Evaluation of the necessity of postoperative imaging after craniosynostosis surgery

Journal ArticleObject. Childhood radiation exposure increases the lifetime risk of cancer from an estimated 0.07 to 0.35%. Neurological evaluation of patients after cranial vault reconstruction for synostosis repair is often complicated by pain medication, sedation, intubation, swelling, and dressings; therefore computed tomography (CT) scans are routinely ordered by some surgeons on the 1st postoperative day. The object of this study was to evaluate the utility of these scans. Methods. Medical records and CT scans were reviewed for patients at the authors' institution who underwent cranial vault reconstruction to repair synostosis between January 1, 2003, and July 31, 2005. Results. Of the 111 patients identified in the review, 84 had a CT scan on postoperative Day 1, and seven of these patients underwent shunt insertion for treatment of hydrocephalus. Thirty-three patients underwent bifrontal craniotomies, whereas 51 underwent total vault reconstruction (TVR). Postoperative CT scans revealed minor contusions in three (9%) of 33 patients in the bifrontal craniotomy group and in seven (14%) of 51 patients in the TVR group. No significant subdural or epidural hematomas were observed. In the seven patients who required shunt placement, two (29%) had CT evidence of shunt malfunction, leading to shunt revision. Conclusions. None of the CT findings analyzed in this series was associated with clinical events such as seizures, prolonged intensive care unit stay, or reoperation in patients without shunt placement after cranial reconstructive procedures, although a relatively high incidence of CT evidence of shunt malfunction was found in patients with shunts. These data do not support the routine use of CT scanning after cranial reconstructive procedures unless the patient has received a shunt for hydrocephalus. Patients who experience unexpected intraoperative or postoperative events should be examined using CT

Retained peritoneal shunt tubing causing hematuria

Journal ArticleThis 14-year-old boy with congenital hydrocephalus underwent initial shunt placement shortly after birth. During his first 6 years of life, multiple ventriculoperitoneal (VP) shunt revisions were performed to address seven shunt malfunctions and one shunt infection (Staphylococcus epidermidis). During the last shunt revision, which took place 8 years before the current presentation, it was noted that the distal peritoneal shunt tubing (Peritoneal Catheter, Standard, Barium Impregnated; Medtronic Inc., Minneapolis, MN) had fractured and was coiled in the pelvis. Nevertheless, the tubing was not retrieved at that time

Optic pathway gliomas: a review

Journal ArticleOptic pathway gliomas represent approximately 3-5% of childhood intracranial tumors. They usually occur in children during the first decade of life and are seen in 11-30% of patients with neurofibromatosis Type 1 (NF1). Although these tumors are typically low-grade gliomas, the clinical course and natural history are highly variable, making treatment paradigms difficult. Overall, however, they are often indolent tumors that can be observed over time for progression without initial treatment, especially in patients with NF1. Chemotherapy is the first-line treatment for progressive tumors, and radiation therapy is reserved for patients with progressive disease who are older than 5-7 years. Surgery is reserved for large tumors causing mass effect or hydrocephalus and tumors confined to the orbit or unilateral optic nerve

A DFT study of dodecahedral beryllium silicide cage clusters

Density functional theory calculations have been conducted on 20- and 32-atom dodecahedral and facecapped dodecahedral cage clusters of beryllium and silicon. Stable Be24Si8, Be12Si8 and Be12Si20 cages are described, as is a stuffed cluster consisting of dodecahedral Si20 with an endohedral icosahedral Be12. Especial stability is associated with clusters in which faces are capped by silicon atoms, acting as electron donors to beryllium atoms.Fil: Fioressi, Silvina Ethel. Universidad de Belgrano. Facultad de Ciencias Exactas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bacelo, Daniel Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Binning, R. C.. Universidad Metropolitana; Estados Unido

Sulfide-binding hemoglobins: Effects of mutations on active-site flexibility

The dynamics of Hemoglobin I (HbI) from the clam Lucina pectinata, from wild-type sperm whale (SW) myoglobin, and from the L29F/H64Q/V68F triple mutant of SW, both unligated and bound to hydrogen sulfide (H2S), have been studied in molecular dynamics simulations. Features that account for differences in H2S affinity among the three have been examined. Our results verify the existence of an unusual heme rocking motion in unligated HbI that can promote the entrance of large ligands such as H2S. The FQF-mutant partially reproduces the amplitude and relative orientation of the motion of HbI's heme group. Therefore, besides introducing favorable electrostatic interactions with H2S, the three mutations in the distal pocket change the dynamic properties of the heme group. The active-site residues Gln-64(E7), Phe-43(CD1), and His-93(F8) are also shown to be more flexible in unligated HbI than in FQF-mutant and SW. Further contributions to H2S affinity come from differences in hydrogen bonding between the heme propionate groups and nearby amino acid residues.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Sulfide-binding hemoglobins: Effects of mutations on active-site flexibility

The dynamics of Hemoglobin I (HbI) from the clam Lucina pectinata, from wild-type sperm whale (SW) myoglobin, and from the L29F/H64Q/V68F triple mutant of SW, both unligated and bound to hydrogen sulfide (H2S), have been studied in molecular dynamics simulations. Features that account for differences in H2S affinity among the three have been examined. Our results verify the existence of an unusual heme rocking motion in unligated HbI that can promote the entrance of large ligands such as H2S. The FQF-mutant partially reproduces the amplitude and relative orientation of the motion of HbI's heme group. Therefore, besides introducing favorable electrostatic interactions with H2S, the three mutations in the distal pocket change the dynamic properties of the heme group. The active-site residues Gln-64(E7), Phe-43(CD1), and His-93(F8) are also shown to be more flexible in unligated HbI than in FQF-mutant and SW. Further contributions to H2S affinity come from differences in hydrogen bonding between the heme propionate groups and nearby amino acid residues.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada