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Biomedical subjects

J M Clayton

Publications and source records attributed to J M Clayton.

12 recordsLinked to original sources
PubMed1995

Protective vaccination with a recombinant fragment of Clostridium botulinum neurotoxin serotype A expressed from a synthetic gene in Escherichia coli.

A completely synthetic gene encoding fragment C, a approximately 50-kDa fragment, of botulinum neurotoxin serotype A was constructed from oligonucleotides. The gene was expressed in Escherichia coli, and full-sized product was produced as judged by Western blot (immunoblot) analysis. Crude extracts of E. coli expressing the gene were used to vaccinate mice and evaluate their survival against challenge with active toxin. Mice given three subcutaneous vaccinations were protected against an intraperitoneal administration of 10(6) 50% lethal doses (ID50) of serotype A toxin. The same mice survived when challenged with 3 LD50 of botulinum toxin serotype E but died when challenged with 10 LD50 of serotype E or 3 LD50 of serotype B. Purified fragment C was compared with the botulinum toxoid vaccine in a vaccination and challenge study. Fragment C was as efficacious in protecting against challenge with active botulinum neurotoxin serotype A as the toxoid vaccine. This recombinant protein product has many properties that make it a good candidate for human use to protect against botulinum toxin.

Animals↗
PubMed1979

Aspirin dosage for infants and children.

The labeled dosage schedule that has long been on pediatric aspirin preparations is at variance with the recommendation in authoritative medical references, studies demonstrating antipyretic effectiveness in children, and the prescribing habits of pediatricians as revealed by a poll conducted by the authors. Aspirin pharmacokinetics are influenced by a number of physiologic factors, as well as by dosage, and complicate the problem of assuring safe and effective pediatric use. Basic pharmacokinetic considerations indicate that the increase in size of individual doses needed to assure therapeutic salicyate blood levels, thereby removing the temptation of parents to administer the drug too often, is made permissible (i.e., safe while effective) by expanding the interdose interval to four hours instead of three. A revised pediatric aspirin disage schedule is presented that better meets the practices of the pediatric community and the needs of consumers.

Age Factors↗
PubMed1977

Sequential circulatory changes in the circumferentially burned limb.

To assess the hemodynamic alterations in the circumferentially burned extremity, Doppler arterial examinations and Xenon-133 washout determinations of muscle blood flow (MBF) were obtained in 27 limbs. In this laboratory normal resting MBF was 2.82+/-0.86 cc/min/100 gm (mean +/- S.E.M., N=26) with no value less than 1.60 cc/min/100 gm. In 27 circumferentially burned limbs, the maximum decrement in MBF occurred by 36 hours following thermal injury. The lowest MBF value in the 11 extremities not requiring escharotomy was 1.50cc/min/100gm. Escharotomy was done in 16 extremities. Mean MBF immediately prior to escharotomy was 1.30+/-0.26cc/min/100gm and improved to 4.43+/-0.52cc/min/100gm following escharotomy (p less than 0.01). Correlation between MBF and Doppler examinations was present in 63% of all studies and in 88% of studies performed immediately before or after escharotomy. The diagnostic sensitivity of Doppler examination required audible recognition of abnormal velocity signals as well as absent velocity signals. Because the intial MBF determination or Doppler examination is not helpful in predicting which extremities will eventually require escharotomy, sequential studies should be done during the first 36-48 hours following thermal injury.

Adolescent↗
PubMed1977

Xenon-133 determination of muscle blood flow in electrical injury.

Xe-133 washout determination of muscle blood flow (MBF) was used to detect muscle ischemia in electrical injury of an experimental animal model and three patients. The control MBF of rabbit hindlimbs, which averaged 11.29 +/- 1.07 cc/min/100 gm, was significantly reduced by electrical injury, to 5.82 +/- 1.49 cc/min/100 gm (p less than 0.001). An electrical injury of 4,000 watt-seconds or greater was associated with uniform MBF less than 1.00 cc/min/100 gm and with histopathologic alterations of muscle necrosis. Thenar MBF less than 1.00 cc/min/100 gm in two patients was associated with muscle necrosis requiring distal arm amputation. The remaining patient with sequential muscle blood flows above this level had uneventful healing of hand electrical injuries. Xe-133 determination of MBF may be a useful objective technique to determine the extent of electrical injury in muscle.

Adult↗