A multiplexed microfluidic system for evaluation of dynamics of immune-tumor interactions.

Recapitulation of the tumor microenvironment is critical for probing mechanisms involved in cancer, and for evaluating the tumor-killing potential of chemotherapeutic agents, targeted therapies and immunotherapies. Microfluidic devices have emerged as valuable tools for both mechanistic studies and for preclinical evaluation of therapeutic agents, due to their ability to precisely control drug concentrations and gradients of oxygen and other species in a scalable and potentially high throughput manner. Most existing in vitro microfluidic cancer models are comprised of cultured cancer cells embedded in a physiologically relevant matrix, collocated with vascular-like structures. However, the recent emergence of immune checkpoint inhibitors (ICI) as a powerful therapeutic modality against many cancers has created a need for preclinical in vitro models that accommodate interactions between tumors and immune cells, particularly for assessment of unprocessed tumor fragments harvested directly from patient biopsies. Here we report on a microfluidic model, termed EVIDENT (ex vivo immuno-oncology dynamic environment for tumor biopsies), that accommodates up to 12 separate tumor biopsy fragments interacting with flowing tumor-infiltrating lymphocytes (TILs) in a dynamic microenvironment. Flow control is achieved with a single pump in a simple and scalable configuration, and the entire system is constructed using low-sorption materials, addressing two principal concerns with existing microfluidic cancer models. The system sustains tumor fragments for multiple days, and permits real-time, high-resolution imaging of the interaction between autologous TILs and tumor fragments, enabling mapping of TIL-mediated tumor killing and testing of various ICI treatments versus tumor response. Custom image analytic algorithms based on machine learning reported here provide automated and quantitative assessment of experimental results. Initial studies indicate that the system is capable of quantifying temporal levels of TIL infiltration and tumor death, and that the EVIDENT model mimics the known in vivo tumor response to anti-PD-1 ICI treatment of flowing TILs relative to isotype control treatments for syngeneic mouse MC38 tumors.

Clinical and neuroimaging findings of Cree leukodystrophy: a retrospective case series.

BACKGROUND AND PURPOSE: CLD is a rapidly progressive and invariably fatal neurodegenerative disorder. We describe clinical and neuroimaging findings in 5 infants with CLD. MATERIALS AND METHODS: Retrospective review of medical records of infants with CLD from the past 11 years at our institution was performed. Relevant clinical and demographic data were recorded. Specific attention was directed toward postmortem examination findings and genetic testing. CT and MR imaging results were reviewed. RESULTS: Five Cree infants were diagnosed with CLD. CT demonstrated bilateral symmetric hypoattenuation of the white matter and globus pallidus. MR imaging demonstrated corresponding T2 hyperintensity in these regions and abnormal signal intensity in the thalami and substantia nigra. Symmetric restricted diffusion in the deep white matter was seen. MRS demonstrated decreased NAA, elevated choline, and the presence of lactate. Postmortem examination in 1 infant showed corresponding poor myelination in the brain stem, cerebellum, deep gray structures, and the cerebral hemispheres. Genetic testing in 2 infants revealed homozygous mutations in the eIF2B5 gene. CONCLUSIONS: Neuroimaging in CLD is striking and is an important tool in diagnosing CLD. Extensive white matter involvement as well as involvement of the globus pallidus and patchy involvement of the thalami and substantia nigra are characteristic. MRS findings are compatible with destruction of normal brain parenchyma with evidence of anaerobic metabolism in the regions of demyelination. Clinical suspicion of VWM in a Native American infant from this region should prompt the consideration of CLD with appropriate imaging work-up and genetic testing.

Incidence of acquired demyelination of the CNS in Canadian children.

BACKGROUND: The incidence of acquired demyelination of the CNS (acquired demyelinating syndromes [ADS]) in children is unknown. It is important that physicians recognize the features of ADS to facilitate care and to appreciate the future risk of multiple sclerosis (MS). OBJECTIVE: To determine the incidence, clinical features, familial autoimmune history, and acute management of Canadian children with ADS. METHODS: Incidence and case-specific data were obtained through the Canadian Pediatric Surveillance Program from April 1, 2004, to March 31, 2007. Before study initiation, a survey was sent to all pediatric health care providers to determine awareness of MS as a potential outcome of ADS in children. RESULTS: Two hundred nineteen children with ADS (mean age 10.5 years, range 0.66-18.0 years; female to male ratio 1.09:1) were reported. The most common presentations were optic neuritis (ON; n = 51, 23%), acute disseminated encephalomyelitis (ADEM; n = 49, 22%), and transverse myelitis (TM; n = 48, 22%). Children with ADEM were more likely to be younger than 10 years, whereas children with monolesional ADS (ON, TM, other) were more likely to be older than 10 years (p < 0.001). There were 73 incident cases per year, leading to an annual incidence of 0.9 per 100,000 Canadian children. A family history of MS was reported in 8%. Before study initiation, 65% of physicians indicated that they considered MS as a possible outcome of ADS in children. This increased to 74% in year 1, 81% in year 2, and 87% in year 3. CONCLUSION: The incidence of pediatric acquired demyelinating syndromes (ADS) is 0.9 per 100,000 Canadian children. ADS presentations are influenced by age.

PLEDs: clinical correlates.

OBJECTIVE: We reviewed our experience in 96 consecutive patients exhibiting periodic lateralized epileptiform discharges (PLEDs) on EEG. METHODS: EEG reports from January 1, 1999 to September 30, 2006 were screened for the term 'PLEDs' and its variants. A retrospective chart review, including examination of neuroimaging and other investigations, was conducted on each patient identified. RESULTS: Acute stroke, tumor and central nervous system infection were the most common etiologies, accounting for 26%, 12% and 12% of cases respectively. Acute hemorrhage and traumatic brain injury combined accounted for another 12%. Previously unreported etiologies included posterior reversible encephalopathy syndrome (PRES), familial hemiplegic migraine and cerebral amyloidosis. There were 9 cases of chronic PLEDs attributable to underlying cortical dysplasia or severe remote cerebral injury, all with an accompanying partial seizure disorder. A prominent role for alcohol withdrawal was noted, and in 6 cases was the sole etiological factor. Fever was present as a potential contributing factor in 40% of cases, and significant metabolic abnormalities in 35%. Seizure activity occurred in 85% of patients overall, but in 100% of patients with PLEDs Plus and BiPLEDs Plus. The overall mortality rate was 27%. Mortality among patients with BiPLEDs however was almost twice that, at 52%. CONCLUSIONS: This case series demonstrates the wide variety of potential PLED etiologies. It also emphasizes that despite advances in neurocritical care, the morbidity and mortality associated with PLEDs has changed little since their recognition four decades ago.

Peripheral neuropathy in a child with Cree leukodystrophy.

The authors describe peripheral nerve involvement in a 12-month-old boy with Cree leukodystrophy. Nerve conduction and genetic studies were performed during investigation of his leukodystrophy. Mutation analysis of the eukaryotic initiation factor 2B5 gene detected homozygosity of the R195 mutation, confirming the diagnosis of Cree leukodystrophy. Median and posterior tibial motor nerve conduction study results were normal, but sensory responses in the median nerves were unobtainable bilaterally, in keeping with a sensory axonal neuropathy. Somatosensory-evoked potentials were absent in the upper extremities and delayed in the lower extremities, confirming sensory nerve involvement. This degree of sensory nerve involvement has not been previously reported in patients with eukaryotic initiation factor 2B5-related disorders. Peripheral neuropathy should be looked for both clinically and with electrodiagnostic studies in patients with eukaryotic initiation factor 2B-related disorders.

Mycoplasma pneumoniae: a cause of coma in the absence of meningoencephalitis.

Mycoplasma pneumoniae encephalitis is a recognized cause of reversible coma in children. As an etiology of infectious encephalitis, it yields a relatively poorer prognosis than most other causes of infectious encephalopathies. Encephalitis is generally diagnosed by a constellation of clinical symptoms and confirmed by a cerebrospinal fluid (CSF) examination revealing cell pleocytosis and elevated protein. That Mycoplasma pneumoniae encephalopathy can occur in the presence of a normal CSF examination is less well appreciated. The authors report two children who presented with coma and normal CSF findings in whom a diagnosis of acute Mycoplasma pneumoniae infection was made. The two children both had rapid and complete recovery over several days. These cases exemplify that coma can result from acute infection with Mycoplasma pneumoniae in the absence of an inflammatory CSF response and that a normal CSF may herald a more favorable prognosis.

Late lateralizing and localizing EEG features of scalp-recorded temporal lobe seizures.

The authors studied the lateralizing value for temporal epileptogenesis of focal or hemispheric EEG ictal features that first appear > or = 5 seconds after hemispheric or diffuse EEG changes or after an artifact-obscured onset, by correlation with side of lobectomy abolishing or producing > or = 90% improvement of complex partial seizures (CPS). One hundred forty-eight seizures in 39 patients rendered seizure-free (SF) by lobectomy lacked early localizing features of which 91 (61%) seizures in 37 (95%) patients had late lateralizing or localizing phenomena. Eighty-seven (96%) of 91 late localizing or lateralizing seizures occurred ipsilateral to lobectomy, involving 35 (95%) of 37 patients. Late contralateral and shifting phenomena occurred in a total of 4 seizures of 2 patients. Among 17 non-SF but > or = 90% improved patients, 30 (48%) of 63 seizures lacking early localizing features showed late localizing or lateralizing phenomena. Of these, twenty (67%) involving 12 (71%) patients occurred ipsilateral to lobectomy. Among the remaining 5 (29%) patients, a total of 5 seizures (17%) were contralateral while 5 (17%) exhibited shifting laterality. These data indicate that seizures with late (> or = 5 seconds) localizing or lateralizing features cannot be discounted when assessing laterality of temporal epileptogenesis but cannot be used as the sole electrographic criterion.

Pathologic findings of multiple sulfatase deficiency reflect the pattern of enzyme deficiencies.

Multiple sulfatase deficiency is a rare metabolic storage disorder that manifests in childhood. It is probably an autosomal-recessive inherited condition, the gene for which has not yet been identified. Clinical features include mental deficiency and a dysmorphic appearance reminiscent of a mucopolysaccharidosis. Unlike most storage disorders, there are multiple deficient enzymes; all are sulfatases, hence the name of the disorder. Biochemical testing reveals accumulation of glycosaminoglycans, sulfatides, and gangliosides in the brain and other tissues of affected patients. In previous accounts of postmortem examinations, white matter histologic and biochemical pathologic findings similar to metachromatic leukodystrophy have been reported. Ganglioside accumulation, secondary to interference with degradative enzyme activity by the accumulating glycosaminoglycans also has been demonstrated. The authors report a case of multiple sulfatase deficiency with only mild deficiencies of the arylsulfatases but with severe deficiencies of iduronate sulfatase and heparan sulfamidase. Pathologic changes were more in keeping with a mucopolysaccharidosis, with minimal white matter changes and deposition of metachromatic material. The authors postulate that the mild leukodystrophic changes but striking features similar to a mucopolysaccharidosis are reflections of the pattern of enzyme deficiency. The pathology of multiple sulfatase deficiency therefore represents an overlap between a leukodystrophy and a mucopolysaccharidosis, with the relative contribution of each pattern apparently depending on the pattern of enzyme deficiency encountered in each patient.

Iron deficiency: a cause of stroke in infants and children.

Iron deficiency is a common pediatric problem affecting 20%-25% of the world's infants. Most commonly causing anemia, iron deficiency is also implicated in such neurologic sequelae as irritability, lethargy, headaches, developmental delay, and infrequently papilledema, pseudotumor cerebri, and cranial nerve abnormalities. Rarely has iron deficiency been recognized as a significant cause of stroke in the adult or pediatric populations. We report a series of 6 children, 6 to 18 months of age, who presented with an ischemic stroke or venous thrombosis after a viral prodrome. All patients had iron deficiency as a consistent finding among the group, and other known etiologies of childhood stroke were excluded. These patients provide evidence of a strong association between iron deficiency and ischemic events in children between 6 and 18 months of age.

Ischemic stroke in children: Relationship to unsuspected trauma.

Thirteen cases of ischemic stroke in children were seen and followed up between 1981 and 1990. Brain hemorrhage and strokes due to meningitis, leukemia, or other malignancy were excluded. In four, no cause was found. Three were related to trauma that preceded the stroke by up to 24 h. Two were due to cardiac emboli, which occurred during cardiac catheterization for dilation of stenotic valves, and two occurred spontaneously in association with mitral valve prolapse. One stroke was related to an inapparent neurocutaneous syndrome, and one was related to a hyperlipidemia. Follow-up showed no recurrence. School performance and developmental assessment was normal in 11 of 13 (one had a learning disability and the other had hyperactivity). Mild motor deficits persisted in five, were moderate in two, and were severe in one. The overall prognosis was best in children under 5 years.

Malignant rhabdoid tumor of the central nervous system with subarachnoid dissemination.

A case of primary central nervous system malignant rhabdoid tumor is presented. Clinical, radiological, and histopathological findings are described in detail. Because of a relatively long clinical course after presentation, it was possible to assess the clinical and radiological response to different treatment modalities: surgery, chemotherapy, and radiotherapy. Despite the complete clinical and radiological response that was achieved after subtotal excision, two cycles of chemotherapy, and high-dose radiotherapy, the tumor recurred within 4 months of completion of the treatment, with wide subarachnoid dissemination. Radiotherapy treatment of whole cranial axis is recommended.

Neurological complications of balloon angioplasty in children.

We report on the occurrence of cerebrovascular accidents as a possible complication of balloon angioplasty in children. The first patient underwent balloon angioplasty for aortic stenosis and subsequently developed a right temporoparietal infarct in the vascular territory of the right middle cerebral artery. The second patient developed a right temporoparietal infarct also in the vascular territory of the right middle cerebral artery following balloon angioplasty of native coarctation of the aorta. This experience suggests that, in addition to the previously reported complications of balloon angioplasty, the occurrence of a potential cerebrovascular accident must be considered in the risk-benefit analysis of this procedure.

Leigh's disease with clinical manifestations of Cornelia de Lange syndrome.

Leigh's disease was found postmortem in a 5-year-old girl who was diagnosed clinically as Cornelia de Lange syndrome at age 1 year. The child's neurological status began to deteriorate rapidly at age 4.5 years and she died suddenly 6 months later. Postmortem examination of the brain revealed bilateral necrosis of the hypothalamus, subthalamic nuclei, midbrain, pons, and medulla. Previous studies have linked Cornelia de Lange syndrome to hypothalamic lesions. This case demonstrates that Leigh's disease, which also damages the hypothalamus, could present with phenotypic features of Cornelia de Lange syndrome.

Hereditary motor sensory neuropathy type I presenting as scapuloperoneal atrophy (Davidenkow syndrome) electrophysiological and pathological studies.

A 14 year old boy with scapuloperoneal muscular atrophy, pes cavus, areflexia and distal sensory loss (Davidenkow syndrome) is described. Nerve conduction velocities were diminished. Sural nerve biopsy demonstrated a reduction in the number of myelinated fibers and early "onion-bulb" formation. These observations support the hypothesis that the scapuloperoneal amyotrophy associated with distal sensory loss may represent a variant of type I hereditary motor sensory neuropathy.

Thyroxine-induced petit mal status epilepticus.

Petit mal status epilepticus was induced by high doses of thyroxine, confirming experimental evidence that thyroxine may lower the seizure threshold. This is another hazard of rapidly correcting the hypothyroid state.

Cerebral monitoring of somatosensory evoked potentials during profoundly hypothermic circulatory arrest.

The factors that influence the functional integrity of the central nervous system during clinical procedures involving profoundly hypothermic circulatory arrest (PHCA) have not been objectively evaluated. Intraoperative monitoring of somatosensory evoked potentials (SEPs) was performed in nine infants undergoing PHCA during repair of congenital cardiac anomalies to investigate the short-term effects of this intervention on neurophysiologic function. Latency prolongation of the primary cortical (N18,P22) and cervical spinal cord (N13) responses, reflecting slowing of neural transmission with hypothermia, occurred as a power function of decreasing systemic temperature (p less than .01). The cortical evoked response disappeared during profound hypothermia (less than 18 degrees C), remaining absent throughout the period of circulatory arrest and for a variable period of time after reperfusion. Regression analysis indicated that the time required for the recovery of the cortical evoked response on reperfusion was a linear function of the time-temperature integral of the arrest period (p less than .001) and the pH at the onset of circulatory arrest (p less than .001). Neurologic complications occurred in three patients and included cortical blindness (n = 2) and a generalized seizure disorder (n = 1). Visual dysfunction was not reflected in the intraoperative SEP recordings, whereas prolonged delay of SEP recovery, indicative of global central nervous system injury, was observed in the patient who experienced seizures after the surgery. This preliminary experience with SEP monitoring during PHCA suggests a role for this modality in determining the short-term effects of this procedure on neurophysiologic function. The recovery characteristics of somatosensory neural transmission appear to be modulated by the duration of, and temperature and pH maintained during, the arrest period.

Electrophysiological studies in five cases of abetalipoproteinemia.

Auditory brainstem responses (ABRs), visual and somatosensory evoked responses (VEPs and SEPs) and nerve conduction studies were conducted in 5 patients with abetalipoproteinemia. The ABRs were normal in all cases. The VEPs were of normal amplitude but of increased latencies in two patients. The four eldest patients had delayed cortical SEPs but normal peripheral sensory nerve conduction studies. The peripheral motor conduction velocities were normal in all cases. The peripheral sensory studies showed normal velocity when a response was seen; however, the amplitude of the response was often reduced or it was absent. The electrophysiological studies reported here support a model of axonal loss of large myelinated fibres with secondary demyelination in abetalipoproteinemia.