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Biomedical subjects

W E Allen

Publications and source records attributed to W E Allen.

At least 127 records · Page 7Linked to original sources

Microcirculation of traumatized spinal cord. A correlation of microangiography and blood flow patterns in transitory and permanent paraplegia.

A relationship of microangiography and blood flow patterns in the contused feline spinal cord is reported. In transitory traumatic paraplegia, an injury from which there is a return of function in several weeks, impaired vascular perfusion occurs in the white matter through 1 hour after contusion, then stabilizes and returns to normal by 24 hours. In permanent traumatic paraplegia, an injury from which no sensory or motor function returns, the vascular perfusion of the white matter continues to decrease after 1 hour and returns to normal by 24 hours at which time irreversible damage has occurred to the major sensory and motor tracts. Within the first 30 minutes post-trauma, intramedullary vasospasm is noted. In both the transitory and permanent lesions the gray matter becomes hemorrhagic and has no evidence of perfusion by fluorescent techniques by 1 hour after injury.

Animals↗

Characteristics of Staphylococcus aureus associated with lysogenic conversion to loss of beta-hemolysin production.

Staphylococcus aureus strains 7-8 and 57 that produce beta-hemolysin but not staphylokinase (beta + K-) were lysogenically converted by certain serological group F bacteriophages to the loss of beta-hemolysin production and the gain in staphylokinase production (beta-K+). Serological group A phage 42E was found to convert S. aureus strains 7-8(beta-K-) and 57 (beta + K-) to beta - K-. Conversion of beta-hemolysin by lysogenization of a serological group A phage has not previously been reported. Phage 42E conversions differed from the group F conversions since staphylokinase was not affected. This indicates that conversion to beta-K+ involves separate loci on the phage chromosome. Several characteristics associated with virulence of staphylococci of human or animal origin other than staju;plomase production (coagulase, DNase, lipase, gelatinase, mannitol fermentation, and phage-sensitivity patterns) were not correlated with lysogenic conversions to loss of beta-hemolysin.

Bacteriophage Typing↗

Preoperative laminagraphic evaluation of the sphenoid sinus for transsphenoidal surgery.

In recent years the transethmoidal and transnasal approaches to the pituitary gland have become increasingly popular. In each case, detailed preoperative analysis of the anatomy of the sphenoid sinus and its boundaries is crucial in facilitating entry to the pituitary fossa and in reducing intraoperative complications. Certain operative difficulties and complications are the result of the marked variability in the anatomy of the sphenoid bone and its sinus. These include: loss of orientation within a capacious sinus; perforation of the carotid artery or cavernous sinus; injury to the optic nerve or ophthalmic artery; and violation of the subarachnoid space with resultant pneumocephalus or cerebrospinal fluid rhinorrhea. Pneumatization develops originally within the presphenoid, beginning anteriorly and proceeding posteriorly. Around the time of puberty the pneumatization usually penetrates up to the spheno-occipital synchondrosis. Dense bony septa remain within the sinus along the plane of fusion of the various sphenoidal segments. Preoperative laminagraphy of these ridges and septa is extremely helpful in planning the safest and most direct route to the sella. Laminagraphy is preferable to routine skull films because the septal detail is unobscured by overlying facial structures. Pleuridirectional laminagraphic motion (circular or hypocycloidal) is preferred to linear motion because of the clarity and detail that they provide.

Humans↗

Ovarian changes during early pregnancy in pony mares in relation to PMSG production.

The ovaries of twenty pregnant mares were examined daily, per rectum, for the first 4 months of gestation and note was made of their estimated size and follicular content. Serial blood samples from sixteen of the mares were assayed for PMSG. A marked seasonal effect was noted on ovarian size, follicular content and ovulation rate during pregnancy but there was no such effect on PMSG production. It is concluded that PMSG is synergistic with gonadotrophins of pituitary origin and that the latter hormone are the primary stimulus on the ovary of the pregnant horse.

Animals↗