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Hogan
Major Support Received
Federal PI NIH Subcontract - "Multicenter Intra-operative
Hypothermia for Aneurysm Trial (IHAST2),"
NIH #38554-01 (7/00-6/05) $40,000 (total)
This is a randomized, multicenter, partially blinded trial to examine
the impact of intraoperative hypothermia (target temp = 33°C)
on long-term outcome in adult patients who have suffered a recent
subarachnoid hemorrhage and undergo an open craniotomy to clip the
aneurysm. Patients will be randomized to normothermic or hypothermic
groups. Long-term (3mo) outcome will be assessed using the Glasgow
Outcome Score (primary outcome variable), NIH Stroke Score, Rankin
Disability Score, Barthel's Activities of Daily Living Index, the
Mini-Mental Status Exam and a 5-exam battery of neuropsychologic
tests.
Federal PI NIH Small Business Investigator Awards Subcontract (with
Third Wave
Technologies) - "Perioperative Genomic Invader Profiles,"
NIH #IR43GM64317 (7/01-6/02) $46,642 (phase 1)
The goal of this project over Phase I is to create and test the
analytical validity of novel Invader mutation detection assays designed
for applications specific to surgery and anesthesia. Invader technology,
based on a highly specific enzyme-substrate reaction, enables direct
analysis of genomic DNA without prior amplification, conferring
advantages in rapidity, cost, and accuracy. The initial series of
experiments will test 200 patients for 23 alleles of established
clinical validity and utility at 12 loci predicting differences
in patient responses to neuromuscular blocking agents (BchE, RYR1,
CACNA1S), opiods and antiarrythmics (CYP2D6), nitrous oxide (MTHFR,
MTR, MTRR, CBS), volatile anesthetics (RYR1, CACNA1S), and the risk
and severity of sepsis (TNF-a, TNF-ß), and thrombosis (FVL,
Prothrombin). The surgical- and anesthesia-specific Invader assays
will be compared to conventional PCR-based methods with disparities
resolved by DNA sequencing. Subsequent Phase II investigations will
add alleles of proven predictive value to multiplexed Invader patient
panels designed for specific applications, and test whether these
can favorably alter clinical outcomes. These data represent the
necessary first steps in the assembly of high-throughput, automated
perioperative genomic profiles incorporating hundreds of genotypes
that can directly modulate risk and enhance the safety of all patients
undergoing surgery.
Non-Federal PI - "Genomic Predictors of Homocysteinemia
after Nitrous Oxide," Doris Duke Innovation in Clinical
Research Award (7/01-6/03) $200,000(total)
The aim of this investigation is to test whether patients with
mutations in genes encoding enzymes responsible for folate and cobalamin
metabolism are at special risk for increased blood levels of homocysteine
after nitrous oxide anesthesia. Acute elevations of homocysteine
promote coagulation and impair vascular relaxation setting the stage
for venous and arterial thrombosis. Thrombotic complications, including
myocardial ischemia, stroke and pulmonary emolus, are particularly
prevalent during the immediate post-operative interval coinciding
with nitrous oxide-induced hyper-homocysteinemia. In turn, common
polymorphisms in genes expressing enzymes which regulate folate
and cobalamin metabolism (the C677T and A1298C alleles of 5, 10
methylene tetrahydrofolate reductase the A256G allele of methionine
synthase, the A66G allele of methionine synthase reductase, and
the 844ins68 variant of cystathionine beta-synthase) have recently
been shown to be independent predictors of homocysteinemia. In this
investigation, two hundred patients undergoing vascular procedures
for disorders associated with a disproportionate prevalence of hyper-homocysteinemia
and thrombosis formation (i.e. carotid endarterectomy, lower extremity
arterial bypass) will have blood drawn before nitrous oxide anesthesia
for detection of the 5 cited mutations, together with folate, cobalamin,
pyridoxine and baseline homocysteine levels. Serial homocysteine
levels will then be measured immediately after surgery, at 24 and
48 hours. Severity of homocysteinemia and allele frequency will
be compared in two hundred age- and gender-matched patients having
non-vascular procedures (i.e. craniotomy) of similar duration and
inspired nitrous oxide concentration. If folate and cobalamin cycle
genotypes correlate with perioperative elevations in serum homocysteine,
patient safety will be enhanced for those at heightened risk by
prophylaxis e.g. pre-surgical folate and cobalamin administration,
and by selection of alternative perioperative management e.g. regional
or intravenous anesthetics avoiding use of nitrous oxide.
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