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Biomedical subjects

M I Carvalho

Publications and source records attributed to M I Carvalho.

8 recordsLinked to original sources

Observation of locked optical kink-antikink spatial shock waves.

We report the first experimental observation of optical spatial shock-wave pairs. The shock waves consist of two coupled kink and antikink beams that remain locked to each other throughout propagation in a nonlinear diffusion-driven photorefractive crystal. These coupled shock-wave pairs move undistorted at angles that fall outside their original angular sector of propagation.

Journal Article↗

Efficacy of clobazam as add-on therapy in patients with refractory partial epilepsy.

PURPOSE: Clobazam (CLB) has an important antiepileptic effect and is less expensive than the new antiepileptic drugs (AEDs), but still has not been considered as first-line drug in the treatment of epilepsy. We evaluated the efficacy of CLB as add-on therapy in patients with refractory partial epilepsy. METHODS: This was an open, retrospective study, conducted at the epilepsy clinic of our university hospital. All patients had chronic epilepsy and were being evaluated for epilepsy surgery. CLB was introduced as add-on therapy (starting with 10 mg/ day) in patients with previous failure of at least two AEDs. Information was obtained from clinical notes and follow-up visits. RESULTS: We evaluated 97 patients, 37 men and 60 women. Ages ranged from 15 to 70 years (mean, 35.8 years). Etiology of epilepsy was hippocampal atrophy in 67 (69%), cortical dysgenesis in nine (9.3%), and other etiologies in nine (9.3%). In 12 (12.3%) patients, the etiology of epilepsy was not identified despite clinical and neurologic investigation. Patients used CLB for a period ranging from 1 month to 7 years and 9 months (mean, 16.7 months) with doses ranging from 10 to 60 mg/day (mean, 29.7 mg/day). Seven (7.2%) patients were seizure free, 48 (49.4%) had > or =50% of improvement in seizure control, 39 (40.2%) had <50% of improvement in seizure control, and in three (3.1%), no data were available. CONCLUSIONS: We conclude that CLB may have efficacy equivalent to that of the new AEDs when used as add-on therapy in patients with refractory epilepsy. CLB should be considered an economic alternative in the treatment of patients with refractory epilepsy.

Adolescent↗

[Familial partial epilepsies].

OBJECTIVE: To investigate the clinical and genetic characteristics of familial partial epilepsies. METHOD: Family history of seizures was questioned in all patients followed in our epilepsy clinics, from October 1997 to December 1998. Those with positive family history were further investigated and detailed pedigrees were obtained. All possibly affected individuals available underwent clinical evaluation. Seizures and epilepsy syndromes were classified according to the ILAE recommendations. Whenever possible, EEG and MRI were performed. RESULTS: Positive family history was identified in 32 unrelated patients. A total of 213 possibly affected individuals were identified, 161 of whom have been evaluated. The number of affected subjects per family ranged from two to 23. Temporal lobe epilepsy (TLE) was identified in 22 families (68%), frontal lobe epilepsy in one family (3%), partial epilepsy with centrotemporal spikes in five families (15%), and other benign partial epilepsies of childhood in four families (12%). Most of the affected individuals in the TLE families (69%) had clinical and/or EEG characteristics of typical TLE. However, the severity of epilepsy was variable, with 76% of patients with spontaneous seizure remission or good control with medication and 24% with refractory seizures, including 7 patients that underwent surgical treatment. In the other 10 families, we identified 39 possibly affected subjects, 23 of whom were evaluated. All had good seizure control (with or without medication) except for one patient with frontal lobe epilepsy. Pedigree analysis suggested autosomal dominant inheritance with incomplete penetrance in all families. CONCLUSION: Family history of seizures is frequent among patients with partial epilepsies. The majority of our families had TLE and its expression was not different from that observed in sporadic cases. The identification of genes involved in partial epilepsies may be usefull in classification of syndromes, to stablish prognosis and optimal treatment.

Adolescent↗

Chlamydia trachomatis in cervical uterine irradiated cancer patients.

Twenty-two women with uterine carcinoma with morphological alterations postradiation treatment suggestive of Chlamydia trachomatis infection were analyzed by direct immunofluorescence. The diagnosis was confirmed in 12 (54.4%) cases. Discussions of the presence of Chlamydia in irradiated cells were not found in the literature. This finding may signify a posttherapeutic morbidity or a preradiation infection.

Adenocarcinoma↗

An outbreak of cryptosporidiosis in a hospital day-care centre.

The investigation of an outbreak of cryptosporidiosis in a hospital day-care centre is reported. Twenty-eight (27%) children and one member of the staff were infected. Most of the cases were symptomatic and the major presenting symptom was watery diarrhoea. Shedding of oocysts continued for a mean of 12 days after diarrhoea had subsided and most of the cases were still excreting oocysts when the first follow-up sample was examined. Intermittent shedding or a carrier state were not seen in any of the cases. Giardia intestinalis cysts were detected in 19 children, 7 of whom showing mixed infection with Cryptosporidium sp., but this association was not statistically significant. All cases recovered without specific therapy. No definite proof could be found to demonstrate the source of the outbreak or the route of transmission but some observations suggesting person-to-person transmission are discussed.

Adult↗

The effects of age, sex and diet on the clastogenic action of cyclophosphamide in mouse bone marrow.

7-week-old and 12-week-old mice of both sexes received either a control or protein-deficient diet for 3 weeks. Afterwards, they were given a single dose of cyclophosphamide (0.5 mg/10 g b.wt.) before being sacrificed. The relationship between age and the clastogenic action of cyclophosphamide can be observed in the bone marrow cells of male mice but not in those of female mice. 12-week-old males on a 75% protein-deficient diet have a lower frequency of cells with cyclophosphamide-induced chromosome aberrations than has the control group. On the contrary, 7-week-old males and females, and 12-week-old females, show that protein-deficient diets act synergistically with the clastogenic action of cyclophosphamide. These results are discussed taking the metabolism of the drug into account. Animal age also plays a role in the formation of chromosome rearrangements; this type of aberration is significantly more frequent in younger animals of both sexes than in older ones exposed to the drug.

Age Factors↗