PROTECTIVE EFFECTS OF HUMANIN-G IN HEMORRHAGIC SHOCK IN FEMALE MICE VIA AMPKα1-INDEPENDENT MECHANISMS

ABSTRACT

Introduction: Despite therapeutic advances in hemorrhagic shock, mortality from multiple organ failure remains high. We previously showed that the α1 subunit of AMP-activated protein kinase (AMPK), a crucial regulator of mitochondrial function, exerts a protective role in hemorrhagic shock. Humanin is a mitochondrial peptide with cytoprotective properties against cellular stress. Here, we investigated whether AMPKα1 influences systemic levels of endogenous humanin in hemorrhagic shock and whether treatment with the synthetic analog humanin-G affords beneficial effects. Methods: AMPKα1 wild-type (WT) and knockout (KO) female mice were subjected to hemorrhagic shock followed by resuscitation with blood and lactated Ringer's solution. In short-term studies, mice were treated with humanin-G or vehicle and sacrificed at 3 h after resuscitation; in survival studies, mice were treated with PEGylated humanin-G and monitored for 7 days. Results: Compared with the vehicle WT group, KO mice exhibited severe hypotension, cardiac mitochondrial damage, and higher plasma levels of Th17 cytokines but had similar lung injury and similar plasma elevation of endogenous humanin. Treatment with humanin-G improved lung injury, mean arterial blood pressure, and survival in both WT and KO mice, without affecting systemic cytokine or humanin levels. Humanin-G also ameliorated cardiac mitochondrial damage and increased adenosine triphosphate levels in KO mice. Beneficial effects of humanin-G were associated with lung cytoplasmic and nuclear activation of the signal transducer and activator of transcription-3 (STAT3) in AMPKα1-independent manner with marginal or no effects on mitochondrial STAT3 and complex I subunit GRIM-19. Conclusions: Our data indicate that circulating levels of humanin increase during hemorrhagic shock in AMPKα1-independent fashion as a defense mechanism to counteract metabolic derangement and that administration of humanin-G affords beneficial effects through STAT3 activation even in the absence of a functional AMPKα1.

Effect of intraoperative fluid type on postoperative systemic inflammatory response and end organ dysfunction following total pancreatectomy with islet autotransplantation in children

PURPOSE

To evaluate the effect of intraoperative fluid type [half normal saline (0.45NS) or lactated Ringer's solution (LR)] on the risk of systemic inflammatory response syndrome (SIRS) and acute kidney injury after total pancreatectomy with islet autotransplantation in children.

METHODS

Retrospective review where demographics, operative details, systemic inflammatory response, and evaluation for end organ dysfunction over the first 5 postoperative days was obtained. Mixed effects Poisson regression compared risk of SIRS and acute kidney injury by intraoperative fluid type.

RESULTS

Forty three patients were included with no difference in demographic characteristics between groups. SIRS was observed in 95, 77, and 71% over post operative days 1, 3, and 5. Intraoperative fluid type was found to not be associated with postoperative SIRS (RR: 0.91, p = 0.23). However, female sex (RR: 1.30, p < 0.01), increased BMI (RR: 1.08, p < 0.01), and longer operative time (RR: 1.07, p < 0.01) were found to be factors that are associated with increased risk of postoperative SIRS. Intraoperative 0.45NS use was associated with increased acute kidney injury compared to LR on postoperative day 1 (52% vs 0%, p < 0.01), but not on postoperative days 3 or 5.

CONCLUSION

Intraoperative fluid type (0.45NS vs LR) does not increase the risk of postoperative SIRS in children after TPIAT. Predictive factors that are associated with an increased risk of eliciting postoperative SIRS includes female sex, increased BMI, and longer operative times.

LEVEL OF EVIDENCE

III.

Risk profile of subcutaneous port placement in small children

BACKGROUND/PURPOSE

Long-term central venous access is a safe and common procedure in children. However, complications with devices are a reality. Smaller children are thought to have a higher rate of complication after port placement, and some surgeons avoid placing ports with an arbitrary weight cutoff out of concern for surgical site morbidity.

METHODS

We performed a multi-institutional retrospective review of 500 patients less than 5 years of age undergoing port placement at three large volume children's hospitals from 2014 to 2018. Patients were divided by weight greater than or less than 10 kg at the time of insertion. Statistical analysis was performed to evaluate for differences in outcomes between the two groups.

RESULTS

The majority of ports were placed for chemotherapy access (71.8%). Other indications included long-term infusions (18.8%) and difficult chronic IV access (9.4%). Of the 500 charts reviewed, 110 (22%) experienced some documented complication (28.9% <10 kg, 20.6% >10 kg, p = 0.096). There were no differences between the two groups in terms of the type or timing of complications. Overall, 16.3% of ports required removal prior to the end of therapy owing to a complication. Complication rate per day with the port in place was not different between the two groups (<10 kg: 0.68 complications/1000 port-days vs >10 kg 0.44 complications/1000 port-days, p = 0.068).

CONCLUSION

Weight less than 10 kg was not associated with a significantly higher incidence of any type of port complication in our cohort. This suggests that concern for complications should not exclude children less than 10 kg from port placement.

TYPE OF STUDY

Multi-institutional retrospective review.

LEVEL OF EVIDENCE

Level III.

Outcomes in the giant omphalocele population: A single center comprehensive experience

BACKGROUND/PURPOSE

Morbidity and mortality in the giant omphalocele population is complicated by large abdominal wall defects, physiologic aberrancies, and congenital anomalies. We hypothesized different anomalies and treatment types would affect outcomes.

METHODS

A 2009-2018 retrospective chart review of giant omphaloceles was performed. Exclusions included cloacal exstrophy, transfer after 3 weeks, surgery prior to transfer, conjoined twins, or not yet achieving fascial closure. Thirty-five patients met criteria and mortality and operative morbidity categorized them into favorable (n = 20) or unfavorable (n = 15) outcomes. Odds ratios analyzed potential predictors. Survivors were stratified into staged (n = 11), delayed (n = 8), and primary closure (n = 6) for subgroup analysis.

RESULTS

Unfavorable outcomes were associated with other major congenital anomalies, sac rupture, and major cardiac anomalies, but had significantly lower odds with increasing gestational age (p = 0.03) and birth weight (p < 0.001). In survivors, the primary group was younger at repair (p < 0.001) and had shorter length of stay (hospital p = 0.02, neonatal intensive care unit p = 0.005). There was no significant difference for sepsis, ventilator days, return to the operating room, or ventral hernia.

CONCLUSIONS

Predictions of overall outcomes in the giant omphalocele population require analysis of multiple variables. Our findings demonstrated increased odds of unfavorable outcomes in major cardiac anomalies, pulmonary hypertension, genetic diagnosis, other major anomalies, polyhydramnios, postnatal sac rupture, increasing omphalocele sac diameter, lower O/E TLV, lower gestational age at birth, lower birth weight, and repair other than primary. In those surviving to repair, surgical outcomes analyses demonstrated an earlier age of repair and a shorter length of stay for those patients able to be closed primarily; however further research is necessary to determine overall superiority between operative treatment types.

LEVEL OF EVIDENCE

Level III.

Hepatic Pseudoaneurysm Incidence After Liver Trauma

BACKGROUND

Posttraumatic hepatic artery pseudoaneurysm is a potentially devastating complication after complex liver injury. Increasing computed tomography (CT) use may lead to more frequent identification of posttraumatic hepatic complications. This study was designed to determine the rate of hepatic pseudoaneurysm after traumatic liver injury.

METHODS

We conducted a retrospective review of patients at an urban level 1 trauma center over 5 y (2012-2016). Injury characteristics, patient management, and complications were extracted from trauma registry data and chart review.

RESULTS

Six hundred thirty-four hepatic injuries (11 no grade/no CT, 159 grade I, 154 grade II, 165 grade III, 93 grade IV, and 52 grade V) were identified from our trauma registry. No patient with a grade I or II injury had a subsequent bleeding complication. Eighteen patients had a documented hepatic pseudoaneurysm: grade III n = 3 (1.8%), grade IV n = 6 (6.5%), grade V n = 9 (17.3%). The median time to pseudoaneurysm identification was 6.5 d. Seven pseudoaneurysms were found on asymptomatic surveillance CT-angiography on average 5 d after injury. Eleven patients were symptomatic at the time of CT-angiography performed at a median of 9 d after admission. Of the 11 symptomatic patients, four were in hemorrhagic shock, and two died from hepatic-related complications.

CONCLUSIONS

The incidence of hepatic artery pseudoaneurysm increases with higher grade liver injury. Aggressive surveillance for hepatic pseudoaneurysm with interval CT-angiography 5-7 d postinjury may be warranted, especially for grade IV and V injuries.

Characterizing Early Inpatient Death After Trauma

BACKGROUND

There is a paucity of data to predict early death or futility after trauma. The objective of this study was to characterize the laboratory values, blood product administration, and hospital disposition for patients with trauma who died within 72 h of admission.

METHODS

All deaths within 72 h of admission over a 5-y period at a level I trauma center were reviewed. Blood transfusion within the first 4 h of arrival and patient disposition from the emergency department to the operating room (OR), surgical intensive care unit, or the neuroscience intensive care unit (NSICU) were analyzed. Kaplan-Meier curves were generated to determine time to death.

RESULTS

A total of 622 subjects were identified; 39.5% died in the emergency department, 10.6% went directly to the OR, 13.6% were admitted to the surgical intensive care unit, and 29.7% admitted to the NSICU. Of these subjects, 201 (32.2%) patients received blood within the first 4 h. By 24 h, early blood transfusion was associated with more rapid death for patients who were admitted to the NSICU (80% versus 60% mortality, P = 0.01) but not for patients taken directly to the OR (80% versus 70% mortality, P = 0.2). Admission coagulopathy by international normalized ratio (P < 0.01), but not anemia (P = 0.64) or acidosis (P = 0.45), correlated with a shorter time to death. In contrast, laboratory values obtained at 4 h after admission did not correlate with time to death.

CONCLUSIONS

Our data demonstrate that admission coagulation derangement and need for early blood product transfusion are the two factors most associated with early death after injury, particularly in those patients with traumatic brain injury. These data will help construct future models for futility of continued care in patients with trauma.

Withdrawal of Antithrombotic Agents and the Risk of Stroke

BACKGROUND AND PURPOSE

Antithrombotic medications are effective for ischemic stroke prevention, but stoppage of these medications is associated with an increased risk of thromboembolism. The frequency of antithrombotic withdrawal in the general population is unknown.

METHODS

We conducted a random phone sample of 2036 households in the Greater Cincinnati metropolitan area, representative of the stroke population by age, sex, and race, to determine the frequency of antithrombotic medication use and stoppage by physicians for medically indicated procedures.

RESULTS

Sixty-two percent of survey respondents reported that they were on an antithrombotic medication. Ten percent of participants reported that they had stopped taking their medication within the past 60 days for a medically indicated intervention. Of those who stopped taking the medication, it was more common for persons taking an anticoagulant to stop their medication (20%) than those taking an antiplatelet agent (9%). Colonoscopies and orthopedic surgeries were the most common reasons for withdrawal of antiplatelet agents, whereas orthopedic and vascular surgeries were the most common reason for withdrawal of anticoagulants.

CONCLUSIONS

Recommended discontinuation of antithrombotic medication for surgical or diagnostic procedures is common practice for persons in the community representative of a stroke population. Because stoppage of these medications is associated with an increased risk of thromboembolic stroke, further clinical trials are needed to determine best management practices in this setting.

Genetic risk factors for insidious equine recurrent uveitis in Appaloosa horses

Appaloosa horses are predisposed to equine recurrent uveitis (ERU), an immune-mediated disease characterized by recurring inflammation of the uveal tract in the eye, which is the leading cause of blindness in horses. Nine genetic markers from the ECA1 region responsible for the spotted coat color of Appaloosa horses, and 13 microsatellites spanning the equine major histocompatibility complex (ELA) on ECA20, were evaluated for association with ERU in a group of 53 Appaloosa ERU cases and 43 healthy Appaloosa controls. Three markers were significantly associated (corrected P-value <0.05): a SNP within intron 11 of the TRPM1 gene on ECA1, an ELA class I microsatellite located near the boundary of the ELA class III and class II regions and an ELA class II microsatellite located in intron 1 of the DRA gene. Association between these three genetic markers and the ERU phenotype was confirmed in a second population of 24 insidious ERU Appaloosa cases and 16 Appaloosa controls. The relative odds of being an ERU case for each allele of these three markers were estimated by fitting a logistic mixed model with each of the associated markers independently and with all three markers simultaneously. The risk model using these markers classified ~80% of ERU cases and 75% of controls in the second population as moderate or high risk, and low risk respectively. Future studies to refine the associations at ECA1 and ELA loci and identify functional variants could uncover alleles conferring susceptibility to ERU in Appaloosa horses.

Legionella pneumophila infection of Drosophila S2 cells induces only minor changes in mitochondrial dynamics

During infection of cells by Legionella pneumophila, the bacterium secretes a large number of effector proteins into the host cell cytoplasm, allowing it to alter many cellular processes and make the vacuole and the host cell into more hospitable environments for bacterial replication. One major change induced by infection is the recruitment of ER-derived vesicles to the surface of the vacuole, where they fuse with the vacuole membrane and prevent it from becoming an acidified, degradative compartment. However, the recruitment of mitochondria to the region of the vacuole has also been suggested by ultrastructural studies. In order to test this idea in a controlled and quantitative experimental system, and to lay the groundwork for a genome-wide screen for factors involved in mitochondrial recruitment, we examined the behavior of mitochondria during the early stages of Legionella pneumophila infection of Drosophila S2 cells. We found that the density of mitochondria near vacuoles formed by infection with wild type Legionella was not different from that found in dotA^– mutant-infected cells during the first 4 hours after infection. We then examined 4 parameters of mitochondrial motility in infected cells: velocity of movement, duty cycle of movement, directional persistence and net direction. In the 4 hours following infection, most of these measures were indistinguishable between wild type and dotA⁻.infection. However, wild type Legionella did induce a modest shift in the velocity distribution toward faster movement compared dotA⁻ infection, and a small downward shift in the duty cycle distribution. In addition, wild type infection produced mitochondrial movement that was biased in the direction of the bacterial vacuole relative to dotA-, although not enough to cause a significant accumulation within 10 um of the vacuole. We conclude that in this host cell, mitochondria are not strongly recruited to the vacuole, nor is their motility dramatically affected.

A 4,103 marker integrated physical and comparative map of the horse genome

A comprehensive second-generation whole genome radiation hybrid (RH II), cytogenetic and comparative map of the horse genome (2n = 64) has been developed using the 5000rad horse x hamster radiation hybrid panel and fluorescence in situ hybridization (FISH). The map contains 4,103 markers (3,816 RH; 1,144 FISH) assigned to all 31 pairs of autosomes and the X chromosome. The RH maps of individual chromosomes are anchored and oriented using 857 cytogenetic markers. The overall resolution of the map is one marker per 775 kilobase pairs (kb), which represents a more than five-fold improvement over the first-generation map. The RH II incorporates 920 markers shared jointly with the two recently reported meiotic maps. Consequently the two maps were aligned with the RH II maps of individual autosomes and the X chromosome. Additionally, a comparative map of the horse genome was generated by connecting 1,904 loci on the horse map with genome sequences available for eight diverse vertebrates to highlight regions of evolutionarily conserved syntenies, linkages, and chromosomal breakpoints. The integrated map thus obtained presents the most comprehensive information on the physical and comparative organization of the equine genome and will assist future assemblies of whole genome BAC fingerprint maps and the genome sequence. It will also serve as a tool to identify genes governing health, disease and performance traits in horses and assist us in understanding the evolution of the equine genome in relation to other species.

Allele frequency and likely impact of the glycogen branching enzyme deficiency gene in Quarter Horse and Paint Horse populations

Glycogen Branching Enzyme Deficiency (GBED), a fatal condition recently identified in fetuses and neonatal foals of the Quarter Horse and Paint Horse lineages, is caused by a nonsense mutation in codon 34 of the GBE1 gene, which prevents the synthesis of a functional GBE protein and severely disrupts glycogen metabolism. The aims of this project were to determine the mutant GBE1 allele frequency in random samples from the major relevant horse breeds, as well as the frequency with which GBED is associated with abortion and early neonatal death using the tissue archives from veterinary diagnostic laboratories. The mutant GBE1 allele frequency in registered Quarter Horse, Paint Horse, and Thoroughbred populations was 0.041, 0.036, and 0.000, respectively. Approximately 2.5% of fetal and early neonatal deaths in Quarter Horse-related breeds submitted to 2 different US diagnostic laboratories were homozygous for the mutant GBE1 allele, with the majority of these being abortions. Retrospective histopathology of the homozygotes detected periodic acid Schiff's (PAS)-positive inclusions in the cardiac or skeletal muscle, which is characteristic of GBED, in 8 out of the 9 cases. Pedigree and genotype analyses supported the hypothesis that GBED is inherited as a simple recessive trait from a single founder. The frequency with which GBED is associated with abortion and neonatal mortality in Quarter Horse-related breeds makes the DNA-based test valuable in determining specific diagnoses and designing matings that avoid conception of a GBED foal.

A 1.3-Mb interval map of equine homologs of HSA2

A comparative approach that utilizes information from more densely mapped or sequenced genomes is a proven and efficient means to increase our knowledge of the structure of the horse genome. Human chromosome 2 (HSA2), the second largest human chromosome, comprising 243 Mb, and containing 1246 known genes, corresponds to all or parts of three equine chromosomes. This report describes the assignment of 140 new markers (78 genes and 62 microsatellites) to the equine radiation hybrid (RH) map, and the anchoring of 24 of these markers to horse chromosomes by FISH. The updated equine RH maps for ECA6p, ECA15, and ECA18 resulting from this work have one, two, and three RH linkage groups, respectively, per chromosome/chromosome-arm. These maps have a three-fold increase in the number of mapped markers compared to previous maps of these chromosomes, and an increase in the average marker density to one marker per 1.3 Mb. Comparative maps of ECA6p, ECA15, and ECA18 with human, chimpanzee, dog, mouse, rat, and chicken genomes reveal blocks of conserved synteny across mammals and vertebrates.

Antiviral activity of Petiveria alliacea against the bovine viral diarrhea virus

BACKGROUND

Natural products are a relevant source of antiviral drugs. Five medicinal plants used in Argentina have been assayed to detect inhibition of viral growth.

METHODS

Antiviral activity of the infusions and methanolic extracts of Aristolochia macroura, Celtis spinosa, Plantago major, Schinus areira, Petiveria alliacea and four extracts obtained from the leaves and stems of the last plant were evaluated by the plaque assay.

RESULTS

P. alliacea, unlike A. macroura, C. spinosa, P. major and S. areira, inhibited bovine viral diarrhea virus (BVDV) replication. Neither P. alliacea nor the assays of the other plants were active against herpes simplex virus type 1, poliovirus type 1, adenovirus serotype 7 and vesicular stomatitis virus type 1. Four extracts of P. alliacea were assayed to detect anti-BVDV activity. Ethyl acetate (EC(50) of 25 microg/ml) and dichloromethane (EC(50) of 43 microg/ml) extracts were active; moreover, promising SI (IC(50)/EC(50)) values were obtained.

CONCLUSION

BVDV is highly prevalent in the cattle population, there are no antiviral compounds available; additionally, it is a viral model of the hepatitis C virus. For these reasons and in view of the results obtained, the isolation and characterization of the antiviral components present in the P. alliacea extracts is worth carrying out in the future.

Cytotoxic effect of Argentine medicinal plant extracts on human hepatocellular carcinoma cell line

Methanolic extracts from Achyrocline satureioides (Dc.) Lam, Aristolochia macroura Gomez, Lithraea molleoides (Vell.) Engl., Schinus molle L., unlike those from Celtis spinosa Spreng, Chenopodium ambrosioides L., Petiveria alliacea L., and Plantago major L. showed cytotoxic activity against a human hepatocellular carcinoma cell line, Hep G2. Schinus molle L. was the most active (IC50=50+/-7 microg/ml). These results call for further studies of these extracts.

Reconstituted syntaxin1a/SNAP25 interacts with negatively charged lipids as measured by lateral diffusion in planar supported bilayers

According to the soluble N-ethylmaleimide-sensitive factor (NSF)-attachment protein (SNAP) receptor hypothesis (SNARE hypothesis), interactions between target SNAREs and vesicle SNAREs (t- and v-SNAREs) are required for membrane fusion in intracellular vesicle transport and exocytosis. The precise role of the SNAREs in tethering, docking, and fusion is still disputed. Biophysical measurements of SNARE interactions in planar supported membranes could potentially resolve some of the key questions regarding the mechanism of SNARE-mediated membrane fusion. As a first step toward this goal, recombinant syntaxin1A/SNAP25 (t-SNARE) was reconstituted into polymer-supported planar lipid bilayers. Reconstituted t-SNAREs in supported bilayers bound soluble green fluorescent protein/vesicle-associated membrane protein (v-SNARE), and the SNARE complexes could be specifically dissociated by NSF/alpha-SNAP in the presence of ATP. The physiological activities of SNARE complex formation were thus well reproduced in this reconstituted planar model membrane system. A large fraction (~75%) of the reconstituted t-SNARE was laterally mobile with a lateral diffusion coefficient of 7.5 x 10(-9) cm(2)/s in a phosphatidylcholine lipid background. Negatively charged lipids reduced the mobile fraction of the t-SNARE and the lipids themselves. Phosphatidylinositol-4,5-bisphosphate was more effective than phosphatidylserine in reducing the lateral mobility of the complexes. A model of how acidic lipid-SNARE interactions might alter lipid fluidity is discussed.

The prevalence of dental erosion in a United States and a United Kingdom sample of adolescents

PURPOSE

A high prevalence of tooth surface loss due to erosion is well recognized in the United Kingdom (UK), but not in the United States (US). This could be due to prevalence or perception or a combination of both. The aim of this study was to measure the prevalence of erosion of the upper permanent incisors in US and UK samples of 11-13 year old children.

METHODS

Convenience samples of 129 subjects were examined in the US and 125 in the UK by two trained examiners. The palatal and buccal surfaces of the upper permanent incisors were assessed for the presence of erosion. Subjects also completed a questionnaire investigating any association between the presence of erosion and possible etiological factors.

RESULTS

The prevalence of erosion was 41% in the US and 37% in the UK samples, this difference was not statistically significant. Similarly no statistically significant difference was found between the sexes. The erosion present was confined to enamel in the vast majority of subjects. The questionnaire did not detect any link between the presence of erosion and possible etiological factors.

CONCLUSION

The results of this study suggest that dental erosion is common in both US and UK adolescent populations. There is a need for a larger study to investigate this issue further.

Tethered polymer-supported planar lipid bilayers for reconstitution of integral membrane proteins: silane-polyethyleneglycol-lipid as a cushion and covalent linker

There is increasing interest in supported membranes as models of biological membranes and as a physiological matrix for studying the structure and function of membrane proteins and receptors. A common problem of protein-lipid bilayers that are directly supported on a hydrophilic substrate is nonphysiological interactions of integral membrane proteins with the solid support to the extent that they will not diffuse in the plane of the membrane. To alleviate some of these problems we have developed a new tethered polymer-supported planar lipid bilayer system, which permitted us to reconstitute integral membrane proteins in a laterally mobile form. We have supported lipid bilayers on a newly designed polyethyleneglycol cushion, which provided a soft support and, for increased stability, covalent linkage of the membranes to the supporting quartz or glass substrates. The formation and morphology of the bilayers were followed by total internal reflection and epifluorescence microscopy, and the lateral diffusion of the lipids and proteins in the bilayer was monitored by fluorescence recovery after photobleaching. Uniform bilayers with high lateral lipid diffusion coefficients (0.8-1.2 x 10(-8) cm(2)/s) were observed when the polymer concentration was kept slightly below the mushroom-to-brush transition. Cytochrome b(5) and annexin V were used as first test proteins in this system. When reconstituted in supported bilayers that were directly supported on quartz, both proteins were largely immobile with mobile fractions < 25%. However, two populations of laterally mobile proteins were observed in the polymer-supported bilayers. Approximately 25% of cytochrome b(5) diffused with a diffusion coefficient of approximately 1 x 10(-8) cm(2)/s, and 50-60% diffused with a diffusion coefficient of approximately 2 x 10(-10) cm(2)/s. Similarly, one-third of annexin V diffused with a diffusion coefficient of approximately 3 x 10(-9) cm(2)/s, and two-thirds diffused with a diffusion coefficient of approximately 4 x 10(-10) cm(2)/s. A model for the interaction of these proteins with the underlying polymer is discussed.

Coadministration of phenytoin and felbamate: evidence of additional phenytoin dose-reduction requirements based on pharmacokinetics and tolerability with increasing doses of felbamate

PURPOSE

This open-label study investigated the pharmacokinetic interaction of phenytoin (PHT) and felbamate (FBM).

METHODS

Ten subjects with epilepsy receiving PHT monotherapy were administered increasing doses of FBM (1,200, 1,800, 2,400-3,600 mg/day) at 2-week intervals. PHT doses were reduced by 20% on an individual basis when evidence of clinically significant intolerance was present. With intolerance, the PHT dose was reduced before the next incremental FBM dose. Blood samples were analyzed for FBM, PHT, and PHT metabolite 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH).

RESULTS

Total PHT plasma concentrations increased with coadministered FBM. PHT Cmax increased from 15.9 microg/ml at baseline to 20.9 microg/ml after 1,200 mg/day FBM and to 26.8 microg/ml after 1,800 mg/day FBM. Four subjects required a 20% PHT dose reduction after 1,800 mg/day FBM and six after the administration of 2,400 mg/day FBM. All subjects required further 20% PHT reductions before 3,600 mg/day FBM. FBM Cmax and AUCT were reduced, and apparent clearance increased compared with data from FBM monotherapy.

CONCLUSIONS

With the initiation of FBM therapy in subjects receiving PHT, the PHT dosage should be reduced by 20%. Further PHT dose reductions are likely to be necessary if the FBM dose is increased. The requirements for reductions in dose might be predicted by clinical signs of PHT intolerance.

Hepatosplenic cat-scratch disease in children: selected clinical features and treatment

We reviewed 19 cases of hepatosplenic cat-scratch disease at Texas Children's Hospital (Houston). The range of the patients' ages was 2 years 4 months to 11 years 8 months. The chief complaint was fever for all patients. The duration of fever before diagnosis was 7 to 56 days (mean, 22 days). Abdominal pain was present in 13 patients (68%). Thirteen children were treated with rifampin alone, and three received rifampin therapy plus gentamicin or trimethoprim-sulfamethoxazole. Once rifampin therapy was initiated alone or in combination, improvement was noted within 1 to 5 days (mean, 2.6 days) for patients who had had prolonged fever the duration of which before rifampin therapy averaged 3 weeks. The most common dosage and duration for our patients were 20 mg/[kg x d] every 12 hours and 14 days, respectively. Rifampin should be considered in the initial antimicrobial treatment of hepatosplenic cat-scratch disease.

Pharmacoeconomic analysis of using Sinemet CR over standard Sinemet in parkinsonian patients with motor fluctuations

OBJECTIVE

To compare the costs of pharmacotherapy in patients with Parkinson's disease before and after converting from standard Sinemet to extended-release Sinemet CR.

DESIGN

Investigators retrospectively reviewed records of patients converting from Sinemet to Sinemet CR for efficacy and total drug costs. Cost-effectiveness was evaluated retrospectively from data collected in prospective Sinemet CR efficacy trials.

SETTING

Parkinson's disease clinic at a tertiary care university teaching hospital.

PATIENTS

100 patients with motor fluctuations who had undergone an initial 6-month course of Sinemet therapy, followed by a 6-month course of Sinemet CR.

MAIN OUTCOME MEASURES

Total cost was measured as the cost of Sinemet formulations plus the costs of other antiparkinson medications. Differences in pre- and postconversion costs were compared by using the paired, two-tailed Student's t-test. A substudy of 39 patients on the cost-effectiveness of conversion measured the ratio of daily medication costs to the daily hours "on" without chorea.

RESULTS

While total daily medication costs after conversion increased by 21%, patients experienced either a comparable or an improved degree of disease control with Sinemet CR. Patients who were also taking selegiline were able to decrease selegiline expense by 20%. The costs of other adjunctive medications did not differ significantly after conversion. The cost-effectiveness analysis revealed an increase in postconversion on time by 2.2 hours (p = 0.0001), accompanied by a $2.85 decrease in total cost per hour on without chorea (p = 0.11).

CONCLUSIONS

Although Sinemet CR is more costly, it may be more cost-effective in patients with motor fluctuations. Some patients may be able to reduce adjunctive medications.

Study of an Argentine mistletoe, the hemiparasite Ligaria cuneifolia (R. et P.) Tiegh. (Loranthaceae)

Ligaria cuneifolia (R. et P.) Tiegh. is an hemiparasite species used in Argentine folk medicine as a substitute for the European mistletoe (Viscum album L.) based on its putative activity of decreasing high blood pressure. This paper analyzes flavonoid composition, protein constituents and the possible immunomodulatory and antitumoral effects of this species. Micromolecular study disclosed quercetin-free, quercetin-glycosylated and proanthocyanidins corresponding to cyanidin monomers, which implies a particular metabolic pathway. Proteins present in L. cuneifolia extracts analyzed by SDS-PAGE presented multiple bands with molecular weights ranging from 14 to 90 kD. These features contribute to the characterization of the native mistletoe. As V. album is being used in cancer treatment due to its immunomodulatory and antitumoral activity, the action of aqueous L. cuneifolia extracts on murine lymphocytes was investigated. Culture of murine spleen cells alone or stimulated with Concanavalin A or lipopolysaccharide in presence of L. cuneifolia extracts indicated a certain stimulation of splenocytes alone and an inhibition of splenocytes stimulated with Concanvalin A or lipopolysaccharide. An inhibitory effect was also observed on the proliferation of murine leukemia cells. In addition, aqueous extracts increased nitric oxide production by murine macrophages. These results suggest that L. cuneifolia extracts exert an immunomodulatory effect on the mouse immune system.

Challenges for pediatric radiology using computed radiography

Many of the challenges that we encountered may be overcome through experience, proper configuration of system, and further software enhancements. The overwhelming benefits of improved image access and immediate consultations create a demand for CR, even with sub-optimal images. The challenge for radiology departments is to execute a deliberate implementation of CR, ensuring that we produce the best quality images without greater radiation dose to the patient.

Beyond benzodiazepines: alternative pharmacologic agents for the treatment of insomnia

OBJECTIVE

To review the epidemiology, etiology, and classification of insomnia and provide an overview of the pharmacologic therapy of insomnia. Novel nonbenzodiazepine hypnotics including zolpidem, zopiclone, and zaleplon, as well as nonprescription products such as valerian and melatonin, are reviewed in detail.

DATA SOURCES

A MEDLINE search was performed to identify relevant clinical studies, case reports, abstracts, and review articles published between April 1992 and December 1997. Key search terms included insomnia, benzodiazepines, zolpidem, zopiclone, zaleplon, Cl 284,846, melatonin, and valerian. Additional references were obtained from the lists of review articles and textbooks.

DATA EXTRACTION AND SYNTHESIS

Data concerning the safety and efficacy of the hypnotic agents were extracted from all available clinical trials and abstracts. Background information regarding insomnia, benzodiazepines, and other hypnotics was extracted from the most current literature, including review articles and textbooks.

CONCLUSIONS

New developments in benzodiazepine receptor pharmacology have introduced novel nonbenzodiazepine hypnotics that provide comparable efficacy to benzodiazepines. Although they may possess theoretical advantages over benzodiazepines based on their unique pharmacologic profiles, they offer few, if any, significant advantages in terms of adverse effects. Over-the-counter agents such as valerian and melatonin may be useful in alleviating mild, short-term insomnia, but further clinical trials are required to fully evaluate their safety and efficacy.

Umbilical metastasis (Sister Mary Joseph's nodule) in a child

Metastatic malignancy to the umbilicus, also known as Sister Mary Joseph's nodule, is a rare condition, which to our knowledge has not been reported in a child. We present a case of an umbilical metastasis from carcinoma of the colon in a boy who was also receiving chemotherapy for mediastinal lymphoblastic lymphoma.

Riluzole: a new agent for amyotrophic lateral sclerosis

OBJECTIVE

To provide a comprehensive review of riluzole, including its mechanism of action, pharmacokinetics, adverse drug reactions, drug interactions, efficacy, and administration. A brief review of amyotrophic lateral sclerosis (ALS) is also included.

DATA SOURCES

A computerized search of the MEDLINE database in May 1996 was used to identify publications regarding ALS, riluzole, and metabolism by CYP1A2. Manufacturer's information on riluzole was used when there was no primary literature.

DATA SYNTHESIS

Riluzole is approximately 90% absorbed following an oral dose. Its bioavailability is 60%. Peak concentrations occur within 1-1.5 hours of administration. Riluzole extensively binds to lipoproteins and albumin. This agent primarily undergoes CYP1A2 hydroxylation and glucuronidation, after which it is eliminated by the kidneys. Clearance is reduced in native Japanese healthy subjects and may be reduced in patients with hepatic impairment. Two trials with a total of 1114 patients addressed the efficacy of riluzole in ALS. Riluzole extended the time to tracheostomy or death, and the effect was greatest with dosages of 100 mg/d or greater. No effect on patients' symptoms or global assessment was detected at 18 or 21 months. Several flaws in these trials have led to questions concerning the validity of these results. The most commonly reported adverse effects of riluzole have been transient elevation of liver enzyme concentrations (2-5 times the upper limit of normal), worsening of asthenia, nausea, vomiting, diarrhea, anorexia, dizziness, vertigo, somnolence, and mouth paresthesia. Not as commonly reported, but still very serious, is neutropenia, which occurred in 3 of 4000 patients.

CONCLUSIONS

Although the benefits of riluzole are questionable and it is expensive, this agent may extend the time to tracheostomy or death in patients with ALS. At present, this is the only agent approved for the treatment of ALS and should be made available for these patients.

The relationship of tinnitus to craniocervical mandibular disorders

Patients with craniocervical mandibular (TMD) disorders can present with tinnitus as a primary or secondary complaint. The embryology and functional anatomy of the middle ear, temporomandibular joint, muscles of mastication and associated tendons, ligaments, blood vessels, nerves and lymphatics was found to be helpful in establishing etiologic concepts which relate tinnitus to these temporomandibular disorders. In addition to etiologic concepts, treatment modalities are described. The authors relate their experiences as well as those of others with different patient populations.

Manganese(II) active site mutants of 3,4-dihydroxyphenylacetate 2,3-dioxygenase from Arthrobacter globiformis strain CM-2

Whereas all other members of the extradiol-cleaving catechol dioxygenase family are iron-dependent, the 3,4-dihydroxyphenylacetate 2,3-dioxygenase (MndD) from Arthrobacter globiformis CM-2 is dependent on manganese for catalytic activity. Recently, the endogenous iron ligands of one family member, the 2,3-dihydroxybiphenyl 1,2-dioxygenase (BphC), were identified crystallographically as two histidines and a glutamic acid [Sugiyama, K., et al. (1995) Proc. Jpn. Acad., Ser. B 71, 32-35; Han, et al. (1995) Science 270, 976-980; Senda, T., et al. (1996) J. Mol. Biol. 255, 735-752]. Though BphC and MndD have low overall sequence identity (23%), the three BphC metal ligands are all conserved in MndD (H155, H214, and E266). In order to determine whether these residues also act as ligands to manganese in MndD, site-directed mutants of each were constructed, purified, and analyzed for activity and metal content. Mutations H155A, H214A, and E266Q yielded purified enzymes with specific activities of <0.1% of that of the wild-type dioxygenase and bound 0.4, 1.8, and 33% of the wild-type level of manganese, respectively. The relatively high level of manganese [with a Mn(II) EPR signal distinctly different from that of the wild-type enzyme] observed for E266Q suggests that the glutamine may act as a weak ligand to the metal. Mutant E266D, which retains the potential metal binding capability of a carboxylate group, exhibited 12% of the wild-type activity in crude extracts, suggesting that Mn remains bound; however, this mutant protein was too unstable to be purified and analyzed for metal content. On the basis of the low activity and metal content of mutant proteins, we propose that the conserved residues H155, H214, and E266 ligate manganese in MndD. As is the case with the superoxide dismutases, the extradiol-cleaving catechol dioxygenases appear to utilize identical coordinating residues for their iron- and manganese-dependent enzymes.

Current developments in neurology, Part II: Advances in the pharmacotherapy of Alzheimer disease, Parkinson's disease, and stroke

Disorders of the central nervous system provide innumerable challenges to the clinician. Often the underlying pathophysiology is not completely understood, thus preventing the design of treatment strategies aimed at correcting the underlying process. In this decade of the brain, basic science research combined with difficult but necessary clinical trials may answer some of these seemingly over-whelming questions for these devastating illnesses.

Current developments in neurology, Part I: Advances in the pharmacotherapy of headache, epilepsy, and multiple sclerosis

When caring for patients with disorders of the central nervous system such as migraine headaches, epilepsy, or MS, clinicians are faced with increasingly complex pharmacotherapeutic options. Pharmacotherapeutic strategies directed toward prevention, reversal, or cure of these diseases are hampered by an incomplete understanding of the underlying pathophysiology. In this decade of the brain, basic science research combined with difficult but necessary clinical trials may answer some seemingly overwhelming questions for these devastating illnesses.

Complications of disease and therapy: a comparison of younger and older patients with Parkinson's disease

The incidence of complications associated with disease and treatment was compared in younger versus elderly patients with Parkinson's disease (PD). One hundred sixty-five patient records were divided according to patient age into two groups ("younger," 41 to 64, and "elderly," > or = 65 years) and reviewed for the incidence of dyskinesias, fluctuations, freezing, psychosis, dementia, depression, and insomnia. Younger patients had a greater incidence of chorea (75.8 percent vs 49.5 percent), dystonia (82.3 percent vs 49.0 percent), fluctuations (90.1 percent vs 68.1 percent), depression (73.2 percent vs 36.8 percent), and insomnia (57.9 percent vs 18.1 percent). There were no significant differences in the incidence of freezing, dementia, or psychosis. At the time of the first adverse event, there was no difference in patient characteristics such as gender, lag time from disease diagnosis to levodopa initiation, disease symptoms at the time of diagnosis, levodopa dose, or concomitant drug use despite the fact that the older group had a longer duration of disease, higher Hoehn and Yahr stage, an older age at onset of PD, and longer duration of levodopa use. Younger patients with PD experience a greater incidence of adverse effects than do elderly PD patients. The spectrum of adverse effects is comparable to those of young-onset (< or = 40 years) patients.

"Subclinical" orthostatic hypotension is associated with dizziness in elderly patients with Parkinson disease

OBJECTIVE

To investigate risk factors associated with subjective complaints of dizziness in 12 elderly patients with Parkinson disease (PD), in whom no obvious cause for this symptom could be found.

DESIGN

A case-controlled study, with patients prospectively recruited in a nonblinded fashion.

SETTING

Patients were seen by one physician at a neurology outpatient clinic between August 1993 and August 1994.

SUBJECTS

Thirty-six patients, all over age 65 years and all with PD; 12 complained of dizziness; 24 did not.

INTERVENTIONS

Patients and controls were screened for blood pressure changes, postural instability, motor severity, multiple sensory deficits, drug use, cardiovascular disease, and diabetes mellitus.

MAIN OUTCOME MEASURES

An orthostatic decrease of systolic BP > 15 mmHg (odds ratio = 6.5; 95% confidence interval = 1.22 - 34.52; chi 2mh = 6.7; p < .01) and an orthostatic decrease of diastolic BP > 5mmHg (odds ratio = 11; 95% confidence interval = 3.15 - 38.39; chi 2mh = 7.14; p < .01) were significant risk factors for complaints of dizziness.

RESULTS

The only significant risk factors linked with dizziness were orthostatic decreases in systolic (15 mmHg) and diastolic (5 mmHg) blood pressure.

CONCLUSIONS

An orthostatic decrease in blood pressure is associated with unexplained feelings of dizziness in elderly PD patients.

Clozapine for the treatment of psychosis in Parkinson's disease: chart review of 49 patients

The records of 49 patients with Parkinson's disease and psychosis who were treated with clozapine for up to 18 months were reviewed. Average starting dose of clozapine was 16 mg. Average maximum dose was 39 mg. The psychotic symptoms improved in 76% of the patients at 3 months, and response to clozapine within the first year ranged from 71% to 80%. This response allowed a maximization of levodopa dose. Improvements in scores on the Unified Parkinson's Disease Rating Scale and tremor subscale were seen in some patients but were not statistically significant. This study, the largest of its kind to date, suggests that clozapine is well tolerated and effective in treating psychosis in patients with Parkinson's disease.

Randomized, Double-Blind, Placebo-Controlled Study of Clonidine in Restless Legs Syndrome

Ten patients with idiopathic restless leg syndrome (RLS) were asked to rate their symptoms at baseline during 2 weeks of placebo and 2 weeks of clonidine treatment by using a four-point scale. On two consecutive nights of each treatment period, polysomnography (PSG) and actigraphic studies were performed. Patients subjectively reported improvement in leg sensations (p = 0.02) and motor restlessness (p = 0.001) while receiving clonidine (mean = 0.5 mg/day). On PSG testing, sleep onset occurred faster with clonidine (12 minutes) compared with placebo (30 minutes) and baseline (47 minutes) (p = 0.006). Adverse findings associated with clonidine treatment included decreased percent REM sleep in the clonidine group (4%) compared with placebo (16%) and baseline (16%) (p = 0.001) and increased REM latency in the clonidine group (195 minutes) compared to the placebo (70 minutes) and baseline groups (89 minutes) (p = 0.028). There were no significant changes in total sleep time, stage 1 and 2 sleep, sleep efficiency, awakenings, arousals or periodic limb movements in sleep. There was a nonstatistical trend toward and increase in stage 3 and 4 sleep and a decrease in motor activity as measured by actigraphic recordings. Globally, seven out of 10 patients felt clonidine was more effective than placebo. Four patients chose to continue clonidine after the study. Clonidine may be an effective treatment for RLS patients who don't have large numbers of sleep-disrupting periodic limb movements but have delayed sleep onset due to leg sensations and subsequent motor restlessness.

Apomorphine for motor fluctuations and freezing in Parkinson's disease

OBJECTIVE

To review the pharmacokinetics and use of apomorphine in patients with Parkinson's disease; to report a case of beneficial outcome with apomorphine in a patient with Parkinson's disease with severe levodopa "on-off" fluctuations and freezing; and to outline the types of patients or situations where apomorphine may be useful.

DATA SOURCES

Case reports, review articles, and relevant clinical studies identified by a MEDLINE search of the English-language literature published between 1975 and October 1994.

STUDY SELECTION

Because all but 2 reports were of open-label design with small sample sizes, all studies identified were evaluated.

DATA EXTRACTION

The following data were extracted from each study: apomorphine treatment duration, dosing, onset, duration, and adverse effects. The following efficacy variables were extracted: percent decrease in off periods, improvement in parkinsonian symptoms, and percent decrease in levodopa dosage.

DATA SYNTHESIS

Efficacy of apomorphine following subcutaneous, rectal, sublingual, and intranasal dosage forms are evaluated. We also describe the use of apomorphine in a patient with Parkinson's disease who experienced on-off fluctuations and freezing. Based on these reports, recommendations for patient selection, product selection, and apomorphine dosing guidelines are presented.

CONCLUSIONS

Apomorphine decreases off time, freezing, and levodopa requirements in patients with Parkinson's disease. It can be administered via a number of different nonoral routes; however, subcutaneous apomorphine is the most extensively studied. Rectal, sublingual, and intranasal routes also have been shown to provide benefit in motor fluctuations, but differ from the subcutaneous route in onset of action, duration of effect, and adverse effect profile.

Severe mid-cervical kyphosis with cord compression in Larsen's syndrome and diastrophic dysplasia: unrelated syndromes with similar radiologic findings and neurosurgical implications

Mid-cervical kyphosis in diastrophic dysplasia (DD) with cord compression and weakness has been recognized for the last three decades. A strikingly similar situation exists in Larsen's syndrome (LS), an otherwise unrelated problem of weakness with lay joints and dislocations with typical facies. Forty patients with DD were studied of whom seven had cervical spine kyphosis: one patient had spontaneous correction over the ensuing two decades. Seven patients with LS were studied of whom four had cervical spine changes with cord compression. There was one sudden death among the patients with LS and no cases of spontaneous correction. Muscle weakness in DD and LS should lead to evaluation of cervical spine kyphosis with cord compression. Plain films, CT and recently MRI are useful.

Clozapine therapy for Parkinson's disease and other movement disorders

Recent research on the role of clozapine in the treatment of Parkinson's disease and other movement disorders is discussed. Most clinical trials have shown resolution of or improvement in psychotic symptoms accompanying Parkinson's disease without worsening of parkinsonian symptoms. Adverse effects appear to be mild at dosages of < 100 mg/day; sedation is the most frequent problem. Most of these studies have serious limitations, however; until better studies have been completed, the decision to use clozapine for Parkinson's disease-related psychosis should be made on a case-by-case basis, with thorough evaluation of risks, benefits, and other therapeutic options. Some patients with Parkinson's disease have shown improvement in tremor and other abnormal movements when given clozapine. Clozapine cannot be recommended for treating tardive dyskinesia on the basis of the research done so far; some trials show dramatic resolution of symptoms, others no benefit. Anticholinergics or dopamine-reuptake inhibitors should be considered before clozapine is given to patients with tardive dyskinesia because of clozapine's potential for serious adverse effects. A few patients with Huntington's disease have responded to clozapine, but again no conclusions can be drawn. Clozapine appears to offer no real advantage over haloperidol for treating choreiform movements in Huntington's disease. The frequency of tics in Tourette's syndrome does not seem to be reduced by clozapine. Clozapine has shown some efficacy as a treatment for psychosis and abnormal movements in Parkinson's disease. Results have been less promising for other movement disorders. Further study in larger populations is needed before any definitive conclusions about clozapine's place in movement disorder therapy can be made.

The effect of felbamate on valproic acid disposition

INTRODUCTION

Felbamate is a new antiepileptic drug approved for partial and secondarily generalized seizures.

DESIGN

Subjects with epilepsy (three men and seven women; age range, 20 to 39 years; weight range, 53 to 88 kg) who were previously stabilized with valproic acid, 9.5 to 31.7 mg/kg/day, received both 600 and 1200 mg felbamate twice a day in an open-label, randomized, crossover study.

RESULTS

Coadministration of 1200 or 2400 mg felbamate increased the mean valproic acid area under the curve (from 802.2 to 1025.4 and 1235.9 mg/hr/ml, respectively), peak concentrations (from 86.1 to 115.1 and 133.4 mg/ml, respectively), and average steady-state concentrations (from 66.9 to 85.5 and 103.0 mg/ml, respectively). No changes were observed in valproic acid time to peak concentration or protein binding. Average steady-state felbamate concentrations were 34.7 mg/ml for 600 mg administered twice daily and 61.2 mg/ml for 1200 mg administered twice daily.

CONCLUSION

When felbamate is added to a regimen of valproic acid, valproic acid doses may require reduction because coadministration of felbamate decreased steady-state valproic acid clearance (28% and 54%, respectively; p < 0.01).

Restless legs syndrome in childhood and adolescence

Restless legs syndrome (RLS) is believed to be a condition primarily of middle to older age. However, it can have its onset in childhood. Five illustrative case histories with an autosomal dominant mode of inheritance are described. A mother and her 3 children (age: 6 1/2, 4 and 1 1/2 years) as well as a 16-year-old patient from a second family have typical RLS signs of leg discomfort (paresthesias) and motor restlessness prevalent at night and at rest, with temporary relief by activity. Polysomnography or videotaping revealed periodic limb movements in sleep (PLMS) and, in some cases, involuntary jerking of the legs was present during wakefulness as well. Clinicians should be aware that RLS can occur in childhood and adolescence and may be more common than heretofore recognized. "Growing pains" and attention deficit hyperactivity disorder (ADHD) are in the differential diagnosis of RLS in childhood.

Felbamate: a new antiepileptic drug

The chemistry, pharmacology, pharmacokinetics, clinical use, adverse effects, drug interactions, and dosage of felbamate are discussed. Felbamate (2-phenyl-1,3-propanediol dicarbamate) is chemically unrelated to any of the other currently marketed antiepileptic drugs (AEDs). It appears that felbamate, like phenobarbital and valproic acid, decreases the frequency of seizures by decreasing seizure spread and increasing seizure threshold. Oral felbamate is at least 90% absorbed, and peak concentrations are reached in one to six hours. The half-life is a little less than one day. A therapeutic range of plasma concentrations has not been determined. Felbamate has been used effectively as monotherapy and adjunctive therapy in patients with partial seizures with or without secondary generalization and as adjunctive therapy in children with partial or generalized seizures associated with Lennox-Gastaut syndrome. Felbamate may also be safe and effective in patients with generalized, absence, atypical absence, juvenile myoclonic, infantile, and gelastic seizures. The most frequently reported adverse effects of felbamate include nausea, anorexia, vomiting, headache, fatigue, somnolence, insomnia, and increased serum aspartate aminotransferase levels. The frequency of adverse effects is greater in patients receiving other AEDs in addition to felbamate. Felbamate affects the pharmacokinetics of phenytoin, carbamazepine, valproic acid, and methsuximide; other AEDs also affect the pharmacokinetics of felbamate. The dosage of felbamate should begin at 400 mg orally three times daily and then increase by 600 mg/day every two weeks to up to 3600 mg/day. If the patient is receiving other AEDs concurrently, their dosage should be decreased as the dosage of felbamate is increased. If the goal is to switch to felbamate, the dosage should be increased weekly as the dosages of other AEDs are reduced. Felbamate offers a safe and effective alternative to other AEDs in the treatment of partial and secondarily generalized seizures; partial and generalized seizures associated with Lennox-Gastaut syndrome; and atypical absence seizures, gelastic seizures, and other difficult to control seizures.