Nonreciprocal Transmission and Reflection of a Chirally Coupled Quantum Dot.

We report strongly nonreciprocal behavior for quantum dot exciton spins coupled to nanophotonic waveguides under resonant laser excitation. A clear dependence of the transmission spectrum on the propagation direction is found for a chirally coupled quantum dot, with spin up and spin down exciton spins coupling to the left and right propagation directions, respectively. The reflection signal shows an opposite trend to the transmission, which a numerical model indicates is due to direction-selective saturation of the quantum dot. The chiral spin-photon interface we demonstrate breaks reciprocity of the system and opens the way to spin-based quantum optical components such as optical diodes and circulators in a chip-based solid-state environment.

Bromide psychosis: a literary case.

Author Evelyn Waugh, noted for such works as Brideshead Revisited, published in 1957 an autobiographical account of his own bromide psychosis in the novel The Ordeal Of Gilbert Pinfold. Until now, however, the fact of his bromide poisoning had gone unrecognized both in biographies of Waugh and in analyses of the novel. Ordeal gives a detailed, accurate, day-by-day description of bromide psychosis. This unusual, witty, and fascinating piece of literature actually provides the most complete monograph on the subject. In this article we review the literature on bromide poisoning, discuss the events of the novel and of Waugh's life in light of his bromide psychosis, and suggest the relevance of the case to medicine.

The rapid change to monotherapy with valproic acid in children.

A review of hospitalized epilepsy patients at Texas Tech University identified 20 children during a 4-year period who had undergone a rapid change from other anticonvulsants to valproate monotherapy. All patients had difficult-to-treat or intractable epilepsy syndromes. In each case, sodium valproate was introduced over a 2- to 4-day period as all other anticonvulsants were withdrawn quickly and sequentially. No acute side effects were seen during hospitalizations, and only one patient reported gastrointestinal complaints. At time of discharge, 12 of the 20 patients were seizure free. Fifteen of the 20 patients were maintained on monotherapy following discharge. By the end of the study period, 12 of the 20 patients showed improvement with valproate, with nine patients experiencing complete seizure control. A rapid switch to valproate monotherapy can be done safely in an inpatient setting.

The use of felbamate to treat infantile spasms.

Based on the initial successful use of felbamate for infantile spasms in an infant with tuberous sclerosis, three additional infants with infantile spasms of different etiologies who had failed conventional therapies were treated with felbamate. Three of the four patients have shown complete resolution of infantile spasms. All responding patients did so within 1 week of starting felbamate. The one treatment failure had an initial reduction of seizure frequency and severity but has not maintained that response long term. Controlled studies are needed to firmly establish that felbamate is both safe and effective for the treatment of infantile spasms. As these cases document, felbamate is currently available for use in infantile spasms, and the frequent conversion of infantile spasms to Lennox-Gastaut syndrome, for which felbamate is approved, makes its use in infantile spasms logical.

Severe myoclonic epilepsy of infancy.

Severe myoclonic epilepsy of infancy (SMEI) is a recently identified seizure disorder with a uniformly poor prognosis. No successful therapy has been found for this disorder. Based on the treatment of 7 patients who qualified for the diagnosis in this report, SMEI has a better prognosis than recognized currently. All 7 patients were responding poorly to phenobarbital, phenytoin, or carbamazepine. Six of them responded to valproate. Two patients became seizure-free during valproate monotherapy. A succinimide was required as a second antiepileptic drug in 3 patients to achieve seizure control. Repeated episodes of "febrile status epilepticus" in 2 patients were controlled with lorazepam. Five of 7 patients are doing significantly better than the literature would suggest is possible. Seizure control can be achieved in SMEI with aggressive use of drugs which are beneficial for myoclonic seizures. Traditional drugs for tonic-clonic seizures are of little or no benefit in SMEI.

Expanded therapeutic range of valproate.

Twenty-five pediatric patients with serum valproate levels above 100 micrograms/ml (therapeutic range: 50-100 micrograms/ml) are reviewed for nondose-related side effects and seizure control. The dose of valproate varied from 50-100 mg/kg/day. All patients had generalized or mixed seizure disorders which were difficult to control. Seizure frequency decreased by more than 50% in 14 patients. For those patients with improved control, valproate levels ranged from 111-196 micrograms/ml. Patients were carefully monitored for side effects; nondose-related side effects were not encountered. Random valproate levels were between 100-200 micrograms/ml. The clinical response to valproate can be augmented by increasing it to the maximum tolerated dose.

The use of imipramine in minor motor seizures.

A study is presented of 15 pediatric patients treated with imipramine for uncontrolled seizures during the past two years. Of these patients, 53% had an initial reduction of seizures of greater than 80%. At one year, 26% were still seizure-free. Drop attacks were especially responsive to therapy; 100% (7/7) responded initially to imipramine therapy. Most patients studied had been receiving valproate and another major antiepileptic drug prior to imipramine therapy. This study confirms previous reports and suggests that the use of imipramine in combination with other antiepileptic drugs provides excellent results, particularly in patients with drop attacks.

Acute cerebellar swelling in varicella encephalitis.

A 4-year-old male developed encephalitis 2 weeks after the onset of varicella. During his evaluation neuroradiologic procedures documented cerebellar edema and demyelination. Cerebrospinal fluid titers confirmed varicella encephalitis. To our knowledge, this patient is the first reported with focal cerebellar edema, an expected finding, with a clinical varicella infection as documented by computed tomography and magnetic resonance imaging.

Variable phenotypes in a family kindred with adrenoleukodystrophy.

Adrenoleukodystrophy, an X-linked recessive disorder characterized by progressive demyelination of the central nervous system and adrenal insufficiency, usually manifests at 4-8 years of age. We report a 20-month-old male who presented with the sudden onset of status epilepticus and cortical blindness; initially, he had complete resolution of these findings, but experienced a relapse 3 months later. The initial computed tomographic scans depicted cerebral edema and possible "watershed infarcts:" however, over the next 2 weeks before discharge from the hospital, the cortical blindness and ataxia both resolved. During the next 2 months, he exhibited no symptoms: he had no seizures and his neurologic examinations were normal. Three months after the initial hospitalization, he developed what the mother believed was "a weakness on his right side." Magnetic resonance imaging confirmed severe white matter disease. Adrenoleukodystrophy was clinically suspected and an assay of plasma levels confirmed an elevation of C26 long-chain saturated fatty acid levels. After the patient's diagnosis of adrenoleukodystrophy was confirmed, long-chain fatty acid levels were obtained on his 5-year-old brother and his mother. This child had the earliest known onset of X-linked adrenoleukodystrophy.

Carbamazepine-exacerbated epilepsy in children and adolescents.

Forty-nine children and adolescents whose seizures reportedly worsened while receiving carbamazepine (CBZ) were studied retrospectively. Twenty-six patients met criteria for excellent documentation of carbamazepine-exacerbated seizures. Four epileptic syndromes were particularly affected: childhood absence epilepsy; focal symptomatic, frontal lobe epilepsy; Lennox-Gastaut syndrome; and severe myoclonic epilepsy of infancy. Eight of the 26 patients developed new-onset absence seizures and three patients with established absence epilepsy experienced absence status. Other seizure types, including atonic, tonic-clonic, and myoclonic, developed in eight patients treated with CBZ, and new generalized spike-and-wave discharges were observed in electroencephalograms of nine patients. CBZ is a widely used, effective antiepileptic drug, particularly for partial or partial complex seizures; however, if uncontrolled, generalized seizures occur after CBZ is prescribed for children or adolescents with absence or mixed seizures, a trial of CBZ discontinuation is warranted. The data reported here do not permit calculation of the incidence of this phenomenon.

Methsuximide therapy of juvenile myoclonic epilepsy.

Currently valproic acid is considered to be the drug of first choice for juvenile myoclonic epilepsy (JME) resulting in a 70-90% control rate for all seizure types associated with JME. In those situations where valproic acid fails to control seizure activity, results in unacceptable side-effects, or is declined due to potential side-effects, an alternative effective monotherapy would be desirable. Five adolescent female patients were placed on methsuximide for JME. All five patients have been seizure free with the use of methsuximide and four out of five are now on methsuximide monotherapy with good success. C.L. has now had complete seizure control on methsuximide monotherapy, a total of 1200 mg a day, for 7 years with the exception of one seizure event occurring on an attempted discontinuation of methsuximide after being 5 years seizure free. Methsuximide monotherapy as demonstrated in these five patients is an effective treatment for JME.

Stimulus and procedural determinants of the forgetting of conditioned fear.

Two studies investigated factors believed to influence the retention of acquired fear in rats. The results show clearly that the lack of forgetting over 24-hr interval reported by previous investigators is due to a depression of performance on the immediate test (3-min retention interval) resulting from the procedure of not handling the rats during conditioning but then handling them on every trial during the retention test. In accord with the McAllister's interpretation of related results, the depression of performance after short retention intervals may be due to a lack of generalization from training to the testing situation. As the retention interval is lengthened, the amount of generalization increases and escape performance improves on a relative basis. The nature of the retention function may be severely distorted by selection of an inappropriate paradigm for its evaluation.

Epidemiology of severe myoclonic epilepsy of infancy.

Severe myoclonic epilepsy of infancy (SMEI) is a newly recognized epileptic syndrome. It is characterized by multiple febrile seizures, often prolonged, subsequent development of uncontrollable mixed-myoclonic seizures, and, eventually, psychomotor retardation. Drugs for myoclonic epilepsy--valproate (VPA), the suximides, and the benzodiazepines--have been shown to be useful in SMEI. Among children with seizures in the National Institute of Neurological and Communicative Disorders and Stroke Collaborative Perinatal Project (NCPP), one individual with SMEI was identified. This finding from the NCPP suggests that the incidence of SMEI is approximately 1 in 40,000 children. Such an incidence is supported by observations at the Texas Tech University Health Sciences Center.

Early severe infantile botulism.

Two neonates with a history of diarrhea, abrupt apnea, and suspected sepsis were proved to have infantile botulism. Initial symptoms in both infants suggested other diagnoses. Electrophysiologic studies were important in confirming the diagnosis. Early severe infantile botulism may be rare but should be considered in neonates who have hypotonia and respiratory arrest or a sepsis-like clinical picture.

Pulsed irrigation enhanced evacuation: new method for treating fecal impaction.

Fecal impaction is a common problem in patients with neurologic impairment. The pulsed irrigation enhanced evacuation (PIEE) procedure is a new method of clearing fecal impactions using pulses of small amounts of warm water to rehydrate stool and improve peristalsis. Thirty-seven PIEE procedures were performed on 28 patients with a variety of neurologic problems. The PIEE procedure was observed to be effective and safe. It should be a useful adjunct to a proper bowel management program.

X-linked hypogonadism, gynecomastia, mental retardation, short stature, and obesity--a new syndrome.

Five male members in four generations of the same family had hypogonadism, gynecomastia, mental retardation, obesity, and short stature. The X-linked mode of inheritance, the distinctive facies, the normal size of the hands and feet, and the true gynecomastia are the main characteristics. Endocrine evaluation and histologic studies of the testes suggest partial hypogonadotropic hypogonadism. This disorder represents a new syndrome distinct from others previously described.

Unexpected seizures during hemodialysis. Effect of dialysate prescription.

To assess the effects of the dialysate prescription on the intradialytic neurological stability of children requiring chronic hemodialysis (HD), continuous EEG monitoring (CEM) was performed on five children before, during and after HD against: (1) low sodium acetate (LAc: Na 132 mEq/l, acetate 38 mEq/l); (2) high sodium acetate (HAc: Na 144 mEq/l, acetate 41 mEq/l), and (3) low sodium bicarbonate (LBi: Na 133 mEq/l, bicarbonate 35 mEq/l) dialysate. Three children, two with clinically well-controlled seizure disorders and one with no seizure history, exhibited subclinical seizures on LAc and HAc but improved neurological stability on LBi. Two children had essentially unchanged CEM studies on any HD regimen. Symptoms of disequilibrium were noted in four of the five children on LAc, two of the five on HAc and only one of the five on LBi. The data suggest that bicarbonate HD may enhance intradialytic neurological stability, particularly in children with known seizure disorders. Furthermore, CEM was found to be a useful tool for evaluating the neurological stability of children during HD.