Alcohol intake is associated with a decreased risk of developing primary biliary cholangitis

BACKGROUND

Primary biliary cholangitis (PBC) is a chronic progressive liver disease of unknown aetiology characterised by immune-mediated destruction of small and medium-sized intrahepatic bile ducts. There are few well-established risk factors and epidemiological studies are needed to further evaluate the pathogenesis of the disease.

AIM

To evaluate the relationship between alcohol intake, smoking and marijuana use with PBC development.

METHODS

We conducted a prevalent case control study of 200 cases and 200 age (within a five year age band) and sex-matched controls, identified from the Victorian PBC prevalence study. We assessed lifetime alcohol intake and smoking behaviour (both tobacco and marijuana) prior to PBC onset and used conditional logistic regression for analyses.

RESULTS

Alcohol intake consistently showed a dose-dependent inverse association with case status, and this was most substantial for 21-30 years and 31-40 years (P_trend < 0.001). Smoking was associated with PBC, with a stronger association with a longer duration of smoking [e.g., adjusted OR 2.27 (95%CI: 1.12- 4.62) for those who had smoked for 20-35 years]. There was no association between marijuana use and PBC.

CONCLUSION

Alcohol appears to have an inverse relationship with PBC. Smoking has been confirmed as an environmental risk factor for PBC. There was no association between marijuana use and PBC.

Evidence-based guideline: Antiepileptic drug selection for people with HIV/AIDS: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Ad Hoc Task Force of the Commission on Therapeutic Strategies of the International League Against Epilepsy

OBJECTIVE

To develop guidelines for selection of antiepileptic drugs (AEDs) among people with HIV/AIDS.

METHODS

The literature was systematically reviewed to assess the global burden of relevant comorbid entities, to determine the number of patients who potentially utilize AEDs and antiretroviral agents (ARVs), and to address AED-ARV interactions.

RESULTS AND RECOMMENDATIONS

AED-ARV administration may be indicated in up to 55% of people taking ARVs. Patients receiving phenytoin may require a lopinavir/ritonavir dosage increase of ~50% to maintain unchanged serum concentrations (Level C). Patients receiving valproic acid may require a zidovudine dosage reduction to maintain unchanged serum zidovudine concentrations (Level C). Coadministration of valproic acid and efavirenz may not require efavirenz dosage adjustment (Level C). Patients receiving ritonavir/atazanavir may require a lamotrigine dosage increase of ∼50% to maintain unchanged lamotrigine serum concentrations (Level C). Coadministration of raltegravir/atazanavir and lamotrigine may not require lamotrigine dosage adjustment (Level C). Coadministration of raltegravir and midazolam may not require midazolam dosage adjustment (Level C). Patients may be counseled that it is unclear whether dosage adjustment is necessary when other AEDs and ARVs are combined (Level U). It may be important to avoid enzyme-inducing AEDs in people on ARV regimens that include protease inhibitors or nonnucleoside reverse transcriptase inhibitors, as pharmacokinetic interactions may result in virologic failure, which has clinical implications for disease progression and development of ARV resistance. If such regimens are required for seizure control, patients may be monitored through pharmacokinetic assessments to ensure efficacy of the ARV regimen (Level C).

Practice parameter update: management issues for women with epilepsy--focus on pregnancy (an evidence-based review): vitamin K, folic acid, blood levels, and breastfeeding: report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and American Epilepsy Society

OBJECTIVE

To reassess the evidence for management issues related to the care of women with epilepsy (WWE) during pregnancy, including preconceptional folic acid use, prenatal vitamin K use, risk of hemorrhagic disease of the newborn, clinical implications of placental and breast milk transfer of antiepileptic drugs (AEDs), risks of breastfeeding, and change in AED levels during pregnancy.

METHODS

A 20-member committee evaluated the available evidence based on a structured literature review and classification of relevant articles published between 1985 and October 2007.

RESULTS

Preconceptional folic acid supplementation is possibly effective in preventing major congenital malformations in the newborns of WWE taking AEDs. There is inadequate evidence to determine if the newborns of WWE taking AEDs have a substantially increased risk of hemorrhagic complications. Primidone and levetiracetam probably transfer into breast milk in amounts that may be clinically important. Valproate, phenobarbital, phenytoin, and carbamazepine probably are not transferred into breast milk in clinically important amounts. Pregnancy probably causes an increase in the clearance and a decrease in the concentration of lamotrigine, phenytoin, and to a lesser extent carbamazepine, and possibly decreases the level of levetiracetam and the active oxcarbazepine metabolite, the monohydroxy derivative.

RECOMMENDATIONS

Supplementing women with epilepsy with at least 0.4 mg of folic acid before they become pregnant may be considered (Level C). Monitoring of lamotrigine, carbamazepine, and phenytoin levels during pregnancy should be considered (Level B) and monitoring of levetiracetam and oxcarbazepine (as monohydroxy derivative) levels may be considered (Level C). A paucity of evidence limited the strength of many recommendations.

Practice parameter update: management issues for women with epilepsy--focus on pregnancy (an evidence-based review): obstetrical complications and change in seizure frequency: report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and American Epilepsy Society

OBJECTIVE

To reassess the evidence for management issues related to the care of women with epilepsy (WWE) during pregnancy, including the risk of pregnancy complications or other medical problems during pregnancy in WWE compared to other women, change in seizure frequency, the risk of status epilepticus, and the rate of remaining seizure-free during pregnancy.

METHODS

A 20-member committee including general neurologists, epileptologists, and doctors in pharmacy evaluated the available evidence based on a structured literature review and classification of relevant articles published between 1985 and February 2008.

RESULTS

For WWE taking antiepileptic drugs, there is probably no substantially increased risk (greater than two times expected) of cesarean delivery or late pregnancy bleeding, and probably no moderately increased risk (greater than 1.5 times expected) of premature contractions or premature labor and delivery. There is possibly a substantially increased risk of premature contractions and premature labor and delivery during pregnancy for WWE who smoke. Seizure freedom for at least 9 months prior to pregnancy is probably associated with a high likelihood (84%-92%) of remaining seizure-free during pregnancy.

RECOMMENDATIONS

Women with epilepsy (WWE) should be counseled that seizure freedom for at least 9 months prior to pregnancy is probably associated with a high rate (84%-92%) of remaining seizure-free during pregnancy (Level B). However, WWE who smoke should be counseled that they possibly have a substantially increased risk of premature contractions and premature labor and delivery during pregnancy (Level C).

Practice parameter update: management issues for women with epilepsy--focus on pregnancy (an evidence-based review): teratogenesis and perinatal outcomes: report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and American Epilepsy Society

OBJECTIVE

To reassess the evidence for management issues related to the care of women with epilepsy (WWE) during pregnancy.

METHODS

Systematic review of relevant articles published between January 1985 and June 2007.

RESULTS

It is highly probable that intrauterine first-trimester valproate (VPA) exposure has higher risk of major congenital malformations (MCMs) compared to carbamazepine and possible compared to phenytoin or lamotrigine. Compared to untreated WWE, it is probable that VPA as part of polytherapy and possible that VPA as monotherapy contribute to the development of MCMs. It is probable that antiepileptic drug (AED) polytherapy as compared to monotherapy regimens contributes to the development of MCMs and to reduced cognitive outcomes. For monotherapy, intrauterine exposure to VPA probably reduces cognitive outcomes. Further, monotherapy exposure to phenytoin or phenobarbital possibly reduces cognitive outcomes. Neonates of WWE taking AEDs probably have an increased risk of being small for gestational age and possibly have an increased risk of a 1-minute Apgar score of <7.

RECOMMENDATIONS

If possible, avoidance of valproate (VPA) and antiepileptic drug (AED) polytherapy during the first trimester of pregnancy should be considered to decrease the risk of major congenital malformations (Level B). If possible, avoidance of VPA and AED polytherapy throughout pregnancy should be considered to prevent reduced cognitive outcomes (Level B). If possible, avoidance of phenytoin and phenobarbital during pregnancy may be considered to prevent reduced cognitive outcomes (Level C). Pregnancy risk stratification should reflect that the offspring of women with epilepsy taking AEDs are probably at increased risk for being small for gestational age (Level B) and possibly at increased risk of 1-minute Apgar scores of <7 (Level C).

Pregnancy registries in epilepsy: a consensus statement on health outcomes

Most pregnant women with epilepsy require antiepileptic drug (AED) therapy. Present guidelines recommend optimizing treatment prior to conception, choosing the most effective AED for seizure type and syndrome, using monotherapy and lowest effective dose, and supplementing with folate. The Epilepsy Therapy Project established the international Health Outcomes in Pregnancy and Epilepsy (HOPE) forum to learn more about the impact of AEDs on the developing fetus, particularly the role of pregnancy registries in studying AED teratogenicity. The primary outcome of interest in these registries is the occurrence of major congenital malformations, with some data collected on minor malformations. Cognitive and behavioral outcomes are often beyond the timeframe for follow-up of these registries and require independent study. The HOPE consensus report describes the current state of knowledge and the limitations to interpretations of information from the various sources. Data regarding specific risks for both older and newer AEDs need to be analyzed carefully, considering study designs and confounding factors. There is a critical need for investigations to delineate the underlying mechanisms and explain the variance seen in outcomes across AEDs and within a single AED.

Atomistic molecular modeling of the effect of chromophore concentration on the electro-optic coefficient in nonlinear optical polymers

We employ fully atomistic molecular modeling to investigate the concentration dependence of the electro-optic coefficient of two guest-host polymer composites. Using classical molecular dynamics, we record the time-evolution of the guest-host system under the application of an external electric field. Through analysis of the orientation of the nonlinear optical chromophores in the guest-host composite with respect to the direction of the external electric field, we calculate the orientational parameter N < cos(3)theta >, with N being the number density of chromophores in the composite. This parameter is directly proportional to the electro-optic coefficient. We find agreement between the concentration dependence of the electro-optic coefficient calculated through our simulation and that from experimental data and also from Monte Carlo models.

Germ-line chimerism and paternal care in marmosets (Callithrix kuhlii)

The formation of viable genetic chimeras in mammals through the transfer of cells between siblings in utero is rare. Using microsatellite DNA markers, we show here that chimerism in marmoset (Callithrix kuhlii) twins is not limited to blood-derived hematopoietic tissues as was previously described. All somatic tissue types sampled were found to be chimeric. Notably, chimerism was demonstrated to be present in germ-line tissues, an event never before documented as naturally occurring in a primate. In fact, we found that chimeric marmosets often transmit sibling alleles acquired in utero to their own offspring. Thus, an individual that contributes gametes to an offspring is not necessarily the genetic parent of that offspring. The presence of somatic and germ-line chimerism may have influenced the evolution of the extensive paternal and alloparental care system of this taxon. Although the exact mechanisms of sociobiological change associated with chimerism have not been fully explored, we show here that chimerism alters relatedness between twins and may alter the perceived relatedness between family members, thus influencing the allocation of parental care. Consistent with this prediction, we found a significant correlation between paternal care effort and the presence of epithelial chimerism, with males carrying chimeric infants more often than nonchimeric infants. Therefore, we propose that the presence of placental chorionic fusion and the exchange of cell lines between embryos may represent a unique adaptation affecting the evolution of cooperative care in this group of primates.

Rank-related maternal effects of androgens on behaviour in wild spotted hyaenas

Within any hierarchical society, an individual's social rank can have profound effects on its health and reproductive success, and rank-related variation in these traits is often mediated by variation in endocrine function. Maternal effects mediated by prenatal hormone exposure are potentially important for non-genetic inheritance of phenotypic traits related to social rank, and thus for shaping individual variation in behaviour and social structure. Here we show that androgen concentrations in wild female spotted hyaenas (Crocuta crocuta) are higher during late gestation in dominant females than in subordinate females. Furthermore, both male and female cubs born to mothers with high concentrations of androgens in late pregnancy exhibit higher rates of aggression and mounting behaviour than cubs born to mothers with lower androgen concentrations. Both behaviours are strongly affected in other mammals by organizational effects of androgens, and both have important effects on fitness in hyaenas. Therefore, our results suggest that rank-related maternal effects of prenatal androgen exposure can adaptively influence offspring phenotype in mammals, as has previously been shown to occur in birds. They also suggest an organizational mechanism for the development of female dominance and aggressiveness in spotted hyaenas, traits that may offset the costs of extreme virilization.

Efficacy and tolerability of the new antiepileptic drugs I: treatment of new onset epilepsy: report of the Therapeutics and Technology Assessment Subcommittee and Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society

OBJECTIVE

To assess the evidence demonstrating efficacy, tolerability, and safety of seven new antiepileptic drugs (AEDs) (gabapentin, lamotrigine, topiramate, tiagabine, oxcarbazepine, levetiracetam, and zonisamide-reviewed in the order in which these agents received approval by the US Food and Drug Administration) in the treatment of children and adults with newly diagnosed partial and generalized epilepsies.

METHODS

A 23-member committee, including general neurologists, pediatric neurologists, epileptologists, and doctors in pharmacy, evaluated the available evidence based on a structured literature review including MEDLINE, Current Contents, and Cochrane library for relevant articles from 1987 until September 2002, with selected manual searches up until 2003.

RESULTS

There is evidence either from comparative or dose-controlled trials that gabapentin, lamotrigine, topiramate, and oxcarbazepine have efficacy as monotherapy in newly diagnosed adolescents and adults with either partial or mixed seizure disorders. There is also evidence that lamotrigine is effective for newly diagnosed absence seizures in children. Evidence for effectiveness of the new AEDs in newly diagnosed patients with other generalized epilepsy syndromes is lacking.

CONCLUSIONS

The results of this evidence-based assessment provide guidelines for the prescription of AEDs for patients with newly diagnosed epilepsy and identify those seizure types and syndromes where more evidence is necessary.

Efficacy and tolerability of the new antiepileptic drugs II: Treatment of refractory epilepsy: Report of the Therapeutics and Technology Assessment Subcommittee and Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society

OBJECTIVE

To assess the evidence demonstrating efficacy, tolerability, and safety of seven new antiepileptic drugs (AEDs) (gabapentin, lamotrigine, topiramate, tiagabine, oxcarbazepine, levetiracetam, and zonisamide) in the treatment of children and adults with refractory partial and generalized epilepsies.

METHODS

A 23-member committee including general neurologists, pediatric neurologists, epileptologists, and doctors in pharmacy evaluated the available evidence based on a structured literature review including MEDLINE, Current Contents, and Cochrane library for relevant articles from 1987 until March 2003.

RESULTS

All of the new AEDs were found to be appropriate for adjunctive treatment of refractory partial seizures in adults. Gabapentin can be effective for the treatment of mixed seizure disorders, and gabapentin, lamotrigine, oxcarbazepine, and topiramate for the treatment of refractory partial seizures in children. Limited evidence suggests that lamotrigine and topiramate are also effective for adjunctive treatment of idiopathic generalized epilepsy in adults and children, as well as treatment of the Lennox Gastaut syndrome.

CONCLUSIONS

The choice of AED depends upon seizure and/or syndrome type, patient age, concomitant medications, AED tolerability, safety, and efficacy. The results of this evidence-based assessment provide guidelines for the prescription of AEDs for patients with refractory epilepsy and identify those seizure types and syndromes where more evidence is necessary.

Dose-response trial of pregabalin adjunctive therapy in patients with partial seizures

BACKGROUND

Pregabalin is an alpha(2)-delta ligand that has anxiolytic, analgesic, and anticonvulsant properties.

OBJECTIVE

To establish the efficacy, safety, and tolerability of pregabalin administered twice-daily (BID) without dose titration as adjunctive treatment in patients with partial seizures and to confirm the dose-response relationship.

METHODS

This 76-center, double-blind, randomized, placebo-controlled, parallel-group study consisted of an 8-week baseline and a 12-week double-blind phase. Patients with refractory partial seizures on one to three antiepileptic drugs were randomly assigned to one of five treatment groups (placebo or 50, 150, 300, and 600 mg/d pregabalin, all administered BID). Efficacy was assessed using seizure frequency reduction and responder rate (> or =50% seizure reduction from baseline). Pharmacokinetic parameters were estimated.

RESULTS

A total of 453 patients were included in the intent-to-treat analysis. The median baseline seizure rate was 10 per month. Seizure frequency reductions from baseline were 7% (placebo; n = 100), 12% (50 mg/d; n = 88), 34% (150 mg/d; n = 86), 44% (300 mg/d; n = 90), and 54% (600 mg/d; n = 89). Responder rates (> or =50% seizure reduction) were 14% (placebo), 15% (50 mg/d), 31% (150 mg/d), 40% (300 mg/d), and 51% (600 mg/d). Discontinuation rates due to adverse events were 5% (placebo), 7% (50 mg/d), 1% (150 mg/d), 14% (300 mg/d), and 24% (600 mg/d). The 150-, 300-, and 600-mg/d pregabalin groups were associated with greater reductions in seizures (p < or = 0.0001) and greater responder rates compared with the placebo group (p < or = 0.006). There was a favorable dose-response trend for both seizure reductions (p < or = 0.0001) and responder rate (p < or = 0.001).

CONCLUSION

Adjunctive therapy with pregabalin 150, 300, and 600 mg/d, given in twice-daily doses without titration, is significantly effective and well tolerated in the treatment of patients with partial seizures as demonstrated in patients with refractory partial seizures.

Postmarketing experience with topiramate and cognition

Ideal antiepileptic drugs (AEDs) are designed to stop seizures with limited central nervous system (CNS) side effects. However, CNS-related treatment-emergent adverse events (TEAEs) often occur in patients receiving AEDs. Topiramate (TPM) is an AED proven to be safe and effective as adjunctive treatment for epilepsy patients with partial seizures. Double-blind, placebo-controlled, multicenter trials demonstrated potential effects on cognition. The P.A.D.S. (post-marketing antiepileptic drug survey) group, a cooperative group of 14 epilepsy centers that collaborate on obtaining data about new AEDs and devices, prospectively collected standardized data forms before and during treatment with TPM for epilepsy, and analyzed the postmarketing experience of CNS TEAEs with TPM. Our results from 701 treated patients show that cognitive complaints were the most common reason to discontinue TPM. The presence of complaints did have predictive value if the patient would discontinue TPM, although was not specific as to when discontinuation would occur. The spectrum of complaints in our open-label prospective multicenter postmarketing study was similar to those observed in controlled clinical trials. We were unable to demonstrate a specific population, dose titration, or concomitant AED that was at risk to discontinue treatment. We conclude that most patients treated with TPM will continue therapy beyond 6 months. Cognitive complaints and not efficacy reflect the primary reason for discontinuing therapy. Psychomotor slowing was the most common complaint, yet most patients elect to continue treatment, with "better" or "much better" ratings of both seizure and global improvement during treatment.

The etiology and diagnosis of status epilepticus

Status epilepticus (SE) is a common, serious, potentially life-threatening, neurologic emergency characterized by prolonged seizure activity. Generalized convulsive status epilepticus (GCSE) is the most widely recognized form of SE. Direct consequences of convulsive movements from SE can result in injury to the body and brain. Nonconvulsive status epilepticus (NCSE) is underrecognized, with controversy surrounding the consequences and treatment. High mortality rates with GCSE have been noted in the past. New treatments for SE are emerging with new parenteral drug formulations as well as new agents for refractory SE, offering an opportunity to improve outcome. Special drug delivery systems, drug combinations, and neuroprotective agents that prevent the subsequent development of epilepsy may soon emerge as future options for treating SE.

Detection of mesial temporal lobe hypoperfusion in patients with temporal lobe epilepsy by use of arterial spin labeled perfusion MR imaging

BACKGROUND AND PURPOSE

Interictal hypometabolism has lateralizing value in cases of temporal lobe epilepsy and positive predictive value for seizure-free outcome after surgery to treat epilepsy. Alterations in regional cerebral metabolism can also be inferred from measurements of regional cerebral perfusion. The purpose of this study was to determine the feasibility of detecting cerebral blood flow (CBF) asymmetries in the mesial temporal lobes using continuous arterial spin labeling perfusion MR imaging, which is a noninvasive method for calculating regional CBF.

METHODS

Twelve patients with medically refractory temporal lobe epilepsy who underwent preoperative evaluation for temporal lobectomy and 12 normal control participants were studied retrospectively. Absolute and normalized mesial temporal CBF measurements were compared between the patient and control groups. Lateralization based on a perfusion asymmetry index was compared with metabolic ((18)[F]-fluorodeoxyglucose positron emission tomography) and hippocampal volumetric asymmetry indices and with clinical lateralization.

RESULTS

Mesial temporal CBF was more asymmetric in patients with temporal lobe epilepsy than in normal control participants, although asymmetric mesial temporal CBF was also found in normal participants, with the left side dominant. Ipsilateral mesial temporal CBF was significantly decreased compared with contralateral mesial temporal CBF in patients with temporal lobe epilepsy. Global CBF measurements were significantly decreased in patients compared with control participants. Asymmetry in mesial temporal blood flow in patients persisted after normalization to global CBF. Lateralization using continuous arterial spin labeling perfusion MR imaging asymmetry index significantly correlated with lateralization based on (18)[F]-fluorodeoxyglucose positron emission tomography hypometabolism, hippocampal volumes, and clinical evaluation.

CONCLUSION

Continuous arterial spin labeling perfusion MR imaging can detect interictal asymmetries in mesial temporal lobe perfusion in patients with temporal lobe epilepsy. This technique is readily combined with routine structural assessment and potentially offers an inexpensive and noninvasive means of screening for asymmetries in interictal mesial temporal lobe function.

The role of new antiepileptic drugs

For many years, epileptologists had few choices for treating seizures. Within the past 20 years several "new generation" antiepileptic drugs (AEDs) were introduced. The most recent additions include oxcarbazepine, levetiracetam, and zonisamide. New agents have been shown in clinical trials to offer similar efficacy compared with older, more established AEDs, but the new agents offer important improvements in safety. Although clinical trials to specifically measure the efficacy of the new AEDs in treating idiopathic generalized epilepsy are rare, the new agents have demonstrated efficacy in treating generalized tonic-clonic convulsions. Data for treatment of Lennox-Gastaut syndrome indicate a clear effect with lamotrigine or topiramate and possibly some effect with zonisamide and levetiracetam. Studies of juvenile myoclonic epilepsy and absence seizures suggest that zonisamide, lamotrigine, topiramate, and levetiracetam may be effective. Each of the new AEDs is effective in controlling partial seizures. These agents may also be appropriate choices for newly diagnosed patients or those whose conditions are refractory to treatment. In clinical trials, patients who are refractory to treatment are often given escalated doses to gain effect, but higher doses also result in more adverse events and higher withdrawal rates. Generally, the higher the dose, the greater the odds of withdrawal, with the exception of levetiracetam, which is not associated with increased withdrawal rates at high doses. Newly diagnosed patients are likely to be controlled with the first therapy given to them. It is therefore important to select an agent with the best safety, efficacy, and tolerability profile possible.

Proof of efficacy trials: endpoints

Seizure frequency data are difficult to work with because they are so variable both between and within patients. Seizures can come in clusters, thereby adding to the variation in seizure frequency. Also, seizure frequency data are non-parametric in nature, making them difficult to analyze by some statistical techniques without transforming them. Therefore, to improve data analysis in proof of efficacy studies, manipulations of seizure frequency are commonly used, such as the proportion of responders above an arbitrary threshold, or the response ratio. Other useful endpoints are time to nth seizure, number of seizure-free days, proportion of seizure-free patients, and assessment of seizure severity using rating scales. The choice of endpoint(s) will depend upon the design of the study.

Status epilepticus arising de novo in hospitalized patients: an analysis of 41 patients

Most of the information on predisposing factors and mortality in status epilepticus (SE) arises from data obtained from patients presenting to the casualty department. However, another population which is frequently seen by consultative neurologists are medically ill patients who develop SE while in hospital. These patients are often notoriously difficult to treat once SE arises. We sought to characterize patients at risk for SE arising when they are hospitalized for other reasons. By doing this, risk factors for developing SE and prognostic indicators might be determined. We retrospectively reviewed records from three urban hospitals in the United States to identify hospitalized patients developing SE over a 1 year period. SE was defined as a clinical seizure lasting 30 minutes or longer, or repeated seizures without recovery. Patients who were admitted in SE or for an epilepsy-related problem, or who were less than 1 year old were excluded from the study. Forty-one patients with in-hospital SE were identified. There were 28 males and 13 females with an age range from 1 to 91 years (mean: 60 years, median: 65 years). The mean interval from hospital admission to the onset of status epilepticus was 26 days. Nineteen (46%) patients had a prior history of either epilepsy or symptomatic seizures, and of these, 10 were inadequately treated as judged by serum anticonvulsant levels at the time SE developed. Focal brain abnormality was present in 26 (63%) patients, the most common of which was stroke (17 patients ). Major metabolic derangements including hypoxia, electrolyte imbalance, hepatic encephalopathy, and sepsis were present in 23 (56%) patients. Eleven (27%) patients were being treated with theophylline preparations at the time SE developed. Mortality in this group of patients with in-hospital SE was 61% (25 deaths), with about one-third dying while in status, and two-thirds dying subsequently in hospital. In this retrospective study, there was no clear relationship between mortality and the duration of SE in this group of patients. In-hospital development of SE is usually related to underlying focal brain abnormality, especially stroke, in combination with systemic metabolic derangement. Prognosis is poor, and appears to be more related to underlying conditions rather than to status duration. More accurate prospective studies are warranted.

Antiepileptic drug interactions

This article reviews the potential interactions of antiepileptic drugs (AEDs) and the pharmacokinetic and pharmacodynamic principles involved. It describes the absorptive and distributive properties of AEDs and the effects on protein binding, hepatic metabolism, and elimination resulting from co-administration of AEDs with food or other drugs. Drug behavior is a function of absorption, metabolism, distribution, and elimination. Administration of either multiple AEDs or a combination of AEDs plus drugs for other conditions can modify any of these physiologic processes, possibly resulting in complex interactions. These may include alterations in the bio-availability and absorption of a drug and changes in half-life and serum level through induction or inhibition of hepatic metabolism. In most cases, increases or decreases in serum concentrations will signal a drug interaction. In other cases, clinically significant drug interactions remain undetected owing to apparently stable serum concentrations. Co-administration of drugs may affect the rate of clearance of one or both drugs. The effect on clearance varies, owing to genetic factors, patient characteristics (age and presence of co-morbidities), and individual responses. AEDs that induce hepatic metabolism can also influence the metabolism of concomitantly administered non-epilepsy medications and can interfere with oral contraceptives, as well as vitamins D and K. Patients with renal insufficiency or advanced age may experience incomplete renal excretion and should receive reduced dosages of drug. Understanding the pharmacokinetics and pharmacodynamic properties of AEDs and the route of metabolism of all competing drugs is important for optimal management of patients with epilepsy and for prevention of avoidable drug interactions.

Interactions among paternal behavior, steroid hormones, and parental experience in male marmosets (Callithrix kuhlii)

Male black tufted-ear marmosets (Callithrix kuhlii) contribute to the rearing of their offspring. Here we evaluated predictions of hypotheses suggesting that (1) T and E2 influence infant-care behavior in male marmosets, (2) levels of T and E2 are modulated by paternal experience, and (3) paternal behavior and levels of T and E2 in male marmosets covary with stress. We observed the behavior of marmosets in their family groups following the birth of infants and evaluated urinary concentrations of T, E2, and the stress hormone cortisol (CORT) among fathers before and after the birth of young. Urinary levels of T, E2, and CORT were lower among males who carried infants at high rates than males who carried at low rates, and T and CORT levels were negatively correlated with carrying rates across all males. Males had significantly lower T levels while carrying the second compared to the first litter and slightly lower rates of infant-carrying, possibly due to assistance provided by offspring of the first litter. There were increases in CORT levels of fathers after the birth of the first litter, but decreases in CORT after the birth of the second. Our results suggest a relationship in C. kuhlii between paternal behavior, hormones, and paternal experience. Rates of infant-carrying appear to be linked to hormone levels, and hormone levels in turn are affected by experience caring for young. Our data also suggest that T, E2, and CORT have synergistic influences on infant-carrying behavior or alternatively that associations between T and E2 and rates of infant-carrying are influenced by stress or other glucocorticoid-related variables. Finally, we propose a hypothesis suggesting that experience-related changes in hormones reinforce the commitment of males to successful breeding partnerships.

Variation in steroid hormones associated with infant care behaviour and experience in male marmosets (Callithrix kuhlii)

We describe temporal patterns of change in paternal behaviour and urinary concentrations of the steroid hormones testosterone (T) and oestradiol (E(2)) in male black tufted-ear marmosets, Callithrix kuhlii, relative to the birth of their young, and test predictions of the hypotheses that (1) high levels of T are incompatible with paternal care and (2) levels of T and E(2)vary with a father's prior experience in his family group. After young were born, levels of urinary T and E(2)remained near prepartum concentrations and rates at which fathers carried infants were below peak levels until the approximate time that postpartum mating ordinarily occurs, suggesting a possible trade-off between readiness to mate and paternal behaviour in C. kuhlii. Infant-carrying behaviour of fathers occurred at its highest rate 3-4 weeks after parturition and coincided with significant declines in urinary levels of T and E(2), providing preliminary support for the hypothesis that these hormones are antagonistic to paternal behaviour. Urinary T and E(2)declined among fathers regardless of whether their young survived to weaning or died at birth, indicating that variation in these hormones after parturition occurs even in the absence of continued stimuli from infants. When adjusted for declines ordinarily associated with aging, urinary T tended to be lower among fathers with a great deal of prior experience caring for young compared with fathers having little or no experience, suggesting that either experience affects T levels of fathers, or that T levels influence fathers' chances of successfully rearing infants. Overall, our results suggest that in male C. kuhlii, T, and possibly E(2), play an important role in balancing the expression of paternal care with that of other reproductive behaviours. Copyright 2000 The Association for the Study of Animal Behaviour.

Social and reproductive conditions modulate urinary cortisol excretion in black tufted-ear marmosets (Callithrix kuhli)

The links between psychosocial stress, social status, reproductive function, and urinary cortisol were assessed in social groups of black tufted-ear marmosets (Callithrix kuhli). Urinary cortisol excretion was monitored in cases of intrafamily conflict ("sibling fights") and in daughters in four distinct social contexts: in the family group, while housed singly or in same-sex pairs, and while paired with a male pairmate. Cortisol excretion was elevated in participants in intra-family conflict on the day of and the day following the conflict, relative to concentrations a week prior to or following the conflict. Daughters in natal family groups had concentrations of cortisol that did not differ from reproductively active adult females. This finding held for daughters who were either anovulatory or undergoing ovulatory cycles while in the natal family group. Natal family members and male pairmates exerted buffering effects on levels of activity in the hypothalamic pituitary adrenal axis (HPA) in female C. kuhli. Placing females in solitary housing led to significantly increased cortisol excretion. In the 2 months subsequent to pairing with a male partner, excreted cortisol concentrations in females declined significantly. Daughters removed from their natal family group and housed with a sister did not exhibit increased cortisol levels. These data reveal that activity in the (HPA) axis in marmosets is sensitive to psychosocial stressors, and that urinary cortisol can provide a useful quantitative measure of HPA reactivity. As in other callitrichids, delayed breeding in daughters and reproductive anomalies in C. kuhli appear to be mediated by mechanisms other than elevated HPA activity.

Pre- and postpartum sex steroids in female marmosets (Callithrix kuhlii): is there a link with infant survivorship and maternal behavior?

Recent studies in primates have suggested that pre- and peripartum sex steroid hormones may be important determinants of maternal behavior and motivation, since higher levels of prepartum estrogen are associated with maternal competency and infant survivorship. To test the cross-species generality of this finding, we monitored excreted profiles of estradiol (E(2)), progesterone metabolites (pregnanediol glucuronide; PdG), and E(2):PdG ratios throughout pregnancy in black tufted-ear marmosets (Callithrix kuhlii). Additionally, we wanted to determine the extent to which variability in maternal carrying effort was related to hormonal factors and relative levels of maternal experience. For six females, hormonal profiles were determined by enzyme immunoassay for two pregnancies, one in which infants survived at least 2 weeks postpartum and one in which infants did not survive. Our within-subjects analyses revealed significant differences in mean prepartum E(2) levels for females in the different infant survival conditions. In contrast to previous findings, however, females exhibited significantly higher prepartum E(2) levels when their infants did not survive a minimum of 2 weeks postpartum, relative to when their infants did survive. Maternal carrying effort was also negatively and significantly correlated with prepartum E(2) levels. Unlike previous reports in callitrichid primates, then, our data suggest that high concentrations of prepartum E(2) in callitrichid primates are not necessarily associated with competent maternal behavior and may instead be associated with poor infant survivorship and inadequate maternal care. Further, our results appear to be convergent with research focusing on human mothers and may represent a common underlying mechanism linking prepartum estrogen and postpartum affect and behavior in some primates.

Management of epilepsy in adolescents and adults

Epilepsy is the most common serious neurological disorder affecting an estimated 50 million people worldwide. Particular focus should be placed on a safe diagnosis, seizure and syndrome classification, and choice of pharmacological and surgical options for a range of patient populations with different health-care requirements. Eight new antiepileptic drugs were licensed in the 1990s with more to come. These new drugs along with earlier resective surgery have led to a better outcome for many more people with this condition.

Functional MRI and the Wada test provide complementary information for predicting post-operative seizure control

Prediction of post-surgical seizure relief and potential cognitive deficits secondary to anterior temporal lobectomy (ATL) are important to pre-surgical planning. Although the intracarotid amobarbital test (IAT) is predictive of post-ATL seizure outcome, development of non-invasive and more precise means for determining post-ATL seizure relief are needed. We previously reported on a technique utilizing functional MRI (fMRI) to evaluate the relative functional adequacy of mesial temporal lobe structures in preparation for ATL. In the present study, we report follow-up outcome data on eight temporal lobe epilepsy (TLE) patients 1-year post-ATL who were evaluated pre-surgically using IAT and fMRI. Functional memory lateralization using fMRI predicted post-ATL seizure outcome as effectively as the IAT. In general, asymmetry of functional mTL activation favouring the non-epileptic hemisphere was associated with seizure-free status at 1-year follow-up. Moreover, when combined, fMRI and IAT provided complementary data that resulted in improved prediction of post-operative seizure control compared with either procedure alone.

Vigabatrin

Vigabatrin (VGB) is a structural analogue of the inhibitory neurotransmitter gamma-amino butyric acid (GABA), which produces its antiepileptic effect by irreversibly inhibiting the degradative enzyme GABA-transaminase. This produces an increase in central nervous system (CNS) GABA levels. VGB is among the few antiepileptic drugs (AEDs) that was synthesized with a specific targeted mechanism in mind and was subsequently demonstrated to function by that mechanism. Tiagabine, a GABA reuptake blocker, is the only other "designer drug" among the currently available AEDs. Therefore, VGB is among the few AEDs for which the mechanism of action is well understood. Recently, safety issues have been raised with regard to the use of vigabatrin. This article reviews the mechanism of action, pharmacokinetics, safety, and efficacy of VGB.

Androgen threshold to activate copulation differs in male rats prenatally exposed to alcohol, stress, or both factors

Few male rats prenatally exposed to a combination of alcohol and stress copulate spontaneously. This study determined adult sensitivity to testosterone (T) in males prenatally exposed to alcohol, to stress, or to both factors. Sexually naive males were tested with receptive females following castration and implantation of 20-, 30-, or 45-mm Silastic T-filled capsules. Serum T levels provided by these implants were measured. The behavior shown by males exposed only to prenatal alcohol did not differ from untreated control animals at any T dosage. Prenatal stress alone diminished the copulatory potential below control levels only when the intermediate T dosage was provided. Few males exposed to both alcohol and stress copulated under the lowest or the intermediate dose of adult T replacement, but most ejaculated normally when the largest capsule was implanted. The threshold to the sexual behavior-activating-properties of adult T exposure was moderately raised by prenatal stress but was severely affected when prenatal stress was combined with alcohol. We conclude that a diminished sensitivity to androgen in adulthood underlies some copulatory deficits resulting from treatments that alter fetal T levels. Such deficits may be concealed when behavior is evaluated in gonadally intact animals.

Hemispheric asymmetries in arousal affect outcome of the intracarotid amobarbital test

Objective: To evaluate changes in arousal and their impact on memory performance during the intracarotid amobarbital test (IAT).

Methods: Along with memory measures, level of arousal was evaluated through clinical ratings and nonverbal self-ratings in epilepsy patients undergoing IAT before anterior temporal lobectomy.

Results: Irrespective of seizure focus, left-sided amobarbital injection resulted in decreased objective and subjective arousal more often than right-side injection. Impaired objective arousal was greater when the left hemisphere was injected second, because of the presumed additive effects of systemic amobarbital residual from the first injection. Decreased objective arousal was related to poorer performance on memory testing following left-hemisphere injection.

Conclusions: The IAT, as practiced in most centers, is biased, so patients with right temporal lobe seizure focus are more likely to “pass” the test, whereas patients with left seizure focus are more likely to “fail” the test. The significant impact of changes in arousal on memory testing needs to be considered when using IAT results to select patients for temporal lobectomy.

Ventricular asystole during vagus nerve stimulation for epilepsy in humans

Electrical stimulation of the vagus nerve, a recently available option for patients with refractory epilepsy, has demonstrated safety and efficacy. We report four patients with refractory epilepsy who experienced ventricular asystole intraoperatively during initial testing for implantation of the vagus nerve stimulator. Acute intraoperative vagus nerve stimulation may create ventricular asystole in humans. Extracorporeal cervical vagus nerve stimulation testing with continuous EKG monitoring intraoperatively before generator implantation is warranted.

Depression in temporal lobe epilepsy before epilepsy surgery

PURPOSE

This study examined the association of depression with laterality of epilepsy surgery in patients with temporal lobe epilepsy before standard lobectomy.

METHODS

Forty-nine patients presented for EEG telemetry for localization of epilepsy and eventual temporal lobectomy. Patients underwent routine neuropsychiatric evaluation blinded for epileptic focus, including ratings on depression. Patients were grouped according to right (n = 25, M = 10/F = 15) and left (n = 24, M = 13/F = 11) temporal lobectomy. Analysis of variance included side of surgery as grouping variable and sex, general depressive, cognitive depressive, and vegetative depressive symptoms as dependent variables. Chi2 analyses included categoric variables of sex, handedness, education, neuropathologic findings, and current affective disorders. t Tests were performed on variables of age, epilepsy duration, and cognitive function.

RESULTS

Right and left temporal epilepsy groups did not differ with regard to sex, handedness, age, duration of epilepsy, education, cognitive function, and neuropathology. Patients with right temporal epilepsy rated higher on general, cognitive. and vegetative depression scores. Women scored higher on general, cognitive, and vegetative depression scores. Current affective disorders were more common in the right temporal epilepsy group.

CONCLUSIONS

Depression ratings and diagnoses were more prominent in patients with right temporal lobe epilepsy and in women in particular. The strength of this laterality finding lies in the selection of patients, as all underwent epilepsy surgery. The finding on gender difference partly reflects the higher incidence of depression in women and needs further exploration. The laterality finding contrasts with recent findings in epilepsy, stroke, and trauma that associate depression with left hemispheric lesions. However, our results are consistent with findings in electrically hyperactive lesions such as gelastic and dacrystic epilepsy.

Close proximity of the heterosexual partner reduces the physiological and behavioral consequences of novel-cage housing in black tufted-ear marmosets (Callithrix kuhli)

The present studies assessed the extent to which heterosexual pairmates could buffer marmosets (Wied's black tufted-ear marmoset, Callithrix kuhli) against stress. Six male and six female marmosets from established groups were exposed to two experimental manipulations together with a control condition. Each condition lasted a total of 4 days. For the two experimental conditions, animals were removed from the family group and housed in a novel cage for 48 h in either the presence or the absence of the heterosexual pairmate. During the 48-h novel-cage housing period and for 48 h upon reunion of the subjects with the family group, concentrations of urinary cortisol were measured in the first void sample of the day and behavioral observations were conducted. When animals were housed alone in a novel cage they exhibited significant elevations in levels of urinary cortisol after 24 and 48 h of novel-cage exposure. In contrast, when marmosets were housed in the novel cage in the presence of the pairmate, levels of urinary cortisol did not change across the 4-day period. The presence of the social partner also reduced the behavioral manifestations of exposure to novelty. Upon reunion with the family group, animals that had been housed in the novel cage alone spent significantly more time in close proximity to the pairmate than animals that had been housed with the partner. A second experiment was conducted to determine the effect that separation from the pairmate, only (independent of any effects of novelty), had on levels of cortisol. Concentrations of urinary cortisol were measured in subjects housed in the familiar home cage, but in the absence of the pairmate, over a 48-h period and compared to concentrations of excreted cortisol immediately prior to separation. Separation from the pairmate did not elevate cortisol levels when the subject was housed in the home cage, suggesting that elevated cortisol levels in animals housed alone in the novel cage were in response to novelty exposure rather than to separation from the pairmate. Since the physical presence of the heterosexual partner reduced the physiological and behavioral effects of novel-cage housing, social attachments might function as homeostatic regulators of HPA function in marmosets.

Medial temporal lobe epilepsy: videotape analysis of objective clinical seizure characteristics

PURPOSE

The syndrome of temporal lobe epilepsy has been described in great detail. Here we focus specifically on the clinical manifestations of seizures originating in the hippocampus and surrounding mesial temporal structures.

METHODS

Seizure origin was confirmed in 67 cases by depth EEG recording and surgical cure after mesial temporal resection.

RESULTS

Among nonlateralized manifestations, we commonly found oral automatisms, pupillary dilatation, impaired consciousness, and generalized rigidity. Appendicular automatisms were often ipsilateral to the seizure focus, whereas dystonia and postictal hemiparesis were usually contralateral. Head deviation, when it occurred early in the seizure, was an ipsilateral finding, but was contralateral to the seizure focus when it occurred late. Clear ictal speech and quick recovery were found when seizures originated in the non-language-dominant hemisphere, but postictal aphasia and prolonged recovery time were characteristic of seizure origin in the language-dominant hemisphere.

CONCLUSIONS

These signs help to define the mesial temporal lobe epilepsy (MTLE) syndrome and often provide information as to the side of seizure origin.

Medical causes of seizures

Seizures are commonly encountered in patients who do not have epilepsy. Factors that may provoke such seizures include organ failure, electrolyte imbalance, medication and medication withdrawal, and hypersensitive encephalopathy. There is usually one underlying cause, which may be reversible in some patients. A full assessment should be done to rule out primary neurological disease. Treatment of seizures in medically ill patients is aimed at correction of the underlying cause with appropriate short-term anticonvulsant medication. Phenytoin is ineffective in the management of seizures secondary to alcohol withdrawal, and in those due to theophylline or isoniazid toxicity. Control of blood pressure is important in patients with renal failure and seizures. Non-convulsive status epilepticus should be considered in any patient with confusion or coma of unclear cause, and electroencephalography should be done at the earliest opportunity. Most ill patients with secondary seizures do not have epilepsy, and this should be explained to patients and their families. Only those patients with recurrent seizures and uncorrectable predisposing factors need long-term treatment with anticonvulsant medication.

Functional MRI lateralization of memory in temporal lobe epilepsy

OBJECTIVE

To determine the feasibility of using functional magnetic resonance imaging (fMRI) to detect asymmetries in the lateralization of memory activation in patients with temporal lobe epilepsy (TLE).

BACKGROUND

Assessment of mesial temporal lobe function is a critical aspect of the preoperative evaluation for epilepsy surgery, both for predicting postoperative memory deficits and for seizure lateralization. fMRI offers several potential advantages over the current gold standard, intracarotid amobarbital testing (IAT). fMRI has already been successfully applied to language lateralization in TLE.

METHODS

fMRI was carried out in eight normal subjects and 10 consecutively recruited patients with TLE undergoing preoperative evaluation for epilepsy surgery. A complex visual scene encoding task known to activate mesial temporal structures was used during fMRI. Asymmetry ratios for mesial temporal activation were calculated, using regions of interest defined in normals. Patient findings were compared with the results of IAT performed as part of routine clinical evaluation.

RESULTS

Task activation was nearly symmetric in normal subjects, whereas in patients with TLE, significant asymmetries were observed. In all nine patients in whom the IAT result was interpretable, memory asymmetry by fMRI concurred with the findings of IAT including two patients with paradoxical IAT memory lateralization ipsilateral to seizure focus.

CONCLUSIONS

fMRI can be used to detect asymmetries in memory activation in patients with TLE. Because fMRI studies are noninvasive and provide excellent spatial resolution for functional activation, these preliminary results suggest a promising role for fMRI in improving the preoperative evaluation for epilepsy surgery.

Molecular pathology of familial hypertrophic cardiomyopathy caused by mutations in the cardiac myosin binding protein C gene

DNA studies in familial hypertrophic cardiomyopathy (FHC) have shown that it is caused by mutations in genes coding for proteins which make up the muscle sarcomere. The majority of mutations in the FHC genes result from missense changes, although one of the most recent genes to be identified (cardiac myosin binding protein C gene, MYBPC3) has predominantly DNA mutations which produce truncated proteins. Both dominant negative and haploinsufficiency models have been proposed to explain the molecular changes in FHC. This study describes two Australian families with FHC caused by different mutations in MYBPC3. The first produces a de novo Asn755Lys change in a cardiac specific domain of MYBPC3. The second is a Gln969X nonsense mutation which results in a truncated protein. Neither mutation has previously been found in the MYBPC3 gene. The consequences of DNA changes on the function of cardiac myosin binding protein C are discussed in relation to current molecular models for this disorder.

Counselling issues in familial hypertrophic cardiomyopathy

To illustrate the variable clinical presentations and rates of progression in familial hypertrophic cardiomyopathy (FHC), phenotypes and genotypes were compared in three FHC families with different genetic defects. In the first family, the FHC abnormality was a protein truncating mutation (Gln969X) in the cardiac myosin binding protein C gene. The second family had a missense change (Asn755Lys) in the same gene. A missense mutation (Arg453Cys) in the cardiac beta myosin heavy chain gene was present in the third family. Penetrance associated with the Gln969X defect was 27% in the age range 0 to 40 years. This was considerably less than the 93% penetrance (0 to 40 years) observed in the two families with missense mutations. The variable penetrance in FHC, as well as the unpredictability of sudden cardiac death, complicates clinical diagnosis and management, including genetic counselling. Although a genetic disease with a predominantly adult onset, there are counselling issues in FHC which set it aside from other adult onset disorders.

Lidar technique for remote measurement of temperature by use of vibrational-rotational Raman spectroscopy

Atmospheric temperature can be measured remotely by a lidar system that measures the ratio of backscattered signals from vibrational-rotational Raman scattering by N(2) to pure vibrational Raman scattering. We present simulations of the performance of an airborne lidar system (based on the Goddard Airborne Raman lidar) that employs this technique.

Psychosocial stress and urinary cortisol excretion in marmoset monkeys (Callithrix kuhli)

Activation of the hypothalamic-pituitary-adrenal (HPA) axis is one of the hallmarks of the physiological responses to psychosocial stressors. The most common method of assessing HPA function is via the measurement of plasma cortisol levels. However, venipuncture involves capture and restraint, which can modify HPA function. We validated a noninvasive procedure for monitoring HPA responses to stressors by measuring excretion of free urinary cortisol. Samples collected throughout the day displayed marked circadian variation, with low cortisol values in first-void samples, followed by a mid-morning peak in cortisol excretion. Concentrations of excreted cortisol declined throughout the day. Exposing marmosets to mild and moderate stressors (11 h isolation in a small cage and manual restraint) increased excreted cortisol concentrations in a dose-dependent fashion: isolation in a small cage led to elevated cortisol in afternoon samples, while manual restraint and isolation produced elevated cortisol in both morning and afternoon samples. The marmoset HPA is differentially sensitive to rather subtle variations in stressors, and these results show that urinary cortisol excretion is a valid and sensitive index of the HPA response to these stressors.

Group size and aggression: 'recruitment incentives' in a cooperatively breeding primate

In many cooperatively breeding birds and mammals, group size is positively correlated with reproductive success. In marmoset and tamarin monkeys, species that display cooperative breeding, the presence of helpers appears to be critical for offspring survival, and breeders might be expected to display social strategies that would regulate group size. This study investigated the association between group size and aggression towards strangers in Wied's black tufted-ear marmosets, Callithrix kuhlifrom small groups (with no helpers present) and large groups (with helpers present). Residents were exposed to multiple presentations of male and female strangers. Breeding females from large groups spent more time in close proximity to strangers, showed higher levels of agonistic displays and engaged in higher levels of aggressive behaviour towards intruders than did breeding females from small groups. Breeding male behaviour did not dramatically differ as a function of group size. After the removal of the intruder, female breeders from large groups showed higher levels of scent-marking relative to baseline observations, and time spent in close proximity to the partner increased after exposure to female intruders in large, but not small, groups. The results reveal that breeders from small groups are tolerant of strangers, which may facilitate the recruitment of additional group members, whereas breeders from large groups, particularly females, are intolerant of strangers, which may inhibit immigration. These findings have implications for understanding mechanisms that regulate immigration in cooperatively breeding animals, and suggest of how breeders from small groups might reconcile the serious limitation of having few or no helpers.

Mechanisms of stroke in sickle cell disease: sickle erythrocytes decrease cerebral blood flow in rats after nitric oxide synthase inhibition

The etiology of stroke in sickle cell disease is unclear, but may involve abnormal red blood cell (RBC) adhesion to the vascular endothelium and altered vasomotor tone regulation. Therefore, we examined both the adhesion of sickle (SS)-RBCs to cerebral microvessels and the effect of SS-RBCs on cerebral blood flow when the nitric oxide (NO) pathway was inhibited. The effect of SS-RBCs was studied in the rat cerebral microcirculation using either a cranial window for direct visualization of infused RBCs or laser Doppler flowmetry (LDF) to measure RBC flow. When fluorescently labeled human RBCs were infused into rats, SS-RBCs had increased adhesion to rat cerebral microvessels compared with control AA-RBCs (P = .01). Next, washed SS-RBCs or AA-RBCs were infused into rats prepared with LDF probes after pretreatment (40 mg/kg intravenously) with the NO synthase inhibitor, N-omega-nitro-L-arginine methyl ester (L-NAME), or the control isomer, D-NAME. In 9 rats treated with systemic L-NAME and SS-RBCs, 5 of 9 experienced a significant decrease in LDF and died within 30 minutes after the RBC infusion (P = .0012). In contrast, all control groups completed the experiment with stable LDF and hemodynamics. Four rats received a localized superfusion of L-NAME (1 mmol/L) through the cranial window followed by infusion of SS-RBCs. Total cessation of flow in all observed cerebral microvessels occurred in 3 of 4 rats within 15 minutes after infusion of SS-RBCs. We conclude that the NO pathway is critical in maintaining cerebral blood flow in the presence of SS-RBCs in this rat model. In addition, the enhanced adhesion of SS-RBCs to rat brain microvessels may contribute to cerebral vaso-occlusion either directly, by disrupting blood flow, or indirectly, by disturbing the vascular endothelium.

Predictors of intellectual performance in adults with intractable temporal lobe epilepsy

The relationships of medical, developmental, social, and familial variables to intellectual performances (IQ scores) were assessed in a sample of 242 adult patients with intractable lateralized temporal lobe epilepsy. Lower IQ scores were associated with low patient and parent education. In addition to the significant contributions of nonneurological social and familial factors to IQ, early age at onset of regular seizures and presence of primary neurological dysfunction in the left cerebral hemisphere were also both independently related to lower IQ. The obtained results suggest that the occurrence of regular seizures during a critical period in early childhood neural maturation poses the greatest risk to cognitive development in the epilepsy population. Total duration of seizures, history of severe convulsive episodes, and the occurrence of another nonepileptic neurological problem in early childhood do not contribute significantly to delayed cognitive development.

Prenatal alcohol and stress interact to attenuate ejaculatory behavior, but not serum testosterone or LH in adult male rats

Restraint stress reduced blood alcohol levels in pregnant rats given a liquid alcohol diet. The male offspring prenatally exposed to both stress and alcohol failed to ejaculate spontaneously, although they copulated normally following exogenous testosterone (T) administration. Males prenatally exposed only to alcohol or only to stress showed no behavioral deficits. Adult serum T and luteinizing hormone levels were normal in both of the fetal alcohol exposed male groups. It appears that the androgen threshold for ejaculatory behavior is elevated in males prenatally exposed to alcohol plus stress and cannot be realized with normal testosterone titers, but it can be attained with exogenous hormone administration. Presumably the alcohol and stress combination interfered with ontogenetic patterns of T needed to fully masculinize the fetal nervous system.

Seizures in temporal lobe epilepsy: I. Reliability of scalp/sphenoidal ictal recording

We determined both (1) the reliability (reproducibility) of seizure onset location in patients with temporal lobe recorded with extracranial EEG and (2) if interictal spike (IIS) location influences that reliability. EEGs were recorded with the 10-20 system and sphenoidal electrodes. Between 1985 and 1993, 166 patients with suspected temporal lobe epilepsy were eligible for inclusion with a total of 734 seizures recorded. Each seizure onset was classified as either localized, lateralized, or nonlocalized. Individual patients were then grouped according to interictal spike location (i.e., unilateral, bilateral, or none) as well as by ictal onset reproducibility patterns (i.e., concordant, semiconcordant, conflicting, or nonlocalized) based on each patient's monitoring session. Seizure onset location was reproducible in 68% of the cases and variable patterns of seizure onset were seen in 32% of patients. Patients with unilateral IIS (68%) were more likely to have consistent ictal onset patterns than patients with bilateral IIS (27%). The first seizure more often predicted subsequent seizure onset patterns when it was localized than when it was nonlocalized. Of 18 patients with conflicting temporal lobe seizures, up to four seizures were necessary to detect independent bilateral temporal lobe seizures.

Social and developmental influences on reproductive function in female Wied's black tufted-ear marmosets (Callithrix kuhli)

Although marmoset social groups may contain multiple adult females, reproduction is typically limited to one breeding female. A variety of endocrine and behavioral mechanisms have been identified that regulate fertility among female marmosets. In the present study, we assessed the mechanism(s) by which fertility is regulated in female black tufted-ear marmosets, Callithrix kuhli. The reproductive status of 10 daughters aged 2-24 months was evaluated by measuring concentrations of urinary pregnane-diol 3 alpha glucuronide (PdG) and luteinizing hormone (LH). Concentrations of the two hormones were typically low in daughters less than 12 months of age, and the profiles suggested anovulation (mean PdG < 2 micrograms/mg Cr and mean LH < 6 ng/mg Cr). Concentrations of PdG rose dramatically in females older than 12 months. Eight subadult daughters commenced ovulatory function while still living with their family, and the remaining two failed to ovulate. The onset of ovarian function coincided with a change in the social environment in two females, but the remaining six females commenced spontaneous ovarian activity that was not associated with any social or environmental factor (mean age: 15.6 +/- 1.6 months). Ovulatory function was monitored in five daughters while housed in their natal family group, while removed from the natal family group and housed singly, and while paired with an unrelated and unfamiliar male. The ovarian cycles of these females housed in the natal group were characterized by significantly shorter luteal phases and reduced PdG concentrations, relative to when the females were housed on their own, and relative to adult breeding females (n = 6). Stimulatory cues from unfamiliar males were not necessary to trigger regular ovarian function in females. In this species, the regulation of fertility in daughters is a complex combination of behavioral and endocrine factors.

Prenatal alcohol and stress interact to attenuate ejaculatory behavior, but not serum testosterone or LH in adult male rats

Restraint stress reduced blood alcohol levels in pregnant rats given a liquid alcohol diet. The male offspring prenatally exposed to both stress and alcohol failed to ejaculate spontaneously, although they copulated normally following exogenous testosterone (T) administration. Males prenatally exposed only to alcohol or only to stress showed no behavioral deficits. Adult serum T and luteinizing hormone levels were normal in both of the fetal alcohol exposed male groups. It appears that the androgen threshold for ejaculatory behavior is elevated in males prenatally exposed to alcohol plus stress and cannot be realized with normal testosterone titers, but it can be attained with exogenous hormone administration. Presumably the alcohol and stress combination interfered with ontogenetic patterns of T needed to fully masculinize the fetal nervous system.