Pharmacokinetic variability of factor VIII concentrates in Chinese pediatric patients with moderate or severe hemophilia A

IMPORTANCE

The use of factor VIII (FVIII) concentrates under pharmacokinetic (PK) guidance has become the main approach for treatment of hemophilia. However, limited PK research has been conducted in Chinese pediatric patients.

OBJECTIVE

To investigate the PK parameters of various FVIII concentrates in Chinese pediatric patients.

METHODS

Seventy-nine patients were enrolled (28 treated with Kogenate FS®, 23 treated with Advate ®, and 28 treated with GreenMono™). All enrolled patients participated in single-dose PK analysis after at least a 3-day washout period. Blood samples were collected predose, as well as at 1 h, 9 h, 24 h, and 48 h after infusion; FVIII levels were measured using a one-stage clotting assay. von Willebrand Factor Antigen (VWF:Ag) levels and blood types were also determined. PK parameters were evaluated by WAPPS-Hemo.

RESULTS

Mean values of terminal elimination half-life time (t1/2) for the Kogenate FS®, Advate®, and GreenMono™ FVIII groups were 12.24 h, 10.18 h, and 9.62 h; median clearance values were 4.16, 6.23, and 5.11 mL·kg-1·h-1; and median in vivo recovery values were 1.97, 1.55, and 1.61 IU/dL per IU/kg. Longer t1/2, higher in vivo recovery, and lower clearance were observed in patients with higher VWF:Ag level who were treated with recombinant concentrates.

INTERPRETATION

Chinese pediatric patients with hemophilia had FVIII PK characteristics similar to those previously observed in non-Chinese children, including large variation among individuals. VWF:Ag level and FVIII brand were associated with differences in FVIII PK. Thus, PK-guided dosing should be used to optimize individualized therapy in Chinese children.

The engagement of the aryl hydrocarbon receptor by tryptophan derivatives can prevent the development of anti-FVIII antibodies in an experimental model of hemophilia A

Patients affected by haemophilia A require treatment with factor VIII (FVIII) protein. The most relevant complication is the development of neutralizing FVIII-specific antibodies or “inihibitors”. We reported that the inhibitor-positive status was associated with reduced activity of the immune-regulatory enzyme indoleamine 2,3-dioxygenase 1 (IDO1), that promotes regulatory effects via the production of tryptophan catabolites, known as kynurenines. Some of those tryptophan derivatives are endogenous ligands for the Aryl hydrocarbon receptor (AhR). In this study we tested the potential of tryptophan-related AhR ligands for inhibiting the development of anti-FVIII antibodies in hemophilic (F8 KO) mice. To this aim, F8 KO mice were treated with recombinant human FVIII (rhFVIII) alone or in combination with selected AhR ligands once weekly for four weeks. Antibody titers were tested by specific ELISA and Bethesda test. All mice treated with rhFVIII developed high-titer anti-FVIII antibodies after 4 weeks of treatment. Administration of a specific tryptophan metabolite prevented the generation of anti-FVIII antibodies in almost 80% of F8 KO mice. The protective effect of these AhR ligands was negated by co-administration of the AhR antagonist CH-223191 or in AhR KO mice. Similar results were obtained by administration of engineered gold nanoparticles loaded with the same tryptophan metabolite and rhFVIII. These results suggest that the engagement of AhR, by specific tryptophan derivatives, may be a possible new strategy to control the immune response to rhFVIII. Our findings might lead to the development of novel immunomodulatory interventions for preventing or eradicating inhibitors in hemophilia A patients.

Bioinspired chemistry based on minimalistic pseudopeptides

For years researchers have tried to understand the molecular behavior of complex biomolecules through the development of small molecules that can partially mimic their function. Now researchers are implementing the reverse approach: using the structural and mechanistic knowledge obtained from those complex systems to design small molecules with defined properties and for specific applications. One successful strategy for constructing bioinspired, minimalistic molecules is to combine natural building blocks that provide functional elements with abiotic fragments that serve as structural scaffolds. Therefore pseudopeptidic compounds, most of them based on C2 symmetric structures, represent a unique opportunity to explore and evaluate this approach. Some of these molecules are as simple as two amino acids connected by a diamino spacer. The results in this Account show how bioinspired minimalistic pseudopeptides can form ordered structures, participate in the recognition and transcription of information events in molecular devices, and catalyze reactions. This strategy allows researchers to design and prepare a variety of open-chain and macrocyclic compounds leading to systems that can self-aggregate to form hierarchically ordered micro- and nanostructures. In addition, small changes in the molecule or external stimuli can regulate the self-aggregation pattern. In the same way, researchers can also tune the molecular movements of simple pseudopeptides through environmental factors, providing a means to control new molecular devices. In addition, some of the prepared model compounds have shown interesting properties in molecular recognition and even as sensors for several targets of interest. Finally we have observed remarkable catalytic activities from these types of molecules, although those results are still far from the efficiency shown by natural peptides. This family of pseudopeptidic compounds offers the opportunity for the more elaborate design of relatively simple abiotic but bioinspired systems that display specific properties. In addition, the results can provide additional information that will increase the molecular understanding of the basic principles that underlie the extraordinary behavior of natural systems.

[Training of executive function in preschool children with combined attention deficit hyperactivity disorder: a prospective, controlled and randomized trial]

INTRODUCTION

School-age children with attention deficit hyperactivity disorder, combined type (ADHD-C) have executive function (EF) alterations. ADHD-C and EF alterations improve with methylphenidate or after training of working memory.

AIM

To determine EF training effect on ADHD-C and EF alterations in preschoolers.

INCLUSION CRITERIA

randomly assigned, 2-4 years old with ADHD-C, from 7-1-2004 to 6-30-2005, normal neurological examination, no evidences of underlying chronic disorders, no taking long term medications and parents agree to train or no EF daily. Parents filled out DSM-IV diagnostic criteria form for ADHD-C and children were tested with the Standard Dimensional Change Card Sort Task at the first visit and once a year from 1 to 3 years. Inattention, hyperactivity/impulsivity and EF average scores were statistically analyzed by the t Student for significance.

RESULTS

Of 25, 13 were trained. ADHD-C incidence went down to 16 (64%), 6 (24%) and 10 (40%) trained and untrained. Incidence was 50, 40 and 25% 100, and 66.66 y 100 after 1, 2 and 3 years with and without training. Inattention average score was 8.25, 8.4 and 7 before and 6, 5.8, and 5.5 before and after 1, 2 and 3 years of training. Hyperactivity/impulsivity average score was 8.5, 8.4 and 7.75 before and 5.75, 5.6, and 5.25 after 1, 2 and 3 years of training. EF average score was 5.2, 4.8, and 5.5 before and 8.5, 10 and 9.5 after 1, 2 and 3 years of training. Degree of improving of inattention, hyperactivity/impulsivity and EF were statistically significant for training of EF for 1, 2 and 3 years (p = 0.013, 0.002, 0.0249).

CONCLUSIONS

Children with preschool ADHD-C and EF disorders should receive training of EF for at least 3 years from age of diagnoses to improve their condition.

[Cerebrovascular accidents in full-term newborn infants]

INTRODUCTION

The purpose of this paper is to review the role of the neurologist in the management of cerebrovascular accidents (CVA) (insults resulting from a sudden obstruction or rupture of an intracranial vessel). This was accomplished by reviewing the literature (PubMed) under the heading of stroke and term neonate.

DEVELOPMENT

CVA in full-term neonates are classified as hematomas and infarcts. Hematomas are classified according to: location, structure (arterial, venous, or sinus), type of malformation (aneurysm, venous malformation, and telangiectasia), and cause of the bleed (vessel wall rupture or hypo-coagulation). Classification according to location is based on compartment supra or infratentorial; space -extra-axial (epidural, subdural, or subarachnoid) or intra-axial (parenchymal or ventricular)-; and region -parietal, temporal, thalamic, etc.-. Infarcts are classified according to vascular and parenchymal factors. The vascular factors are the structure, the cause of the obstruction -extramural, mural or intramural (thrombus or embolus)-. The parenchymal factors are type of damage (pale vs hemorrhagic) and location. Patients with suspected embolism should have ultrasound neck. Coagulation studies should be done in patients with hematomas and infracts. Multiple causes may be present in each case. Anticoagulation is only used in small pale infarcts of cardiac embolic origin.

CONCLUSION

The neurologist roles in the management of CVA are to classify the event, select the appropriate investigation, and implement treatment.

[Treatment of herpes simplex encephalitis in children]

INTRODUCTION

Herpes simplex encephalitis (HSE) is a focal infectious disease of the central nervous system (CNS) acknowledged the world over as being severe.

DEVELOPMENT

The epidemiology is well known in developed countries. It presents in patients over the age of 3 months. The mechanism by which the virus reactivates and penetrates into the CNS is still not fully understood. A timely diagnosis is crucial so that early treatment can be established within the first four days of the infectious process. By so doing, it becomes possible to raise the chances of survival by over 50%. The physician should have a strong suspicion when faced with a patient with symptoms of encephalitis, especially if he or she has focal neurological manifestations, including manifestations in the neuropsychiatric sphere. The non-invasive diagnostic method par excellence is high-sensitivity magnetic resonance imaging studies of the brain within the first 24-48 hours following the onset of the clinical signs and symptoms. Determination of viral DNA in cerebrospinal fluid by the polymerase chain reaction method is the technique with the highest degree of sensitivity and specificity available for carrying out the diagnosis. Effective treatment is intravenous acyclovir: 30 mg/kg/day in three doses.

CONCLUSIONS

Encephalitis produced by the herpes virus is a disease that is dreaded because of the high mortality rate and the devastation it causes in the living conditions of survivors. Our aim is to stimulate the clinical suspicion of HSE so that pharmacological treatment can be established even while diagnostic tests are being carried out. We suggest early neuropsychological evaluation and follow-up of the manifestations of focal sequelae related to the frontotemporal regions.

[Executive function disorders]

AIM

To review the development, anatomy and physiology of executive functions (EF) in normal and pathological conditions.

DEVELOPMENT

EF consist of several internal mental process design to solve mental and environmental complex problems in an efficient and acceptable way to the person and the society. EF include inhibition of behavior and irrelevant information, nonverbal working memory, verbal working memory, self-regulation of affect, motivation and arousal, planning, decision making, self monitoring of the entire solving problem process and self evaluation of the results of the action taken. The anatomical substrate is at the prefrontal lobe cortex and its afferent and efferent structures. Neurotransmitters involved in activation of neurons at the prefrontal cortex are dopamine and norepinephrine and in less degree acetylcholine and serotonine.

CONCLUSIONS

Disorders of one or more of the EF in children and adolescents are found in attention deficit/hyperactivity disorder, Tourette syndrome, bipolar disease, depression, obsessive-compulsive disorders, autism and traumatic brain injury.

Outcome after later combined brachial plexus and shoulder surgery after birth trauma

Of 22 infants aged between 11 and 29 months who underwent a combined reconstruction of the upper brachial plexus and shoulder for the sequelae of a birth injury, 19 were followed up for two or more years. The results were evaluated using a modified Gilbert scale. Three patients required a secondary procedure before follow-up. Three patients had a persistent minor internal rotation contracture. All improved by at least two grades on a modified Gilbert scale.

[Hyperbaric oxygen treatment for children with cerebral palsy]

AIMS

Demand from parents has made hyperbaric oxygenation (HO) inhalation the most popular and rapid growing therapy for children with cerebral palsy (CP). To review peer reviewed articles of HO in children with CP to determine its efficacy and risks, literature was searched on-line using PubMed indexed for MEDLINE (1996-2003) for articles under CP and HO headings.

METHOD

We found 16 references: 5 articles (1 uncontrolled pilot study, 2 from a single controlled study, 1 case report of complications and 1 revision) and 11 letters to the editor. The control study showed significant improvements in the middle, at the end and 3 months after 40 treatments with OH (O2=100%/1.75 AA) and placebo (O2=21%/1.3 AA) in the gross motor function measure, (2.9% vs 3%), self-control, auditory attention and visual working memory. There were no significant differences between the groups. Side effects included barometric otitis media (48.2% and 22.2% in the OH and placebo groups). The authors and the Advisory Scientific Committee of the American Academy of Cerebral Palsy and Developmental Medicine agreed that the positive results in both groups were due to a participation effect. The Southern Africa Undersea and Hyperbaric Association discouraged the ongoing, widespread, and informal use of HO for children with CP in South Africa based on the results of this randomized controlled study.

CONCLUSION

There are no scientific evidences for the use of HO in children with CP. Risks include barometric otitis media.

[Generalized neonatal hypotonia]

Generalized neonatal hypotonia implies a pathologically decreased postural tone involving at least the extremities, trunk and neck occurring during the first month of life. The gestational age of the neonate, the behavioral state of the neonate at the time of the examination, and the possibility of pseudoparalysis (due to generalized pain) should be considered when evaluating a neonate for the possibility of generalized hypotonia. The evaluation of neonates with hypotonia should be guided by the characteristic of the muscular dynamic reflexes, primitive reflexes, the relation between the degree of hypotonia and weakness and findings during several maneuvers (traction, ventral and horizontal suspension, plantar response and response to forward displacement from a lying position). Possible sites of pathology in neonates with hypotonia include: (1) brain, (2) brain stem, (3) cervical spine, (4) cerebellum, (5) lower motor neurons in the brain stem and spine; (6) nerve, (7) myoneural junction, and (8) muscles.

[The effect of interictal epileptiform discharges on cognitive function in children with idiopathic epilepsy]

INTRODUCTION

Transient cognitive disorders (CD) in benign rolandic epilepsy (BRE), the most common of idiopathic partial epilepsy (IPE), may be secondary to interictal epileptiform discharges (IED).

OBJECTIVES

To determine incidence and risk factors for persistent TC in students with IE before, during and after antiepileptic (AE).

PATIENTS AND METHODS

INCLUSION CRITERIA

6 12 years old, IPE, controlled for 2 years with AE, and follow up for 5 years.

EVALUATIONS

intelligence (Wechsler III), learning (Wechsler), academic level (Woodcock Johnson) and attention/behavior (O Conners R).

VARIABLES

sex, age of onset, seizure type, interval between first seizure and AE onset, EEG results and AE type.

ANALYSIS

chi square.

RESULTS

Fourteen children had decreased learning and attention span with impulsivity, hyperactivity, low tolerance and agressivity during remission; 12 (85,71%) with temporal lobe epilepsy: 6 (50%) with IED in the left dominant hemisphere, 2 (16,67%) with IED in the right temporal lobe in left dominant hemisphere children, 2 (16,67%) in both temporal lobes in left dominant hemisphere children and 2 (14,29%) with ERB and IED. MRI were normal.

CONCLUSIONS

Children with idiopathic temporal lobe epilepsy and IED in the left dominant hemisphere are at higher risk for CD than children with other types of IPE. To control the seizures and to abolish the IED are recommended in an attempt to prevent these cognitive disorders

[Cerebral malformation in the newborn: holoprosencephaly and agenesis of the corpus callosum]

OBJECTIVE

To review the embriology and clinical aspects of holoprosencephaly and agenesis of the corpus callosum.

DEVELOPMENT

The rostral neuropore closes at 24 days of gestation. At 74 days of gestations axons cross through the dorsal region of the commissural plaque and start forming the corpus callosum. At 115 days of gestations the corpus callosum reaches its adult form. Holoprosencephaly occurs due to rostral mesodermal dysfunction. The etiology of holoprosencephaly is heterogenous. The risk of holoprosencephaly of neonates born to mother with gestational diabetes is 1 2 %. Agenesis of the corpus callosum not associated to holoprosencephaly is due to a disorder of telencephalic midline. Pyruvate dehydrogenase and non ketotic hyperglycinemia can produce agenesis corpus callosum. The prognosis of patients with agenesis of the corpus callosum is dictated by the associated central nervous system and none central nervous system anomalies.

CONCLUSIONS

Knowledge of the embriology of holoprosencephaly and agenesis of the corpus callosum are necessary to understand their radiological appearance. The evaluation of a neonate with these conditions requires genetic and metabolic evaluations.

[Neurophysiological evaluation of children with peripheral neuropathy]

OBJECTIVE

The purpose of this review is to demostrate the value and limitations of neurophysiological evaluation of children with peripheral neuropathy.

DEVELOPMENT

The neurophysiological evaluation (NPE) is an extension of the neurologic examination. The NPE has a high diagnostic sensitiviy but lacks etiologic specificity. The NPE includes motor and sensory nerve conduction velocity studies (NCV), needle EMG, somatosensory evoked potential (SEP) and motor evoked potential (MEP). The NCV allows to determine the component of the peripheral nerve fiber involved (axon and/or myelin), type of fibers affected (motor and/or sensory), the location of the lesion (proximal and/or distal) and the pattern of the nerve involvement (segmental or continuos). The EMG allows to determine the presence and degree of denervation and reinervation.

CONCLUSIONS

The combination of NCV, EMG, SEP and MEP allow: 1. To localize a lesion to the diferent regions of the peripheral nervous system (preganglionic and/or postganglionic segments of dorsal root, ventral root, spinal nerve, plexus and peripheral nerves); 2. To determine severity and prognosis; 3. To select candidates for reconstructive exploratory surgery; and 4. To determine treatment efficacy and/or natural course of the disease

[The effect of discontinuation of methylphenidate at adolescence onset on adult attention deficit hyperactivity disorder]

INTRODUCTION

The positive effect of methylphenidate on children and adults with ADHD is well known. However, the effect of discontinuation of methylphenidate at adolescence onset on adult s ADHD is unknown. Objective. To determine the effect of discontinuation of methylphenidate at adolescence onset on adult s attention deficit, hyperactivity, impulsivity and functional disabilities.

PATIENTS AND METHODS

Adults and their parents, spouses and/or friends were requested to fill out the same criteria diagnosis form filled out by their parents and teachers before (7 years of age), during (7.5 years of age) and at the end of treatment (12 years of age). They took methylphenidate (0.1 0.5 mg/kg/day) from age 7 to 12 years because ADHD. Inattention, hyperactivity, impulsivity and functional disability were statistically analyzed by the paired sample method before, during at the end of treatment and at age 27 years.

RESULTS

Methylphenidate used for 5 years (7.5 12 years of age) improved significantly (p< 0.001) the average score for inattention, hyperactivity, impulsivity and functional impairment compared to pre (7 year of age) and post (27 years of age) treatment. The discontinuation of methylphenidate for 15 years (12 27 year of age) deteriorate significantly the average score for inattention and functional impairment when pre adolescent and adult values were compared (p< 0.001).

CONCLUSIONS

The results strongly suggest that methylphenidate must be used throughout the adulthood to avoid the degree of inattention and functional disability found in this study.

[Acute autoimmune polyradiculoneuropathies]

Landry Guillain Barr Sthrol Syndrome (LGBS) is an acute autoimmune monophasic and selflimiting polyradiculoneuropathy affecting patients aged 19 to 59 years (1.7/100,000/year) more than below 18 year of age (0.8/100,000/year). Diagnostic criteria require: I. Progressive motor weakness of more than one limb, and II) absent muscle stretch reflexes. Features that strongly support the diagnosis are: 1. Cease of progression of weakness by 4 weeks, relative symmetrical involvement of the limbs, presence of mild sensory symptoms or signs, involvement of cranial nerves VII (50%) more than IX, X, III, IV and VI, recovery within 2 to 3 weeks after progression stop, presence of autonomic dysfunction, and absent of fever at onset; 2. Cerebral spinal fluid elevation of protein after first week of symptoms and less than 10 mononuclear leukocytes/mm3 except HIV seropositive patients (<50 cells/mm3), and 3. Nerve conduction slowing (<60% of normal ) or block at some point during the illness (80%), and increased distal motor latency up to 3 times above normal and F wave latency. There are four well defined clinical, pathological, neurophysiological and serological subtypes. Acute inflamatory demyelinating polyradiculoneuropathy (90%) and Miller Fisher syndrome (5%) are primarily demyelinating. Acute motor axonal neuropathy and acute motor sensory axonal neuropathy are primarily axonal (5%). Treatment includes supportive care and immunotherapy with high doses of intravenous IgG and plasmapheresis.

[New techniques used to monitor cerebral function in the newborn]

INTRODUCTION

Continuous display four channels EEG monitoring and near infrared spectroscopy (NIRS) are relatively new and valuable techniques used for continuous brain monitoring in the neonatal period. Supporting the value of continuous display four channels EEG monitoring in the evaluation of neonates with paroxysmal motor events is a study recently conducted at Miami Children s Hospital.

DEVELOPMENT

In this study 30 events were captures in 88 hours of simultaneous continuous display four channels EEG monitoring and continuous video EEG telemetry recording in five patients. Fourteen of the events were consider epileptic and 16 were considered non epileptic after evaluation of the continuous display four channels EEG monitoring printed epochs.

RESULTS

The continuous video EEG telemetry confirmed the diagnosis for all the events. Several studies attest to the usefulness of NIRS in neonates and in older children with pathologies similar to those seeing in neonates.

CONCLUSIONS

1. NIRS is the best method to monitor regional cerebral oxygen saturation; 2. Regional cerebral oxygen saturation values are primarily those of the venous circulation in the subcortical white matter below the sensor; 3. Values of regional oxygen saturation should be considered not independently but only relative as a change over time; 4. Decreased regional cerebral oxygen saturation may be a sign of impending or established hypoxemia or hypotension, increased cerebral metabolic demands, or a cerebral oxygenation or perfusion problem that involve only brain, and 5. NIRS should be used in conjunction with arterial oxygen saturation and pressure monitoring (to detect hypoxemia and hypotension), with EEG to detect increased cerebral metabolic demands (electroencephalographic seizures) and with anterior cerebral artery Doppler ultrasound to detect perfusion (decreased flow velocity) and oxygenation (constant flow velocity) problems that involve only the brain.

Continuous-display four-channel electroencephalographic monitoring in the evaluation of neonates with paroxysmal motor events

The objective of this study was to determine the value of continuous-display four-channel electroencephalographic (EEG) monitoring to distinguish epileptic front nonepileptic paroxysmal motor events. Five full-term neonates with paroxysmal motor events were included in the study. Nurses were instructed to print contiguous pages of the continuous-display four-channel EEG monitoring and to activate the event marker on the simultaneously conducted continuous video-EEG telemetry unit during each paroxysmal motor event. The printouts from the continuous-display four-channel EEG monitoring were interpreted and compared with the corresponding segments of continuous video-EEG telemetry. Thirty paroxysmal motor events were captured. Sixteen paroxysmal motor events were epileptic, and 14 were nonepileptic. The interpretation of the printouts of the continuous four-channel EEG monitoring concurred with an independent interpretation of the corresponding video-EEG telemetry segments in all of the events. Continuous-display four-channel EEG monitoring is a valuable tool in the evaluation of neonates with paroxysmal motor events since it reliably distinguishes epileptic and nonepileptic events.

Internal carotid artery thrombus: an underdiagnosed source of brain emboli in neonates?

We report a full-term neonate with a left middle cerebral artery infarct, narrowing of the internal carotid artery detected by magnetic resonance angiography and B-mode ultrasonography, and a large thrombus at the origin of the internal carotid artery detected by B-mode ultrasonography. Internal carotid arterial thrombus is seldom considered the source of middle cerebral arterial embolus in neonates. We suggest that B-mode ultrasonography of the carotid artery be included in the diagnostic evaluation of middle cerebral artery infarcts in neonates.

Intravenous valproate dosing in neonates

The loading dosage of intravenous valproate required to achieve a desired serum concentration in neonates is not known. Two neonates with seizures received loading doses of intravenous valproate over 30 minutes. Serum valproate concentrations were measured 45 minutes and 3 hours after initiation of the infusion. Both neonates had received phenobarbital and phenytoin before the loading infusions. In the first patient, a loading dose of intravenous valproate of 10 mg/kg increased the 45-minute postinfusion serum valproate concentration to 41 microg/mL with a 3-hour postinfusion serum valproate concentration of 33 microg/mL. In the second patient, a loading dose of 25 mg/kg increased the 45-minute postinfusion serum valproic acid concentration to 100 microg/mL with a 3-hour postinfusion serum valproic acid concentration of 78 microg/mL. We found that each 1 mg/kg of intravenous valproate increased the 45-minute and 3-hour postinfusion serum valproic acid concentrations by approximately 4 microg/mL and 3 microg/mL, respectively. We suggest that these figures be used to calculate the desirable loading dose of intravenous valproate in neonates until larger studies are conducted. The volume of distribution and the serum clearance of valproate were approximately 0.245 L/kg and 25 mL/h/kg, respectively.

Optically active dioxatetraazamacrocycles: chemoenzymatic syntheses and applications in chiral anion recognition

Two new C2 and D2 symmetrical dioxatetraaza 18-membered macrocycles [(R,R)-1 and (S,S,S,S)-2] are efficiently synthesized in enantiomerically pure forms by a chemoenzymatic method starting from (+/-)-trans-cyclohexane-1,2-diamine. The protonation constants and the binding constants with different chiral dicarboxylates are determined in aqueous solution by means of pH-metric titrations. The triprotonated form of (S,S,S,S)-2 shows moderate enantioselectivity with malate and tartrate anions (deltadeltaG=0.62 and 0.66 kcal mol(-1), respectively), being the strongest binding observed in both cases with the L enantiomer. Good enantiomeric discrimination is obtained with tetraprotonated (R,R)-1 and N-acetyl aspartate, the complex with the D-enantiomer being 0.92 kcalmol(-1) more stable than its diastereomeric counterpart. Despite the lack of enantioselectivity of tri- and tetraprotonated (R,R)-1 for the tartrate anion, a very good diastereopreference for meso-tartrate is found. All these experimental results allow us to propose a model for the host-guest structure based on coulombic interactions and hydrogen bonds.

Neoplasm as a cause of brachial plexus palsy in neonates

Two patients with neonatal onset of arm weakness resulting from neoplastic involvement of the brachial plexus who were initially considered to have obstetric brachial plexus palsies are reported. The first patient was a 7-day-old female who presented with a left supraclavicular mass that was first detected at 2 days of age and left proximal arm weakness. The weakness involved the whole arm within 3 days. The mass was a malignant rhabdoid tumor. The second patient was a 28-month-old male who presented with slowly progressive right arm weakness, which began at 3 weeks of age, and episodes of scratch marks on the arm that began at 4 months of age. Magnetic resonance imaging revealed a plexiform neurofibroma of the brachial plexus. The features that are suggestive of a brachial plexus palsy caused by a neoplasm rather than of obstetric brachial plexus palsy include the following: the onset of weakness after the first day of age, with a progressive course; a history of a normal delivery and birth weight; the absence of signs of a traumatic injury or injuries; the appearance before 7 days of age of a growing supraclavicular mass without radiographic evidence of a clavicular fracture; and recurrent scratch marks on the weak arm.

Focal upper extremity neuropathy in neonates

Focal upper extremity neuropathies are common in neonates. The brachial plexus is the most common site involved. Brachial plexus injuries may involve different structures, thus producing different clinical presentations: complete brachial plexus palsy, Duchenne-Erb palsy, upper-middle trunk brachial plexus palsy, Klumpke palsy, fascicular brachial plexus palsy, and bilateral brachial plexus palsy. The causes of brachial plexus palsy are obstetric injury, intrauterine compression, humeral osteomyelitis, hemangioma, exostosis of the first rib, neck compression, and neoplasm. The differential diagnosis of brachial plexus palsy includes pseudoparesis, amyoplasia congenita, congenita varicella syndrome, and neurological lesions at other neuroanatomical levels. The cause and the degree of injury dictate the prognosis. The prognosis of obstetric brachial plexus injury is usually good.

Neurophysiological evaluation of children with traumatic radiculopathy, plexopathy, and peripheral neuropathy

Neurophysiological evaluation of children with traumatic peripheral nervous system injury is accomplished with electromyography, motor and sensory nerve conduction studies, and somatosensory and motor-evoked potentials. Preoperative neurophysiological tests are performed if motor deficits persist for more than 3 months. Evidence of reinnervation on these neurophysiological tests predates clinical recovery by weeks, hence they help determine the site of the lesion and provide objective measures for selecting candidates for surgical exploration. Intraoperative neurophysiological tests help to identify and confirm the integrity of nerves and to develop the optimal surgical strategy. Postoperative evaluations every 3 to 6 months may determine efficacy of treatment.

Single photon emission computed tomographic evaluation of brainstem release phenomenon and seizure in neonates

We report the ictal brain single photon emission computed tomographic (SPECT) findings in two neonates. One neonate had hypoxic-ischemic encephalopathy, a disorganized discontinuous electroencephalogram (EEG) background, lethargy, seizures, and brainstem release phenomena. A brain SPECT was performed during a brainstem release phenomenon characterized by a 34-second sustained tonic posture of the right arm and chewing. It did not reveal focal cerebral hemisphere hyperfusion. The second neonate had hemimegalencephaly, low-voltage irregular EEG background, and seizures. A brain SPECT was performed during a seizure characterized by a 32-second sustained tonic posture of the right arm. It revealed focal hyperperfusion in the posterior region of the left hemisphere. The brain SPECT findings in these patients indicate that despite clinically similar events, brainstem release phenomena and seizures have different perfusion characteristics, and refute the theory that brainstem release phenomena are due to epileptic foci in the cerebral hemispheres undetectable by EEG.

[Syndrome of Ohtahara]

INTRODUCTION

A literature review using the term Ohtahara syndrome and early infantile epileptic encephalopathy revealed 51 cases.

DEVELOPMENT

The characteristics of these cases were: 1) early onset of seizures; 2) tonic seizures; 3) poor response to treatment; 4) mental retardation; 5) poor prognosis; 6) burst-suppression EEG pattern; 7) evolution to West syndrome, and 8) multiple causes. These characteristics are non specific. No cause was found in most cases. The onset of seizures was between 7 hours and 86 days of age. The most frequent brain imaging abnormality was diffuse atrophy. ACTH was effective in a few cases and hemispherectomy was successful in one case.

CONCLUSION

We believe that Ohtahara syndrome and early myoclonic encephalopathy are the same entity.

[Evaluation of children with developmental disorders by evoked potentials and event-related potentials]

INTRODUCTION AND DEVELOPMENT

Evoked potentials evaluation of children with central nervous system developmental disorders o dysfunctions is better than clinical and imaging assessment for determination of: 1) conceptional age, 2) auditory and visual threshold, 3) integrity of sensory pathways, 4) neurologic motor outcome, and 5) course and evaluation of treatment of neurometabolic disorders.

CONCLUSIONS

However, it is not the same for predicting or making the diagnosis of the majority of primary developmental disorders (autism, receptive and expressive language disorders, learning disability, attention deficit disorders and Gilles de la Tourette syndrome.

[Clinical presentations, differential diagnosis and management of obstetric brachial palsy]

INTRODUCTION

The brachial plexus originates from C5 to T1 spinal segments. The brachial plexus includes the ventral ramus, trunks, divisions, cords and branches.

DEVELOPMENT AND CONCLUSIONS

Brachial plexus injuries produce clinical syndromes. The Duchenne-Erb syndrome is the most frequent presentation of obstetric brachial plexus injury. The differential diagnosis of brachial plexus palsy include decreased arm movements due to pain, or weakness caused by a lesion of the nervous system outside in the brachial plexus, or by a lesion in the brachial plexus due to non-obstetrical causes. Management of these patients initially includes considering the possibility of clavicular and humeral fractures and posterior subluxation of the shoulder; and subsequently considering the possibilities of subscapularis muscle contraction or posterior shoulder subluxation in patients that develop internal rotation contracture of the shoulder; or flexion, pronation or supination contracture in patients with forearm deformation. Treatment consist of physical therapy, administration of botulinum toxin, electrical stimulation, neurolysis, nervatization, removal of neuromas and nerve grafting, treatment of fractures and subluxation, release of muscle contracture and tendon transplantation.

[Surgical treatment of children with brachial plexus paralysis]

OBJECTIVE AND METHODS

A variety of surgical procedures exist for early repair of the nerve injury in obstetrical brachial plexus palsy, including neuroma excision and nerve grafting, neurolysis and neurotization. Secondary deformities of the shoulder, forearm, and hand can similarly be reconstructed using soft tissue and skeletal procedures. This review describes our surgical approach to maximize the ultimate functional outcome in infants and children with obstetrical brachial plexus palsy.

Similar brain SPECT findings in subclinical and clinical seizures in two neonates with hemimegalencephaly

Brain single-photon emission computed tomography (SPECT) findings during clinical and subclinical seizures were compared in two neonates with hemimegalencephaly. Interictal and ictal brain SPECT were performed in two neonates. The ictal studies were performed during a clinical seizure in one neonate and during a subclinical seizure in another neonate. They revealed similar focal hemispheric hyperperfusion at the electroencephalographic seizure foci in both cases. The similar perfusion patterns imply that clinical and subclinical seizures place similar metabolic demands on the cerebral tissue involved in the generation of electroencephalographic seizures in neonates with cerebral dysgenesis and suggest that clinical and subclinical seizures should be treated similarly in this population.

[Neurophysiological assessment of children with obstetric brachial plexus palsy]

INTRODUCTION

The objectives of the neurophysiological evaluation of infants with brachial plexus palsy are to determine the time of occurrence of the lesion, to locate the lesion and to determine its course.

METHODS AND CONCLUSIONS

These objectives are achieved by studying affected upper extremity muscles by needle electromiography (EMG) and affected nerves by motor and sensory conduction studies. EMG is performed in the first week of life in those patients with brachial plexus palsy of unknown etiology to determine the age of the lesion for medico-legal reasons. EMG is performed before surgery for tendon transfer in the selected muscles to assure that they are normal. EMG and motor and sensory conduction studies are performed at the age of 3 and 6 months in infants with less than 4 muscle weakness to determine candidates for surgical exploration. Motor and sensory nerve conduction studies are performed intraoperative to determine the functional status of the affected axons and the best surgical procedure (neurotization, neurolysis and/or neuroma resection and homologous nerve graft).

[The evaluation of a newborn in a coma]

Coma is differentiated from sleep by the absence of a normal arousal response and from death by the presence of heart beats and the absence of brain death criteria. Most causes of coma are readily diagnosed and treated. Others require a test whose results are not immediately available, transportation or a risky procedure and empirical treatment has to be considered. In addition to treating the cause of coma, treatment of the systemic and neurological causes of secondary brain damage is paramount.

[Cerebral palsy therapy]

Unfortunately, in spite of the advances in foetal and perinatal medicine in the last twenty years, the incidence of cerebral palsy has remained unchanged (1.5-2.5 per 1000 live births). It has even possibly risen slightly in premature babies of low birth weight, in parallel with the increased survival of these babies. In spite of modern techniques of rehabilitation, 25% of these patients cannot walk and 35% are mentally retarded. This costs society 5,000 million dollars annually, not counting the loss of opportunity and the emotional and economic burden imposed on these families. The development of new preventive measures such as the use of antagonists of the cortical excitatory amino acids (which when in excess may cause irreversible cerebral damage in cases of hypoxic-ischaemic encephalopathy of the new born). Intramuscular botulinum toxin and continuous intrathecal baclofen seem to promise a reduction in the incidence and functional incapacity of cerebral palsy.

Bilateral tonic-clonic epileptic seizures in non-benign familial neonatal convulsions

We report an electroclinical pattern considered characteristic of benign familial neonatal convulsions (BFNC) in two neonates without BFNC. Both neonates were products of uncomplicated pregnancies, labor, and deliveries. The cause of the seizures was not established. There was no family history of seizures or epilepsy. Seizures started on the second and third days after birth. Ten seizures were captured by continuous video-EEG telemetry. The electroclinical events began with generalized tonic posturing coinciding with the appearance of diffuse attenuation of the EEG activity. After several seconds, bilateral clonic movements accompanied by bilateral repetitive sharp waves or spikes occurred in the EEG. One patient had normal development; the other became autistic. We conclude that the electroclinical pattern occurring in BFNC can occur in other types of neonatal seizures.

[Single photon emission computer tomography in the differential diagnosis of the paroxysmal clinical events in newborns]

Conventional computerized cranial tomography by single photon emission (TLCESF) is a nuclear medicine technique which makes use of a radioactive chemical complex to obtain a qualitative image of cerebral, cerebellar and brain-stem vascularization. This technique shows the changes in vascularization which occur between (decrease) and during (increase) the clinical events of paroxysmal epilepsy (ECP) in the area of origin. This technique is indicated in neonates with ECP which does not disappear on etiological treatment, where a non-epileptic cause cannot be ruled out on clinical grounds and where there are no associated encephalographic epileptic changes during the ECP.

Reversible dementia and apparent brain atrophy during valproate therapy

Two children developed severe cognitive and behavioral deterioration suggestive of a degenerative disease while being treated with sodium valproate for idiopathic, localization-related epilepsy with centrotemporal spikes. Magnetic resonance imaging revealed marked central and generalized cortical and cerebellar atrophy. In both patients, clinical symptoms and signs cleared in a few weeks following valproate withdrawal. The magnetic resonance imaging appearance improved within 3 months in 1 of the patients and normalized in both after 6 and 12 months. No metabolic changes were associated with the clinical or imaging abnormalities. Although the mechanism of this rare idiosyncratic complication of valproate therapy is unknown, we advocate discontinuing valproate therapy in all epileptic patients with neuromental deterioration or brain atrophy of unknown etiology.

Linear nevus sebaceous syndrome. A review

We report a case of linear nevus sebaceous syndrome with large areas of calcification involving multiple layers of the posterior aspects of both eyes. This patient had a normal neurological examination despite dysplastic brain changes. We discuss and review the multiple clinical presentation and embryopathogenesis of this disorder.

Spinal cord involvement in encephalocraniocutaneous lipomatosis

Encephalocraniocutaneous lipomatosis is a rare hamartomatosis involving the craniofacial region and the central nervous system. The most prominent clinical features are large areas of scalp alopecia, soft subcutaneous craniofacial masses, lipomas, connective tissue nevi of the eyelids and surrounding areas, pterygium-like choriostoma of the ocular conjunctiva, mental retardation, motor deficit, and seizures. Of the eight patients reported previously, three had spinal cord evaluations and two had evidence of lipomatosis. We report the third patient with this association, review the literature of encephalocraniocutaneous lipomatosis, and stress the importance of spinal cord evaluation during the newborn period.