence patterns of performance on these tests. The present study examined data on the Boston Naming Test (BNT) from a total of 1,131 subjects, including 719 normals, 325 patients with Alzheimer's disease, and 87 patients with temporal lobe epilepsy. The effects of age, education, gender, and diagnostic group were examined with respect to overall scores, the influence of phonemic cuing, and performance on individual items. Profiles of scores on individual items were similar across diagnostic groups, suggesting that anomia is characterized by quantitative rather than qualitative changes in naming performance. Age and education systematically influenced scores. There was a significant effect of gender across diagnostic groups (males scoring higher than females), which appears to be due to performance on specific items. Phonemic cuing effects were similar across groups. The results are discussed with respect to the neuropsychological construct of confrontation naming and the clinical interpretation of performance on the BNT.

An empirically derived short form of the Boston naming test

The Boston Naming Test (BNT) is one of the most commonly used tests of confrontation naming. The length of the test, particularly when administered to impaired patients, has prompted the derivation of several abbreviated forms. Short forms of the BNT have typically been equated in terms of difficulty, but not empirically derived for discriminating between normals and anomic patients. Furthermore, most reports to date have been limited in sample size and generalizability. The present study examined BNT data from a total of 1,044 subjects, including 719 normals and 325 patients with Alzheimer's disease (AD). Scores were calculated for the entire 60-item version as well as for eight previously reported short forms. The scores were examined for the effects of age, education, and gender, as well as for the ability of each form to discriminate between AD patients and normals. There was a significant effect of age, education, and gender on all previously published forms, and the short forms varied in their ability to discriminate between patients and controls. A stepwise discriminant analysis was conducted to empirically derive a new, gender-neutral short form with discriminability comparable to the full 60-item test. Norms from this sample on the empirically derived short form are reported.

A review of asthma care guidelines in the United States

This article reviews the guidelines currently in use in the United States for anti-inflammatory and bronchodilator therapy for mild, moderate and severe asthma both intermittent and persistent.

Abnormal relaxin secretion during pregnancy in women with type 1 diabetes

To test the hypothesis that relaxin may play a role in the fetal abnormalities associated with pregnancy in type 1 diabetic women, we previously compared gestational relaxin concentrations in diabetic and clinically normal women using a porcine relaxin radioimmunoassay (RIA): Serum immunoactive relaxin was significantly (P < 0.001) elevated in the diabetic women. To confirm and extend this work in a larger group of subjects, we have now used an enzyme-linked immunosorbent assay (ELISA) specific for human H2 relaxin (the normal human gene product) to determine immunoactive serum relaxin concentrations in serial samples from 61 Type 1 diabetic and 21 normal pregnant women. Samples from 22 of the diabetic and nine of the normal women were also directly compared in the porcine relaxin RIA. ELISA-determined serum relaxin was higher (P < 0.001) at 24 and 36 weeks of pregnancy in type 1 diabetic women than in controls, confirming previous findings. However, the geometric mean increase in immunoactive relaxin concentration in identical samples from pregnant diabetic women over that of controls was significantly greater with the RIA than with the ELISA (271% vs 44%; P < 0.001). To investigate this discrepancy, the specificity and epitope selectivity of the RIA and the ELISA were compared using several synthetic polypeptides, including human relaxins H1 and H2, and relaxin and insulin derivatives. Both assays showed great specificity, but the porcine RIA selectively identified the epitopes of the receptor-binding domain of the relaxin B chain and cross-reacted strongly with H1 and H2 relaxins. In contrast, only the H2 peptide was detected by the ELISA antiserum. Therefore, the marked discrepancy between the RIA and the ELISA could be due to the presence in the diabetic samples of another relaxin-like molecule in addition to the normal H2 relaxin. The biological consequences of elevated serum relaxin in diabetic pregnancy remain to be elucidated.

Neuropsychological performance of monozygotic twins discordant for bipolar disorder

BACKGROUND

A paradigm that involves cognitive assessment of monozygotic (MZ) twins discordant for a neuropsychiatric disorder (here bipolar illness) allows for the examination of both disease-specific impairments (in the comparison of affected to unaffected twins) and risk factors (in the comparison of unaffected twins to normal twins).

METHODS

Neuropsychological functions were evaluated in seven MZ twin pairs discordant for bipolar illness and seven pairs of normal MZ twins in an attempt to highlight cognitive abilities associated with manifestations of disease and genetic risk factors. At the time of testing, 3 of the affected twins were euthymic, 2 had depressive symptoms, and 2 had manic symptoms; all were receiving medication. All twins receive neuropsychological tests to evaluate intelligence, attention, visuospatial skills, language, learning and memory, and problem solving.

RESULTS

Statistical analyses revealed that the affected twins were significantly impaired as compared to the unaffected (and normal) twins on some measures of visuospatial functioning and some verbal memory measures. In contrast to a sample of MZ twins discordant for schizophrenia studied previously, the cognitive impairments we observed in bipolar twins were mild in nature and fairly circumscribed. The unaffected twins performed significantly worse than normal controls on a Brown-Petersen memory task, verbal list learning, and overall Wechsler Memory Quotient.

CONCLUSIONS

These data suggest that while some visuospatial deficits and verbal memory deficits may be features of bipolar disorder related to disease parameters, mild attenuations in overall memory or retrieval function may be related to genetic factors associated with the illness.

Stressors and concerns in teen asthma

Adolescents are uniquely susceptible to poor outcome with asthma because of their desire for autonomy, denial of disease, preference for immediate gain rather than prophylaxis, restricted ability to control their psychosocial and physical environment, and difficult transition to health care. Tobacco smoking as well as related drug abuse and passive exposure to tobacco is a major obstacle to managing adolescent asthma, together with atopy and psychosocial problems. Recent investigations indicate that adolescents are uniquely susceptible to tobacco industry promotions and logos because of these developmental characteristics. By understanding adolescent development, behavior and peer group impact, with its spectrum from early to late adolescence, clinicians can target their educational interventions more successfully in asthma. Health care provision for the adolescent with asthma requires a multidisciplinary team spearheaded by a primary care provider with the expert guidance of an allergist, outreach nurse, mental health worker, and social service representative. This care must be negotiated with an appropriate educational plan on the basis of NHLBI guidelines to be successful. Medications should be prescribed no more than twice a day, whenever possible, in conjunction with an action plan on the basis of peak flow readings to warn the adolescent when to use more medication and when to call the clinician. The plan should empower adolescents by recognizing their need for autonomy with self-management, enabling them to have a safe and comfortable lifestyle, and being physically and mentally at ease with their peers, family, school, and work environments.

Effect of troglitazone on fibrinolysis and activated coagulation in patients with non-insulin-dependent diabetes mellitus

The objective of this study was to determine if treatment of non-insulin-dependent diabetes mellitus (NIDDM) patients with the "insulin sensitizer" troglitazone, both as monotherapy and in combination with insulin, corrects the impaired fibrinolysis and activated coagulation associated with NIDDM. Patients participating in two clinical trials comparing troglitazone and placebo in patients with NIDDM were studied at the time of randomization and after 26 weeks of treatment. Eighteen patients were treated with troglitazone (ten in combination with insulin and eight as monotherapy) and eight were treated with placebo (four in each trial). Plasma concentrations of plasminogen activator inhibitor (PAI-1), prothrombin fragment F1+2, fibrinogen, and von Willebrand Factor (vWF) activity were measured. Plasma PAI-1 concentrations fell significantly from a mean of 68.8 +/- 32.3 ng/mL to 40.4 +/- 20.4 in the troglitazone treated group, but did not change significantly in the placebo treated group. Plasma PAI-1 concentrations were elevated in 15 patients treated with troglitazone and fell to normal in eight of them. There was no significant change in plasma F1+2, vWF, and fibrinogen, but plasma C-peptide and triglyceride concentrations fell significantly with troglitazone. This study demonstrates that troglitazone treatment is associated with a significant fall in plasma PAI-1 antigen concentrations in patients with NIDDM and, therefore, may have a beneficial effect on fibrinolysis.

The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS): preliminary clinical validity

Neuropsychological assessment of older individuals with dementing illnesses has suffered from a lack of appropriately designed test instruments. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was developed for the dual purposes of identifying and characterizing abnormal cognitive decline in the older adult and as a neuropsychological screening battery for younger patients. The entire battery takes less than 30 minutes to administer, and yields scaled scores for five cognitive domains. The current study reports preliminary clinical validity results with the RBANS, comparing very mildly demented patients with a diagnosis of probable Alzheimer's disease (n = 20) to patients with Huntington's disease (n = 20) and normal controls (n = 40). Although the patient groups had essentially identical total scores on the RBANS, they exhibited opposite profiles, differing significantly on four of the five subsections. The AD patients performed most poorly on Language, and Delayed Memory subsections, while the HD patients obtained their lowest scaled scores on the Attention and the Visuospatial/Constructional subsections. These results are consistent with the neuropsychological profiles of these dementing disorders derived from lengthier standardized tests and experimental investigations. In addition, even those patients who performed above the suggested cut-off points on the MMSE and the Dementia Rating Scale scored significantly below their controls on the RBANS. These data suggest that the RBANS is effective at both detecting and characterizing dementia of different etiologies.

Standardized assessment of concussion (SAC): on-site mental status evaluation of the athlete

OBJECTIVE

This study investigated the clinical utility of the Standardized Assessment of Concussion (SAC) in detecting concussion in athletes.

METHOD

Athletic trainers administered the SAC to 568 nonconcussed high school and college football players prior to the 1995 and 1996 football seasons. Thirty-three of these players experienced concussion and were tested immediately following injury; 28 of the 33 underwent additional follow-up testing 48 hours after the injury.

RESULTS

Concussed players scored significantly below nonconcussed controls on all SAC measures and significantly below their own pre-injury baseline performance. Follow-up testing documented return to preinjury baseline.

CONCLUSION

These findings support the SAC's effectiveness in detecting concussion and tracking recovery in order to determine a player's fitness to return to play.

Pyrogenicity of etiocholanolone and interleukin-1 in New and Old World Monkeys

Etiocholanolone (5beta-androstan-3alpha-ol-17-one; designated E) is one of the major products of metabolism of testosterone and androstenedione (androst-4-ene-3,17-dione) in many mammalian species, including humans. E and several other 5beta-reduced steroids have been found to induce fever in humans. The pyrogenic effect of these steroids has been shown to be due to the release of interleukin-1 (IL-1) from the leukocytes that are mobilized in response to the steroid injections. Old World Monkeys such as Rhesus monkeys (Macaca mu/atta), metabolize androgens similarly to humans, and E is a normal metabolite. However, New World Monkeys such as Squirrel monkeys (Saimiri sciureus), lack hepatic 5alpha- and 5beta-steroid reductases and excrete androgens primarily in an unaltered state; E is not produced. Therefore, we postulate that Squirrel monkeys likewise may have lost the ability to respond to 17-ketosteroids such as E. To test this hypothesis, adult male Rhesus and Squirrel monkeys were treated with E, and their rectal temperatures were recorded over a 24-hr period. Rhesus monkeys exhibited a rise of up to 3 degrees F following E injection. Squirrel monkeys, on the other hand, did not exhibit any increase in rectal temperature over the 24-hr period, even when doses up to 250 times the effective human dose were used. However, both species responded to injected IL-1alpha with a robust increase in rectal temperature. The data show that E is pyrogenic in Rhesus, but not Squirrel monkeys. The findings support the notion that injected E may induce release of IL-1 in Rhesus monkeys, but not in Squirrel monkeys.

Regulatory sequences for the amplification and replication of the ribosomal DNA minichromosome in Tetrahymena thermophila

We have analyzed the cis-acting sequences that regulate rRNA gene (rDNA) replication in Tetrahymena thermophila. The macronucleus of this ciliated protozoan contains 9,000 copies of a 21-kbp minichromosome in the form of a palindrome comprising two copies of the rDNA. These are derived from a single chromosomally integrated copy during conjugation through selective amplification and are maintained by replicating once per cell cycle during vegetative growth. We have developed a transformation vector and carried out a deletion analysis to determine the minimal sequences required for replication, amplification, and/or stable maintenance of the rDNA molecule. Using constructs containing progressively longer deletions, we show that only a small portion (approximately 900 bp) of the rDNA is needed for extrachromosomal replication and stable maintenance of this molecule. This core region is very near but does not include the rRNA transcription initiation site or its putative promoter, indicating that replication is not dependent on normal rRNA transcription. It includes two nearly identical nuclease-sensitive domains (D1 and D2), one of which (D1) corresponds to the physical origin of replication determined previously. Deletion of both domains abolishes replication, whereas deletion of either domain allows the molecules to replicate, indicating that only one domain is required. In addition to this core region, we have found several DNA segments, including a tandem array of a 21-nucleotide repeat (type II repeats) and sequences within the rRNA coding region, that play distinctive and important roles in maintaining the rDNA at a high copy number.