Josep Cadafalch

Proton magnetic resonance spectroscopy pattern of progressive multifocal leukoencephalopathy in AIDS

The objective was to determine whether the use of intermediate echo times (135 ms) in proton magnetic resonance spectroscopy (1H-MRS) detects a homogenous pattern in progressive multifocal leukoencephalopathy (PML) in HIV-1 infected people, and to confirm the results of previous studies.  Six patients infected with HIV-1, with PML established by biopsy, and six healthy age and sex matched volunteers were evaluated to define their spectroscopic pattern. 1H-MRS spectra performed at 1.5 T were obtained with the STEAM sequence: TE/TM/TR, 20 ms/13.7 ms/2000 ms; 2500 Hz, size 2048 points, 256 acquisitions (STEAM-20) and with the PRESS sequence; TE/TR, 135 ms/2000 ms; 2500 Hz, size 2048 points, 256 acquisitions (PRESS-135). A single voxel was placed on the lesions and on the parieto-occipital white matter of controls. The peaks of N-acetylaspartate (NAA), choline (Cho), myoinositol (mI), lactate, and lipids were considered, and the results were expressed using creatine as reference.  Spectra of PML lesions were characterised by significantly reduced NAA, lactate presence, and by significantly increased Cho and lipids compared with control group values.  These results indicate that 1H-MRS detects a homogenous pattern in PML lesions. Recent studies, together with this, suggest that 1H-MRS may help in the diagnostic approach to patients with suspected PML lesions associated with AIDS.

VITAMIN B-12 ABNORMALITIES IN HIV-INFECTED PATIENTS

Abstract: A prospective study of 60 consecutively admitted patients with HIV infection was performed to document the prevalence, etiology and manifestations of low serum vitamin B‐12 in such patients. Low serum B‐12 levels were found in 10 patients (16.7%). In 6, vitamin B‐12 absorption was impaired and hog intrinsic factor addition did not improve it. Patients with low vitamin B‐12 levels showed lower hemoglobin, leukocytes, lymphocytes, CD4 lymphocytes and CD4/CD8 lymphocyte ratio than HIV patients with physiological serum vitamin B‐12 levels. However, bone marrow megaloblastosis was found in only 3 low vitamin B‐12 patients and the deoxyuridine suppression test was pathological in only 1 case. In 7 patients, parented treatment was begun with variable response despite serum vitamin B‐12 correction. In conclusion, low serum vitamin B‐12 is often found in HIV‐infected patients and it could be related to malabsorption, but clear megaloblastic abnormalities and treatment response could not be demonstrated. A decreased concentration of the serum binders due to disturbances in the leukocytes and related immunocompetent cell may play an additional role.

Conditioning of rotational behavior after the administration of a single dose of apomorphine in rats with unilateral denervation of the dopaminergic nigrostriatal pathway: relevance to drug addiction

Our aim is to study the relationship of drug activation of the dopamine neurotransmission system and the conditioning of environmental stimuli present at the time of drug administration. We injected a single dose of apomorphine (0.05 mg/kg SC) in rats with the nigrostriatal dopamine pathways unilaterally denervated with 6-hydroxydopamine, which generates rotational behavior contralateral to the lesioned hemisphere. We observed rotational behavior without apomorphine administration when animals were reexposed at different time intervals to the same environment in which they performed turning behavior. The present findings show that this rotational behavior can be conditioned to environmental stimuli in a strong and long-lasting way. In light of the relationship between opioids and the dopaminergic system, similar conditioning could take place in the learning processes implicated in drug addiction.

Rotational behaviour induced by theophylline in 6-OHDA nigrostriatal denervated rats is dependent on the supersensitivity of striatal dopaminergic receptors

We studied apomorphine- and theophylline-induced rotational behaviour in rats with a unilateral 6-hydroxydopamine lesion of the dopaminergic nigrostriatal pathway. It was seen that there was a direct correlation between the number of apomorphine- and theophylline-induced contralateral turns. These data suggest the existence of a relationship between theophylline-induced rotational behaviour and the degree of supersensitivity of the striatal dopaminergic receptors. Because the rotational behaviour induced by theophylline is in the same direction as dopaminergic agonists, contralateral to the nigrostriatal pathway lesion, these results suggest the possibility of a direct dopaminergic agonism of methylxanthines.