Cortisol metabolism, postnatal depression and weight changes in the first 12 months postpartum

BACKGROUND & OBJECTIVES

Postnatal depression correlates with postpartum weight retention, and dysregulated cortisol metabolism is evident in depressed individuals. Cortisol metabolism, BMI and metabolic phenotype are robustly associated, but the role of cortisol metabolism in postnatal mental health and weight loss has never been examined.

DESIGN

A longitudinal observation.

PATIENTS

Forty nine healthy women with uncomplicated pregnancy.

MEASUREMENTS

BMI and urinary steroid metabolites at 1 week and 1, 3, 6 and 12 months postpartum. Validated urinary steroid metabolite ratios were measured to determine the activities of 11β-hydroxysteroid dehydrogenases (11β-HSD) that interconvert inactive cortisone and active cortisol and the 5α-reductases that clear cortisol to its inactive metabolites. Postnatal depression symptoms were measured at 1, 6 and 12 months.

RESULTS

Low 5α-reductase activity was associated with greater weight loss across the first year, independent of demographics, breastfeeding and depression. Postpartum BMI change was unrelated to postnatal depression at any time. Symptoms of postnatal depression were related to higher cortisol metabolite production at 12 months, independent of demographics and breastfeeding.

CONCLUSIONS

Greatest weight loss in the postpartum year was associated with lower conversion of cortisone to cortisol and lower conversion of cortisol to its metabolites, supporting previous work that demonstrates the facilitative role of lower 5α-reductase and 11β-HSD-1 in weight loss. Greater depression symptoms were associated with higher cortisol metabolite production rates. Whilst weight and mental health are both associated with dysregulation of the HPA axis, there may be different pathways towards depressed and obese phenotypes in healthy postpartum samples.

Severe respiratory illness associated with a nationwide outbreak of enterovirus D68 in the USA (2014): a descriptive epidemiological investigation

BACKGROUND

Enterovirus D68 (EV-D68) has been infrequently reported historically, and is typically associated with isolated cases or small clusters of respiratory illness. Beginning in August, 2014, increases in severe respiratory illness associated with EV-D68 were reported across the USA. We aimed to describe the clinical, epidemiological, and laboratory features of this outbreak, and to better understand the role of EV-D68 in severe respiratory illness.

METHODS

We collected regional syndromic surveillance data for epidemiological weeks 23 to 44, 2014, (June 1 to Nov 1, 2014) and hospital admissions data for epidemiological weeks 27 to 44, 2014, (June 29 to Nov 1, 2014) from three states: Missouri, Illinois and Colorado. Data were also collected for the same time period of 2013 and 2012. Respiratory specimens from severely ill patients nationwide, who were rhinovirus-positive or enterovirus-positive in hospital testing, were submitted between Aug 1, and Oct 31, 2014, and typed by molecular sequencing. We collected basic clinical and epidemiological characteristics of EV-D68 cases with a standard data collection form submitted with each specimen. We compared patients requiring intensive care with those who did not, and patients requiring ventilator support with those who did not. Mantel-Haenszel χ(2) tests were used to test for statistical significance.

FINDINGS

Regional and hospital-level data from Missouri, Illinois, and Colorado showed increases in respiratory illness between August and September, 2014, compared with in 2013 and 2012. Nationwide, 699 (46%) of 1529 patients tested were confirmed as EV-D68. Among the 614 EV-D68-positive patients admitted to hospital, age ranged from 3 days to 92 years (median 5 years). Common symptoms included dyspnoea (n=513 [84%]), cough (n=500 [81%]), and wheezing (n=427 [70%]); 294 (48%) patients had fever. 338 [59%] of 574 were admitted to intensive care units, and 145 (28%) of 511 received ventilator support; 322 (52%) of 614 had a history of asthma or reactive airway disease; 200 (66%) of 304 patients with a history of asthma or reactive airway disease required intensive care compared with 138 (51%) of 270 with no history of asthma or reactive airway disease (p=0·0004). Similarly, 89 (32%) of 276 patients with a history of asthma or reactive airway disease required ventilator support compared with 56 (24%) of 235 patients with no history of asthma or reactive airway disease (p=0·039).

INTERPRETATION

In 2014, EV-D68 caused widespread severe respiratory illness across the USA, disproportionately affecting those with asthma. This unexpected event underscores the need for robust surveillance of enterovirus types, enabling improved understanding of virus circulation and disease burden.

FUNDING

None.

Severe enterovirus 68 respiratory illness in children requiring intensive care management

BACKGROUND

Enterovirus 68 (EV-D68) causes acute respiratory tract illness in epidemic cycles, most recently in Fall 2014, but clinical characteristics of severe disease are not well reported.

OBJECTIVES

Children with EV-D68 severe respiratory disease requiring pediatric intensive care unit (PICU) management were compared with children with severe respiratory disease from other enteroviruses/rhinoviruses.

STUDY DESIGN

A retrospective review was performed of all children admitted to Children's Mercy Hospital PICU from August 1-September 15, 2014 with positive PCR testing for enterovirus/rhinovirus. Specimens were subsequently tested for the presence of EV-D68. We evaluated baseline characteristics, symptomatology, lab values, therapeutics, and outcomes of children with EV-D68 viral infection compared with enterovirus/rhinovirus-positive, EV-D68-negative children.

RESULTS

A total of 86 children with positive enterovirus/rhinovirus testing associated with respiratory symptoms were admitted to the PICU. Children with EV-D68 were older than their EV-D68-negative counterparts (7.1 vs. 3.5 years, P=0.01). They were more likely to have a history of asthma or recurrent wheeze (68% vs. 42%, P=0.03) and to present with cough (90% vs. 63%, P=0.009). EV-D68 children were significantly more likely to receive albuterol (95% vs. 79%, P=0.04), magnesium (75% vs. 42%, P=0.004), and aminophylline (25% vs. 4%, P=0.03). Other adjunctive medications used in EV-D68 children included corticosteroids, epinephrine, and heliox; 44% of EV-D68-positive children required non-invasive ventilatory support.

CONCLUSIONS

EV-D68 causes severe disease in the pediatric population, particularly in children with asthma and recurrent wheeze; children may require multiple adjunctive respiratory therapies.

Comparative evaluation of Taqman real-time PCR and semi-nested VP1 PCR for detection of enteroviruses in clinical specimens

BACKGROUND

Molecular diagnostic tests to detect enterovirus in clinical specimens usually target highly conserved sites in the 5'-non-translated region, allowing detection of all members of the genus. The sequences in the 5'-NTR do not correlate with serotype, but PCR and sequencing of the VP1 region can be used for typing; this system has largely replaced traditional antigenic typing.

OBJECTIVE

To investigate the relative performance of two common enterovirus assays.

STUDY DESIGN

We compared the relative sensitivities of Taqman real-time RT-PCR (rRT-PCR) and a VP1 semi-nested PCR (RT-snPCR) assay in which sequencing the VP1 amplicon also provides typing information.

RESULTS

There was 89% concordance between the two methods among the 371 clinical specimens tested (74 positive in both assays and 257 negative in both assays). Twenty-seven rRT-PCR-negative/VP1-positive specimens were confirmed positive by sequencing; 13 specimens were rRT-PCR-positive/VP1-negative.

CONCLUSIONS

The results suggest that either assay can produce satisfactory results, but that using both assays in parallel should provide the highest sensitivity for clinical diagnostic testing.

A 1-year, placebo-controlled preservation of function survival study of donepezil in AD patients

OBJECTIVE

To examine the effects of donepezil compared with placebo on the preservation of function in patients with AD over a 1-year period.

METHODS

This was a prospective, 54-week, double-blind, placebo-controlled, survival to endpoint study. Patients were required to have at entry: a diagnosis of probable AD (National Institute of Neurological and Communicative Disorders and Stroke criteria); Mini-Mental State Examination score of 12 to 20; Clinical Dementia Rating of 1 or 2; modified Hachinski ischemia score < or =4; and capability of performing 8 of 10 instrumental activities of daily living and 5 of 6 basic activities of daily living. Patients (n = 431) were randomized to placebo or donepezil (5 mg/day for 28 days, 10 mg/day thereafter). Outcome measures were the AD Functional Assessment and Change Scale, the Mini-Mental State Examination, and Clinical Dementia Rating scale. At each visit, investigators determined whether predefined criteria for clinically evident decline in functional status had been met. Patients who met the endpoint criteria were discontinued per protocol.

RESULTS

Donepezil extended the median time to clinically evident functional decline by 5 months versus placebo. The probability of patients treated with donepezil remaining in the study with no clinically evident functional loss was 51% at 48 weeks, compared with 35% for placebo. The Kaplan-Meier survival curves for the two treatment groups were different (p = 0.002, log-rank test).

CONCLUSIONS

Patients with AD continue to show detectable disease progression over time, but treatment with donepezil for 1 year was associated with a 38% reduction in the risk of functional decline compared with placebo.

Regulation of molecular motor proteins

Motor proteins in the kinesin, dynein, and myosin superfamilies are tightly regulated to perform multiple functions in the cell requiring force generation. Although motor proteins within families are diverse in sequence and structure, there are general mechanisms by which they are regulated. We first discuss the regulation of the subset of kinesin family members for which such information exists, and then address general mechanisms of kinesin family regulation. We review what is known about the regulation of axonemal and cytoplasmic dyneins. Recent work on cytoplasmic dynein has revealed the existence of multiple isoforms for each dynein chain, making the study of dynein regulation more complicated than previously realized. Finally, we discuss the regulation of myosins known to be involved in membrane trafficking. Myosins and kinesins may be evolutionarily related, and there are common themes of regulation between these two classes of motors.

Perspectives in the management of Alzheimer's disease: clinical profile of donepezil

Donepezil HCI is a piperidine-based reversible acetylcholinesterase (AChE) inhibitor, chemically distinct from other cholinesterase (ChE) inhibitors and rationally designed to treat the symptoms of Alzheimer's disease (AD). It is highly selective for AChE in the central nervous system (CNS), with little or no affinity for butyrylcholinesterase (BuChE). In preclinical studies in animals, donepezil produced increased CNS acetylcholine. The resultant enhancement of cholinergic activity gave rise to improved performance by rats on tests of learning and memory, with no evidence of hepatic or renal toxicity. In subsequent phase I clinical evaluations in healthy volunteers, donepezil demonstrated favorable pharmacokinetic, pharmacodynamic and safety profiles. Its long terminal disposition half-life supported once-daily administration, with no requirement for dose modification in the elderly or in patients with renal or hepatic impairment. A 14-week, phase II dose-finding study in patients with mild to moderate AD (Clinical Dementia Rating [CDR], 1-2; Mini-Mental State Examination [MMSE], 10-26) showed that donepezil at a dose of 5 mg/day produced highly significant improvements in cognition (as measured by the Alzheimer's Disease Assessment Scale, cognitive subscale [ADAS-cog]). Subsequently, two pivotal parallel-group, placebo-controlled phase III trials (of 15 and 30 weeks' duration) showed highly statistically significant improvements in ADAS-cog, MMSE, Clinician's Interview-Based Impression of Change with caregiver input (CIBIC plus) and CDR-SB (Sum of the Boxes) scores, compared with placebo, in mild to moderate AD patients treated with either 5 or 10 mg/day donepezil. Adverse events in the phase II and III trials were mild and transient and resolved with continued donepezil administration. The donepezil clinical trials program has shown that this drug is a clinically effective and well-tolerated once-daily treatment for the symptoms of mild to moderate AD.

The RNA-binding protein HuD is required for GAP-43 mRNA stability, GAP-43 gene expression, and PKC-dependent neurite outgrowth in PC12 cells

The RNA-binding protein HuD binds to a regulatory element in the 3' untranslated region (3' UTR) of the GAP-43 mRNA. To investigate the functional significance of this interaction, we generated PC12 cell lines in which HuD levels were controlled by transfection with either antisense (pDuH) or sense (pcHuD) constructs. pDuH-transfected cells contained reduced amounts of GAP-43 protein and mRNA, and these levels remained low even after nerve growth factor (NGF) stimulation, a treatment that is normally associated with protein kinase C (PKC)-dependent stabilization of the GAP-43 mRNA and neuronal differentiation. Analysis of GAP-43 mRNA stability demonstrated that the mRNA had a shorter half-life in these cells. In agreement with their deficient GAP-43 expression, pDuH cells failed to grow neurites in the presence of NGF or phorbol esters. These cells, however, exhibited normal neurite outgrowth when exposed to dibutyryl-cAMP, an agent that induces outgrowth independently from GAP-43. We observed opposite effects in pcHuD-transfected cells. The GAP-43 mRNA was stabilized in these cells, leading to an increase in the levels of the GAP-43 mRNA and protein. pcHuD cells were also found to grow short spontaneous neurites, a process that required the presence of GAP-43. In conclusion, our results suggest that HuD plays a critical role in PKC-mediated neurite outgrowth in PC12 cells and that this protein does so primarily by promoting the stabilization of the GAP-43 mRNA.

A lipid A analog, E5531, blocks the endotoxin response in human volunteers with experimental endotoxemia

BACKGROUND

Endotoxin (lipopolysaccharide [LPS]) has been associated with sepsis and the high mortality rate seen in septic shock. The administration of a small amount of LPS to healthy subjects produces a mild syndrome qualitatively similar to that seen in clinical sepsis. We used this model to test the efficacy of an endotoxin antagonist, E5531, in blocking this LPS-induced syndrome.

METHODS

In a placebo-controlled, double-blind study, we randomly assigned 32 healthy volunteers to four sequential groups (100, 250, 500, or 1000 microg of E5531). Each group of eight subjects (six assigned to E5531, two assigned to placebo) received a 30-min intravenous infusion of study drug. LPS (4 ng/kg) was administered to all subjects as an intravenous bolus in the contralateral arm at the midpoint of the infusion. Symptoms, signs, laboratory values, and hemodynamics (by echocardiogram) were evaluated at prospectively defined times.

RESULTS

In subjects receiving placebo, LPS caused headache, nausea, chills, and myalgias. E5531 led to a dose-dependent decrease in these symptoms that was statistically significant (p < .05) except for myalgias. The signs of endotoxemia (fever, tachycardia, and hypotension) were consistently inhibited at the three higher doses (250, 500, and 1000 microg, p < .05). Tumor necrosis factor-alpha and interleukin-6 blood levels were both lower in those who received E5531 (p < .0001). The C-reactive protein level and white blood cell count response were decreased at all doses (p < .0001). The hyperdynamic cardiovascular state (high cardiac index and low systemic vascular resistance) associated with endotoxin challenge was significantly inhibited at the higher doses of E5531.

CONCLUSIONS

E5531 blocks the symptoms and signs and cytokine, white blood cell count, C-reactive protein, and cardiovascular response seen in experimental endotoxemia. This agent is a potent inhibitor of endotoxin challenge in humans and may be of benefit in the prevention or treatment of sepsis and septic shock.

Long-term efficacy and safety of donepezil in the treatment of Alzheimer's disease: final analysis of a US multicentre open-label study

This multicentre, open-label study evaluated the long-term efficacy and safety of donepezil in the treatment of patients with mild to moderately severe Alzheimer's disease (AD). The 133 patients who entered the study had previously completed a 14-week randomized, double-blind, placebo-controlled study with donepezil. In this open-label study, patients were treated initially with 3 mg per day donepezil, which could be increased to 5, 7 and 10 mg per day in a step-wise fashion. Patients attended the clinic for assessments at 3-week intervals for the first 12 weeks, then subsequently at 12-week intervals for up to 240 weeks (254 cumulative weeks). Efficacy was assessed using the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) and the Clinical Dementia Rating-Sum of the Boxes scale (CDR-SB), and data were compared with those predicted for historical untreated AD patients. During the first 6-9 months of the study, mean ADAS-cog and CDR-SB scores showed evidence of clinical improvement from baseline. After this time scores gradually deteriorated. Overall the decline was less than that estimated if this cohort of patients had not been treated. The most common adverse events were related to the nervous and digestive systems, and were generally mild and transient, resolving without the need for dose modifications. There was no evidence of hepatotoxicity. In conclusion, these data demonstrate that donepezil is a well-tolerated, realistic symptomatic treatment for AD over a period of up to 4.9 years. An interim report of the first 98 weeks of the study has been published previously.

Membrane trafficking, organelle transport, and the cytoskeleton

Cytoskeleton-associated motor proteins typically drive organelle movements in eukaryotic cells in a manner that is tightly regulated, both spatially and temporally. In the past year, a novel organelle transport mechanism utilizing actin polymerization was described. Important advances were also made in the assignment of functions to several new motors and in our understanding of how motor proteins are regulated during organelle transport. In addition, insights were gained into how and why organelles are transported cooperatively along the microtubule and actin cytoskeletons, and into the importance of motor-mediated transport in the organization of the cytoskeleton itself.

Diminished matrix metalloproteinase 2 (MMP-2) in ectomesenchyme-derived tissues of the Patch mutant mouse: regulation of MMP-2 by PDGF and effects on mesenchymal cell migration

Platelet-derived growth factors (PDGF) regulate cell proliferation, survival, morphology, and migration, as well as deposition and turnover of the extracellular matrix. Important roles for the A form of PDGF (PDGF-A) during connective tissue morphogenesis have been highlighted by the murine Patch mutation, which includes a deletion of the alpha subunit of the PDGF receptor. Homozygous (Ph/Ph) embryos exhibit multiple connective tissue defects including cleft face (involving the first branchial arch and frontonasal processes), incomplete heart septation, and heart valve abnormalities before they die in utero. Analyses of the cell biology underlying the defects in Ph/Ph embryos have revealed a deficit in a matrix metalloproteinase (MMP-2) and one of its activators (MT-MMP) that are likely to be involved in cell migration and tissue remodeling, two processes necessary for normal cardiac and craniofacial development. Morphogenesis of these structures requires infiltration of ectomesenchymal precursors and their subsequent deposition and remodeling of extracellular matrix components. First branchial arch and heart tissue from E10.5 embryos were examined by gelatin zymography and RT-PCR in order to characterize the expression of MMPs in these tissues. Of the MMPs examined, only MMP-2 and one of its activators, MT-MMP, were expressed in the first arch and heart at this stage of development. Tissues from Ph/Ph embryos exhibited a significant decrease in both MMP-2 and MT-MMP compared to tissues from normal embryos of the same developmental stage. In order to assess whether this decrease affects the motile activity of mesenchymal cells, cell migration from Ph/Ph branchial arch explants was compared to migration from normal arch tissue and found to be significantly less. In addition, the migratory ability of branchial arch cells from normal explants could be reduced in a similar manner using a specific MMP inhibitor. Although it is still unclear whether the MMP-2 reduction is a direct result of the absence of response of Ph/Ph cells to PDGF-A treatment of normal branchial arch cells in vitro with recombinant PDGF-AA significantly upregulated MMP-2 protein. Together, these results suggest that PDGF-A regulates MMP-2 expression and activation during normal development and that faulty proteinase expression may be at least partially responsible for the developmental defects exhibited by Ph/Ph embryos.

The effects of donepezil in Alzheimer's disease - results from a multinational trial

Donepezil has been shown to be well tolerated and to improve cognition and global function in patients with mild to moderately severe Alzheimer's disease (AD). The current trial was undertaken to investigate further the efficacy and safety of donepezil, in a multinational setting, in patients with mild to moderately severe AD. This 30-week, placebo-controlled, parallel-group study consisted of a 24-week, double-blind treatment phase followed by a 6-week, single-blind, placebo washout. Eight hundred and eighteen patients with mild to moderately severe AD were randomly allocated to treatment with single, daily doses of 5 or 10 mg donepezil, or placebo. The two primary efficacy measures were: a cognitive performance test, the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) and a global evaluation, the Clinician's Interview-Based Impression of Change with caregiver input (CIBIC plus). Secondary outcome measures included the Sum of the Boxes of the Clinical Dementia Rating Scale (CDR-SB), a modified Interview for Deterioration in Daily living activities in Dementia (IDDD) and a patient rated quality of life assessment. Statistically significant improvements in cognitive and global function were observed, as evaluated by ADAS-cog and CIBIC plus, respectively, in both the 5 and 10 mg/day donepezil groups, compared with placebo. Treatment-associated changes were also observed in functional skills, as shown by improved scores on the CDR-SB and the complex-tasks component of the IDDD. A dose-response effect was evident, with the 10 mg/day donepezil group demonstrating greater benefits in all outcome measures than the 5 mg/day group. Donepezil was well tolerated by this patient population and did not produce any clinically significant laboratory test abnormalities. The results of this study confirm that donepezil is effective and well tolerated in treating the symptoms of mild to moderately severe AD.

cis-acting regulatory elements in the GAP-43 mRNA 3'-untranslated region can function in trans to suppress endogenous GAP-43 gene expression

The expression of the GAP-43 gene is controlled partly by changes in the stability of its mRNA, a process that is mediated by the interaction of specific sequences in the 3'-untranslated region (3'UTR) with neuronal-specific RNA-binding proteins. Limiting amounts of these trans-acting factors are available in the cell, thus we proposed that overexpression of the GAP-43 3'UTR could affect the levels of the endogenous mRNA via competitive binding to specific RNA-binding proteins. In this study, we show that chronic expression of GAP-43 3'UTR sequences in PC12 cells causes the depletion of the endogenous mRNA and consequent reduction of GAP-43 protein levels. The levels of the mRNAs for c-fos, the amyloid precursor protein (APP) and the microtubule associated protein tau, all three containing similar 3'UTR sequences, were not affected by the treatment. These results thus suggest that the effect of excess GAP-43 3'UTR is specific for its corresponding mRNA. We also used an HSV (herpes simplex virus)-1 vector and a mammalian expression vector with an inducible promoter to acutely express a 10 to 50 fold excess of 3'UTR sequences. Under these conditions, we found that transient expression of the GAP-43 3'UTR was effective in inhibiting both GAP-43 gene expression and neurite outgrowth in nerve growth factor (NGF)-treated PC12 cells and in primary neuronal cultures. These results underscore the role of 3'UTR sequences in the control of GAP-43 gene expression and suggest that overexpression of specific 3'UTR sequences could be used as a potential tool for probing the function of other post-transcriptionally-regulated proteins during neuronal differentiation.

Immune consequences of stroke and cerebral palsy in adults

The possibility that brain damage results in a sustained dysregulation of lymphocyte responsiveness to the lymphokine, interleukin-2 (IL-2), was investigated in individuals who had experienced a unilateral stroke in adulthood or who presented with spastic hemiparesis since childhood. Following verification of unilateral brain damage via neuromotor assessment, and determination of their health status, blood samples were obtained to evaluate a panel of immune measures. Soluble interleukin-2 receptor (sIL-2R) and lymphocyte proliferative and cytolytic responses in the subjects with stroke or cerebral palsy were compared to age- and gender-matched controls. In addition, lymphocyte populations were enumerated via flow cytometry, and lymphocyte cyclic AMP (cAMP) levels were determined. Circulating blood levels of sIL-2R were significantly elevated in all individuals that had experienced unilateral brain damage. Cytolytic activity also failed to be stimulated to the normal level by in vitro treatment of lymphocytes with IL-2. Further, lymphocytes from the stroke subjects proliferated significantly less after mitogen and IL-2 stimulation. These functional differences were not accounted for by an abnormal leukocyte profile, although phenotypic analyses revealed subtle differences in the natural killer cell subsets. Overall, the findings indicate that individuals with brain damage may not respond appropriately when immune activation is required. These immune differences appear to be a stable trait given that they were manifested after both perinatal and adult brain insult in otherwise healthy, independently living individuals.

Pharmacokinetic and pharmacodynamic profile of donepezil HCl following single oral doses

AIM

The aim of this study was to characterize the pharmacokinetic and pharmacodynamic profile of donepezil HCl, a chemically distinct and specific acetylcholinesterase (AChE) inhibitor for the treatment of Alzheimer's disease, following administration of single oral doses.

METHODS

This was a double-blind, randomized, single-dose, placebo-controlled, sequential-group, ascending-dose study in healthy male volunteers (n = 48). Six dose levels were investigated, ranging from 0.3 to 6.0 mg. Donepezil concentrations in plasma were determined by HPLC with UV detection. Pharmacodynamic activity was determined by the radioenzymatic measurement of erythrocyte membrane acetylcholinesterase (rbc-AChE) inhibition.

RESULTS

The pharmacokinetic disposition of donepezil was observed to be both linear and dose proportional following single-dose administration. The mean peak plasma concentration (Cmax) of donepezil was observed at 4.1+/-1.5 h. The mean terminal disposition half-life was 81.5+/-22.0 h. The post-absorption phase of the plasma concentration-time curves for the 4.0 mg and 6.0 mg doses appeared to be biphasic, but the rate of donepezil clearance was independent of dose. Plasma concentrations for the 0.3, 0.6 and 0.9 mg dose groups were generally below the level of HPLC detection (2.0 ng ml(-1)), preventing accurate characterization of these doses. A direct correlation was observed between plasma donepezil concentrations and extent of AChE inhibition. For the 4.0 and 6.0 mg donepezil dose groups, maximal AChE inhibition (Emax) ranged from 33% to 35% and there was significant correlation between AChE inhibition and donepezil plasma concentration (P<0.005).

CONCLUSIONS

The pharmacokinetics of donepezil were found to be linear and dose proportional following the administration of single doses to healthy volunteers. A direct correlation was also observed between plasma donepezil concentrations and AChE inhibition. The extended half-life of donepezil makes it suitable for once-daily dosing.

Pharmacokinetic and pharmacodynamic profile of donepezil HCl following evening administration

AIMS

The primary objective of this study was to characterize the pharmacokinetics and pharmacodynamics of single daily doses of donepezil (5 and 10 mg) each evening for 28 consecutive days. A secondary objective was to measure the plasma protein binding of donepezil at steady state.

METHODS

This was a double-blind, randomized, multiple-dose study in healthy male (n=13) and female (n=3) volunteers. Subjects were randomized to receive, once daily, either oral doses of 5 mg donepezil for 28 days or doses of 5 mg donepezil for 7 days followed by 10 mg donepezil for 21 days. All doses were administered in the evening. Donepezil concentrations and protein binding in plasma were determined by HPLC with UV detection and equilibrium dialysis, respectively. Inhibition of acetylcholinesterase (AChE) activity in red blood cell (rbc) membranes was assessed using a specific radioenzyme assay.

RESULTS

The pharmacokinetics of donepezil were linear, dose proportional and stationary over the course of the study. Mean Cmax, tmax, AUC(0-24), t1/2 and Vlambda(z)/F at steady state were 34.1 ng ml(-1), 3.0 h, 634.8 ng h ml(-1), 72.7 h, and 11.81 kg(-1), respectively, for the 5 mg group and 60.5 ng ml(-1), 3.9 h, 1127.8 ng h ml(-1), 73.5 h and 11.61 kg(-1), respectively, for the 10 mg group. Accumulation of the drug was observed for 14-21 days, until steady state was achieved. A direct consistent relationship was observed between donepezil plasma concentration and percentage rbc-AChE inhibition during each 24 h evaluation period, indicating no hysteresis in donepezil pharmacodynamics. The pharmacodynamic parameters, Emin, Emax and Ess, were 62.2%, 71.8% and 65.3%, respectively, for the 5 mg donepezil dose, and 74.7%, 83.6% and 77.8%, respectively, for the 10 mg donepezil dose. Donepezil was 95.6% bound to plasma protein at steady state. The binding was high capacity and low affinity, and neither concentration nor time dependent. Both dosage regimens were well tolerated; no clinically significant changes in laboratory or vital sign parameters were observed in any subject.

CONCLUSIONS

The measured pharmacokinetic and pharmacodynamic parameters for both 5 and 10 mg day(-1) donepezil administered in the evening are in good agreement with previous results obtained with morning administration, indicating no time of dosing effect.

Pharmacokinetic and pharmacodynamic profile of donepezil HCl following multiple oral doses

AIM

The aim of this study was to characterize the pharmacokinetics and pharmacodynamics of donepezil HCl, a new, chemically distinct and specific acetylcholinesterase (AChE) inhibitor for the treatment of Alzheimer's disease, following multiple-dose administration.

METHODS

This was a double-blind, randomized, placebo-controlled, multiple-dose study in healthy male volunteers (n=27). Three dose levels were investigated in sequential order: 1, 3 and 5 mg. Each dose was administered orally, once a day, for 21 consecutive days. Donepezil concentrations in plasma were quantified by HPLC. Pharmacodynamic activity was determined by the radioenzymatic measurement of erythrocyte membrane acetylcholinesterase (rbc-AChE) inhibition.

RESULTS

The pharmacokinetic disposition of donepezil was observed to be dose proportional. The mean terminal disposition half-life was 79.5+/-19.0 h which resulted in a slow approach to steady state (14-21 days). A four- to sixfold increase in donepezil plasma concentration was observed during this time; however, no further increase was evident after achievement of steady state. The mean donepezil plasma concentration at steady state (Css) was 14.2 ng ml(-1). Neither the rate of accumulation nor the rate of clearance was dose dependent. Inhibition of rbc-AChE was directly correlated with donepezil concentration over a wide concentration range, with the higher concentrations showing the expected hyperbolic relationship. Donepezil was well tolerated by all subjects with no clinically significant changes in laboratory or physical parameters observed at any dose.

CONCLUSIONS

The pharmacokinetics of donepezil were found to be dose proportional following the administration of multiple doses to healthy volunteers. A predictable relationship was also observed between plasma donepezil concentrations and rbc-AChE inhibition. The half-life of donepezil makes it suitable for once-daily dosing.

Donepezil improves cognition and global function in Alzheimer disease: a 15-week, double-blind, placebo-controlled study. Donepezil Study Group

BACKGROUND

Donepezil hydrochloride (Aricept) is a selective acetylcholinesterase inhibitor developed for the treatment of Alzheimer disease. This phase 3 study was 1 of 2 pivotal trials undertaken to establish the efficacy and safety of using donepezil in patients with mild to moderately severe Alzheimer disease.

OBJECTIVES

To further examine the efficacy and safety of using donepezil in the treatment of patients with mild to moderately severe Alzheimer disease. To examine the relationships between plasma donepezil concentrations, inhibition of red blood cell acetylcholinesterase activity, and clinical response.

METHODS

This was a 12-week, double-blind, placebo-controlled, parallel-group trial with a 3-week single-blind washout. Outpatients at 23 centers in the United States were randomized to receive placebo, 5 mg of donepezil hydrochloride, or 10 mg of donepezil hydrochloride (5 mg/d during week 1 then 10 mg/d thereafter) administered once daily at bedtime. Primary efficacy was measured using the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) and Clinician's Interview-Based Impression of Change including caregiver information (CIBIC plus).

RESULTS

A total of 468 patients entered the study, more than 97% of whom were included in the intention-to-treat (end point) analyses. The use of donepezil produced statistically significant improvements in ADAS-cog, CIBIC plus, and Mini-Mental State Examination scores, relative to placebo. The mean drug-placebo differences, at end point, for the groups receiving 5 mg/d and 10 mg/d of donepezil hydrochloride were, respectively, 2.5 and 3.1 units for ADAS-cog (P<.001); 0.3 and 0.4 units for CIBIC plus (P< or =.008); and 1.0 and 1.3 units for Mini-Mental State Examination (P< or =.004). On the CIBIC plus scale, 32% and 38% of patients, respectively, treated with 5 mg/d and 10 mg/d of donepezil hydrochloride demonstrated clinical improvement (a score of 1, 2, or 3) compared with placebo (18%). The mean (+/-SEM) donepezil plasma concentrations at study end point were 25.9 +/- 0.7 ng/mL and 50.6 +/- 1.9 ng/mL in the groups receiving dosages of 5 mg/d and 10 mg/d, respectively. Corresponding mean (+/-SEM) percentages of inhibition of red blood cell acetylcholinesterase activity were 63.9% +/- 0.9% and 74.7% +/- 1.2% for these 2 dosages, respectively. There was a statistically significant positive correlation between plasma concentrations of donepezil and acetylcholinesterase inhibition; the EC50 (50% effect) was obtained at a concentration of 15.6 ng/mL. A plateau of inhibition (80%-90%) was reached at plasma donepezil concentrations higher than 50 ng/mL. The correlations between plasma drug concentrations and both ADAS-cog (P<.001) and CIBIC plus (P = .006) were also statistically significant, as were the correlations between red blood cell acetylcholinesterase inhibition and change in ADAS-cog (P<.001) and CIBIC plus (P = .005). The incidence of treatment-emergent adverse events with both dosages of donepezil (68%-78%) was comparable with that observed with placebo (69%). The use of 10 mg/d of donepezil hydrochloride was associated with transient mild nausea, insomnia, and diarrhea. There were no treatment-emergent clinically significant changes in vital signs or clinical laboratory test results. More important, the use of donepezil was not associated with the hepatotoxic effects observed with acridine-based cholinesterase inhibitors.

CONCLUSION

Donepezil hydrochloride (5 and 10 mg) administered once daily is a well-tolerated and efficacious agent for treating the symptoms of mild to moderately severe Alzheimer disease.

Long-term efficacy and safety of donepezil in the treatment of Alzheimer's disease: an interim analysis of the results of a US multicentre open label extension study

The long-term efficacy and safety of donepezil (up to 10 mg/day) was evaluated in a multicentre, non-randomised, open-label extension study of 133 patients with mild to moderate Alzheimer's disease (AD) who had completed a previous 14-week double-blind, placebo-controlled trial of donepezil. Assessments were conducted at three-weekly intervals for 12 weeks, then 12-weekly for up to 192 weeks. Efficacy, assessed by the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) and Clinical Dementia Rating-Sum of the Boxes (CDR-SB), was examined in comparison with published data of untreated AD patients. Safety was monitored by physical examinations, laboratory tests and vital sign measurements. Results of this interim analysis (at 98 weeks) show that donepezil produced improvements in cognition which remained superior to baseline for 38 weeks. CDR-SB likewise showed improvement, with scores maintained near baseline values for 26 weeks. Scores for both instruments then increased as expected in a progressive disease. However, the slope of score progression was less than has been historically reported for untreated patients. While the lack of a concurrent placebo group does not allow conclusions about the ability of donepezil to attenuate disease progression, the data, nonetheless, demonstrate that there is no loss of treatment benefit over 98 weeks. Donepezil was well tolerated, with no evidence of hepatotoxicity.

Myosin cooperates with microtubule motors during organelle transport in melanophores

Melanophores offer an outstanding system for the study of intracellular motility. These cells aggregate their pigment-filled melanosomes to the cell center or disperse them throughout the cytoplasm in response to hormonal modulation of intracellular cyclic AMP levels in order to effect color changes in lower vertebrates [1]. Previous work from our laboratory demonstrated a role for microtubule-based motors in melanosome transport and we succeeded in reconstituting their regulated motility along microtubules in vitro [2,3]. Here we demonstrate that, in addition to microtubule-mediated motility, melanosomes purified from Xenopus melanophores exhibit unidirectional movement along actin filaments in vitro as well. Immunoblotting analysis shows that these organelles possess the actin-based organelle motor, myosin-V. In vivo, melanosomes are able to slowly disperse in the absence of microtubules, and this slow dispersion requires the integrity of the actin cytoskeleton. Furthermore, in cells with dispersed pigment, disruption of filamentous actin induces a rapid, microtubule-dependent aggregation of melanosomes to the cell center. Our results, together with the accompanying paper by Rodionov et al. [4], demonstrate that the concerted efforts of both microtubule-based and actin-based motors are required for proper melanosome distribution in melanophores. This is the first example of a biochemically defined organelle in possession of both plus-end and minus-end directed microtubule motors and a myosin; coordinated activity of all three motors is essential for organelle motility in vivo.

A 24-week, double-blind, placebo-controlled trial of donepezil in patients with Alzheimer's disease. Donepezil Study Group

The efficacy and safety of donepezil as a treatment for patients with mild to moderate Alzheimer's disease (AD) was investigated in a multicenter, double-blind study. Patients were randomly assigned to treatment with placebo (n = 162), 5 mg/d donepezil (n = 154), or 10 mg/d donepezil (n = 157) for 24 weeks followed by a 6-week, single-blind placebo washout. The primary efficacy measures were the cognitive portion of the Alzheimer's Disease Assessment Scale (ADAS-cog) and the Clinician's Interview Based Assessment of Change-Plus (CIBIC plus), with the Mini-Mental State Examination (MMSE), Clinical Dementia Rating Scale-Sum of the Boxes (CDR-SB), and patient rated Quality of Life (QoL) used as secondary measures. Cognitive function, as measured by the ADAS-cog, was significantly improved in the 5- and 10-mg/d donepezil groups as compared with the placebo group at weeks 12, 18, and 24. Clinician's global ratings on the CIBIC plus also improved in both the 5- and 10-mg/d donepezil groups relative to placebo. At the end of the 6-week placebo washout phase, ADAS-cog scores and CIBIC plus ratings were not significantly different for the three groups. Significant treatment benefits were also observed consistently in both the 5- and 10-mg/d groups on the MMSE and the CDR-SB, but there was no consistent effect on the patient-rated QoL. Cholinergic side effects (primarily diarrhea, nausea, and vomiting) were reported more often in the 10-mg/d group than either the 5-mg/d or placebo groups. Side effects were transient and generally mild in severity. These data indicate that donepezil is a well-tolerated drug that improves cognition and global function in patients with mild to moderate AD.

Regulated bidirectional motility of melanophore pigment granules along microtubules in vitro

Although many types of membrane-bound organelles rely upon microtubule-based transport for their proper placement within the cytoplasm, the molecular mechanisms that regulate intracellular motility remain largely unknown. To address this problem, we have studied the microtubule-dependent dispersion and aggregation of pigment granules from an immortalized Xenopus melanophore cell line. We have reconstituted pigment granule motility along bovine brain microtubules in vitro using a microscope-based motility assay. Pigment granules, or melanosomes, move along single microtubules bidirectionally; however, analysis of the polarities of this movement shows that melanosomes that have been purified from dispersed cells exhibit mostly plus end-directed motility, while movement of organelles from aggregating cells is biased toward the minus end. Removal of all soluble proteins from the melanosome fractions by density gradient centrifugation does not diminish organelle motility, demonstrating that all the components required for transport have a stable association with the melanosome membranes. Western blotting shows the presence of the plus end-directed motor, kinesin-II, and the minus end-directed motor, cytoplasmic dynein in highly purified melanosomes. Therefore, purified melanosomes retain their ability to move along microtubules as well as their regulated state. Direct biochemical comparison of melanosomes from aggregated and dispersed cells may elucidate the molecular mechanisms that regulate organelle transport in melanophores.

The efficacy and safety of donepezil in patients with Alzheimer's disease: results of a US Multicentre, Randomized, Double-Blind, Placebo-Controlled Trial. The Donepezil Study Group

This study evaluated the efficacy and safety of donepezil in patients with mild to moderately severe Alzheimer's disease, and examined the relationships between plasma donepezil concentration, red blood cell acetylcholinesterase (AChE) activity and clinical response. The trial was of a multicenter, double-blind, parallel-group design and patients were randomised to once-daily treatment with either donepezil (1, 3 or 5 mg) or placebo. The 12-week double-blind phase was followed by a 2-week single-blind placebo washout. 161 patients (55-85 years of age) entered the study and 141 completed treatment. Patients treated with donepezil showed dose-related improvements in the Alzheimer's Disease Assessment Scale-cognitive subscale score (ADAS-cog) and in MMSF scores. The improvements in ADAS-cog were statistically significantly greater with donepezil 5 mg/day than with placebo. There was a 50% reduction in the percentage of patients showing clinical decline with donepezil at 5 mg/day (11%) relative to placebo (20%). In addition, a statistically significant correlation between plasma concentrations of donepezil and AChE inhibition was demonstrated. A plateau of inhibition (76-84%) was reached at plasma donepezil concentrations > 50 ng/ml. The correlation between plasma drug concentrations and ADAS-cog (p = 0.014), MMSE (p = 0.023) and patient quality of life scores, assessed by the patient (p = 0.037) were also statistically significant, as was the correlation between AChE inhibition and change in ADAS-cog (p = 0.008). The incidence of treatment-emergent adverse events with all three dosages of donepezil (64-68%) was comparable to that observed with placebo (65%). Donepezil had no clinically significant effect on vital signs, haematology or clinical biochemistry tests. Importantly, donepezil was not associated with any hepatotoxicity, as observed with acridine-based cholinesterase inhibitors.

Transforming growth factor-beta 1 differentially regulates proliferation, morphology, and extracellular matrix expression by three neural crest-derived neuroblastoma cell lines

We reported previously (S. L. Rogers, P. J. Gegick, S. M. Alexander, and P. G. McGuire, Dev. Biol. 151, 191-203, 1992) that transforming growth factor-beta 1 (TGF beta 1) inhibited proliferation, up-regulated fibronectin synthesis, and suppressed melanogenesis in a population of quail neural crest cells in vitro. Here, we report that cell lines derived from the parent SK-N-SH neuroblastoma line (R. A. Ross, B. A. Spengler, and J. L. Biedler, J. Natl. Cancer Inst. 71, 741-747, 1983) respond differentially to TGF beta 1, and their responses provide further insights into the actions of this growth factor on neural crest subpopulations. The SH-EP cell line exhibits primarily nonneuronal traits and responded to TGF beta 1 with increased thymidine uptake after 6 days of culture, increased expression of fibronectin mRNA and protein, and decreased laminin synthesis. Many SH-EP cells also acquired a dramatically elongated morphology, reminiscent of Schwann cells in culture. Thymidine uptake by the neuronal SY5Y cell line was not substantially altered. Neither fibronectin mRNA nor protein was detectable in either TGF beta 1-treated or untreated cultures, although laminin synthesis was upregulated by the growth factor. In TGF beta 1-treated cultures of the intermediate SH-IN cell line, which has been reported to display both neuronal and nonneuronal characteristics, there was marked flattening of many cells, a steady decrease in thymidine uptake, and increased expression of both fibronectin and laminin. The observed responses of SH-IN cells mimic those observed in primary neural crest cultures and appear to represent similar differentiation toward a mesenchymal phenotype. These results substantiate the idea that closely related but diverging neural crest-derived cell types respond selectively to TGF beta 1 and demonstrate that these SK-N-SH-derived cell lines will be useful in experimental approaches that will allow us to infer mechanisms underlying regulation of neural crest differentiation.

Comparative purification of recombinant HIV-1 and HIV-2 reverse transcriptase: preparation of heterodimeric enzyme devoid of unprocessed gene product

A procedure for producing and purifying recombinant HIV-1 and HIV-2 reverse transcriptase (RT) is described. These enzymes are produced by Escherichia coli-transformed with a plasmid containing the gene encoding for either the human immunodeficiency virus type 1 (HIV-1) or HIV-2 RT protein. Both proteins are partially processed by host cell proteases giving rise to a mixture of heterodimeric and nonheterodimeric products, which are subsequently resolved to near homogeneity by chromatography on phosphocellulose, Q-Sepharose, and hydrophobic interaction HPLC. Both HIV-1 (66/51 kDa) and HIV-2 (68/54 kDa) heterodimeric enzymes devoid of excess unprocessed (p66 or p68) precursors are isolated, enabling comparative enzymatic characterization of the fully active (and biologically relevant) heterodimeric forms. Homogenous HIV-1 and HIV-2 RT purified by this methodology exhibit near equivalent polymerase and RNase H activities.

Transforming growth factor-beta alters differentiation in cultures of avian neural crest-derived cells: effects on cell morphology, proliferation, fibronectin expression, and melanogenesis

Neural crest cell differentiation is responsive to a variety of extrinsic signals that include extracellular matrix (ECM) molecules and growth factors. Transforming growth factor-beta (TGF-beta) has diverse, cell type-specific effects, many of which involve regulation of synthesis of ECM molecules and their cell surface receptors. We are studying both separate and potentially interrelated influences of ECM and growth factors on crest differentiation and report here that TGF-beta alters several aspects of crest cell behavior in vitro. Clusters of quail neural crest cells were cultured in the presence and absence of 400 pM TGF-beta 1 and examined at 1, 3, and 5 days. When examined at 5 days, there was a dramatic decrease in the number of melanocytes in treated cultures, regardless of the onset or duration of TGF-beta treatment. With continuous TGF-beta treatment, or with treatment only during crest cluster formation on explanted neural tubes, many cells increased in area, becoming extremely flat. These changes were evident beginning on Day 3. While quantitative analyses of video images documented the size increase, several aspects of motility were relatively unchanged. Synthesis of fibronectin (FN) by approximately 11% of cells on Day 3 and 31% of cells on Day 5 was demonstrated by immunocytochemistry and was associated with a sixfold increase in FN mRNA by Day 5. Experiments which correlated FN immunoreactivity with incorporation of bromodeoxyuridine suggested that the population of large, flat, FN-positive cells did not proliferate selectively and that there was a slower rate of proliferation in TGF-beta-treated cultures than in untreated cultures. The large FN-immunoreactive cells resemble cells derived from cephalic neural crest and raise interesting questions concerning potential roles for TGF-beta in regulating crest differentiation in vivo.

Immunological correlates of seasonal fluctuations in mood and behavior and their relationship to phototherapy

Immunological parameters were studied before and after phototherapy, with bright and dim light, in 38 individuals with a range of retrospectively reported seasonal changes in mood and behavior. There was a significant negative correlation between the degree of mood and behavioral difficulties in fall and winter (seasonality) and the total number of circulating natural killer cells. Changes in the numbers of circulating helper T cells correlated significantly with changes in mood following phototherapy. Moreover, mitogen-induced lymphocyte blastogenesis increased significantly after phototherapy, but there was no significant difference between the bright and dim light treatments. The results suggest that cellular immune function is associated with both seasonality and response to phototherapy.

Substratum effects on cell dispersal, morphology, and differentiation in cultures of avian neural crest cells

Adhesive extracellular matrix (ECM) molecules appear to play roles in the migration of neural crest cells, and may also provide cues for differentiation of these cells into a variety of phenotypes. We are studying the influences of specific ECM components on crest differentiation at the levels of both individual cells and cell populations. We report here that the glycoproteins fibronectin and laminin differentially affect melanogenesis in cultures of avian neural crest-derived cells. Clusters of neural crest cells were allowed to form on explanted neural tubes for 24 and 48 hr, and then subcultured on uncoated glass coverslips or coverslips coated with fibronectin or laminin. The morphology of cells varied on the three substrata, as did patterns of cell dispersal. Crest cells dispersed most rapidly and extensively on fibronectin. In contrast, cells on laminin dispersed initially, but then assumed a stellate morphology and rapidly formed small aggregates. Cell dispersal was minimal on glass substrata, resulting in a uniformly dense distribution. These patterns of dispersal were similar in subcultures of both 24- and 48-hr clusters, although dispersal of cells from older clusters was less extensive. The rate and extent of melanogenesis correlated with patterns of cell dispersal. Cell from 24-hr clusters underwent melanogenesis significantly more slowly on fibronectin than on the other two substrata. Pigment cells began to differentiate by 2 days of subculture in the cell aggregates on laminin and in the dense centers of cultures on untreated glass. By 5 days, there was significantly more melanogenesis in cultures on laminin and glass than on fibronectin substrata. Melanogenesis in cultures of 48-hr clusters was more rapid and extensive on control (glass) substrata than on fibronectin or laminin, correlating with reduced cell dispersal. We conclude that fibronectin and laminin, which are found along neural crest migratory pathways in vivo, can affect melanogenesis in vitro by regulating patterns of cell dispersal.

The effects of phototherapy in the general population

Patients with recurrent winter depression and its subsyndromal form have been reported to benefit from bright full-spectrum light (phototherapy). In order to determine whether this treatment (2 h in the morning) during winter is effective in a random sample of the general population we investigated the responses of 20 subjects with varying degrees of winter difficulties. A control group (n = 20) matched for the degree of seasonality, age, and sex was treated with dim light. Individuals were selected from a larger survey sample of the Montgomery County population (MD, U.S.A.) and were comparable to the latter in their degree of winter difficulties. Enhancement of environmental light does not, on the basis of the present study, appear to be indicated for the public at large, but rather for a subgroup of individuals with histories of winter difficulties.

Phototherapy in individuals with and without subsyndromal seasonal affective disorder

Antidepressant and energizing effects of bright light exposure (phototherapy) have been widely reported to occur in patients with seasonal affective disorder. We have attempted to evaluate whether other segments of the population might benefit from phototherapy, most notably individuals with subsyndromal seasonal affective disorder, as well as healthy individuals with no winter difficulties (controls). We have studied 20 subjects in each of these two categories and have found that bright artificial light did not alter mood and behavior in controls. In contrast, individuals with subsyndromal seasonal affective disorder responded favorably to treatment with bright environmental light. A dose of 5 hours of bright light exposure, divided between morning and evening, was more effective than 2 hours of exposure. This finding may have practical implications for establishing optimal environmental lighting conditions for those individuals whose winter difficulties do not meet criteria for seasonal affective disorder.

Phototherapy in subsyndromal seasonal affective disorder (S-SAD) and "diagnosed" controls

Antidepressant and energizing effects of bright light exposure have been widely reported to occur in patients with seasonal affective disorder (SAD). In order to evaluate whether other segments of the population might also benefit from this treatment, we studied 20 normal individuals with mild SAD-like symptoms (subsyndromal SAD, S-SAD) and 20 with no reported seasonal difficulties (non-S-SAD). Whereas S-SAD individuals benefited from phototherapy, non-S-SAD normals did not. This finding raises the questions of whether a history of seasonal problems might be a marker of vulnerability to affective episodes and if S-SAD individuals might be considered as a high risk population in this regard.

Cell adhesion and neurite extension in response to two proteolytic fragments of laminin

Studies from several laboratories have suggested that laminin contains at least two domains that selectively mediate cell type-specific behavior. In this study, two proteolytic fragments of laminin are evaluated for their ability to interact with three different populations of embryonic chicken cells. A 600 kDa thrombin fragment, derived from the central portion of the laminin molecule, supports attachment of dorsal root ganglion (DRG), spinal cord (SC), and heart cells. Neurons from both DRGs and SCs extend neurites in response to this fragment. Quantitatively, both cell adhesion and neurite extension on the 600 kDa fragment are comparable to these responses to intact laminin. A 440 kDa chymotrypsin fragment, derived from either intact laminin or the 600 kDa fragment, does not support equivalent responses. Fewer DRG cells attach to this fragment and neurites are shorter than on the 600 kDa fragment. Heart and SC cell attachment is also reduced in comparison with activity of the 600 kDa fragment, and SC neurites do not form on the 440 kDa fragment. These results suggest that there are at least two cell binding domains in the laminin molecule, one with which a variety of cell types can interact and another that may mediate more restricted cellular responses. The latter site appears to be relatively inactive for SC and heart cell adhesion but supports limited attachment and neurite extension by DRG neurons.

Growth cone migration across extracellular matrix components depends on integrin, but migration across glioma cells does not

To promote neurite elongation, nerve growth cones must adhere to other surfaces. A complex of integral membrane glycoproteins mediates cell binding to the extracellular glycoproteins fibronectin and laminin (Horwitz et al., J Cell Biol 101:2134-2144, 1985). The receptor complex, named integrin, binds to fibronectin by recognition of a specific peptide sequence, Arg-Gly-Asp-Ser (RGDS), in the fibronectin molecule (Pierschbacher and Ruoslahti, Proc Natl Acad Sci USA 81:5985-5988, 1984). We have used antibodies to integrin and an RGDS synthetic peptide to probe the functions of integrin in the migration of growth cones extended from sensory and spinal cord neurons of chick embryos. Analyses of time lapse videotapes of growth cone migration before and after adding RGDS indicated that 2 mM RGDS rapidly inhibits growth cone movement on substrata coated with fibronectin or a fragment of fibronectin containing the RGDS sequence. RGDS has no effect on growth cone movement on laminin or on a surface coated with material deposited from heart conditioned medium. However, a monclonal antibody to the integrin complex (10 micrograms/ml CSAT) completely blocks growth cone movement on substrata treated with fibronectin, laminin, or heart conditioned medium. Thus integrin may be involved in growth cone adhesion to several extracellular molecules, although the selective effects of RGDS indicate that the integrin complex may have heterogeneous sites for interaction with different components of the extracellular matrix. CSAT antibody has no discernible effect, however, on growth cone migration across the upper surfaces of C6 glioma cells. These data indicate that the surfaces of nerve growth cones contain multiple binding molecules that mediate different adhesive interactions during migration.

Selective interaction of peripheral and central nervous system cells with two distinct cell-binding domains of fibronectin

Mechanisms of cell interaction with fibronectin have been studied with proteolytic fibronectin fragments that have well-defined ligand binding properties. Results of a previous study (Rogers, S. L., J. B. McCarthy, S. L. Palm, L. T. Furcht, and P. C. Letourneau, 1985, J. Neurosci., 5:369-378) demonstrated that (a) central (CNS) and peripheral (PNS) nervous system neurons adhere to, and extend neurites on a 33-kD carboxyl terminal fibronectin fragment that also binds heparin, and (b) neurons from the PNS, but not the CNS, have stable interactions with a 75-kD cell-binding fragment and with intact fibronectin. In the present study domain-specific reagents were used in inhibition assays to further differentiate cell surface interactions with the two fibronectin domains, and to define the significance of these domains to cell interactions with the intact fibronectin molecule. These reagents are (a) a soluble synthetic tetrapeptide Arg-Gly-Asp-Ser (RGDS; Pierschbacher, M. D., and E. Ruoslahti, 1984, Nature (Lond.), 309:30-33) representing a cell-binding determinant in the 75-kD fragment, and (b) an antibody raised against the 33-kD fragment that binds specifically to that fragment. Initial cell attachment to, and neurite extension upon, fibronectin and the two different fragments was evaluated in the presence and absence of the two reagents. Attachment of both PNS and CNS cells to intact fibronectin was reduced in the presence of RGDS, the former more so than the latter. In contrast, the antibody to the 33-kD fragment did not affect attachment of PNS cells to fibronectin, but significantly decreased attachment of CNS cells to the molecule. RGDS inhibited attachment of CNS cells to the molecule. RGDS inhibited attachment of both cell types to the 75-kD fragment to a greater degree than it did attachment to the intact molecule. Cell interaction with the 33-kD fragment was not affected by RGDS. Reduction of neurite lengths (determined after 24 h of culture) by the domain-specific reagents paralleled the reduction in initial adhesion to each substratum. Therefore, it appears that (a) both PNS and CNS cells have receptors for each cell-binding domain of fibronectin, (b) the receptor(s) for the two domains are distinct, with attachment to the 33-kD fragment being independent of RGDS, and (c) the relative importance of each domain to cell interaction with intact fibronectin is different for CNS and PNS cells.

The Purdue Pegboard: norms for 14- to 19-year-olds

The purpose of this study was to collect normative data on the Purdue Pegboard, a test of finger dexterity, for individuals aged 14 to 19 years. Three trials were administered to 176 subjects from the seven-county Milwaukee area. Results indicated that females performed better than males on three out of four subtests, suburban subjects scored better than urban subjects on two of four subtests, and scores increased with age. The normative data collected provide a means of comparing a patient's score with normal individuals of the same sex and age and aid in determining a patient's need for therapy and in setting appropriate treatment goals.

Seasonal affective disorder in children and adolescents

The authors studied seven children with symptoms of seasonal affective disorder. During the winter months the children regularly experienced irritability, fatigue, school difficulties, sadness, and sleep changes as well as other symptoms of seasonal affective disorder found in adults. An open trial of bright environmental light reversed many of these symptoms and improved mood and psychosocial functioning in the winter months. School counselors and therapists should consider seasonal affective disorder in the differential diagnosis of children with school difficulties that are most prominent in the fall-winter semester.

Distribution of laminin in the developing peripheral nervous system of the chick

During axonal elongation in the developing peripheral nervous system, the temporal and spatial distribution of adhesive molecules in extracellular matrices and on neighboring cell surfaces may provide "choices" of pathways for growth cone migration. The extracellular matrix glycoprotein laminin appears in early embryos and mediates neuronal adhesion and neurite extension in vitro. In this study, we have examined the distribution of laminin at early periods of peripheral nervous system development. The distribution of laminin, demonstrated by immunostaining frozen sections of chick embryos, was compared to the distribution of fibronectin and of early peripheral neurites as revealed with an antibody to a neurofilament-associated protein. Laminin is present in the neural tube basement membrane, in early ganglia, and in developing dorsal and ventral roots, where the laminin staining pattern parallels that of neurofilaments. In early ganglia and nerve roots, laminin immunostaining defines loose "meshworks" rather than basement membranes, which seem to form slightly later in these structures. In contrast, fibronectin is absent in neural tube basement membrane, ganglia, and nerve roots, although it is present along neural crest migratory pathways and in intersomitic spaces. Our observations of laminin distribution are consistent with the possibility that laminin provides an adhesive surface for neurite extension at some stages of early peripheral nervous system development.

Disposition of 8-methoxypsoralen in the rat: methodology for measurement, dose-dependent pharmacokinetics, tissue distribution and identification of metabolites

The pharmacokinetics and metabolism of 8-methoxypsoralen (8-MOP) were measured in the catheterized rat after a single i.v. dose. Blood samples were collected serially and analyzed using a sensitive and specific assay for [14C]-8-MOP. Total body clearance of 8-MOP was 7.3, 3.9, 1.7, 1.0, 0.78 and 0.42 liters/kg/hr at doses of 0.2, 1.0, 2.5, 5.0, 10 and 20 mg/kg, respectively. The decline in total body clearance indicates that elimination of 8-MOP is dose-dependent in the rat. After i.v. administration of 10 mg/kg of 8-MOP, 71 and 26% of the dose was recovered within 72 hr in the urine and feces, respectively. Unchanged 8-MOP accounted for less than 1% of the excreted radioactivity. In tissue distribution studies at 0.5, 2 and 5 hr after i.v. administration, 8-MOP distributed rapidly to all tissues and concentrated in the fat and kidneys. The concentration of 8-MOP in the skin was 0.4 to 0.6 times that in the blood. Eleven metabolites of 8-MOP were detected in the urine. The metabolites identified after enzymatic hydrolysis were 8-hydroxypsoralen; 5-hydroxy-8-methoxypsoralen; 5,8-dihydroxypsoralen; 5,8-dioxopsoralen; 6-(7-hydroxy-8-methoxycoumaryl)-acetic acid and 8-MOP (formed by ring closure of a coumaric acid metabolite). Thus, these studies indicate that 8-MOP is metabolized in the rat by 1) O-demethylation; 2) hydroxylation at position 5; 3) hydrolysis of the lactone ring and 4) oxidation of the furan ring, a pathway already confirmed in insects, dogs and humans.

Neuron-specific interactions with two neurite-promoting fragments of fibronectin

Proteolytic fragments of fibronectin were used to identify regions of the molecule that support neurite extension and to investigate further the differential behavior of central and peripheral nervous system neurons in response to fibronectin (Rogers, S. L., P. C. Letourneau, S. L. Palm, J. B. McCarthy, and L. T. Furcht (1983) Dev. Biol. 98: 212-220). Fibronectin fragments with differing biological activities were produced by proteolytic digestion with trypsin and cathepsin D and sequential affinity chromatography on gelatin-agarose and heparin-Sepharose. The resulting fragments (described by Smith, D. E., D. F. Mosher, R. B. Johnson, and L. T. Furcht (1982) J. Biol. Chem. 257: 5831-5838; Smith, D. E., and L. T. Furcht (1982) J. Biol. Chem. 257: 6518-6523 included an NH2-terminal 27,000-dalton peptide that weakly binds heparin, a 46,000-dalton gelatin-binding fragment, a series of fragments (80,000 to 125,000 daltons) from the center of the molecule containing previously described cell-binding activity, two major peptides of Mr = 33,000 and 66,000 that bind heparin strongly and are thought to originate from the A and B chains, respectively, of plasma fibronectin, and a 31,000-dalton COOH-terminal peptide containing a free sulfhydryl from the A chain of the molecule. Tissue culture dishes were treated with these proteolytic preparations, and dissociated embryonic chick peripheral (PNS) and central nervous system (CNS) cells were cultured on each experimental substratum in serum-free medium. The fibronectin fragments were evaluated for ability to promote cell attachment, neurite initiation, and maintenance of neurite growth. The 27,000-, 46,000-, and 31,000-dalton preparations did not promote cell attachment or neurite extension. Both PNS and CNS neurons attached to and extended stable neurites upon the COOH-terminal heparin-binding preparation containing the 33,000- and 66,000-dalton peptides. A differential response of the neurons to the 80,000- to 125,000-dalton "cell-binding" peptides was observed: whereas PNS neurons maintained neuritic growth on this preparation for at least 48 hr, CNS neurons extended neurites during the first 24 hr of culture but, by 48 hr, withdrew these neurites and became increasingly clumped. On the basis of (1) the observed neuronal responses to the heparin binding and "cell binding" regions, and (2) the different ligand-binding properties of these regions, we propose that cell attachment and neurite extension can be mediated and/or modulated by two separate regions of fibronectin and that cellular response to the intact molecule may involve multivalent interactions.

Serum levels of C-reactive protein in neonatal respiratory distress syndrome

Serum levels of C-reactive protein (CRP) were measured within 96 hours of birth in 55 neonates with respiratory distress syndrome (RDS), 19 neonates with no significant medical illness other than an unstable cardiovascular state, and 13 neonates with a variety of pulmonary and extra-pulmonary problems either alone or in combination with RDS. The median serum CRP level in patients with RDS (2 micrograms/ml) was neither elevated nor different from CRP levels in infants with unstable cardiovascular systems (median CRP level, 2 micrograms/ml); however, neonates with other problems including pneumonia, aspiration, and extrapulmonary sepsis had significantly elevated serum CRP values (median 24 micrograms/ml). CRP levels are not elevated in neonatal RDS. Measurement of this acute phase reactant provides a rapid and reliable means of helping to distinguish infants with uncomplicated RDS from those with other serious pulmonary and extrapulmonary disease.

Stretch receptors in regenerated rat muscle

Although muscle spindles are known to be present in regenerated muscles, it has not previously been reported whether they have any electrophysiological activity. In the present study, rat extensor digitorum longus muscles were traumatized so as to cause all muscle fibers to degenerate; the muscle nerves were either left intact to promote subsequent reinnervation or severed to impede reinnervation. After 2-4 months of regeneration, the muscles were subjected to stretch stimuli and sensory activity was recorded electrophysiologically. Many of the muscles contained stretch-sensitive units that behaved like muscle spindles, although the responses were often highly adaptive and somewhat erratic. In general, the responses from muscles with the nerve left intact were more normal than those from muscles in which the nerve had been severed. Silver staining of the same muscles showed that morphologically recognizable muscle spindles were present, but all were abnormal to varying degrees. These results demonstrate that regenerated muscles can regain some degree of sensory activity in addition to motor functions. The prospect of restored sensory activity may be critical in evaluating the efficacy of graft or transplant procedures for human muscles.