Bi-allelic mutations of CCDC88C are a rare cause of severe congenital hydrocephalus

Congenital or infantile hydrocephalus is caused by genetic and non-genetic factors and is highly heterogeneous in etiology. In recent studies, a limited number of genetic causes of hydrocephalus have been identified. To date, recessive mutations in the CCDC88C gene have been identified as a cause of non-syndromic congenital hydrocephalus in three reported families. Here, we report the fourth known family with two affected individuals with congenital hydrocephalus due to a homozygous mutation in the CCDC88C gene identified by whole exome sequencing. Our two newly described children, as well as the previously published ones, all shared several features including severe infantile-onset hydrocephalus, mild to severe intellectual delay, varying degrees of motor delay, and infantile onset seizures. All identified homozygous mutations in CCDC88C abolish the PDZ binding site necessary for proper CCDC88C protein function in the Wnt signaling pathway. Our report further establishes CCDC88C as one of the few known recessive causes of severe prenatal-onset hydrocephalus. Recognition of this syndrome has important diagnostic and genetic implications for families identified in the future.

Epilepsy surgery after treatment of pediatric malignant brain tumors

Epilepsy surgery is common in the face of benign brain tumors, but rarely for patients with a history of malignant brain tumors. Seizures are a common sequelae in survivors of malignant pediatric brain tumors. Medical management alone may not adequately treat epilepsy, including in this group. We report four cases of patients who previously underwent gross total resection, radiation therapy, and chemotherapy for successful treatment of malignant brain neoplasia, yet suffered from medically intractable seizures. All underwent surgery for treatment of epilepsy with extension of the original resection. Despite the aggressive primary treatment of the neoplasm, and the potential for diffuse cerebral insults, all benefited from focal surgical resection. Aggressive surgical management of intractable epilepsy can be considered in survivors of malignant brain tumors.

Use of [11C]aminocyclohexanecarboxylate for the measurement of amino acid uptake and distribution volume in human brain

A quantitative positron emission tomographic (PET) method to measure amino acid blood-brain barrier (BBB) transport rate and tissue distribution volume (DV) has been developed using 11C-labeled aminocyclohexanecarboxylate (ACHC), a nonmetabolized amino acid analogue. Dynamic PET data were acquired as a series of 15 scans covering a total of 60 min and analyzed by means of a two-compartment, two-parameter model. Functional images were calculated for the amino acid transport rate constants across the BBB and the amino acid DV in the brain. Results show [11C]ACHC to have an influx rate constant in gray matter of approximately 0.03-0.04 ml g-1 min-1, indicating a single-pass extraction fraction of approximately 5-7%. The intersubject coefficient of variation was approximately 15% while intrasubject variability of repeat scans was only slightly greater than 5%. Studies were performed in 15 young normal volunteer control subjects, 5 elderly controls, 7 patients with probable Alzheimer's disease, and one patient with phenylketonuria. Results indicate that [11C]-ACHC will serve as the basis of a method for measuring amino acid transport rate and DV in the normal and pathological human brain.

Morphologic alteration of cultured arterial smooth muscle cells by cyclic stretching

Cyclic stretching of smooth muscle cells in culture resulted in a two- to fivefold increase in protein and collagen synthesis. The same in vitro system was utilized to relate changes in smooth muscle cell morphology to mechanical stress. Smooth muscle cells, grown in culture from rabbit aorta explants, were transferred to purified elastic membranes derived from bovine aorta. The membranes were either subjected to stretching and relaxation 52 times per minute or stretched and held stationary for 8, 48, or 56 hr. Profiles of rough endoplasmic reticulum (RER) were counted and myofilament content estimated from electron micrographs of 100 cells for each experiment. Cells from cyclically stretched preparations were compared with stationary cells derived from the same subculture. Myofilaments were largely replaced by RER in cyclically stretched cells and there was a reciprocal relationship between RER and myofilament content in individual cells. In cells from stationary preparations, myofilament content also diminished with time but RER profiles were few. At 56 hr, RER profiles numbered 16.7 +/- 1.7 in stretched cells compared with 3.6 +/- 1.3 in stationary cells (P less than 0.05). Cyclically stretched cells formed numerous intercellular contacts and showed little evidence of cytoplasmic degradation while stationary cells showed few contacts and contained numerous cytosomes and lamellar bodies. The results suggest that cyclic stretching resulted in the formation of RER or the preservation of myofilaments and that immobility resulted in the disappearance of myofilaments and cytoplasmic degradation.(ABSTRACT TRUNCATED AT 250 WORDS)