Cicero Galli Coimbra

Only certain antiepileptic drugs prevent seizures induced by pilocarpine.

Seizures produced in rats by systemically administered pilocarpine (PILO) provide a model for studying the generation and spread of convulsive activity in the forebrain. PILO, 380 mg/kg, induces a sequence of behavioral and electroencephalographic alterations indicative of motor limbic seizures and status epilepticus which is followed by widespread damage to the limbic forebrain resembling that occurring subsequent to prolonged intractable seizures in humans. The present study was undertaken to determine whether clinically utilized antiepileptic drugs share an ability to suppress seizures and brain damage elicited by PILO in rats. Clonazepam, ED50 0.35 mg/kg (0.25-0.49), phenobarbital, 23.4 mg/kg (18.5-29.6), and valproic acid, 286 mg/kg (202-405), prevented the buildup of limbic seizures and protected against seizure-related brain damage. Pretreatment with trimethadione, 179 mg/kg (116-277), resulted in a moderate protection against PILO-induced seizures, whereas carbamazepine, 10-50 mg/kg, and diphenylhydantoin, 10-200 mg/kg, blocked neither convulsions nor brain damage produced by the drug. Surprisingly, ethosuximide, 196 mg/kg (141-272), and acetazolamide, 505 mg/kg (332-766), both lowered the threshold for seizures induced by PILO and converted a non-convulsant dose of PILO, 200 mg/kg, into a convulsant one. These results indicate that only certain anticonvulsant drugs elevate the threshold for PILO-induced seizures and prevent the occurrence of epilepsy-related brain damage. The resistance of seizures produced by PILO in rats to antiepileptic drugs reaffirms the clinically obvious lack of effective treatments for limbic convulsions.

Implications of ischemic penumbra for the diagnosis of brain death

The data reviewed here suggest the possibility that a global reduction of blood supply to the whole brain or solely to the infratentorial structures down to the range of ischemic penumbra for several hours or a few days may lead to misdiagnosis of irreversible brain or brain stem damage in a subset of deeply comatose patients with cephalic areflexia. The following proposals are advanced: 1) the lack of any set of clinically detectable brain functions does not provide a safe diagnosis of brain or brain stem death; 2) apnea testing may induce irreversible brain damage and should be abandoned; 3) moderate hypothermia, antipyresis, prevention of arterial hypotension, and occasionally intra-arterial thrombolysis may contribute to good recovery of a possibly large subset of cases of brain injury currently regarded as irreversible; 4) confirmatory tests for brain death should not replace or delay the administration of potentially effective therapeutic measures; 5) in order to validate confirmatory tests, further research is needed to relate their results to specific levels of blood supply to the brain. The current criteria for the diagnosis of brain death should be revised.

High doses of riboflavin and the elimination of dietary red meat promote the recovery of some motor functions in Parkinson's disease patients

Abnormal riboflavin status in the absence of a dietary deficiency was detected in 31 consecutive outpatients with Parkinsons disease (PD), while the classical determinants of homocysteine levels (B6, folic acid, and B12) were usually within normal limits. In contrast, only 3 of 10 consecutive outpatients with dementia without previous stroke had abnormal riboflavin status. The data for 12 patients who did not complete 6 months of therapy or did not comply with the proposed treatment paradigm were excluded from analysis. Nineteen PD patients (8 males and 11 females, mean age +/- SD = 66.2+/-8.6 years; 3, 3, 2, 5, and 6 patients in Hoehn and Yahr stages I to V) received riboflavin orally (30 mg every 8 h) plus their usual symptomatic medications and all red meat was eliminated from their diet. After 1 month the riboflavin status of the patients was normalized from 106.4+/-34.9 to 179.2+/-23 ng/ml (N = 9). Motor capacity was measured by a modification of the scoring system of Hoehn and Yahr, which reports motor capacity as percent. All 19 patients who completed 6 months of treatment showed improved motor capacity during the first three months and most reached a plateau while 5/19 continued to improve in the 3- to 6-month interval. Their average motor capacity increased from 44 to 71% after 6 months, increasing significantly every month compared with their own pretreatment status (P < 0.001, Wilcoxon signed rank test). Discontinuation of riboflavin for several days did not impair motor capacity and yellowish urine was the only side effect observed. The data show that the proposed treatment improves the clinical condition of PD patients. Riboflavin-sensitive mechanisms involved in PD may include glutathione depletion, cumulative mitochondrial DNA mutations, disturbed mitochondrial protein complexes, and abnormal iron metabolism. More studies are required to identify the mechanisms involved.

A pilot study assessing the effect of prolonged administration of high daily doses of vitamin D on the clinical course of vitiligo and psoriasis

Autoimmunity has been associated with vitamin D deficiency and resistance, with gene polymorphisms related to vitamin D metabolism frequently described in affected patients. High doses of vitamin D3 may conceivably compensate for inherited resistance to its biological effects. This study aimed to assess the efficacy and safety of prolonged high-dose vitamin D3 treatment of patients with psoriasis and vitiligo. Nine patients with psoriasis and 16 patients with vitiligo received vitamin D3 35,000 IU once daily for six months in association with a low-calcium diet (avoiding dairy products and calcium-enriched foods like oat, rice or soya “milk”) and hydration (minimum 2.5 L daily). All psoriasis patients were scored according to “Psoriasis Area and Severity Index” (PASI) at baseline and after treatment. Evaluation of clinical response of vitiligo patients required a quartile grading scale. All patients presented low vitamin D status (serum 25(OH)D3 ≤ 30 ng/mL) at baseline. After treatment 25(OH)D3 levels significantly increased (from 14.9 ± 7.4 to 106.3 ± 31.9 ng/mL and from 18.4 ± 8.9 to 132.5 ± 37.0 ng/mL) and PTH levels significantly decreased (from 57.8 ± 16.7 to 28.9 ± 8.2 pg/mL and from 55.3 ± 25.0 to 25.4 ± 10.7 pg/mL) in patients with psoriasis and vitiligo respectively. PTH and 25(OH)D3 serum concentrations correlated inversely. The PASI score significantly improved in all nine patients with psoriasis. Fourteen of 16 patients with vitiligo had 25–75% repigmentation. Serum urea, creatinine and calcium (total and ionized) did not change and urinary calcium excretion increased within the normal range. High-dose vitamin D3 therapy may be effective and safe for vitiligo and psoriasis patients.

Protective effect of systemic treatment with cyclosporine A after global ischemia in rats

Systemic administration of cyclosporine A (CsA) in single daily doses provides a powerful protection to the ischemic rat brain only to sites where the blood-brain barrier (BBB) is disrupted. This study was aimed at evaluating the effectiveness of prolonged treatment and multiple daily doses of systemic CsA following transient global ischemia in rats without BBB breakdown. Multiple daily doses selectively enhanced cell survival at 7-day recovery in regions displaying delayed neuronal death (DND). The effect was dose dependent, enhanced by prolonging the treatment or further fractionating daily doses, and not accompanied by drug-induced hypothermia. These results suggest that CsA-susceptible immune mediators of DND may be active during the first days following transient global ischemia. Conversely, postischemic hyperthermia may enhance and/or perpetuate similar mechanisms and trigger Alzheimer-like neurodegeneration, as recently reported.

Neuroprotective effect of oral choline administration after global brain ischemia in rats

Abstract Choline – now recognized as an essential nutrient – is the most common polar group found in the outer leaflet of the plasma membrane bilayer. Brain ischemia-reperfusion causes lipid peroxidation triggering multiple cell death pathways involving necrosis and apoptosis. Membrane breakdown is, therefore, a major pathophysiologic event in brain ischemia. The ability to achieve membrane repair is a critical step for survival of ischemic neurons following reperfusion injury. The availability of choline is a rate-limiting factor in phospholipid synthesis and, therefore, may be important for timely membrane repair and cell survival. This work aimed at verifying the effects of 7-day oral administration with different doses of choline on survival of CA1 hippocampal neurons following transient global forebrain ischemia in rats. The administration of 400 mg/kg/day divided into two daily doses for 7 consecutive days significantly improved CA1 pyramidal cell survival, indicating that the local availability of this essential nutrient may limit postischemic neuronal survival.

Riboflavin Deficiency, Brain Function, and Health

Vitamin B2 primarily or secondarily participates in a much wider range of critical metabolic pathways than currently recognized. An inherited disorder of the cellular uptake and trafficking of vitamin B2 metabolites may result in poor intestinal absorption, increased urinary loss, and disrupted homeostasis of vitamin B2 metabolites in the CNS. It may affect 10%–15% of the general population and be the most prevalent genetic risk factor for several human diseases. The implications include altered metabolism of several biomolecules and enzyme systems of well-established pathophysiologic relevance such as vitamins B6, B9 (folate), B12, D3, NO, lipids, amino acids, proteins, DNA, cytochrome P-450 and other enzyme systems, HO, and homocysteine. Oxidative stress, and both apoptotic and necrotic phenomena may be enhanced. Due to the loss of the brain privilege for vitamin B2 supply, this inherited condition may be particularly relevant for CNS diseases such as migraine, brain ischemia, traumatic brain injury, neurodegenerative disorders (especially Parkinson and Alzheimer’s diseases), epilepsy, multiple sclerosis, and for Guillain-Barre syndrome, myasthenia, and mitochondrial myopathies. This chapter aims at providing an overview of the potential pathophysiologic, preventive, and therapeutic implications of this prevalent (yet poorly recognized) inherited metabolism disorder for neurological diseases.

Hyperthermia induced after recirculation triggers chronic neurodegeneration in the penumbra zone of focal ischemia in the rat brain

Chronic neurodegenerative processes have been identified in the rat forebrain after prolonged survival following hyperthermia (HT) initiated a few hours after transient global ischemia. Since transient global ischemia and ischemic penumbra share pathophysiological similarities, this study addressed the effects of HT induced after recirculation of focal brain ischemia on infarct size during long survival times. Adult male Wistar rats underwent intra-luminal occlusion of the left middle cerebral artery for 60 min followed by HT (39.0-39.5 degrees C) or normothermia. Control procedures included none and sham surgery with and without HT, and middle cerebral artery occlusion alone. Part I: 6-h HT induced at recirculation. Part II: 2-h HT induced at 2-, 6-, or 24-h recirculation. Part III: 2-h HT initiated at recirculation or 6-h HT initiated at 2-, 6- or 24-h recirculation. Survival periods were 7 days, 2 or 6 months. The effects of post-ischemic HT on cortex and striatum were evaluated histopathologically by measuring the area of remaining tissue in the infarcted hemisphere at -0.30 mm from bregma. Six-hour HT initiated from 6-h recirculation caused a significant decrease in the remaining cortical tissue between 7-day (N = 8) and 2-month (N = 8) survivals (98.46 +/- 1.14 to 73.62 +/- 8.99%, respectively). When induced from 24-h recirculation, 6-h HT caused a significant reduction of the remaining cortical tissue between 2- (N = 8) and 6-month (N = 9) survivals (94.97 +/- 5.02 vs 63.26 +/- 11.97%, respectively). These data indicate that post-ischemic HT triggers chronic neurodegenerative processes in ischemic penumbra, suggesting that similar fever-triggered effects may annul the benefit of early recirculation in stroke patients over the long-term.

Análise quantitativa da deglutição de parkinsonianos pré e pós-riboflavina

Purpose to verify the quantitative changes in the swallowing dynamics in patients with Parkinson´s disease submitted to treatment with riboflavin, red meat and poultry removed during one year period. Methods sixteen patients with Parkinson´s disease participated in the study; the mean age was 67.25 years, the mean degree of disease severity was II to III, and the mean time since the diagnosis of the disease was 3.5 years. Videofluoroscopic evaluations were performed before and one year after treatment with riboflavin and diet with restriction of read meat and poultry. Analyzed were presence of complaints related to swallowing and quantitative analyses of swallowing includind computerized measurements of hyoid bone and cricoid cartilage displacement, opening of the superior esophageal sphincter and pharyngeal constriction. Results decrease of complaints was observed after administration of riboflavin. About the quantitative measures after riboflavin, there were a increase in the opening of the superior esophageal sphincter for all consistencies offered, an increase in the pharyngeal constriction for the thickened liquid, a reduction in the hyoide bone displacement, and an increase or a reduction in the cricoid cartilage displacement for each consistency, with significant reduction for the liquid. Conclusion quantitative measurements made in the movement of organs associated with swallowing showed no significant differences between pre-and post-riboflavin, and red meat and poultry removed.