NMDA receptor activation during epileptiform responses in the dentate gyrus of epileptic patients.

We previously showed that a low frequency (1 Hz) train of perforant path stimulation evokes burst discharges in the dentate gyrus of hippocampal slices obtained from patients surgically treated for intractable temporal lobe epilepsy. We report here that multiple population spikes that characterize the burst discharge are blocked reversibly by the specific NMDA receptor antagonist, D-(-)-2-amino-5-phosphonovaleric acid (D-APV). The epileptiform discharge evoked in human dentate gyrus by stimulation trains of 1 Hz could be reproduced in the rat dentate gyrus in vitro by the same stimulation protocol but required the presence of low concentrations (0.2-0.6 mM) of extracellular magnesium. We suggest that low frequency orthodromic stimulation of dentate granule cells through the perforant path progressively evokes an increase in the activation of NMDA receptors resulting in burst discharges in tissue from epileptic patients.     

CEEG mapping in drug-free schizophrenics. Differences from healthy subjects and changes induced by haloperidol treatment.

A topographic CEEG investigation was carried out in 20 drug-free, DSM-IIIR diagnosed schizophrenics and in a group of matched healthy controls. The effects of acute and chronic haloperidol treatment were then assessed in the patient group. On the baseline recording, schizophrenics showed a widespread increase in delta, theta 1 and beta 3 amplitude. Acute haloperidol administration produced a decrease in delta and an increase in slow beta amplitude. After 28 days of treatment, delta and fast beta were reduced while theta 2 and alpha 1 were increased. CEEG abnormalities in schizophrenic subjects appear, therefore, to be reduced by chronic neuroleptic treatment.     

Olfactory bulb DA receptors may be located on terminals of the olfactory nerve.

The glomerular layer of the olfactory bulb contains a substantial population of dopaminergic neurons. We determined the quantity and location of D1 and D2 dopamine receptors which are the presumed targets of these neurons. Binding of the D1 selective ligand [3H]SCH23390 was slightly above background and was distributed through all layers of the bulb except the olfactory nerve layer. In contrast there were relatively high levels of [3H]spiperone binding to D2 DA receptors in the glomerular and olfactory nerve layers. The presence of relatively high concentrations of D2 DA receptors in both the nerve layer and glomerular layer suggests the novel hypothesis that these receptors may be localized on terminals of the olfactory nerve.     

Preclinical profile of stereoisomers of the anticonvulsant remacemide in mice

Stereoisomers of remacemide (racemate form) were compared for anticonvulsant efficacy and safety in mice. In the maximal electroshock seizure (MES) test for oral efficacy, the (-) stereoisomer, FPL 14145, was more potent than the racemate or the (+) stereoisomer, FPL 14144. Respective ED50 values (expressed as mg/kg) were: remacemide, 58; FPL 14145, 45; FPL 14144, 79. In 2 of 3 tests for neural impairment, FPL 14145 yielded significantly better therapeutic indices (toxic dose 50/ED50) than the racemate. The margin of safety (estimated median lethal dose ED50) was more favorable for FPL 14144: remacemide, 15.1; FPL 14144, 18.9; FPL 14145, 15.7. The duration of protection against MES indicated the stereoisomers were longer acting than the racemate. After intravenous administration the order of potency against MES was similar: FPL 14145 greater than remacemide greater than FPL 14144. Following daily administration of the oral ED98 for 4 days, with a dose response curve run on day 5, the MES ED50 values for all compounds were increased. The test indicates tolerance. In the pentylenetetrazol infusion test the racemate and FPL 14144 demonstrated more proconvulsant properties than FPL 14145. Intraperitoneal administration of 50 mg/kg or more produced changes in behavior with all compounds. At higher doses the racemate and FPL 14145 elicited more severe symptoms with death at 200 mg/kg.     

Long-term cognitive deficits in patients after surgery on aneurysms of the anterior communicating artery.

The long term recovery of a series of 27 patients who had undergone rupture and repair of an aneurysm of the anterior communicating artery was assessed using a number of neuropsychological measures. Testing took place 12 to 84 months post surgery. On the basis of the results from tests of intellect, memory, and conceptual learning, three subgroups of patients were identified: those with persuasive cognitive defects, those with evidence of residual frontal lobe damage and those who showed no evidence of dysfunction. The occurrence of cerebral vasospasm was the most consistent predictor of long term cognitive deficit.     

Use of a computer-based health risk appraisal by older adults

BACKGROUND. A health risk appraisal (HRA) is a tool for health promotion. Conversational microcomputer-based HRAs may be more cost effective than other HRA formats. The acceptability of conversational HRAs, however, has not been demonstrated for older adults. METHODS. We studied the acceptability of a conversational microcomputer-based HRA in a sample of 247 adults at the Minnesota State Fair and the Senior Options Exposition. All users were offered the appraisal via mouse or keyboard interface. Acceptability was measured in terms of user-reported helpfulness, intent to change, time of use, and willingness to view HRA health recommendations. Data on completion time and willingness to view HRA recommendations were collected for Senior Exposition users only. Regression analyses were used to examine the combined impact of interface (mouse or keyboard), location (State Fair or Senior Exposition), age, and sex on user acceptability. Results. Interface and location had no effect on helpfulness or change ratings. Older users rated the appraisal more helpful (P less than .007). Both older and female users reported more intent to change behavior (P = .016, both). Time to use the appraisal was related to interface, age, and sex. Mouse users (P less than .0001), older users (P less than .0001) and female users (P less than .05) took significantly longer to use the appraisal. Significantly more mouse users declined to see recommendations (P less than .02). CONCLUSIONS. Older users can derive as much or more value from conversational health risk appraisals as younger users; however, a mouse interface may be less effective for this age group.     

An improved method for determining 89Sr and 90Sr in urine

A method has been developed for the rapid isolation and quantitation of 89Sr and 90Sr in urine samples. The radiostrontium is concentrated from the bulk urine sample by coprecipitation with calcium phosphate. The precipitate is then wet ashed with nitric acid, and a solution of the resulting residue in 2 M HNO3-0.5 M Al(NO3)3 is passed through an extraction chromatographic column containing a supported crown ether that preferentially retains strontium. Sorbed strontium may then be eluted from the column with either dilute HNO3 or water and counted via liquid scintillation. A new counting scheme that permits quantitation of both 89Sr and 90Sr on the same day the separation is performed is described.     

Predictors of oral health quality of life in older adults

There is limited information regarding oral health status and other predictors of oral health‐related quality of life. An association between oral health status and perceived oral health‐related quality of life (OHQOL) might help clinicians motivate patients to prevent oral diseases and improve the outcome of some dental public health programs. This study evaluated the relationship between older persons' OHQOL and their functional dentition, caries, periodontal status, chronic diseases, and some demographic characteristics. A group of 733 low‐income elders (mean age 72.7 ISD=4.71, 55.6% women, 55.1% members of ethnic minority groups in the U.S. and Canada) enrolled in the TEETH clinical trial were interviewed and examined as part of their fifth annual visit for the trial. OHQOL was measured by the Geriatric Oral Health Assessment Index (GOHAI); oral health and occlusal status by clinical exams and the Eichner Index; and demographics via interviews. Elders who completed the four‐year assessment had an average of 21.5 teeth (SD=6.9). with 8.5 occluding pairs (SD=4.6), and 32% with occlusal contacts in all four occluding zones. Stepwise multiple regressions were conducted to predict total GOHAI and its subscores (Physical, Social, and Worry). Functional dentition was a less significant predictor than ethnicity and being foreign‐bom. These variables, together with gender, years since immigrating, number of carious roots, and periodontal status, could predict 32% of the variance in total GOHAI, 24% in Physical, 27% in Social, and 21 % in the Worry subscales. These findings suggest that functional dentition and caries influence older adults' OHQOL, but that ethnicity and immigrant status play a larger role.