Increased coherence among striatal regions in the theta range during attentive wakefulness

The striatum, the largest component of the basal ganglia, is usually subdivided into associative, motor and limbic components. However, the electrophysiological interactions between these three subsystems during behavior remain largely unknown. We hypothesized that the striatum might be particularly active during exploratory behavior, which is presumably associated with increased attention. We investigated the modulation of local field potentials (LFPs) in the striatum during attentive wakefulness in freely moving rats. To this end, we implanted microelectrodes into different parts of the striatum of Wistar rats, as well as into the motor, associative and limbic cortices. We then used electromyograms to identify motor activity and analyzed the instantaneous frequency, power spectra and partial directed coherence during exploratory behavior. We observed fine modulation in the theta frequency range of striatal LFPs in 92.5 ± 2.5% of all epochs of exploratory behavior. Concomitantly, the theta power spectrum increased in all striatal channels (P < 0.001), and coherence analysis revealed strong connectivity (coefficients >0.7) between the primary motor cortex and the rostral part of the caudatoputamen nucleus, as well as among all striatal channels (P < 0.001). Conclusively, we observed a pattern of strong theta band activation in the entire striatum during attentive wakefulness, as well as a strong coherence between the motor cortex and the entire striatum. We suggest that this activation reflects the integration of motor, cognitive and limbic systems during attentive wakefulness.

Increased coherence among striatal regions in the theta range during attentive wakefulness.

The striatum, the largest component of the basal ganglia, is usually subdivided into associative, motor and limbic components. However, the electrophysiological interactions between these three subsystems during behavior remain largely unknown. We hypothesized that the striatum might be particularly active during exploratory behavior, which is presumably associated with increased attention. We investigated the modulation of local field potentials (LFPs) in the striatum during attentive wakefulness in freely moving rats. To this end, we implanted microelectrodes into different parts of the striatum of Wistar rats, as well as into the motor, associative and limbic cortices. We then used electromyograms to identify motor activity and analyzed the instantaneous frequency, power spectra and partial directed coherence during exploratory behavior. We observed fine modulation in the theta frequency range of striatal LFPs in 92.5 ± 2.5% of all epochs of exploratory behavior. Concomitantly, the theta power spectrum increased in all striatal channels (P < 0.001), and coherence analysis revealed strong connectivity (coefficients >0.7) between the primary motor cortex and the rostral part of the caudatoputamen nucleus, as well as among all striatal channels (P < 0.001). Conclusively, we observed a pattern of strong theta band activation in the entire striatum during attentive wakefulness, as well as a strong coherence between the motor cortex and the entire striatum. We suggest that this activation reflects the integration of motor, cognitive and limbic systems during attentive wakefulness.

Terbinafine (250 mg/day): an effective and safe treatment of cutaneous sporotrichosis.

BACKGROUND: There are a few studies on the treatment of sporotrichosis. The standard drug used is itraconazole. However, the use of itraconazole is limited by its interaction with other drugs. OBJECTIVE: To evaluate the effectiveness and safety of 250 mg terbinafine for the treatment of cutaneous sporotrichosis in patients in whom itraconazole use is not possible. METHODS: We performed a descriptive study of cutaneous sporotrichosis cases treated with 250 mg terbinafine for which itraconazole was contraindicated or resulted in severe or moderate pharmacological interactions. Sporotrichosis was diagnosed based on the isolation of S. schenckii. RESULTS: Fifty patients seen between July 2005 and September 2007 were included. Forty-five (92%) patients reported contact with a sick cat and 47 (94%) presented comorbidities (high blood pressure: 64.0%; diabetes mellitus: 30.0%; dyslipidemia: 16.7%; depression: 10.0%; migraine: 2.1%; Parkinsonís disease: 2.1%; peptic ulcer disease: 2.1%; heart failure: 2.1%, and arrhythmia: 2.1%). All patients used some medication interacting with itraconazole (psycholeptics: 36.0%; antidiabetic agents: 28.0%; hypolipemiant agents: 18.0%; calcium-channel blockers: 16.0%; anticonvulsants: 8.0%; cardiotropic drugs: 6.3%; antacids: 6.3%, and antiparkinsonian agent: 2.1%). Most patients (96%) were cured within a mean period of 14 weeks. The drug was discontinued due to a skin rash in one patient. There were no cases of recurrence of the mycosis within a mean follow-up period of 37 weeks. CONCLUSIONS: This study suggests that 250 mg/day terbinafine is an effective and well-tolerated alternative to drug therapy of cutaneous sporotrichosis in a population in which itraconazole use is not possible.

Disseminated dermatophytosis caused by Microsporum gypseum in an AIDS patient: response to terbinafine and amorolfine.

A 51-year-old white male, native of Rio de Janeiro, Brazil, with advanced AIDS and in chronic use of imidazoles for oral candidosis, presented erythematous, desquamative, pruriginous plaques of 1 month evolution on the trunk, inguinal/crural region, and lower limbs. The diagnosis of dermatophytosis was based on the isolation of Microsporum gypseum from scales scraped from the skin lesions. The lesions regressed after 30 days treatment with itraconazole, 100 mg day(-1). After interruption of this antifungal, the mycosis recurred 2 months later, along with a toe onychomycosis also caused by M. gypseum. Attempted reintroduction of itraconazole at higher dose was unsuccessful. Patient responded well to treatment with terbinafine 250 mg day(-1) for 45 days. However, the medication had to be interrupted as a result of the emergence of a disseminated erythematous/papulous rash. Topical treatment with amorolfine cream was then performed, with a good clinical and mycological response.

Absence-like seizures in adult rats following pilocarpine-induced status epilepticus early in life.

Administration of pilocarpine causes epilepsy in rats if status epilepticus (SE) is induced at an early age. To determine in detail the electrophysiological patterns of the epileptogenic activity in these animals, 46 Wistar rats, 7-17 days old, were subjected to SE induced by pilocarpine and electro-oscillograms from the cortex, hippocampus, amygdala, thalamus and hypothalamus, as well as head, rostrum and vibrissa, eye, ear and forelimb movements, were recorded 120 days later. Six control animals of the same age range did not show any signs of epilepsy. In all the rats subjected to SE, iterative spike-wave complexes (8.1 0.5 Hz in frequency, 18.9 9.1 s in duration) were recorded from the frontal cortex during absence fits. However, similar spike-wave discharges were always found also in the hippocampus and, less frequently, in the amygdala and in thalamic nuclei. Repetitive or single spikes were also detected in these same central structures. Clonic movements and single jerks were recorded from all the rats, either concomitantly with or independently of the spike-wave complexes and spikes. We conclude that rats made epileptic with pilocarpine develop absence seizures also occurring during paradoxical sleep, showing the characteristic spike-wave bursts in neocortical areas and also in the hippocampus. This is in contrast to the well-accepted statement that one of the main characteristics of absence-like fits in the rat is that spike-wave discharges are never recorded from the hippocampal fields.

Absence-like seizures in adult rats following pilocarpine-induced status epilepticus early in life

Administration of pilocarpine causes epilepsy in rats if status epilepticus (SE) is induced at an early age. To determine in detail the electrophysiological patterns of the epileptogenic activity in these animals, 46 Wistar rats, 7-17 days old, were subjected to SE induced by pilocarpine and electro-oscillograms from the cortex, hippocampus, amygdala, thalamus and hypothalamus, as well as head, rostrum and vibrissa, eye, ear and forelimb movements, were recorded 120 days later. Six control animals of the same age range did not show any signs of epilepsy. In all the rats subjected to SE, iterative spike-wave complexes (8.1 ± 0.5 Hz in frequency, 18.9 ± 9.1 s in duration) were recorded from the frontal cortex during absence fits. However, similar spike-wave discharges were always found also in the hippocampus and, less frequently, in the amygdala and in thalamic nuclei. Repetitive or single spikes were also detected in these same central structures. Clonic movements and single jerks were recorded from all the rats, either concomitantly with or independently of the spike-wave complexes and spikes. We conclude that rats made epileptic with pilocarpine develop absence seizures also occurring during paradoxical sleep, showing the characteristic spike-wave bursts in neocortical areas and also in the hippocampus. This is in contrast to the well-accepted statement that one of the main characteristics of absence-like fits in the rat is that spike-wave discharges are never recorded from the hippocampal fields.

Adult T-cell leukemia/lymphoma associated with HTLV-1 infection in a Brazilian adolescent.

We present the case of a 15-year-old patient infected with HTLV-1 who developed a cutaneous T-cell lymphoma, confirmed by histopathological and immunohistochemical examination, as well as clinically and hematologically confirmed leukemia. The patient died 3 months after initial presentation of the disease. The rarity of the disease in this age group justifies the present report.

Sporotrichosis: an emergent zoonosis in Rio de Janeiro.

During the period from 1987 to 1998, 13 cases of human sporotrichosis were recorded at the Research Center Evandro Chagas Hospital (CPqHEC) in Rio de Janeiro. Two of these patients related scratch by a sick cat. During the subsequent period from July 1998 to July 2000, 66 human, 117 cats and 7 dogs with sporotrichosis were diagnosed at the CPqHEC. Fifty-two humans (78.8%) reported contact with cats with sporotrichosis, and 31 (47%) of them reporting a history of a scratch or bite. This epidemic, unprecedented in the literature, involving cats, dogs and human beings may have started insidiously before 1998.

Entomophthoramycosis by Conidiobolus coronatus. Report of a case successfully treated with the combination of itraconazole and fluconazole.

Rhinoentomophthoramycosis caused by Conidiobolus coronatus in a 61-year old woman was unsuccessfully treated during 8 years with all the antifungals available in the Brazilian market, including potassium iodide for 1 month, sulfamethoxazole plus trimethoprim for 2 months, amphotericin B, total dose of 1130 mg, cetoconazole, 400 mg/day for 6 months, fluconazole, 200 mg/day, for at least 2 months and, itraconazole, 400 mg/day for 2 months, followed by 200 mg/day for 4 more months. Complete clinical and mycological cure was achieved using itraconazol 400 mg/day in association with fluconazol 200 mg/day during 24 months. After cure she was submitted to plastic surgery to repair her facial deformation. Today she remains clinically and mycologically cured after 59/60 months (5 years!) without any specific antifungal. We thus suggest the use of the combination of itraconazole and fluconazole as an additional option for the treatment of this mycosis.

Interpretation and clinical correlation of serological tests in paracoccidioidomycosis.

In order to correlate the findings of two serological tests, double immunodiffusion (IDD) and immunoblotting (IB), with the clinical diagnosis and follow-up of paracoccidioidomycosis (PCM), 325 serum samples from PCM patients were tested at the beginning of specific therapy and after its completion. Group I included 245 PCM patients at the onset of symptoms without treatment. In 221 cases (90.2%) the IDD showed positive reactions and in 24 (9.8%) the results were negative. Of the 24 IDD negative samples, 23 were investigated by IB and were positive. Group II included 80 PCM patients under follow-up after treatment. There were four cases of relapse in which the IDD and IB tests were positive (100%). Among the 76 cases with inactive mycotic infection, the IDD was negative in 71.2% and positive in 28.8%; the IB was positive in all cases (100%). The control group (Group III) included 27 samples from patients with other mycoses, tuberculosis and from healthy individuals. All showed negative IDD tests but positive reactions with IB, which could be abolished by serum dilutions without altering the PCM reactivity. Therefore, the utilization of the IB, an immunoenzymatic method for the diagnosis of PCM, raised the sensitivity to 100%.

Isolation of Sporothrix schenckii from the nails of domestic cats (Felis catus).

We report the first isolation of Sporothrix schenckii from the nail surfaces of cats. The fungus grew from nail clippings of three cats associated with three household outbreaks of sporotrichosis involving cats and human beings. The identification of the isolates was based on macroscopic and microscopic morphological characteristics at 25 degrees C and conversion of S. schenckii to the yeast-like form at 37 degrees C.

Chronic pulmonary histoplasmosis in the State of Rio de Janeiro, Brazil.

Three cases of chronic pulmonary histoplasmosis affecting aged patients with chronic obstructive pulmonary disease are reported. They had a history of recurrent episodes of respiratory infection and presented radiological lung lesions inducing a misdiagnosis of chronic pulmonary tuberculosis of the adults. The diagnosis of histoplasmosis, suggested by the immunodiffusion test and the detection of yeastlike cells in smeared and stained sputum, was confirmed by the isolation and identification of Histoplasma capsulatum var. capsulatum in selective media. The treatment was carried out with amphothericin B and ketoconazole or itraconazole. Clinical, radiologic, mycologic and serologic improvement was obtained in all the patients. However, relapses occurred within a period of 1 to 18 months after the interruption of the treatment. Mycological diagnosis and the difficulties observed in the treatment were discussed. In addition data on the epidemiology of histoplasmosis in the state of Rio de Janeiro, Brazil, were presented.

Prevalence of epileptic seizures along the wakefulness-sleep cycle in adult rats submitted to status epilepticus in early life.

In 70 adult Wistar rats submitted to pilocarpine-induced status epilepticus in early life the electro-oscillograms were recorded from neocortical areas 10, 3 and 17, from CA1 and CA3 hippocampal fields and, in 10 rats, also from the ventrolateral nuclei and amygdala. Head, eye, rostrum + vibrissae, ear and forelimb movements were recorded as well. Fifty rats were subjected to 4-hour daily recording sessions and 20 to continuous 24-hour recordings. In all the rats spike-wave discharges (SWD) were found in every site from which the electro-oscillograms were recorded, and clonic seizures were also displayed by all the animals. Most seizures (83.75%, mean = 6.59 fits/h) were concentrated in nearly 9 h and 16.25% (mean = 0. 77 fits/h) in the remaining 15 h. Eye movements occurred during 49. 2% of the total duration of motor events, the head moved in 42.8% and the rostrum + vibrissae in 8.1% of the time, departing from normal rats. Therefore, pilocarpine-induced status epilepticus produces striking changes in the wakefulness-sleep cycle characteristics.