Efficient choice of colored noise in the stochastic dynamics of open quantum systems

The stochastic Liouville-von Neumann (SLN) equation describes the dynamics of an open quantum system reduced density matrix coupled to a non-Markovian harmonic environment. The interaction with the environment is represented by complex colored noises which drive the system, and whose correlation functions are set by the properties of the environment. We present a number of schemes capable of generating colored noises of this kind that are built on a noise amplitude reduction procedure [Imai et al., Chem. Phys. 446, 134 (2015)CMPHC20301-010410.1016/j.chemphys.2014.11.014], including two analytically optimized schemes. In doing so, we pay close attention to the properties of the correlation functions in Fourier space, which we derive in full. For some schemes the method of Wiener filtering for deconvolutions leads to the realization that weakening causality in one of the noise correlation functions improves numerical convergence considerably, allowing us to introduce a well-controlled method for doing so. We compare the ability of these schemes, along with an alternative optimized scheme [Schmitz and Stockburger, Eur. Phys. J.: Spec. Top. 227, 1929 (2019)1951-635510.1140/epjst/e2018-800094-y], to reduce the growth in the mean and variance of the trace of the reduced density matrix, and their ability to extend the region in which the dynamics is stable and well converged for a range of temperatures. By numerically optimizing an additional noise scaling freedom, we identify the scheme which performs best for the parameters used, improving convergence by orders of magnitude and increasing the time accessible by simulation.

Pharmacological disinhibition enhances paced breathing following complete spinal cord injury in rats

Respiratory dysfunction is one of the most devastating and life-threatening deficits that occurs following cervical spinal cord injury (SCI). Assisted breathing with mechanical ventilators is a necessary part of care for many cervical injured individuals, but it is also associated with increased risk of secondary complications such as infection, muscle atrophy and maladaptive plasticity. Pre-clinical studies with epidural stimulation (EDS) have identified it as an alternative/additional method to support adequate lung ventilation without mechanical assistance. The full potential of EDS, however, may be limited by spinal inhibitory mechanisms within the injured spinal cord. The goal of the present work is to assess the potential improvement for EDS in combination with pharmacological disinhibition of spinal circuits following complete high cervical SCI. All experiments were performed in decerebrate, unanesthetized, non-paralyzed (n = 13) and paralyzed (n = 8) adult Sprague-Dawley rats 6 h following a complete C1 transection. The combination of high-frequency EDS (HF-EDS) at the C4 spinal segment with intrathecal delivery of GABA and glycine receptors antagonists (GABAzine and strychnine, respectively) resulted in significantly increased phrenic motor output, tidal volume and amplitude of diaphragm electrical activity compared to HF-EDS alone. Thus, it appears that spinal fast inhibitory mechanisms limit phrenic motor output and present a new neuropharmacological target to improve paced breathing in individuals with cervical SCI.

Treatment of hyperprolactinemia: a systematic review and meta-analysis

BACKGROUND

Hyperprolactinemia is a common endocrine disorder that can be associated with significant morbidity. We conducted a systematic review and meta-analyses of outcomes of hyperprolactinemic patients, including microadenomas and macroadenomas, to provide evidence-based recommendations for practitioners. Through this review, we aimed to compare efficacy and adverse effects of medications, surgery and radiotherapy in the treatment of hyperprolactinemia.

METHODS

We searched electronic databases, reviewed bibliographies of included articles, and contacted experts in the field. Eligible studies provided longitudinal follow-up of patients with hyperprolactinemia and evaluated outcomes of interest. We collected descriptive, quality and outcome data (tumor growth, visual field defects, infertility, sexual dysfunction, amenorrhea/oligomenorrhea and prolactin levels).

RESULTS

After review, 8 randomized and 178 nonrandomized studies (over 3,000 patients) met inclusion criteria. Compared to no treatment, dopamine agonists significantly reduced prolactin level (weighted mean difference, -45; 95% confidence interval, -77 to -11) and the likelihood of persistent hyperprolactinemia (relative risk, 0.90; 95% confidence interval, 0.81 to 0.99). Cabergoline was more effective than bromocriptine in reducing persistent hyperprolactinemia, amenorrhea/oligomenorrhea, and galactorrhea. A large body of noncomparative literature showed dopamine agonists improved other patient-important outcomes. Low-to-moderate quality evidence supports improved outcomes with surgery and radiotherapy compared to no treatment in patients who were resistant to or intolerant of dopamine agonists.

CONCLUSION

Our results provide evidence to support the use of dopamine agonists in reducing prolactin levels and persistent hyperprolactinemia, with cabergoline proving more efficacious than bromocriptine. Radiotherapy and surgery are useful in patients with resistance or intolerance to dopamine agonists.

Recovery of inspiratory intercostal muscle activity following high cervical hemisection

Anatomical and neurophysiological evidence indicates that thoracic interneurons can serve a commissural function and activate contralateral motoneurons. Accordingly, we hypothesized that respiratory-related intercostal (IC) muscle electromyogram (EMG) activity would be only modestly impaired by a unilateral cervical spinal cord injury. Inspiratory tidal volume (VT) was recorded using pneumotachography and EMG activity was recorded bilaterally from the 1st to 2nd intercostal space in anesthetized, spontaneously breathing rats. Studies were conducted at 1-3 days, 2 wks or 8 wks following C2 spinal cord hemisection (C2HS). Data were collected during baseline breathing and a brief respiratory challenge (7% CO(2)). A substantial reduction in inspiratory intercostal EMG bursting ipsilateral to the lesion was observed at 1-3 days post-C2HS. However, a time-dependent return of activity occurred such that by 2 wks post-injury inspiratory intercostal EMG bursts ipsilateral to the lesion were similar to age-matched, uninjured controls. The increases in ipsilateral intercostal EMG activity occurred in parallel with increases in VT following the injury (R=0.55; P<0.001). We conclude that plasticity occurring within a "crossed-intercostal" circuitry enables a robust, spontaneous recovery of ipsilateral intercostal activity following C2HS in rats.

Clinical review. Risk factors for low bone mass-related fractures in men: a systematic review and meta-analysis

CONTEXT

Testing men at increased risk for osteoporotic fractures has been recommended.

OBJECTIVE

The aim of this study was to estimate the magnitude of association and quality of supporting evidence linking multiple risk factors with low bone mass-related fractures in men.

DATA SOURCES

We searched MEDLINE, EMBASE, Web of Science, SCOPUS and Cochrane CENTRAL through February 2010. We identified further studies by reviewing reference lists from selected studies and reviews.

STUDY SELECTION

Eligible studies had to enroll men and quantitatively evaluate the association of risk factors with low bone density-related fractures.

DATA EXTRACTION

Reviewers working independently and in duplicate determined study eligibility and extracted study description, quality, and outcome data.

DATA SYNTHESIS

Fifty-five studies provided data sufficient for meta-analysis. The quality of these observational studies was moderate with fair levels of multivariable adjustment and adequate exposure and outcome ascertainment. Statistically significant associations were established for age, low body mass index, current smoking, excessive alcohol use, chronic corticosteroid use, history of prior fractures, history of falls, history of hypogonadism, history of stroke, and history of diabetes. Statistical heterogeneity of the meta-analytic estimates of all associations was significant except for chronic corticosteroid use. None of these associations were of large magnitude (i.e. adjusted odds ratios were generally <2). No evidence supporting a particular effective testing or screening strategy was identified.

CONCLUSIONS

Multiple risk factors for fractures in men were identified, but their usefulness for stratifying and selecting men for bone density testing remains uncertain.

Clinical review. Comparative effectiveness of drug treatments to prevent fragility fractures: a systematic review and network meta-analysis

CONTEXT

Osteoporosis and osteopenia are associated with increased fracture incidence.

OBJECTIVE

The aim of this study was to determine the comparative effectiveness of different pharmacological agents in reducing the risk of fragility fractures.

DATA SOURCES

We searched multiple databases through 12/9/2011.

STUDY SELECTION

Eligible studies were randomized controlled trials enrolling individuals at risk of developing fragility fractures and evaluating the efficacy of bisphosphonates, teriparatide, selective estrogen receptor modulators, denosumab, or calcium and vitamin D.

DATA EXTRACTION

Reviewers working independently and in duplicate determined study eligibility and collected descriptive, methodological quality, and outcome data.

DATA SYNTHESIS

This network meta-analysis included 116 trials (139,647 patients; median age, 64 yr; 86% females and 88% Caucasians; median follow-up, 24 months). Trials were at low to moderate risk of bias. Teriparatide had the highest risk reduction of fractures (odds ratios, 0.42, 0.30, and 0.50 for hip, vertebral, and nonvertebral fractures, respectively) and the highest probability of being ranked first for efficacy (probabilities of 42, 49, and 79% for hip, vertebral, and nonvertebral fractures, respectively). However, differences to denosumab, zoledronate, risedronate, ibandronate, and alendronate were not statistically significant. Raloxifene and bazedoxifene were likely less effective, although these data were limited. Calcium and vitamin D were ineffective given separately but reduced the risk of hip fractures if given in combination (odds ratio, 0.81; 95% confidence interval, 0.68–0.96).

CONCLUSIONS

Teriparatide, bisphosphonates, and denosumab are most effective in reducing the risk of fragility fractures. Differences in efficacy across drugs are small; therefore, patients and clinicians need to consider their associated harms and costs.

The association of hypertriglyceridemia with cardiovascular events and pancreatitis: a systematic review and meta-analysis

BACKGROUND

Hypertriglyceridemia may be associated with important complications. The aim of this study is to estimate the magnitude of association and quality of supporting evidence linking hypertriglyceridemia to cardiovascular events and pancreatitis.

METHODS

We conducted a systematic review of multiple electronic bibliographic databases and subsequent meta-analysis using a random effects model. Studies eligible for this review followed patients longitudinally and evaluated quantitatively the association of fasting hypertriglyceridemia with the outcomes of interest. Reviewers working independently and in duplicate reviewed studies and extracted data.

RESULTS

35 studies provided data sufficient for meta-analysis. The quality of these observational studies was moderate to low with fair level of multivariable adjustments and adequate exposure and outcome ascertainment. Fasting hypertriglyceridemia was significantly associated with cardiovascular death (odds ratios (OR) 1.80; 95% confidence interval (CI) 1.31-2.49), cardiovascular events (OR, 1.37; 95% CI, 1.23-1.53), myocardial infarction (OR, 1.31; 95% CI, 1.15-1.49), and pancreatitis (OR, 3.96; 95% CI, 1.27-12.34, in one study only). The association with all-cause mortality was not statistically significant.

CONCLUSIONS

The current evidence suggests that fasting hypertriglyceridemia is associated with increased risk of cardiovascular death, MI, cardiovascular events, and possibly acute pancreatitis.Précis: hypertriglyceridemia is associated with increased risk of cardiovascular death, MI, cardiovascular events, and possibly acute pancreatitis.

Glycemic control in non-critically ill hospitalized patients: a systematic review and meta-analysis

BACKGROUND

The effect of intensive therapy to achieve tight glycemic control in patients hospitalized in non-critical care settings is unclear.

METHODS

We conducted a systematic review and meta-analysis to determine the effect of intensive glycemic control strategies on the outcomes of death, stroke, myocardial infarction, incidence of infection, and hypoglycemia. We included randomized and observational studies. Bibliographic databases were searched through February 2010. Random effects model was used to pool results across studies.

RESULTS

Nineteen studies (nine randomized and 10 observational studies) were included. The risk of bias across studies was moderate. Meta-analysis demonstrates that intensive glycemic control was not associated with significant effect on the risk of death, myocardial infarction, or stroke. There was a trend for increased risk of hypoglycemia (relative risk, 1.58; 95% confidence interval, 0.97-2.57), particularly in surgical studies and when the planned glycemic target was achieved. Intensive glycemic control was associated with decreased risk of infection (relative risk, 0.41; 95% confidence interval, 0.21-0.77) that was mainly derived from studies in surgical settings.

CONCLUSION

Intensive control of hyperglycemia in patients hospitalized in non-critical care settings may reduce the risk of infection. The quality of evidence is low and mainly driven by studies in surgical settings.

Clinical review: The effect of vitamin D on falls: a systematic review and meta-analysis

CONTEXT

Vitamin D affects bone and muscle health and likely reduces the risk of falls in the elderly.

OBJECTIVE

The aim of this systematic review is to summarize the existing evidence on vitamin D use and the risk of falls.

DATA SOURCES

We searched electronic databases from inception through August 2010.

STUDY SELECTION

Eligible studies were randomized controlled trials in which the intervention was vitamin D and the incidence of falls was reported.

DATA EXTRACTION

Reviewers working in duplicate and independently extracted study characteristics, quality, and outcomes data.

DATA SYNTHESIS

Odds ratio and associated 95% confidence interval were estimated from each study and pooled using the random effects model.

RESULTS

We found 26 eligible trials of moderate quality that enrolled 45,782 participants, the majority of which were elderly and female. Vitamin D use was associated with statistically significant reduction in the risk of falls (odds ratio for suffering at least one fall, 0.86; 95% confidence interval, 0.77-0.96). This effect was more prominent in patients who were vitamin D deficient at baseline and in studies in which calcium was coadministered with vitamin D. The quality of evidence was low to moderate because of heterogeneity and publication bias.

CONCLUSIONS

Vitamin D combined with calcium reduces the risk of falls. The reduction in studies without calcium coadministration did not reach statistical significance. The majority of the evidence is derived from trials enrolling elderly women.

Vitamin D and cardiovascular outcomes: a systematic review and meta-analysis

CONTEXT

Several studies found association between vitamin D levels and hypertension, coronary artery calcification, and heart disease.

OBJECTIVE

The aim of this study was to summarize the evidence on the effect of vitamin D on cardiovascular outcomes.

DESIGN AND METHODS

We searched electronic databases from inception through August 2010 for randomized trials. Reviewers working in duplicate and independently extracted study characteristics, quality, and the outcomes of interest. Random-effects meta-analysis was used to pool the relative risks (RR) and the weighted mean differences across trials.

RESULTS

We found 51 eligible trials with moderate quality. Vitamin D was associated with nonsignificant effects on the patient-important outcomes of death [RR, 0.96; 95% confidence interval (CI), 0.93, 1.00; P = 0.08], myocardial infarction (RR, 1.02; 95% CI, 0.93, 1.13; P = 0.64), and stroke (RR, 1.05; 95% CI, 0.88, 1.25; P = 0.59). These analyses were associated with minimal heterogeneity. There were no significant changes in the surrogate outcomes of lipid fractions, glucose, or diastolic or systolic blood pressure. The latter analyses were associated with significant heterogeneity, and the pooled estimates were trivial in absolute terms.

CONCLUSIONS

Trial data available to date are unable to demonstrate a statistically significant reduction in mortality and cardiovascular risk associated with vitamin D. The quality of the available evidence is low to moderate at best.

Factors influencing cancer risk perception in high risk populations: a systematic review

Background

Patients at higher than average risk of heritable cancer may process risk information differently than the general population. However, little is known about clinical, demographic, or psychosocial predictors that may impact risk perception in these groups. The objective of this study was to characterize factors associated with perceived risk of developing cancer in groups at high risk for cancer based on genetics or family history.

Methods

We searched Ovid MEDLINE, Ovid Embase, Ovid PsycInfo, and Scopus from inception through April 2009 for English-language, original investigations in humans using core concepts of "risk" and "cancer." We abstracted key information and then further restricted articles dealing with perceived risk of developing cancer due to inherited risk.

Results

Of 1028 titles identified, 53 articles met our criteria. Most (92%) used an observational design and focused on women (70%) with a family history of or contemplating genetic testing for breast cancer. Of the 53 studies, 36 focused on patients who had not had genetic testing for cancer risk, 17 included studies of patients who had undergone genetic testing for cancer risk. Family history of cancer, previous prophylactic tests and treatments, and younger age were associated with cancer risk perception. In addition, beliefs about the preventability and severity of cancer, personality factors such as "monitoring" personality, the ability to process numerical information, as well as distress/worry also were associated with cancer risk perception. Few studies addressed non-breast cancer or risk perception in specific demographic groups (e.g. elderly or minority groups) and few employed theory-driven analytic strategies to decipher interrelationships of factors.

Conclusions

Several factors influence cancer risk perception in patients at elevated risk for cancer. The science of characterizing and improving risk perception in cancer for high risk groups, although evolving, is still relatively undeveloped in several key topic areas including cancers other than breast and in specific populations. Future rigorous risk perception research using experimental designs and focused on cancers other than breast would advance the field.

High-risk antimicrobial prescriptions among ambulatory patients on warfarin

WHAT IS KNOWN AND OBJECTIVE

Warfarin is a potent anticoagulant with many drug-drug interactions, including antimicrobials. There is limited data on the frequency of prescription of high-risk antimicrobials to patients on warfarin. To examine the frequency of prescriptions for potentially interacting antimicrobials in ambulatory patients on warfarin and the impact of warfarin on the prescription of high-risk antimicrobials.

METHODS

A retrospective cohort study of patients with pharmacy benefits who had ≥1 claim for an oral antimicrobial between 1 January 2008 and 31 December 2008 was conducted, utilizing a pharmacy benefits database. Demographic data including age, gender, chronic disease score (CDS) and geographic location were determined. Warfarin users were defined as any patient with ≥1 claim for warfarin during the follow-up period. Antimicrobials considered high risk for potential interaction with warfarin based on existing literature included trimethoprim/sulfamethoxazole, levofloxacin, ciprofloxacin, metronidazole and fluconazole. Multivariate analysis was used to determine the impact of warfarin use and other factors on high-risk antimicrobial prescription.

RESULTS AND DISCUSSION

A total of 4,568,150 patients with ≥1 claim for antimicrobials during 2008 were analysed. Of them, 110,192 (2·4%) also had one or more claims for warfarin. Among all antimicrobial prescriptions in warfarin users, 42·6% were for high-risk antimicrobials. The mean number of antimicrobial prescriptions was 3·0 in warfarin users versus 2·4 in warfarin non-users (P-value <0·001). After adjusting for age, gender, CDS and geography, the odds of exposure to high-risk antimicrobials was 42% lower (OR 0·58; P-value <0·001) in warfarin users compared with warfarin non-users.

WHAT IS NEW AND CONCLUSIONS

A high percentage (42·6%) of antimicrobial prescriptions among warfarin users were for high-risk antimicrobials that carry excess bleeding risk. Although clinicians were somewhat less likely to prescribe high-risk antimicrobials to warfarin users compared with non-users, the incidence of co-prescription remains high.

Natural history of nonfunctioning pituitary adenomas and incidentalomas: a systematic review and metaanalysis

CONTEXT

The natural history of pituitary incidentalomas (PIs) and nonfunctioning pituitary adenomas (NFPAs) remains poorly understood.

OBJECTIVE

The objective of the study was to synthesize the literature on the prognostic factors involved in the progression of PIs and NFPAs in patients followed up conservatively.

DATA SOURCES

We searched MEDLINE, EMBASE, and Cochrane CENTRAL. We sought to identify further studies by reviewing the reference lists from selected studies and reviews and by querying experts.

STUDY SELECTION

Eligible studies were longitudinal observational cohort studies that enrolled patients with PIs/NFPAs and followed them up without any treatment from the time of detection and reported on mortality, lesion progression, and development of pituitary hormonal deficiency, apoplexy, or visual field defects.

DATA EXTRACTION

Reviewers working independently and in duplicate determined studies' eligibility and collected descriptive, methodological quality, and outcome data. Event rates per 100 person-years (PYs) and associated 95% confidence intervals (CIs) were estimated from each study and pooled using the random-effects model.

DATA SYNTHESIS

The 11 included studies had noncomparative single-cohort design. Follow-up duration ranged from 3 to 15 yr. There was a greater tendency for tumor growth in macroadenomas (12.5 per 100 PYs; 95% CI 7.9, 17.2) and in solid lesions (5.7 per 100 PYs; 95% CI 2.3, 9.2) in comparison with microadenomas (3.3 per 100 PYs; 95% CI 2.1, 4.5) and cystic lesions (0.05 per 100 PYs; 95% CI 0.0, 0.2). The development of pituitary apoplexy and worsening of visual field defects were rare. The overall incidence of new endocrine dysfunction was 2.4 per 100 PYs; 95% CI 0.0, 6.4. The majority of these analyses were associated with significant heterogeneity. There was a trend that did not reach statistical significance for greater incidence of pituitary apoplexy and new endocrine dysfunction worsening in macroadenomas compared with microadenomas. The quality of the evidence (risk of bias) was very low due to heterogeneity, methodological limitations, and imprecision caused by the small number of events.

CONCLUSIONS

Despite the relatively high prevalence of PIs/NFPAs, the evidence on the natural history of these entities is scarce and of low quality. PIs/NFPAs seem to have fairly rare complications that may be more common when lesions are large (>10 mm) and solid.

Outcomes of surgical treatment for nonfunctioning pituitary adenomas: a systematic review and meta-analysis

BACKGROUND

Surgery is commonly used in the management of pituitary nonfunctioning adenomas (NFPA). The goal of this systematic review and meta-analysis is to evaluate the effect of surgery on mortality, surgical complications, pituitary function and vision.

METHODS

We searched MEDLINE, EMBASE and Cochrane CENTRAL, queried experts and reviewed the reference list of included publications. Eligible studies were comparative and noncomparative longitudinal studies that enroled patients with NFPA who underwent surgery (alone or in combination with other therapies). Reviewers, working independently and in duplicate, determined study eligibility with adequate reproducibility and extracted descriptive, quality and outcome data. Risks, relative risks (RR) and 95% confidence intervals (CIs) were estimated from each study and pooled using random-effects meta-analysis.

RESULTS

Most included studies were uncontrolled case series in which patients received a combination of surgery and radiotherapy. The overall quality of the evidence was very low. Median follow-up was 4·29 years. When surgery was not combined with radiotherapy, there was an increased risk of tumour recurrence (RR 1·97; 95% CI, 1·15-3·35). Complications were more likely with the transcranial than with the transsphenoidal approach (mortality RR 4·89; 95% CI, 3·15-6·47; new anterior pituitary deficits RR 4·90; 95% CI, 2·94-7·82; and persistent diabetes insipidus RR 2·50; 95% CI, 1·05-5·35). Overall, transsphenoidal surgery had fairly low perioperative mortality (≤ 1%) and low complication rate (≤ 5% for all patient-important outcomes), but only less than a third of the patients had improvement in pituitary function.

CONCLUSIONS

Observational evidence supports the association between a combined approach of transsphenoidal surgery with radiotherapy and improvements in visual field defects and reduction in tumour recurrence.

Prenatal dexamethasone use for the prevention of virilization in pregnancies at risk for classical congenital adrenal hyperplasia because of 21-hydroxylase (CYP21A2) deficiency: a systematic review and meta-analyses

CONTEXT

Prenatal treatment with dexamethasone to prevent virilization in pregnancies at risk for classical congenital adrenal hyperplasia (CAH) remains controversial.

OBJECTIVE

To conduct a systematic review and meta-analyses of studies that evaluated the effects of dexamethasone administration during pregnancies at risk for classical CAH because of 21-hydroxylase deficiency (CYP21A2).

DATA SOURCES

We searched MEDLINE, EMBASE, and Cochrane CENTRAL from inception through August 2009. Review of reference lists and contact with CAH experts further identified candidate studies.

STUDY SELECTION

Reviewers working independently and in duplicate determined trial eligibility. Eligible studies reported the effects on either foetal or maternal outcomes of dexamethasone administered during pregnancy compared to a control group that did not receive any treatment.

DATA EXTRACTION

Reviewers working independently and in duplicate determined the methodological quality of studies and collected data on patient characteristics, interventions, and outcomes.

DATA SYNTHESIS

We identified only four eligible observational studies (325 pregnancies treated with dexamethasone). The methodological quality of the included studies was overall low. Meta-analysis demonstrates a reduction in foetus virilization measured by Prader score in female foetuses treated with dexamethasone initiated early during pregnancy (weighted mean difference, -2.33, 95% CI, -3.38, -1.27). No deleterious effects of dexamethasone on stillbirths, spontaneous abortions, foetal malformations, neuropsychological or developmental outcomes were found although these data are quite sparse. There was increased oedema and striae in the mothers treated with dexamethasone. There were no data on long-term follow-up of physical and metabolic outcomes in children exposed to dexamethasone.

CONCLUSIONS

The observational nature of the available evidence and the overall small sample size of the whole body of the literature significantly weaken inferences about the benefits and harms of dexamethasone in this setting. Dexamethasone seems to be associated with reduction in foetus virilization without significant maternal or foetal adverse effects. However, this review underscores the current uncertainty and further investigation is clearly needed. The decision about initiating treatment should be based on patients' values and preferences and requires fully informed and consenting parents.

The phrenic motor nucleus in the adult mouse

The present study was performed to establish an anatomical context for studies of phrenic motor function in mouse models of central nervous system trauma and disease. Application of cholera toxin β-subunit to the diaphragm of adult C57BL/6 mice revealed a columnar organization of phrenic motoneurons (PhMNs) which extended from rostral C3 to C6. Injection of Miniruby into the ventrolateral medulla revealed decussating, anterogradely labeled axons in the cervical spinal cord. In addition, application of the transneuronal tracer pseudorabies virus (PRV) to the right hemidiaphragm demonstrated a population of putative pre-phrenic interneurons at the level of the infected PhMN pool. These neuroanatomical features of the mouse phrenic nucleus are consistent with those described in other species and provide a foundation for studies of neuroplasticity and repair in relation to a functionally and anatomically identified spinal network.

Clinical review: Adult height in patients with congenital adrenal hyperplasia: a systematic review and metaanalysis

CONTEXT

Treatment for patients with congenital adrenal hyperplasia (CAH) may affect the final height of these patients.

OBJECTIVE

Our objective was to determine the distribution of achieved height in patients with classic CAH diagnosed at infancy or early childhood and treated with glucocorticoids.

DATA SOURCES

We searched MEDLINE, EMBASE, Cochrane Library, ISI Web of Science, and Scopus through September 2008; the reference sections of included studies; and expert files.

STUDY SELECTION

Eligible studies included patients diagnosed with CAH before age 5 and followed to final height.

DATA EXTRACTION

Reviewers working in duplicate independently extracted data on study characteristics and outcomes and determined each study's risk of bias.

DATA SYNTHESIS

The sd score (SDS) for final height and corrected height (defined as final height SDS - midparental height SDS) were estimated from each study and pooled using random-effects metaanalysis. The I(2) statistic was used to assess inconsistency in results across studies.

RESULTS

We found 35 eligible studies, most of which were retrospective single-cohort studies. The final height SDS achieved by CAH patients was -1.38 (-1.56 to -1.20; I(2) = 90.2%), and the corrected height SDS was -1.03 (-1.20 to -0.86; I(2) = 63.1%). This was not significantly associated with age at diagnosis, gender, type and dose of steroid, and age of onset of puberty. Mineralocorticoid users had a better height outcome in comparison with the nonusers (P = 0.02).

CONCLUSION

Evidence derived from observational studies suggests that the final height of CAH patients treated with glucocorticoids is lower than the population norm and is lower than expected given parental height.

Flower petal microtexture is a tactile cue for bees

Honeybees are shown to be able to detect, learn, and discriminate between microsculptured epidermes of flower petals. The sensilla trichodea at the tips of the bees' antennae are in the same size range as the microsculptural features of the petals (ca. 10 mum), which presumably deflect these mechanoreceptive sensilla in characteristic ways. Honeybees were trained to associate reward with one floral texture and to choose that over another. Further, the bees also recognized differences in textures at different ends of petals of the same species. The phenomenon is significant in that it suggests another way in which insect pollinators can discriminate between the flowers of different plant species and so act as species isolators. Also, the microsculptural patterns differ from one end of a petal to the other and, therefore, can be used as nectar-guides by foraging bees. This study presents a previously unreported conditioned response to texture by insects and shows the functional significance of a floral character used in plant taxonomy.

Graded unilateral cervical spinal cord injury and respiratory motor recovery

We examined the potential contribution of ventromedial (VM) tissue sparing to respiratory recovery following chronic (1 mo) unilateral C2 spinal cord injury (SCI) in rats. Preserved white matter ipsilateral to the injury was quantitatively expressed relative to contralateral white matter. The ipsilateral-to-contralateral white matter ratio was 0 after complete C2 hemisection (C2HS) and 0.23+/-0.04 with minimal VM sparing. Inspiratory (breath min(-1)) and phrenic frequency (burst min(-1)), measured by plethysmography (conscious rats) and phrenic neurograms (anesthetized rats) respectively, were both lower with minimal VM sparing (p<0.05 vs. C2HS). Tidal volume also was greater in minimal VM sparing rats during a hypercapnic challenge (p<0.05 vs. C2HS). In other C2 hemilesioned rats with more extensive VM matter sparing (ipsilateral-to-contralateral white matter ratio=0.55+/-0.05), respiratory deficits were indicated at 1 mo post-injury by reduced ventilation during hypercapnic challenge (p<0.05 vs. uninjured). Anterograde (ventral respiratory column-to-spinal cord) neuroanatomical tracing studies showed that descending respiratory projections from the brainstem are present in VM tissue. We conclude that even relatively minimal sparing of VM tissue after C2 hemilesion can alter respiratory outcomes. In addition, respiratory deficits can emerge in the adult rat after high cervical SCI even when relatively extensive VM sparing occurs.

Age-related differences in the local cellular and molecular responses to injury in developing spinal cord of the opossum, Monodelphis domestica

Immature spinal cord, unlike adult, has an ability to repair itself following injury. Evidence for regeneration, structural repair and development of substantially normal locomotor behaviour comes from studies of marsupials due to their immaturity at birth. We have compared morphological, cellular and molecular changes in spinal cords transected at postnatal day (P)7 or P14, from 3 h to 2 weeks post-injury, in South American opossums (Monodelphis domestica). A bridge between severed ends of cords was apparent 5 days post-injury in P7 cords, compared to 2 weeks in P14. The volume of neurofilament (axonal) material in the bridge 2 weeks after injury was 30% of control in P7- but < 10% in P14-injured cords. Granulocytes accumulated at the site of injury earlier (3 h) in P7 than in P14 (24 h)-injured animals. Monocytes accumulated 24 h post-injury and accumulation was greater in P14 cords. Accumulation of GFAP-positive astrocytes at the lesion occurred earlier in P14-injured cords. Neurites and growth cones were identified ultrastructurally in contact with astrocytes forming the bridge. Results using mouse inflammatory gene arrays showed differences in levels of expression of many TGF, TNF, cytokine, chemokine and interleukin gene families. Most of the genes identified were up-regulated to a greater extent following injury at P7. Some changes were validated and quantified by RT-PCR. Overall, the results suggest that at least some of the greater ability to recover from spinal cord transection at P7 compared to P14 in opossums is due to differences in inflammatory cellular and molecular responses.

Changes in blood-brain barrier permeability to large and small molecules following traumatic brain injury in mice

The entry of therapeutic compounds into the brain and spinal cord is normally restricted by barrier mechanisms in cerebral blood vessels (blood-brain barrier) and choroid plexuses (blood-CSF barrier). In the injured brain, ruptured cerebral blood vessels circumvent these barrier mechanisms by allowing blood contents to escape directly into the brain parenchyma. This process may contribute to the secondary damage that follows the initial primary injury. However, this localized compromise of barrier function in the injured brain may also provide a 'window of opportunity' through which drugs that do not normally cross the blood-brain barriers are able to do so. This paper describes a systematic study of barrier permeability in a mouse model of traumatic brain injury using both small and large inert molecules that can be visualized or quantified. The results show that soon after trauma, both large and small molecules are able to enter the brain in and around the injury site. Barrier restriction to large (protein-sized) molecules is restored by 4-5 h after injury. In contrast, smaller molecules (286-10,000 Da) are still able to enter the brain as long as 4 days postinjury. Thus the period of potential secondary damage from barrier disruption and the period during which therapeutic compounds have direct access to the injured brain may be longer than previously thought.

Breakdown of the blood-brain barrier to proteins in white matter of the developing brain following systemic inflammation

Compromised blood-brain barrier permeability resulting from systemic inflammation has been implicated as a possible cause of brain damage in fetuses and newborns and may underlie white matter damage later in life. Rats at postnatal day (P) 0, P8 and P20 and opossums (Monodelphis domestica) at P15, P20, P35, P50 and P60 and adults of both species were injected intraperitoneally with 0.2-10 mg/kg body weight of 055:B5 lipopolysaccharide. An acute-phase response occurred in all animals. A change in the permeability of the blood-brain barrier to plasma proteins during a restricted period of postnatal development in both species was determined immunocytochemically by the presence of proteins surrounding cerebral blood vessels and in brain parenchyma. Blood vessels in white matter, but not grey matter, became transiently permeable to proteins between 10 and 24 h after lipopolysaccharide injection in P0 and P8 rats and P35-P60 opossums. Brains of Monodelphis younger than P35, rats older than P20 and adults of both species were not affected. Permeability of the blood-cerebrospinal fluid (CSF) barrier to proteins was not affected by systemic inflammation for at least 48 h after intraperitoneal injection of lipopolysaccharide. These results show that there is a restricted period in brain development when the blood-brain barrier, but not the blood-CSF barrier, to proteins is susceptible to systemic inflammation; this does not appear to be attributable to barrier "immaturity" but to its stage of development and only occurs in white matter.

Effect of caloric restriction on the 24-hour plasma DHEAS and cortisol profiles of young and old male rhesus macaques

Although dietary caloric restriction (CR) can retard aging in laboratory rats and mice, it is unclear whether CR can exert similar effects in long-lived species, such as primates. Therefore, we tested the effect of CR on plasma levels of dehydroepiandrosterone sulfate (DHEAS), a reliable endocrine marker of aging. The study included six young (approximately 10 years) and ten old (approximately 25 years) male rhesus macaques, approximately half of the animals in each age group having undergone >4 years of 30% CR. Hourly blood samples were collected remotely for 24 hours, through a vascular catheter, and assayed for DHEAS and cortisol. Both of these adrenal steroids showed a pronounced diurnal plasma pattern, with peaks occurring in late morning, but only DHEAS showed an aging-related decline. More importantly, there was no significant difference in plasma DHEAS concentrations between the CR animals and age-matched controls. These data fail to support the hypothesis that CR can attenuate the aging-related decline in plasma DHEAS concentrations, at least not when initiated after puberty.

Calorie restriction attenuates age-related alterations in the plasma membrane antioxidant system in rat liver

Aging is associated with increased production of reactive oxygen species and oxidation-induced damage to intracellular structures and membranes. Caloric restriction (CR) is the only non-genetic method proven to extend lifespan in mammals. Although the mechanisms of CR remain to be clearly elucidated, reductions in oxidative stress have been shown to increase lifespan in several model systems. Oxidative stress can be attenuated by CR. Mitochondria and plasma membrane (PM) are normal sources of free radicals. The PM has a trans-membrane redox system that provides electrons to recycle lipophilic antioxidants, such as alpha-tocopherol and coenzyme Q (CoQ). The idea developed in this study is that the PM is intimately involved in cellular physiology controlling the relationship of the cell to its environment. PM is the key for protecting cellular integrity during aging. Specifically, we have investigated age-related alterations and the effects of CR in the trans-PM redox (antioxidant) system in rat liver. We found that age-related declines in the ratio of CoQ(10)/CoQ(9) and alpha-tocopherol in liver PM were attenuated by CR compared to those fed ad libitum (AL). CoQ-dependent NAD(P)H dehydrogenases were increased in CR old rat liver PMs. As a consequence, the liver PM of CR old rats was more resistant to oxidative stress-induced lipid peroxidation than AL rats. Thus, our results suggest that CR induces a higher capacity to oxidize NAD(P)H in the PM of old rat livers and as a result, a higher resistance to oxidative stress-induced damage.

Changes in blood chemistry and hematology variables during aging in captive rhesus macaques (Macaca mulatta). J Med Primatol 30:161-173, 2001

The Primate Aging Database (PAD) is being developed to assist research using nonhuman primate models for various gerontological applications. We provide now an update of an earlier report providing data on hematological and blood chemistry values for rhesus monkeys across the adult lifespan. These data were collected from several research colonies and have been submitted to rigorous statistical analyses to identify relationships with chronological age.

Effects of dietary caloric restriction and aging on thyroid hormones of rhesus monkeys

Plasma levels of thyroid hormones - triiodothyronine (T 3 ), thyroxin (T 4 ), and thyroid-stimulating hormone (TSH) were measured in male and female rhesus monkeys (Macaca mulatta) fed either ad libitum or a 30 % calorie-restricted (CR) diet (males for 11 years; females for 6 years). The same hormones were measured in another group of young male rhesus monkeys during adaptation to the 30 % CR regimen. Both long- and shorter-term CR diet lowered total T 3 in plasma of the monkeys. The effect appeared to be greater in younger monkeys than in older counterparts. No effects of CR diet were detected for either free or total T 4, although unlike T 3, levels of this hormone decreased with age. TSH levels also decreased with age, and were increased by long-term CR diet in older monkeys only. No consistent effects of shorter-term CR diet were observed for TSH. In the light of the effects of the thyroid axis on overall metabolism, these results suggest a possible mechanism by which CR diets may elicit their well-known beneficial 'anti-aging' effects in mammals.

Developmental changes in ketogenic enzyme gene expression during sheep rumen development

Ketogenesis is the conversion of acetyl-CoA to the ketone bodies acetoacetate and beta-hydroxybutyrate (BHBA). In hepatic ketogenesis, which occurs during fasting in both nonruminant and ruminant animals, the source of acetyl-CoA is the mitochondrial oxidation of predominantly long-chain fatty acids. In the mature, fed ruminant animal, the ruminal epithelium is also capable of producing ketone bodies. In this case, the source of acetyl-CoA is the mitochondrial oxidation of butyrate produced by the microbial fermentation of feed. The purposes of this study were to determine ontogenic and dietary effects on ketogenic enzyme gene expression in developing lamb ruminal epithelium. Twenty-seven conventionally reared lambs and twenty-seven milk-fed lambs were slaughtered between 1 and 84 d of age. Six additional milk-fed lambs were weaned (the fed group) or maintained on milk replacer with a volatile fatty acid gavage (the VFA group) until 84 d of age. At slaughter, total RNA was extracted from samples of ruminal epithelium. The expression of the genes encoding acetoacetyl-CoA thiolase, the first enzyme in the ketogenic pathway, and 3-hydroxy-3-methylglutaryl-CoA synthase, the rate-limiting enzyme in the ketogenic pathway in nonruminant liver, were examined. Acetoacetyl-CoA thiolase and 3-hydroxy-3-methylglutaryl-CoA synthase mRNA concentrations increased with age independent of diet. 3-Hydroxy-3-methylglutaryl-CoA synthase mRNA levels in ruminal epithelium obtained from milk-fed lambs were low before 42 d of age, but a marked increase occurred by 42 d of age. At 84 d of age, there were no differences in acetoacetyl-CoA thiolase and 3-hydroxy-3-methylglutaryl-CoA synthase expression due to diet. The pattern of the expression of these genes, in particular, 3-hydroxy-3-methylglutaryl-CoA synthase, parallels the rate of production of BHBA by rumen epithelial cells isolated from the same lambs, which increased to conventionally reared adult levels at 42 d of age and did not differ with diet. In conclusion, development of the ketogenic capacity of the ruminal epithelium occurs as the animal ages, regardless of dietary treatment. Thus, the expression of the genes encoding the ketogenic enzymes are not affected by the presence of VFA in the ruminal lumen.

Nonhuman primate models of skeletal and reproductive aging

BACKGROUND

Bone loss, osteoarthritis (OA) and age-related changes in reproduction are some of the most apparent and troubling results of advancing age in the human population. The significance of these changes underscores the need for developing appropriate animal models to study aging of bone and the reproductive system.

OBJECTIVE

This review surveys the literature regarding the current state of nonhuman primates (NHP) as models for skeletal and reproductive aging in humans.

RESULTS

Several species of NHP exhibit age-related bone loss as well as changes in the mineral content and architecture of bone that are similar to those reported in humans. In addition, since aged females of some species of NHP exhibit cessation of menses and serum hormone profiles consistent with those described in peri- and premenopausal women, they provide useful models of postmenopausal bone loss. Sensitivity to surgical estrogen depletion and hormone replacement has also been demonstrated in female NHP. Spontaneous development of degenerative arthritis, analogous to humans in age at onset, joint involvement and histologic changes, suggest that NHP are suitable for the study of human OA. Many similarities exist between female NHPs and women in age-related changes in reproductive function including hormone concentrations, menstrual cycling, fertility and the development of endometriosis. Changes in male sexual behavior and fertility with age are also comparable in men and male NHP.

CONCLUSIONS

Genetic similarity, long lives and similar reproductive endocrinology suggest that NHPs are likely candidates as models of skeletal and reproductive aging in humans. Current data confirm that several species of NHP exhibit changes in bone and reproduction that are comparable to those known to occur in humans.

Cryptosporidium parvum infection requires host cell actin polymerization

The intracellular protozoan parasite Cryptosporidium parvum accumulates host cell actin at the interface between the parasite and the host cell cytoplasm. Here we show that the actin polymerizing proteins Arp2/3, vasodilator-stimulated phosphoprotein (VASP), and neural Wiskott Aldrich syndrome protein (N-WASP) are present at this interface and that host cell actin polymerization is necessary for parasite infection.

Dietary caloric restriction prevents the age-related decline in plasma melatonin levels of rhesus monkeys

Rhesus monkeys exhibit an age-associated decrease in peak plasma melatonin levels analogous to that reported for humans. This decrease is essentially abolished in monkeys subjected to a 30% reduction in caloric intake over a 12-yr period. The caloric restriction (CR) effect does not seem to be a reversal, but rather a long-term prevention, of the age-related decline in hormone concentrations. The age effect does not seem to be due to a phase shift in the peak of melatonin secretions, as has been observed in some populations of aged humans. It is also extremely unlikely that the CR effect simply reflects a phase shift, since old monkeys on the diet have nocturnal melatonin levels equal to or greater than adult fully fed controls. Thus, if peak times (approximately 0200 h) were actually shifted, maximal levels in old CR monkeys would be even higher. These findings, coupled with previous observations in humans, suggest that peak plasma melatonin levels may represent a possible candidate "biomarker of aging" in primates. Moreover, this index of age-associated physiological decrement seems to be inhibited by dietary CR.

Strategy for identifying biomarkers of aging in long-lived species

If effective anti-aging interventions are to be identified for human application, then the development of reliable and valid biomarkers of aging are essential for this progress. Despite the apparent demand for such gerotechnology, biomarker research has become a controversial pursuit. Much of the controversy has emerged from a lack of consensus on terminology and standards for evaluating the reliability and validity of candidate biomarkers. The initiation of longitudinal studies of aging in long-lived non-human primates has provided an opportunity for establishing the reliability and validity of biomarkers of aging potentially suitable for human studies. From the primate study initiated in 1987 at the National Institute on Aging (NIA), the following criteria for defining a biomarker of aging have been offered: (1) significant cross-sectional correlation with age; (2) significant longitudinal change in the same direction as the cross-sectional correlation; (3) significant stability of individual differences over time. These criteria relate to both reliability and validity. However, the process of validating a candidate biomarker requires a greater standard of proof. Ideally, the rate of change in a biomarker of aging should be predictive of lifespan. In short-lived species, such as rodents, populations differing in lifespan can be identified, such as different strains of rodents or groups on different diets, such as those subjected to calorie restriction (CR), which live markedly longer. However, in the NIA primate study, the objective is to demonstrate that CR retards the rate of aging and increases lifespan. In the absence of lifespan data associated with CR in primates, validation of biomarkers of aging must rely on other strategies of proof. With this challenge, we have offered the following strategy: If a candidate biomarker is a valid measure of the rate of aging, then the rate of age-related change in the biomarker should be proportional to differences in lifespan among related species. Thus, for example, the rate of change in a candidate biomarker of aging in chimpanzees should be twice that of humans (60 vs 120 years maximum lifespan); in rhesus monkeys three times that of humans (40 vs 120 years maximum lifespan). The realization of this strategy will be aided by developing a primate aging database, a project that was recently launched in cooperation with the NIA, the National Center for Research Resources, and the University of Wisconsin Regional Primate Research Center.

Dietary caloric restriction prevents the age-related decline in plasma melatonin levels of rhesus monkeys

Rhesus monkeys exhibit an age-associated decrease in peak plasma melatonin levels analogous to that reported for humans. This decrease is essentially abolished in monkeys subjected to a 30% reduction in caloric intake over a 12-yr period. The caloric restriction (CR) effect does not seem to be a reversal, but rather a long-term prevention, of the age-related decline in hormone concentrations. The age effect does not seem to be due to a phase shift in the peak of melatonin secretions, as has been observed in some populations of aged humans. It is also extremely unlikely that the CR effect simply reflects a phase shift, since old monkeys on the diet have nocturnal melatonin levels equal to or greater than adult fully fed controls. Thus, if peak times (approximately 0200 h) were actually shifted, maximal levels in old CR monkeys would be even higher. These findings, coupled with previous observations in humans, suggest that peak plasma melatonin levels may represent a possible candidate "biomarker of aging" in primates. Moreover, this index of age-associated physiological decrement seems to be inhibited by dietary CR.

Indium-cadmium-oxide films having exceptional electrical conductivity and optical transparency: clues for optimizing transparent conductors

Materials with high electrical conductivity and optical transparency are needed for future flat panel display, solar energy, and other opto-electronic technologies. In(x)Cd(1-x)O films having a simple cubic microstructure have been grown on amorphous glass substrates by a straightforward chemical vapor deposition process. The x = 0.05 film conductivity of 17,000 S/cm, carrier mobility of 70 cm2/Vs, and visible region optical transparency window considerably exceed the corresponding parameters for commercial indium-tin oxide. Ab initio electronic structure calculations reveal small conduction electron effective masses, a dramatic shift of the CdO band gap with doping, and a conduction band hybridization gap caused by extensive Cd 5s + In 5s mixing.

Changes in blood chemistry and hematology variables during aging in captive rhesus macaques (Macaca mulatta)

Identifying changes with age in physiological variables of captive nonhuman primates will aid in the proper treatment and clinical diagnosis of these animals, as well as enhance our understanding of nonhuman primate models for human aging. Information for 33 physiological variables was obtained from the Primate Aging Database, a multi-centered database being developed for clinical and research use. Using multiple regression analyses, we investigated the relationship of age to hematological variables, blood chemistry and body weight in 345 captive rhesus monkeys (age range 7-30 years) from three different primate research facilities. The analyses revealed that 15 of these variables show a significant relationship with chronological age and are altered in older as compared with adult animals. Here we present the first phase of a project that will: a) identify changes with age in physiological variables among adult captive rhesus macaques; and b) characterize normative values for the aging rhesus population.

Age-related changes in cytokine production by leukocytes in rhesus monkeys

Using a variety of experimental rodent and human models, age-related alterations in cytokine production by immune cells have been described extensively. While the precise mechanism(s) responsible for such age-related changes in cytokine responses remain unclear, it seems likely that these changes may have a significant effect on immune cell function. In an attempt to clarify such changes in aging primates, we examined cytokine production by white cells derived from a controlled colony of rhesus monkeys (Macaca mulatta). Non-fractionated whole blood and peripheral blood mononuclear cells (PBMCs) were obtained from male monkeys of different ages (6-28 years), and were subsequently evaluated for their ability to express mRNA and protein for the cytokines, IL-10, IL-6, IFNgamma, IL-1beta, and TNFalpha, following in vitro stimulation with polyclonal mitogens. Our results suggest that white blood cells derived from aged rhesus monkeys exhibit a significant increase in their ability to produce the Th2-associated cytokine, IL-10, upon stimulation with lipopolysaccharide (LPS) when compared to white cells derived from younger counterparts. Similarly, a significant age-related decrease in the expression of the Th1-associated cytokine, IFNgamma, was also observed using phytohemagglutinin (PHA)-stimulated PBMCs. No significant age-related differences in the production of IL-1beta or TNFalpha were observed in response to any stimulation, but there was limited evidence of an age-related increase in IL-6 production. Overall, our results suggest that a possible systemic change from a Th0/Th1 to a Th2-like cytokine profile occurs in circulating leukocytes derived from aging primates. We believe that such age-related alterations in cytokine production may play a role in the reduced immune responses observed in elderly human populations.

Aging and caloric restriction in nonhuman primates: behavioral and in vivo brain imaging studies

In a long-term longitudinal study of aging in rhesus monkeys, a primary objective has been to determine the effects of aging and caloric restriction (CR) on behavioral and neural parameters. Through the use of automated devices, locomotor activity can be monitored in the home cages of the monkeys. Studies completed thus far indicate a clear age-related decline in activity consistent with such observations in many other species, including humans. However, no consistent effects of CR on activity have been observed. Selected groups of monkeys have also been involved in brain imaging studies, using magnetic resonance imaging (MRI) and positron emission tomography (PET). MRI studies completed thus far reveal a clear age-related decline in the volumes of the basal ganglia, the putamen, and the caudate nucleus, with no change in total brain volume. PET analysis has revealed an age-related decline in the binding potential of dopamine D2 receptors in the same brain regions. These results are consistent with findings in humans. Although additional longitudinal analysis is needed to confirm the present results, it would appear that locomotor activity, volume of the basal ganglia, as well as dopamine D2 receptor binding potential provide reliable, noninvasive biomarkers of aging in rhesus monkeys.

Accuracy and precision of dual-energy X-ray absorptiometry for body composition measurements in rhesus monkeys

Accuracy of body composition measurements by dual-energy X-ray absorptiometry (DXA) was compared with direct chemical analysis in 10 adult rhesus monkeys. DXA was highly correlated (r-values > 0.95) with direct analyses of body fat mass (FM), lean mass (LM) and lumbar spine bone mineral content (BMC). DXA measurements of total body BMC were not as strongly correlated (r-value = 0.58) with total carcass ash content. DXA measurements of body FM, LM and lumbar spine BMC were not different from data obtained by direct analyses (P-values > 0.30). In contrast, DXA determinations of total BMC (TBMC) averaged 15%, less than total carcass ash measurements (P = 0.002). In conclusion, this study confirms the accurate measurement of fat and lean tissue mass by DXA in rhesus monkeys. DXA also accurately measured lumbar spine BMC but underestimated total body BMC as compared with carcass ash determinations.

Caloric restriction in primates

Caloric restriction (CR) remains the only nongenetic intervention that reproducibly extends mean and maximal life span in short-lived mammalian species. This nutritional intervention also delays the onset, or slows the progression, of many age-related disease processes. The diverse effects of CR have been demonstrated many hundreds of times in laboratory rodents and other short-lived species, such as rotifers, water fleas, fish, spiders, and hamsters. Until recently, the effects of CR in longer-lived species, more closely related to humans, remained unknown. Long-term studies of aging in nonhuman primates undergoing CR have been underway at the National Institute on Aging (NIA) and the University of Wisconsin-Madison (UW) for over a decade. A number of reports from the NIA and UW colonies have shown that monkeys on CR exhibit nearly identical physiological responses as reported in laboratory rodents. Studies of various markers related to age-related diseases suggest that CR will prevent or delay the onset of cardiovascular disease, diabetes, and perhaps cancer, and preliminary data indicate that mortality due to these and other age-associated diseases may also be reduced in monkeys on CR, compared to controls. Conclusive evidence showing that CR extends life span in primates is not presently available; however, the emerging data from the ongoing primate studies strengthens the possibility that the diverse beneficial effects of CR on aging in rodents will also apply to nonhuman primates and perhaps ultimately to humans.

Caloric restriction in primates and relevance to humans

Dietary caloric restriction (CR) is the only intervention conclusively and reproducibly shown to slow aging and maintain health and vitality in mammals. Although this paradigm has been known for over 60 years, its precise biological mechanisms and applicability to humans remain unknown. We began addressing the latter question in 1987 with the first controlled study of CR in primates (rhesus and squirrel monkeys, which are evolutionarily much closer to humans than the rodents most frequently employed in CR studies). To date, our results strongly suggest that the same beneficial "antiaging" and/or "antidisease" effects observed in CR rodents also occur in primates. These include lower plasma insulin levels and greater sensitivity; lower body temperatures; reduced cholesterol, triglycerides, blood pressure, and arterial stiffness; elevated HDL; and slower age-related decline in circulating levels of DHEAS. Collectively, these biomarkers suggest that CR primates will be less likely to incur diabetes, cardiovascular problems, and other age-related diseases and may in fact be aging more slowly than fully fed counterparts. Despite these very encouraging results, it is unlikely that most humans would be willing to maintain a 30% reduced diet for the bulk of their adult life span, even if it meant more healthy years. For this reason, we have begun to explore CR mimetics, agents that might elicit the same beneficial effects as CR, without the necessity of dieting. Our initial studies have focused on 2-deoxyglucose (2DG), a sugar analogue with a limited metabolism that actually reduces glucose/energy flux without decreasing food intake in rats. In a six-month pilot study, 2DG lowered plasma insulin and body temperature in a manner analagous to that of CR. Thus, metabolic effects that mediate the CR mechanism can be attained pharmacologically. Doses were titrated to eliminate toxicity; a long-term longevity study is now under way. In addition, data from other laboratories suggest that at least some of the same physiological/metabolic end points that are associated with the beneficial effects of underfeeding may be obtained from other potential CR mimetic agents, some naturally occurring in food products. Much work remains to be done, but taken together, our successful results with CR in primates and 2DG administration to rats suggest that it may indeed be possible to obtain the health- and longevity-promoting effects of the former intervention without actually decreasing food intake.

Physiologic effects of lowering caloric intake in nonhuman primates and nonobese humans

Caloric restriction (CR) reduces the rate of aging and increases life span in all small animal species studied to date, but the effects of CR in humans remain uncertain. This review summarizes current knowledge of the effects of CR in nonhuman primates and humans. The results suggest that CR has a range of beneficial effects in nonhuman primates studied under laboratory conditions, and short-term markers of CR seen in animal models appear to occur in humans subject to CR also. However, the overall benefit of CR in human populations remains to be established, and studies in human populations are needed.

Calorie restriction and skeletal mass in rhesus monkeys (Macaca mulatta): evidence for an effect mediated through changes in body size

Little is known regarding the effects of prolonged calorie restriction (CR) on skeletal health. We investigated long-term (11 years) and short-term (12 months) effects of moderate CR on bone mass and biochemical indices of bone metabolism in male rhesus monkeys across a range of ages. A lower bone mass in long-term CR monkeys was accounted for by adjusting for age and body weight differences. A further analysis indicated that lean mass, but not fat mass, was a strong predictor of bone mass in both CR and control monkeys. No effect of short-term CR on bone mass was observed in older monkeys (mean age, 19 years), although young monkeys (4 years) subjected to short-term CR exhibited slower gains in total body bone density and content than age-matched controls. Neither biochemical markers of bone turnover nor hormonal regulators of bone metabolism were affected by long-term CR. Although osteocalcin concentrations were significantly lower in young restricted males after 1 month on 30% CR in the short-term study, they were no longer different from control values by 6 months on 30% CR.

A nonhuman primate model of age-related bone loss: a longitudinal study in male and premenopausal female rhesus monkeys

Aging is associated with gradual bone loss in men and premenopausal women, with an accelerated rate of loss after menopause in women. Although many studies have investigated bone loss due to surgically induced estrogen depletion, little is known regarding normal age-related changes in bone mass in animal models. We used dual-energy X-ray absorptiometry (DXA) to measure bone mineral density (BMD), bone mineral content (BMC), and projected area (PA) at four skeletal sites over 4 years in 20 premenopausal female (8-23 years) and 29 male (8-27 years) rhesus monkeys (Macaca mulatta). Forearm BMD declined with age in both male and female monkeys. Lean mass was positively associated with BMD at all sites in males and with the distal radius in females. Serum osteocalcin declined and urinary cross-links increased with age in males but not females. Serum 25-hydroxyvitamin D concentrations decreased with age in females, and a similar trend was observed in males. In conclusion, an age-related decline in forearm BMD was observed in male and female rhesus monkeys. Total body BMC declined over time in older females, with a similar trend in males. Changes in markers of bone turnover with age were also observed in male monkeys. The results of this longitudinal study suggest that the rhesus monkey is a potential model for age-related changes in the human skeleton.

Energy restriction does not alter bone mineral metabolism or reproductive cycling and hormones in female rhesus monkeys

Energy restriction (ER) extends the life span and slows aging and age-related diseases in short-lived mammalian species. Although a wide variety of physiological systems have been studied using this paradigm, little is known regarding the effects of ER on skeletal health and reproductive aging. Studies in rhesus monkeys have reported that ER delays sexual and skeletal maturation in young male monkeys and reduces bone mass in adult males. No studies have examined the chronic effects on bone health and reproductive aging in female rhesus monkeys. The present cross-sectional study examined the effects of chronic (6 y) ER on skeletal and reproductive indices in 40 premenopausal and perimenopausal (7-27 y old) female rhesus macaques (Macaca mulatta). Although ER monkeys weighed less and had lower fat mass, ER did not alter bone mineral density, bone mineral content, osteocalcin, 25-hydroxyvitamin D, 1,25-hydroxyvitamin D or parathyroid hormone concentrations, menstrual cycling or reproductive hormone concentrations. Body weight and lean mass were significantly related to bone mineral density and bone mineral content at all skeletal sites (total body, lumbar spine, mid and distal radius; P: < or = 0.04). The number of total menstrual cycles over 2 y, as well as the percentage of normal-length cycles (24-31 d), was lower in older than in younger monkeys (P: < or = 0.05). Older monkeys also had lower estradiol (P: = 0.02) and higher follicle-stimulating hormone (P: = 0.02) concentrations than did younger monkeys. We conclude that ER does not negatively affect these indices of skeletal or reproductive health and does not alter age-associated changes in the same variables.

A rapid immunoassay predicts BRCA1 and BRCA2 mutations in buccal cells

We developed a rapid, non-invasive, and inexpensive, assay capable of identifying BRCA1 and BRCA2 (BRCA) mutations in buccal cells. To determine the predictive value of this immunoassay, a double blind study of 13 high risk individuals was conducted by two independent teams. As greater than 90% of BRCA mutations result in protein truncations, a diminished anti-carboxy immunoreactivity relative to anti-amino immunoreactivity was scored as predictive for mutation. Comparison to BRCA DNA analysis was undertaken. The positive and negative predictive values were 90% and 100% respectively (p<0.02), suggesting great promise as an inexpensive and rapid screen for BRCA mutations.

Interoperability of biodiversity databases: biodiversity information on every desktop

Data about biodiversity are either scattered in many databases or reside on paper or other media not amenable to interactive searching. The Global Biodiversity Information Facility (GBIF) is a framework for facilitating the digitization of biodiversity data and for making interoperable an as-yet-unknown number of biodiversity databases that are distributed around the globe. In concert with other existing efforts, GBIF will catalyze the completion of a Catalog of the Names of Known Organisms and will develop search engines to mine the vast quantities of biodiversity data. It will be an outstanding tool for scientists, natural resource managers, and policy-makers.

Immunohistochemical analysis of BRCA2 expression in normal human buccal cells

Previously we demonstrated that protein coded by the BRCA1 gene was expressed in normal human buccal cells. The present study confirmed that BRCA2 protein was similarly expressed in these cells. Messenger RNA for BRCA2 was detected with sequential use of two primer sets. Pooled cell samples from healthy donors reacted strongly with two commercially available antibodies, I17 and C15. Immunoreactivity was present in both cytoplasmic and nuclear compartments. We conclude buccal cells will provide a suitable model for exploration of normal BRCA function.

An antibody assay predictive of BRCA1 mutations in ovarian tumors and normal tissue

To determine whether immunohistochemistry can identify BRCA1 mutations, immunohistochemical (IH) analysis was undertaken on paraffin sections of paired ovarian cancer and normal tissue using antibodies against both terminal regions of the BRCA1 protein. Ten patients at risk for BRCA1 mutations were studied. The results of BRCA1 mutation analysis and IH were compared. In tumor, IH correctly identified the presence or absence of loss of heterozygosity in all specimens. In all uninvolved specimens, IH correctly identified the presence or absence of a germline mutation. The sensitivity, specificity, positive and negative predictive values were 100% suggesting promise as a rapid and inexpensive screen.

Nonhuman primate models in biogerontology

A variety of animal models are utilized in biogerontological studies including yeast, nematodes, fruit flies, hamsters, mice, rats, and nonhuman primates. Species selection for research is based on many factors including economic feasibility, husbandry, generalizability of findings, available background information, adaptability to experimentation, and often, relevance to human aging. Each model offers its own strengths and limitations; however, nonhuman primates offer the unique advantage of phylogenetic proximity to humans. Among others, costs to purchase and maintain research subjects represent major limitations of nonhuman primate models. Although several nonhuman primate species have been utilized in aging research, rhesus monkeys (Macaca mulatta) are the best characterized and most extensively studied in biomedical gerontology. Nonhuman primate models have been employed as models for human aging in many research areas including neurobiology, skeletal, and reproductive aging and age-related diseases such as cardiovascular disease and diabetes. Primate models are now also being utilized to study interventions into aging such as caloric restriction. It will be several more years until definitive conclusions regarding lifespan effects can be made. However, existing data strongly suggest that many of the beneficial effects reported in rodents on CR also occur in primate models thereby strengthening the possibility that this nutritional paradigm may also impact favorably upon human aging.