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Biomedical subjects

Bernard L Maria

Publications and source records attributed to Bernard L Maria.

16 recordsLinked to original sources
PubMed2006

Selective migration of neuralized embryonic stem cells to stem cell factor and media conditioned by glioma cell lines.

BACKGROUND: Pluripotent mouse embryonic stem (ES) cells can be induced in vitro to become neural progenitors. Upon transplantation, neural progenitors migrate toward areas of damage and inflammation in the CNS. We tested whether undifferentiated and neuralized mouse ES cells migrate toward media conditioned by glioma cell lines (C6, U87 & N1321) or Stem Cell Factor (SCF). RESULTS: Cell migration assays revealed selective migration by neuralized ES cells to conditioned media as well as to synthetic SCF. Migration of undifferentiated ES cells was extensive, but not significantly different from that of controls (Unconditioned Medium). RT-PCR analysis revealed that all the three tumor cell lines tested synthesized SCF and that both undifferentiated and neuralized ES cells expressed c-kit, the receptor for SCF. CONCLUSION: Our results demonstrate that undifferentiated ES cells are highly mobile and that neural progenitors derived from ES cells are selectively attracted toward factors produced by gliomas. Given that the glioma cell lines synthesize SCF, SCF may be one of several factors that contribute to the selective migration observed.

Journal Article↗
PubMed2006

Parenting stress and its relationship to the behavior of children with Joubert syndrome.

This study describes the relationship between parenting stress and behavior in children with Joubert syndrome, a rare genetic neurodevelopmental disorder. Parents (N = 43) reported severely impaired child adaptive behaviors. Most children did not show maladaptive behaviors, but a subset of approximately 20% displayed significant problems in areas such as inattention, overactivity, social withdrawal, and atypical behaviors. Mothers (59%) and fathers (40%) reported elevated levels of parenting stress. A hierarchical regression, including demographics, adaptive behavior, and maladaptive behavior, predicted 67% of the variance in mothers' stress and 40% of the variance in fathers' stress. Maladaptive behaviors uniquely contributed to maternal and paternal stress. The child's adaptive behavior level contributed significantly to parenting stress for mothers but not for fathers. Findings provide a better understanding of the impact of child behavior on parents caring for a child with Joubert syndrome.

Activities of Daily Living↗
PubMed2006

Oromotor and communication findings in joubert syndrome: further evidence of multisystem apraxia.

This study provides descriptive information in the areas of oromotor abilities and communication to better understand the spectrum of disability in individuals with Joubert syndrome. Participants included 21 individuals with the diagnosis of Joubert syndrome (mean age 10.45 years). Participants completed oromotor and receptive language measures. In addition, all of the participants' speech and gesture communication from a narrative task was coded and analyzed from videotape. Caregivers reported the participants' level of fine and gross motor function. The results show that individuals with Joubert syndrome exhibit a distinct oromotor pattern consistent with verbal and lingual apraxias. Despite significant motor skills deficits and oculomotor apraxia, persons with Joubert syndrome produced gestures when communicating, and those whose speech was less intelligible used a higher rate of gesture compared with those with greater verbal output. These findings suggest a new form of apraxia not previously described in the condition and are consistent with previous research that suggests that persons with Joubert syndrome typically do not exhibit classic symptoms of autism spectrum disorder.

Adolescent↗
PubMed2005

Case of desmoplastic infantile ganglioglioma secreting ceruloplasmin.

Desmoplastic infantile ganglioglioma is a rare World Health Organization (WHO) grade I tumor commonly arising in early infancy and usually presenting with both solid and cystic components. We report a case of a large midline-enhancing desmoplastic infantile ganglioglioma in which newly formed cysts in communication with lateral ventricles contained highly proteinaceous fluid. Proteomic analysis of the fluid showed three proteins not normally found in cerebrospinal fluid. Immunohistochemical analysis of the tumor sample showed that the desmoplastic infantile ganglioglioma produced a high concentration of ceruloplasmin, which probably accounts for most of the 30- to 40-fold increase in protein compared with normal cerebrospinal fluid. To our knowledge, this is the first report of ceruloplasmin secretion by a brain tumor, and ongoing studies on the mechanism might yield novel approaches to reducing cyst production and protein content in an otherwise stable solid tumor.

Brain Neoplasms↗
PubMed2004

Molar tooth sign of the midbrain-hindbrain junction: occurrence in multiple distinct syndromes.

The Molar Tooth Sign (MTS) is defined by an abnormally deep interpeduncular fossa; elongated, thick, and mal-oriented superior cerebellar peduncles; and absent or hypoplastic cerebellar vermis that together give the appearance of a "molar tooth" on axial brain MRI through the junction of the midbrain and hindbrain (isthmus region). It was first described in Joubert syndrome (JS) where it is present in the vast majority of patients with this diagnosis. We previously showed that the MTS is a component of several other syndromes, including Dekaban-Arima (DAS), Senior-Löken, and COACH (cerebellar vermis hypoplasia (CVH), oligophrenia, ataxia, coloboma, and hepatic fibrosis). Here we present evidence that the MTS is seen together with polymicrogyria, Váradi-Papp syndrome (Orofaciodigital VI (OFD VI)), and a new syndrome with encephalocele and cortical renal cysts. We also present a new patient with COACH syndrome plus the MTS. We propose that the MTS is found in multiple distinct clinical syndromes that may share common developmental mechanisms. Proper classification of patients with these variants of the MTS will be essential for localization and identification of mutant genes.

Abnormalities, Multiple↗
PubMed2004

Sturge-Weber syndrome: a review.

Sturge-Weber syndrome is a rare disorder that occurs with a frequency of approximately 1 per 50,000. The disease is characterized by an intracranial vascular anomaly, leptomeningeal angiomatosis, most often involving the occipital and posterior parietal lobes. Facial cutaneous vascular malformations, seizures, and glaucoma are among the most common symptoms and signs. Stasis results in ischemia underlying the leptomeningeal angiomatosis, leading to calcification and laminar cortical necrosis. The clinical course is highly variable and some children experience intractable seizures, mental retardation, and recurrent strokelike episodes. In this review, we describe the syndrome's characteristic features, clinical course, and optimal management.

Epilepsy↗
PubMed2004

Cerebral and cerebellar motor activation abnormalities in a subject with Joubert syndrome: functional magnetic resonance imaging (MRI) study.

Joubert syndrome is an autosomal recessive disorder characterized by hypotonia, ataxia, developmental delay, and a distinctive hindbrain malformation involving the cerebellum and brain stem, visualized radiographically on magnetic resonance imaging (MRI) as the "molar tooth sign." In postmortem brains from subjects with Joubert syndrome, there is an apparent absence of decussation of both corticospinal and superior cerebellar tracts, although the functional significance has not been elucidated. We sought to explore the cerebral and cerebellar activation pattern elicited by finger tapping in an adolescent with Joubert syndrome and in a normal control subject using functional MRI. In contrast to the typical highly lateralized activation seen in our control subject, the subject with Joubert syndrome demonstrated striking bilateral activation of the sensorimotor and cerebellar cortex. Although our functional MRI data do not indicate a clear absence of decussation, the abnormal activation pattern observed suggests altered brain functional organization in relation to anatomic differences. Malformation of the hindbrain could result in recruitment of alternative pathways, similar to what has been observed following ischemic injury to the developing or mature central nervous system.

Adolescent↗
PubMed2002

Primary antiphospholipid syndrome presenting with a branch retinal artery occlusion in a 15-year-old boy.

Acute vascular events are rare in the pediatric population, but there is an association with the presence of antiphospholipid antibodies. When there is no other underlying medical disorder, this is referred to as primary antiphospholipid syndrome. We present a case of a 15-year-old boy who developed an acute superior branch retinal artery occlusion. Complete evaluation revealed significant elevations in antiphospholipid antibodies. To our knowledge, there are no cases in children of primary antiphospholipid syndrome presenting with this clinical manifestation.

Adolescent↗
PubMed2002

Ex vivo high-resolution magnetic resonance imaging of the brain in Joubert's syndrome.

This study employs ex vivo high-resolution magnetic resonance imaging (MRI) to examine anatomic structures in an intact brain of a child with Joubert's syndrome. Several of the specific hindbrain malformations associated with Joubert's syndrome are well resolved with ex vivo MRI, including the "molar tooth sign," which arises from enlarged and maloriented superior cerebellar peduncles, hypoplastic vermis, and deepening of the interpeduncular fossa. Superior resolution was achieved compared with that of in vivo MRI and included visualization of the inferior olives. One high-resolution study also showed that the decreased width of the brainstem isthmus is probably caused by failure of superior cerebellar peduncles to cross the midline at that level. The results of this study suggest that high-resolution MRI may be useful in screening the brainstem for malformations that can be studied histologically in a much more targeted fashion.

Child, Preschool↗