Decrease in cerebellar blood flow in patients with Friedreich's ataxia: A TC-HMPAO SPECT study of three cases

Three cases of Friedreich's ataxia were submitted to diverse neuroradiological procedures in order to determine the extent of atrophic processes in the central nervous system. All patients underwent computerized-tomography scan, Magnetic Resonance Imaging, and HMPA-single Photon emission computerized tomography studies, focusing in cerebellar lobes. A slight atrophy was observed in the vermis and the cerebellar lobes with CT scan and MRI. In contrast a significant decrease in cerebellar blood flow was shown by TC-HMPAE SPECT study. The significance of these findings in understanding physiopathological mechanisms in Friedreich's ataxia is discussed.

[Depression and temporal epilepsy. The possible role of laterality of the epileptic foci and of gender]

From a prospective study of 47 epileptic patients (26 men and 21 women) 25 with a left and 22 with a right temporal epileptic focus, the authors show that depression measured by the HARD score, is more severe in males, with a left epileptic focus. These results and the vulnerability to depression of left temporal lobe epileptic patients are analyzed.

[Value of local cerebral hypoperfusion in the diagnosis of frontal syndromes. Importance in medical expert assessment of head injuries]

The importance of the symptoms linked to a frontal disorder in the intellectual and behavioral sequelas of severe cranial trauma, is now measured carefully because these troubles are one of the most important obstacle to the social and professional come-back. The handicap linked to a disorder of the frontal lobe is not well known in all its neurological, mental and sociological dimensions because the diagnosis is not easy. To help to this diagnosis, the study of cerebral blood flow with SPECT is usefull in medical practice. We present here 4 clinical cases of post-trauma frontal syndrome not easy to measure. With a measure of cerebral blood flow with SPECT, it was observed a decrease of frontal blood flow, that allowed to link the neuropsychological symptom to a frontal lobe disorder. It seems that in these conditions the post-trauma frontal syndrome is not so uncommon.

Depression and partial epilepsy: relevance of laterality of the epileptic focus

In a prospective study of 50 epileptic patients (20 with a left hemisphere epileptic focus, 20 with a right one and 10 with a cryptogenic generalized epilepsy), the authors show that depression as appreciated by the H.A.R.D. score, is more frequent and severe in partial epilepsy in males, and when the epileptic focus is localized on left hemisphere. This association is related to the duration of epilepsy, the number of seizures, but not to age or medication status. Vulnerability of left hemisphere to depression is analysed, and neuro-chemical mechanisms are discussed.

Migraine in patients with history of centro-temporal epilepsy in childhood: a Hm-PAO SPECT study

The authors report the results of a retrospective controlled study on the incidence of migraine in centro-temporal epilepsy compared to absence epilepsy, partial epilepsy and a group of patients with cranial trauma without epilepsy. The following observations from this series of 129 patients were made. Migraine was present in 63% of the patients with centro-temporal epilepsy (rolandic epilepsy), in 33% with absence epilepsy, in 7% with partial epilepsy and in 9% of the cranial trauma group. These results suggest that the association of centro-temporal epilepsy and migraine is non-fortuitous and also to a lesser degree in absence epilepsy. The role of neurotransmitters in this association is discussed. No decrease in cerebral blood flow was observed in 12 patients with rolandic epilepsy on a Hm-PAO SPECT study.

Efferent neurotransmission of circadian rhythms in Limulus lateral eye. II. Intracellular recordings in vitro

We investigated efferent neurotransmission in the Limulus lateral eye by studying the action of pharmacological agents on responses of photoreceptor cells in vitro. We recorded transmembrane potentials from single cells in slices of retina that were excised during the day and maintained for several days in a culture medium. Potentials recorded in the absence of pharmacological agents resemble those recorded from cells in vivo during the day. Octopamine, a putative efferent neurotransmitter, induced changes in photoreceptor potentials that mimicked in part those generated at night by a circadian clock located in the brain. Specifically, octopamine (100 to 500 microM) decreased the frequency of occurrence of quantum bumps in the dark and increased the amplitude of photoreceptor responses to intermediate and high light intensities. Similar actions were produced by naphazoline (25 to 100 microM, potent agonist of octopamine), forskolin (8 to 400 microM, activator of adenylate cyclase), IBMX (1 mM, inhibitor of phosphodiesterase), and 8-bromo-cAMP (500 microM, analogue of cAMP). 8-bromo-cGMP (500 microM, analogue of cGMP) decreased the rate of spontaneous quantum bumps only. Our results support the hypothesis that (1) octopamine is an efferent neurotransmitter of circadian rhythms in the Limulus eye and that (2) it activates adenylate cyclase to increase levels of the second messenger, cAMP, in photoreceptor cells. Circadian changes in photoreceptor responses to moderate intensities may be a specific action of cAMP, since cGMP has no effect. Circadian changes in the rate of spontaneous quantum bumps may involve a less specific intermediate, since both cAMP and cGMP reduce bump rate. Characteristics of the retinal slice preparation precluded a detailed study of the effects of pharmacological agents on retinal morphology.

[Tolerance and prognostic value of Thallium 201 myocardial tomoscintigraphy with dipyridamole in the aged subject]

The authors present a retrospective study of 46 consecutive patients aged from 70 to 79 years (mean 73.3 +/- 2.5 years) with suspected coronary artery disease who, being unfit for exercise tests, were explored by myocardial scintigraphy with thallium 201 after coronary dilatation with intravenous dipyridamole. The examination was well tolerated by 30 patients. Such classical side-effects as chest pain, malaise, dizziness, headache, flushing, vomiting and transient arrhythmia or repolarization disorders were recorded, but they were not more frequent than in younger subjects. However, the occurrence of severe hypotensive malaise relieved by theophylline in two cases and of angina in about one third of patients with myocardial ischaemia means that the procedure must be performed under close supervision. A fall in blood pressure (-11 mmHg on average) and a rise in heart rate (+8 beats/min on average) were usual. Post-scintigraphy follow-up of patients over a mean period of 11.1 +/- 6.2 months showed that a reversible defect of thallium 201 uptake, due to redistribution, is a highly selective indicator of patients who are particularly exposed to a cardiac accident in the short--or mid-term. Only one out of 26 patients without reversible ischaemia (4 p. 100) subsequently presented with a major coronary event (unstable angina). In contrast, in the group of 20 patients with reversible ischaemia three required early myocardial revascularization; furthermore, five serious accidents (29 p. 100) occurred among the 17 patients who were left under medical treatment, including two sudden deaths, two cases of unstable angina and one case of myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Fourier and factorial analysis: an objective and comparative evaluation on a cardiac phantom

Orthogonal and oblique factor analysis represent an alternative to Fourier analysis in the evaluation of cardiac dynamic behaviour in gated blood pool studies. In order to estimate their respective places, orthogonal factor analysis (OFA), factor analysis of dynamic structures (FADS) and Fourier analysis (FA) are tested on a dynamic and periodical phantom with well known and reproducible kinetics. The phantom data are acquired under standard conditions by varying the counting rates and the temporal frequency sampling. To compare the results of the three methods with maximal objectivity, the relative contribution of each component is calculated. With standard acquisition conditions, FA and OFA give very close results. Only a minor advantage in evaluation of small phase differences is observed with OFA. FADS solutions are effectively related to the dynamic behaviour of the phantom, but their interpretation is more complicated and the quality of the oblique factors is reduced as the number of calculated factors increases. The influence of the counting statistics on FA, OFA and FADS is very similar. However, in cases of undersampling, robustness is demonstrated with the factorial technics.

[Treatment of neonatal hypothyroidism. Comparative effects of levothyroxine and thyroid extracts]

The authors compare the effects of treatment with thyroid extracts and levothyroxine on T3, T4 and TSH levels in 2 groups of 8 hypothyroid infants. Serum TSH levels were lower in infants receiving thyroid extracts on and after the 15th day. The interest of a treatment associating T4 and T3 and of adapted doses of LT4 is discussed.

Emission computerized axial tomography from multiple gamma-camera views using frequency filtering

Emission computerized axial tomography is achievable in any nuclear medicine department from multiple gamma camera views. Data are collected by rotating the patient in front of the camera. A simple fast algorithm is implemented, known as the convolution technique: first the projection data are Fourier transformed and then an original filter designed for optimizing resolution and noise suppression is applied; finally the inverse transform of the latter operation is back-projected. This program, which can also take into account the attenuation for single photon events, was executed with good results on phantoms and patients. We think that it can be easily implemented for specific diagnostic problems.