CONTEXT Deficits in cerebral glucose utilization have been identified in patients
with cognitive dysfunction attributed to various disease processes, but their
prognostic and diagnostic value remains ...to be defined. OBJECTIVE To assess the sensitivity and specificity with which cerebral metabolic
patterns at a single point in time forecast subsequent documentation of progressive
dementia. DESIGN, SETTING, AND PATIENTS Positron emission tomography (PET) studies of 18Ffluorodeoxyglucose
in 146 patients undergoing evaluation for dementia with at least 2 years'
follow-up for disease progression at the University of California, Los Angeles,
from 1991 to 2000, and PET studies in 138 patients undergoing evaluation for
dementia at an international consortium of facilities, with histopathological
diagnoses an average of 2.9 years later, conducted from 1984 to 2000. MAIN OUTCOME MEASURES Regional distribution of 18Ffluorodeoxyglucose in each
patient, classified by criteria established a priori as positive or negative
for presence of a progressive neurodegenerative disease in general and of
Alzheimer disease (AD) specifically, compared with results of longitudinal
or neuropathologic analyses. RESULTS Progressive dementia was detected by PET with a sensitivity of 93% (191/206)
and a specificity of 76% (59/78). Among patients with neuropathologically
based diagnoses, PET identified patients with AD and patients with any neurodegenerative
disease with a sensitivity of 94% and specificities of 73% and 78%, respectively.
The negative likelihood ratio of experiencing a progressive vs nonprogressive
course over the several years following a single negative brain PET scan was
0.10 (95% confidence interval, 0.06-0.16), and the initial pattern of cerebral
metabolism was significantly associated with the subsequent course of progression
overall (P<.001). CONCLUSION In patients presenting with cognitive symptoms of dementia, regional
brain metabolism was a sensitive indicator of AD and of neurodegenerative
disease in general. A negative PET scan indicated that pathologic progression
of cognitive impairment during the mean 3-year follow-up was unlikely to occur.
It is difficult to accurately forecast the clinical course of many patients presenting with mild cognitive problems. The utility in prognostic evaluation of various parameters of brain structure and ...function that can now be noninvasively measured remains to be clearly defined. The present work examined the value of regional cerebral metabolism, assessed with positron emission tomography (PET) and
18Ffluoro-2-deoxyglucose, in this context. PET scans of 167 patients (mean Mini-Mental State Examination (MMSE)=24 of 30 possible points) were classified as being positive or negative for evidence of progressive dementia. Results of scans were compared to patients’ subsequent clinical course in general and in particular, to their changes in MMSE scores, for up to 10 years following PET. Data were further stratified according to the predictions of referring physicians based upon clinical assessments that had been performed up until the time of PET. Among those patients for whom a progressive dementing course had been predicted by PET criteria (but not those who were predicted by PET criteria to remain stable) a significant decline in general cognitive performance and MMSE scores occurred in the period following PET. Among those patients predicted by clinical criteria to have a progressive dementing illness, 94% of those with positive PET scans did suffer a progressive decline, while only 25% of those with negative scans progressed (relative risk 3.8). Similarly, among those patients who had been predicted by clinical criteria to remain cognitively stable, 74% of those with positive PET scans nevertheless suffered progressive decline, compared with 4% of those with negative PET scans (relative risk 18.4). These data indicate that evaluation of brain metabolism by PET in appropriately selected patients may improve the accuracy of clinical prognostic assessment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The components of a diagnosis in the fetal alcohol spectrum consider, among other domains, evidence of prenatal alcohol exposure, facial features, neurological or neuropsychological deficits, and ...neuroanatomical form. Most of these assessments are based on traditional sorts of quantifications (e.g., length measures, IQ scores, quantity of alcohol drunk by the mother), but for one of the domains, the morphometric assessment of neuroanatomical form as abnormal in a way suggesting fetal alcohol damage, the associated quantifications are relatively recent. For purposes of a forensic report, this morphometric component of the diagnostic judgment would seem to go best in the form of one classic statistical quantity, the likelihood ratio (odds ratio) of two hypotheses as they both attempt to explain the form of a particular structure within the defendant's brain (in our approach, the midcurve of the corpus callosum). On one hypothesis, the subject is presumed to be from a normal population; on the other, he is from a group all characterized by diagnosable fetal alcohol damage. Our article explains in simple terms how the forensic physician might wish to couch that component of the FASD diagnostic system for the purpose of aiding those in the courtroom who have the task of determining guilt or culpability.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, PRFLJ, SAZU, UILJ, UKNU, UL, UM, UPUK
By means of emission computed tomography (ECT), we used 18F-fluorodeoxyglucose (18FDG) and 13N-ammonia (13NH3) as indicators of abnormalities in local cerebral glucose utilization (LCMRglc) and ...relative perfusion, respectively. The ECAT positron tomograph was used to scan normal control subject and 10 stroke patients at various times during recovery. In normal subjects, mean CMRglc was 5.28 +/- 0.76 mg per 100 gm tissue per minute (mean +/- SD; N = 8). In patients with stroke, mean CMRglc in the contralateral hemisphere was moderately decreased during the first week, profoundly depressed in irreversible coma, and normal after clinical recovery. Quantification was restricted by incomplete understanding of tracer behavior in diseased brain, but relative local distributions of 18FDG and 13NH3 trapping qualitatively reflected the increases and decreases as well as coupling and uncoupling expected for local alterations in glucose utilization and perfusion in stroke. Early after cerebrovascular occlusion there was a greater decrease in local trapping of 13NH3, than 18FDG within the infarct, probably because of increased anaerobic glycolysis. Otherwise, 18FDG was a more sensitive indicator of cerebral dysfunction than was 13NH3. Hypometabolism, due to deactivation or minimal damage, was demonstrated with the 18FDG scan in deep structures and broad zones of cerebral cortex that appeared normal on x-ray computed tomography and technetium 99m pertechnetate scans. In its present state of development, the 18FDG ECT method should aid in defining the location and extent of altered brain in studies of disordered function after stroke. With improved knowledge of tracer behaviour in diseased brain, the method has promise for mapping the response to therapeutic intervention and increasing our understanding of how the human brain responds to stroke.
Placed 8 food-deprived black rat snakes on a schedule of 5-day water-deprivation periods followed by drinking tests in a runway and 2-day periods with water in their cages. Mean body weight loss ...during 5 successive deprivation periods was almost invariant, and mean recovery on the drinking tests closely matched weight loss. Latency to drink decreased over successive tests. Ss were then water deprived for 5-, 12-, and 19-day periods, each followed by a drinking test and 2-days access to water. Recovery on the drinking tests was proportional to weight loss, and the mean weight recovered on the tests did not differ significantly from the levels maintained during the subsequent periods of access to water, indicating that water loss was accurately replaced at the 1st opportunity.
Newborn garter snakes were fed earthworms either daily (Group D, n=9) or weekly (Group W, n=6) for 13 weeks. Both groups then were fed weekly for 3 weeks, then were totally food deprived for three ...weeks, followed by 1 week of daily feeding. By the fourth week of life all snakes in Group D were longer and heavier than any in Group W. In 13 weeks, Group D increased a mean of 285 per cent in weight and 162 per cent in length. Corresponding values for Group W were 184 and 134 per cent. When fed weekly, snakes increased substantially in weight after feeding, but lost much of the increase during the week. However, during the last 2 weeks of the 3-week deprivation period, mean percentage body weight losses for Groups D and W were only 6.72 and 7.50, and they rapidly gained weight when feeding was resumed.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
A patient had recurrent episodes of acute glomerulonephritis following exacerbations of chronic relapsing pancreatitis. Light microscopy of the renal biopsy performed during the episode of acute ...glomerulonephritis showed fibroepithelial crescents involving 70% of the glomeruli. The patient recovered without specific therapy. The time interval involved and the presence of subendothelial deposits with mesangial deposition of C3 complement and IgM suggest immune complex injury.
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