PubMed Health⌕ Search

Biomedical subjects

W J Gardner

Publications and source records attributed to W J Gardner.

18 recordsLinked to original sources
PubMed1979

Isolation and characterisation of guanine auxotrophs in Saccharomyces cerevisiae.

Mutants of yeast which are auxotrophic for guanine have been isolated from two prototrophic haploid strains, one of which carried the suppressor of purine excretion, su-pur, and the other carried the alternative allele, su-pur+. The mutants were allocated to three genes, gual, gua2, and gua3, between which no close linkage was demonstrable. Mutants of all three genes were recessive and showed normal Mendelian segregation in crosses. The gene gual was shown by an in vivo enzyme assay procedure to specify guanosine 5'-phosphate (GMP) synthetase, the second enzyme involved in the biosynthesis of GMP from inosine 5'-phosphate (IMP). Mutants of this gene excrete large amounts of purine derivatives, predominantly xanthosine, into guanine-free, but not into guanine-supplemented, medium. The gene gau2 is probably involved in the biosynthesis of riboflavin from guanine nucleotides; the phenotype of these mutants suggests a possible interaction between aromatic amino acid metabolism and riboflavin biosynthesis. No role for gua3 can be assigned on the evidence so far available, but it is not involved in the specification of IMP dehydrogenase, the first enzyme involved in the synthesis of GMP and IMP.

Cell-Free System↗
PubMed1979

Klippel-Feil syndrome, iniencephalus, anencephalus, hindbrain hernia and mirror movements: overdistention of the neural tube.

Bony anomalies encountered in the 'no neck' form of Klippel-Feil syndrome (KFS) are a wide, short, fused, bifid, retroflexed spinal canal; craniolacunia, cranium bifidum, and acrania. The only symptom may be mirror movement (MM). The CNS anomalies are hindbrain hernia, hydrocephalus, hydromyelia, syringomyelia, meningocele, myelocele, encephalocele, and anencephalus. In severe KFS, i.e. iniencephalus (IN) and in anencephalus (AN), the inion is in contact with the back. In both there is hindbrain hernia and the left thorax may contain the stomach tethered to an anterior spina bifida. KFS results from distortion of somites by an overdistended neural tube. A neural tube that fails to close cannot overdistend.

Adolescent↗
PubMed1977

Hydrodynamic factors in Dandy-Walker and Arnold-Chiari malformations.

The Dandy-Walker malformation (DWM) is hydrocephalus that primarily affects the fourth ventricle, whose overdistention involves also the aqueduct and third ventricle. However, just the opposite is true in the Arnold-Chiari malformation (ACM) since the hydrocephalus is limited to the lateral ventricles which squeeze the third ventricle between them and compress the aqueduct and fourth ventricle. The evidence indicates that both result from hydrodynamic stresses in embryonal and early fetal life. This communication is offered in rebuttal to some statements in an otherwise authoritative and comprehensive article.

Arnold-Chiari Malformation↗
PubMed1977

Terminal ventriculostomy for syringomyelia.

The clinical course of 12 patients who underwent terminal ventriculostomy for syringomyelia is presented. Opening the central canal at the tip of the conus medullaris is a relatively benign procedure that improves the symptoms of syringomyelia and syringobulbia. This canal normally terminates at the tip of the conus, but in each of the 12 surgical specimens it continued into the filum terminale for distances up to 8 cm. In most cases the tip of the conus was located more caudally than normal, indicating some degree of tethering in fetal life. This belief is supported by the fact that the newborn, whose conus is tethered to a lipoma at the sacral level, may develop syringomyelia in adult life.

Adult↗
PubMed1977

Syringomyelia.

Explore the source record for details and available documents.

Humans↗
PubMed1976

""Non-communicating'' syringomyelia: a non-existent entity.

Encroachment by man's overlarge forebrain is responsible for the anatomic substrate of syringomyelia, i.e. a hindbrain hernia developing in fetal life with persisting hydromyelia. Communication between the syrinx and 4th ventricle is readily disclosed at operation, but because of postmortem shrinkage, almost never at autopsy. Syringomyelia developing in 16 of 864 post-traumatic paraplegics has been classified non-communicating. However, the syrinx, its fluid, and the ultimate clinical picture are the same as in the non-traumatic, and surgical exposure has disclosed the communication. The symptoms develop because the traumatic subarachnoid block exaggerates the causative intracranial fluid pulse waves by eliminating the dampling effect of the yielding dural sac below. A non-traumatic spinal block also may result in syringomyelia.

Cerebrospinal Fluid↗
PubMedDate not supplied

Long term results in the management of craniopharyngiomas.

The results of surgical treatment, with and without radiotherapy, in 50 patients with craniopharyngioma treated over a 26-year period at the Cleveland Clinic are presented. Thirty-five patients were operated upon before the introduction of the operating microscope, and 30 of these survived operation. In this group of 30 patients, long term survival (5 to 24 years) occurred in 8 of 10 (80%) nonradiated patients who were considered to have had total excision. Nine of 11 patients (82%) who had aggressive subtotal excision and radiation therapy have survived from 3 to 17 years. Seven of nine patients (78%) died 1 to 14 years after subtotal excision without radiation therapy. Since the introduction of the operating microscope in 1972, 15 patients have had surgical treatment, and 12 of these have survived.

Adult↗