Sequence dependence of charge transport properties of DNA.

The electrical conduction through three short oligomers (26 base pairs, 8 nm long) with differing numbers of GC base pairs was measured. One strand is poly(A)-poly(T), which is entirely devoid of GC base pairs. Of the two additional strands, one contains 8 and the other 14 GC base pairs. The oligomers were adsorbed on a gold substrate on one side and to a gold nanoparticle on the other side. Conducting atomic force microscope was used for obtaining the current versus voltage curves. We found that in all cases the DNA behaves as a wide band-gap semiconductor, with width depending on the number of GC base pairs. As this number increases, the band-gap narrows. For applied voltages exceeding the band-gap, the current density rises dramatically. The rise becomes sharper with increasing number of GC base pairs, reaching more than 1 nA/nm2 for the oligomer containing 14 GC pairs.

Early mobilization after sliding achilles tendon lengthening in children with spastic cerebral palsy.

Equinus deformity is a common finding in children with cerebral palsy and may be treated by Achilles tendon lengthening. To prevent recurrence, some authors recommend immobilizing the operated leg with an above-knee cast for six weeks, followed by use of a night splint or orthosis. Nevertheless, there are recurrence rates of up to 20.5%. The aim of this study was to evaluate the long-term result of postoperative immobilization for two weeks in a below-knee cast and early weight bearing, without the use of a splint or orthosis. Thirty-six children (52 feet) with spastic cerebral palsy underwent sliding Achilles tendon lengthening. Follow-up of five to ten years showed a comparable recurrence rate (19.2%) to that reported with the standard, more stringent management approach. Most of the recurrences were in children operated on before five years of age. We believe earlier motion helps to sustain the tendon length achieved at surgery and allows for earlier independent gait.

Ineffectiveness of oral coenzyme Q10 supplementation in 3-methylglutaconic aciduria, type 3.

Coenzyme Q10 was administered under placebo controlled blinded crossover conditions to six subjects suffering from type 3 3-methylglutaconic aciduria ('optic atrophy plus'), following a report of benefit. Despite attainment of high plasma levels of coenzyme Q10, no clinical benefit was observed and there was no diminution of urinary excretion of 3-methylglutaconic acid.

Iraqi-Jewish kindreds with optic atrophy plus (3-methylglutaconic aciduria type 3) demonstrate linkage disequilibrium with the CTG repeat in the 3' untranslated region of the myotonic dystrophy protein kinase gene.

Iraqi-Jewish optic atrophy plus is an autosomal recessive condition characterized by infantile optic atrophy, an early onset movement disorder, and 3-methylglutaconic aciduria. Other features include spastic paraplegia, mild ataxia, mild cognitive deficiency and dysarthria. This disorder was identified in inbred Iraqi-Jewish kindreds in which relationships between most of the affected individuals were unknown. In this study we identify linkage to chromosome 19q13.2-q13.3 by using a DNA pooling strategy to perform a genome wide screen followed by a high density search for shared segments among affected individuals in candidate regions identified in the initial genome wide screen. A significantly high positive lod score of 6.14 at zero recombination was obtained for the CTG repeat in the 3' untranslated region of the myotonic dystrophy protein kinase gene. The existence of multiple recombinant individuals indicates the disease interval can be further narrowed with additional markers. Linkage disequilibrium was seen in six polymorphic markers across a 1 Mb interval. This region is well characterized and contains several candidate genes.

3-Methylglutaconic aciduria in "optic atrophy plus".

Behr's syndrome consists of recessively inherited infantile optic atrophy, together with chronic neurological disturbances such as ataxia, extrapyramidal dysfunction, and juvenile spastic paresis. This syndrome was found to be relatively common among Iraqi Jews. For our study, 18 such patients underwent metabolic study. All 18 showed abnormally elevated excretion of 3-methylglutaconic acid in their urine. The basic enzymatic defect is as yet unknown. We recommend that patients with early optic atrophy, and especially those with motor dysfunction, be examined for this organic aciduria.

A familial syndrome of infantile optic atrophy, movement disorder, and spastic paraplegia.

We describe 19 cases of a familial syndrome consisting of infantile optic atrophy and an early movement disorder in which chorea predominated. About one-half the patients developed spastic paraparesis during the second decade of life. Ataxia and cognitive deficits were common, usually of mild degree. Seventeen of the patients were females. Sixteen had similarly affected siblings, but none had affected parents. All but one belonged to the Iraqi Jewish community in Israel, giving a minimal prevalence rate in this ethnic group of about 1:10,000.

Late neuropsychologic status after childhood head trauma.

A neurologic and neuropsychologic test battery was administered to a sample of 35 children drawn from all those in a defined geographic area who had been hospitalized for head trauma before age 7 during the years 1970-1976. Examination was performed 3 1/2 to 10 years after injury, at age 6-15. Twelve subjects had been diagnosed at the time of injury as suffering moderate insult and had been referred to the metropolitan neurosurgical center, while twenty-three with only mild injury had been retained for observation in a local pediatric ward. The twelve with more severe insult were significantly inferior to the other subjects on the Block Design and Coding subtests of the revised Wechsler Intelligence Scale for Children. The Koppitz score of the Bender Test, the WISC-R scatter, the Benton Visual Retention Test, the GATB Motor Speed Test and the Bourdon-Wiersma Vigilance Test showed less diagnostic power and failed to distinguish between the group with more severe injury and that with less. A detailed and carefully scored neurologic examination also failed to distinguish between the two groups. The findings suggest that relatively common traumatic injury may be associated with detectable late cognitive deficit, and that some WISC-R subtests may be among the best measures for detecting such deficit.

Neonatal neurofibromatosis: unusual manifestations with malignant clinical course.

A family with neurofibromatosis is reported in which the proband was an infant in whom the diagnosis was established at birth. In this case, the presenting symptom was a large tumor of the tongue and macrocephaly. Cafe-au-lait spots appeared early, as did additional subcutaneous tumors, with skeletal involvement and severe psychomotor retardation. The rapid growth of the tumor, its spread within the mediastinum, neck and oral cavity, led to a strangulating death at one year of age. The disease originates from early embryonic involvement of the neural crest and from tissues derived from its caudal end. It is probably caused by a single pleiotropic gene transmitted as an autosomal dominant trait, with varying expression of the disease in different members of the same family.