[Attentional deficits].
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Biomedical subjects
Publications and source records attributed to B F Michel.
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BACKGROUND: AD is characterized by cerebral deposition of beta-amyloid plaques with amyloid beta-peptide (Abeta) 42 as the major peptide constituent, along with neurofibrillary tangles and neuronal loss. In transgenic mice, active immunization against Abeta42 removes these plaques and improves cognitive function. A Phase I study in AD patients demonstrated good safety and tolerability of multiple injections of aggregated Abeta42 (AN1792) with QS-21 as adjuvant. METHODS: Three hundred seventy-two patients with mild to moderate AD were randomized to receive IM injections of AN1792 or placebo (4:1) at baseline and at months 1, 3, 6, 9, and 12 in a multicenter Phase II safety, tolerability, and pilot efficacy study. Dosing was terminated after four early reports of meningoencephalitis, but follow-up continued. The study remains blinded, and further results will be reported after its termination. RESULTS: Symptoms and laboratory findings consistent with meningoencephalitis occurred in 18 of 298 (6%) patients treated with AN1792 compared with 0 of 74 on placebo (p = 0.020). Sixteen of the 18 had received two doses, one had received one dose, and one had received three doses of the study drug before symptoms occurred. The median latency from the first and last injections to symptoms was 75 and 40 days. No case occurred later than 6 months after the first immunization. Anti-Abeta42 antibody titers were not correlated with the occurrence or severity of symptoms or relapses. Twelve patients recovered to or close to baseline within weeks, whereas six remain with disabling cognitive or neurologic sequelae. All 18 patients remain alive to date (December 31, 2002), 6 months to >1 year after symptom onset. CONCLUSIONS: Postvaccination meningoencephalitis occurred without clear relation to serum anti-Abeta42 antibody titers. Potential mechanisms such as T-cell and microglial activation may be responsible and are under consideration to develop a safer anti-Abeta immunotherapy for AD.
DFT (fronto-temporal dementia) was diagnosed in 33 patients (17 males and 16 females), mean age 74.9 years, using the criteria from Neary et al. (1998). The severity of the disease was evaluated based on the presence or absence of 4 clinical groups of signs (behavioral, affective, neurological signs and language) allowing the calculation of a global clinical ratio on 20. A CT-scan and a Single Photon Emission Computed Tomography (SPECT) scan using Tc99m-ECD with quantification of brain perfusion were then performed. This study confirmed the classical clinical forms of DFT: a psycho-affective form (21%), where negative symptoms are predominant, and a behavioral disinhibited form (9%). Most of our cases (40%) corresponded to a global form. Finally we also identified a fourth clinical form: cognitive form because of predominance of language disturbances (30%). Concerning SPECT, we found 4 topographic forms: frontal global (46%), frontal superior (24%), frontal inferior (15%) and frontal unilateral (12%). In the frontal inferior form, behavioral disturbances were correlated to the intensity of frontal inferior hypoperfusion, corresponding to an orbito-frontal dysfunction. In the frontal superior form, psycho-affective disturbances (apathy) were correlated with frontal superior hypoperfusion (anterior cingulum and superior dorso-lateral cortex). Finally, in global and frontal inferior SPECT forms, language disturbances were correlated with a frontal inferior hypoperfusion (prefrontal and inferior left frontal cortex).
We describe the follow-up of a cohort of 255 Alzheimer's disease (AD) patients (81 males, 174 females) treated by tacrine during 4 years. We performed the survey of hepatic, cholinergic and general tolérance. Drug efficacy was measured by MMS examination on weeks 0, 18, 30, 52, 104, 156 and 208. A total of 190 patients (74.5 percent) were dropped out of this study, 75 (29 percent) for adverse events. We found 85 hepatic (33 percent), 79 cholinergic (31 percent), 31 (12 percent) neuropsychiatric and 72 general (28 percent) side effects. In term of drug efficacy we observed a global decline of 2.5 MMS points during the first year and 2 MMS points between W52 and W156. Tacrine's symptomatic efficacy, defined as the number of patients improved or stabilized at W30, was present in 50 patients (46 percent) among the 109 patients reaching W30. The intensity of symptomatic efficacy was expressed by a 2.7 MMS points increase in 37 patients improved on W30. The long term effects of Tacrine, measured by the MMS score at one year, showed a positive impact as the MMS was 2.5 points above the expected score in non treated AD patients. This study raises the practical problem of optimal cholinesterase inhibitors use in AD and the theoretical question of long term action of cholinesterase inhibitors on cerebral lesions of AD.
Ursodeoxycholic acid is a protective agent against liver toxicity caused by some drugs. In the present pilot study, we assessed the effect of this bile acid on tacrine-induced hepatotoxicity. Fourteen patients with a diagnosis of Alzheimer's disease received tacrine and ursodeoxycholic acid (13 mg/kg/day) for 105 days. Serum ALAT was the main evaluation criterion. Serum levels of ALAT were compared with those of 100 patients who had been treated with tacrine in the same centre. In patients receiving ursodeoxycholic acid, ALAT serum levels were normal in 93 per cent of cases vs. 69 per cent in control patients and moderate hepatotoxicity (ULN < ALAT < 3 ULN) did not occur while it was present in 25 per cent of controls (p = 0.036). In contrast, the percentage of patients with ALAT > 3 ULN was similar in the two groups (7 per cent vs. 6 per cent). These present findings suggest that UDC could prevent moderate tacrine-induced hepatotoxicity. These results should be confirmed in a controlled therapeutical trial.
Follow-up of patients in memory units raises problems of structure, team, diseases, evaluation and organization. Structures could be within the hospital, for early diagnosis, or outside hospital for prevention. The medical team is organized around the neurologist, must integrate different medical specialists (neurologist, psychiatrist, geriatrician) and be composed minimally of a clinician and a psychologist. Diseases range from memory complaint to very serious diseases such as Alzheimer's, vascular or post-traumatic dementia. Therapy includes cognitive stimulation and drug clinical trials. Evaluation requires medico-psycho-social analysis of the patient and his/her family. Memory consulting units could be integrated in a caring network organised in a modular fashion or like a geriatric hospital.
We report our first 100 cases of Alzheimer's (AD) patients treated with tacrine (Cognex) for a period of one year. At the beginning of treatment the mean Mini-Mental-Status (MMS) score was 15.1. To date 71 patients are still under treatment (12 for more than 12 months). Forty-three instances of side-effects were observed, of which 31 involved hepatic side-effects with an increase in ALAT > IN (normal value) (6 cases > 3N), the mean date of appearance was 10.4 +/- 6.8 weeks, there were 16 cholinergic side-effects (nausea, vomiting, diarrhoea), plus 4 neurologic and 2 cutaneous side-effects. These side-effects led to the arrest of the treatment in 19 cases (16 for hepatic toxicity). Treatment was reattempted after interruption in 13 cases; successfully in 3 instances only. The measure of tacrine efficacy was based on 52 MMS score re-evaluations in week 18: there was an increase of the MMS score in 22 cases (3.3 points +/- 2.5), a stabilisation in 11 cases and a decrease in 19 cases (3.3 points +/- 2.2.). In week 30, the MMS scores (35 patients) increased in 9 cases (3.6 points +/- 2.4), stabilized in 5 cases and decreased in 21 cases (3.9 points +/- 3.3). At week 52, only 28 per cent of the patients were considered as either improved or stabilized. We conclude that there is a necessity for close follow-up of tacrine-treated patients, and that globally at 8 months there is an improvement or a stabilization in 40 per cent of patients and long term (at one year) a stabilizing effect on AD patients.