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Lipid rafts, cell membrane domains with unique composition and properties, modulate the membrane distribution of receptors and signaling molecules facilitating the assembly of active signaling platforms. However, the underlying mechanisms that link signal transduction and lipid rafts are not fully understood, mainly because of the transient nature of these membrane assemblies. Several methods have been used to study the association of membrane receptors with lipid rafts. In the first part of this chapter, a description of how biochemical methods such as raft disruption by cholesterol depletion agents are useful in qualitatively establishing protein association with lipid rafts is presented. The second part of this chapter is dedicated to imaging techniques used to study membrane receptor organization and lipid rafts. We cover conventional approaches such as confocal microscopy to advanced imaging techniques such as homo-FRET microscopy and superresolution methods. For each technique described, their advantages and drawbacks are discussed.

The incidence and prevalence of multiple sclerosis (MS) varies geographically as shown through extensive epidemiological studies performed mainly in developed countries. Nonetheless, scant data is available in Latin America and the Caribbean (LAC). The objective of this review is to assess epidemiological data of MS in LAC. We conducted a systematic review of published articles and gray literature from January 1995 to May 2011. Twenty-two studies met the inclusion criteria after full-text review. Incidence data were found in only three studies and ranged from 0.3 to 1.9 annual cases per 100,000 person-years. Prevalence was reported in 10 studies and ranged from 0.83 to 21.5 cases per 100,000 inhabitants. The most prevalent subtype of MS was the relapsing–remitting form (48% to 91% of the series). No data about mortality were found. This study showed low frequency for MS in LAC compared with North American and European countries. The role of environmental and genetic factors should be well studied, providing new insights about its etiology.

To describe the use of preadmission statins in patients with cerebrovascular accident and the possible predictive factors.Cross-sectional observational study of 795 consecutive patients with acute cerebrovascular accident. We assessed the differences among patients who were on preadmission statins (161) and those who were not (634), regarding vascular risk factors and clinical and neurosonological atherothrombotic disease markers. For univariate analysis, we used squared chi test, and for multivariate analysis, logistic regression analysis.Preadmission statins were 20.3%. In high vascular risk patients defined based on National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III), this reached 28% and it might be 72%. Predictive factors for preadmission statins use were, in a positive sense, the antecedent of hypercholesterolemia diagnosis (OR = 189; 95% CI = 58-615; por = 0.001) and stroke (OR = 2.1; 95% CI = 1.2-3.6; por = 0.01), and in a negative sense, smoking (OR = 0.38; 95% CI = 0.18-0.81; p = 0.012).In our population of patients with stroke, the predictive factors of preadmission statins did not adjust to the current therapeutic NCEP-ATP III recommendations; treatment with statins in high vascular risk population was way below the indications, it was 28% and it might be 72%.

Only a minority of patients with acute stroke are eligible for fibrinolysis, and the main reason for this is that time runs out and goes beyond the therapeutic window. The chief delay occurs prior to arrival at the hospital, but there is also a nosocomial delay, which has received far less attention.The purpose of our study was to describe the data on delays occurring before and after arrival at the hospital in a sample of patients with acute stroke, and to analyse possible associated factors, including the overload on health care services in the Emergency department, an aspect that has not previously been evaluated.Epidemiological data, times of delays before and after entering the hospital, means of transport used and the health care workload in the Emergency department of the day of admission were collected for all the stroke patients admitted to the Stroke Unit of the Hospital General Universitario de Alicante throughout the period under study.From an initial sample of 460 patients, 423 were finally included in the study, with a mean delay before and after admission to hospital of 3.99 and 2.36 hours, respectively. Use of an ambulance and the haemorrhagic and transient ischemic attack subtypes were linked to a shorter delay before reaching the hospital, and arrival during the night shift was the only factor associated to a longer delay once inside the hospital.In our environment, there is a need to establish strategies aimed at shortening the times stroke patients take to reach the hospital and the time that elapses before they are attended.

The link between cardiovascular risk factors and carotid atheromatosis has been shown to be more important in middle aged subjects than in the elderly.Our aim was to study the frequency of carotid and intracranial atheromatosis in a population over the age of 80 and to compare the presence of neurosonological anomalies depending on whether the patients have suffered a stroke or not. We also wished to compare the findings according to the sex of the patient.Patients over the age of 80 were studied at our Neurosonology laboratory using carotid and transcranial Doppler ultrasonography. The patients were analysed according to whether they had suffered an ischemic stroke or not. With regard to the carotid, a distinction was made between normal, non-significant atheromatosis and significant atheromatosis (stenosis50%). Intracranially, both the middle cerebral artery (normal, stenosis, microangiopathy and post-stenosis) and the basilar artery (normal, stenosis, microangiopathy and hyperdynamics) were studied.We recorded data concerning 832 patients: 342 males (44.1%), mean age 83.63 +/- 3.25 years, and 527 (63.3%) with stroke. The carotid study was pathological, with a higher frequency in stroke patients (32.1% compared with 41.9%; p = 0.002). The presence of atheromatosis was significantly linked to a higher risk of suffering a stroke and more intensely to its being more severe. Carotid studies were pathological with a higher frequency among males (28.7% compared with 40%; p0.001). No significant differences were found intracranially in any of the parameters analysed.There is a high frequency of carotid atheromatosis in patients over 80 years of age. Regardless of the age, carotid atheromatosis appears even more frequently in patients who have suffered a stroke and in males, and is significantly associated to the risk of suffering a stroke. Intracranially, no differences were found.

Carotid stenosis has been reported as being associated to lacunar infarcts (LI) with variable frequency, but the aetiopathogenic relation between them is still subject to some controversy.Our aim was to describe the prevalence of carotid disorders in a neurosonological study of a sample of patients with LI.We analysed the results of the neurosonological study conducted on patients with clinical-radiological criteria of LI who were admitted to our Stroke Unit during the period of study.We studied 140 patients, and results were normal in only 42% of the cases. Stenosis50% was found in 10% of the cases and plaque without stenosis in 40.3% of the patients. In patients without plaque there was an increase in the tunica intima-media thickness in 7.2% of the cases.In most of the patients with LI there were anomalies in the study of the carotid performed using ultrasound scanning.

Atrial fibrillation is present in 24% of the population over 60 and it increases the risk of stroke by 2,4% 3%/year. Antithrombotic treatment is considered as the treatment of choice for cardioembolic stroke prevention in this patients. As far as we know there are not relevant data about the influence of these treatments on the type of stroke that may develop in these patients.Analyze whether there are differences in the clinical profile and functional prognosis after stroke in patients with atrial fibrillation depending on the type of treatment they were on at the time of occurrence of the event.We identified 67 patients who were admitted consecutively to our stroke unit with a stroke and atrial fibrillation over a period of 2 years. Patients were classified according to the type of antithrombotic treatment they were on. Functional prognosis was estimated by Rankin score at discharge.Treated patient showed a non significant tendency to suffer less severe strokes and present a better functional situation at discharge than those who were not on prophylactic treatment. Treated patients had a significant higher prevalence of previous TIA (44,2% vs 9,1%; p= 0,0042) and HBP (81,4% vs 52%; p= 0,041) than non treated patients. Embolic strokes were more frequent in non treated patients.Antithrombotic treatment not only prevents strokes but may also contribute to the development of less severe strokes with a better functional prognosis in patients with AF and does not contribute to increase complications in these group of patients.

Pituitary adenylate cyclase-activating polypeptide (PACAP), a novel peptide of the secretin/glucagon/vasoactive intestinal polypeptide superfamily, has been initially characterized in mammals in 1989 and, only 2 years later, its counterpart has been isolated in amphibians. A number of studies conducted in the frog Rana ridibunda have demonstrated that PACAP is widely distributed in the central nervous system (particularly in the hypothalamus and the median eminence) and in peripheral organs including the adrenal gland. The cDNAs encoding the PACAP precursor and 3 types of PACAP receptors have been cloned in amphibians and their distribution has been determined by in situ hybridization histochemistry. Ontogenetic studies have revealed that PACAP is expressed early in the brain of tadpoles, soon after hatching. In the frog Rana ridibunda, PACAP exerts a large array of biological effects in the brain, pituitary, adrenal gland, and ovary, suggesting that, in amphibians as in mammals, PACAP may act as neurotrophic factor, a neurotransmitter and a neurohormone.

To evaluate monotherapy treatment with the anticonvulsant drug gabapentin, its efficacy and tolerability when used in patients with partial and secondary generalized partial epileptic seizures of recent onset who had not received treatment or who, in spite of treatment with other antiepileptic drugs failed to attain control over their seizures.We made an open prospective study of 50 patients diagnosed as having partial and secondarily generalized partial epileptic seizures. The patients were given treatment at their first visit and them regularly followed up for two years. Treatment was given progressively until a maintenance dose of 1.200 mg/day was reached, and the dose them adjusted individually.We included 50 patients in the study; 78% were treated with gabapentin. Ten percent stopped this treatment because it was ineffective. All the patients who continued their treatment with gabapentin had their seizures reduced by over 50%. This reduction in the number of seizures is statistically significant (p0.05) for patients with partial and secondarily generalized partial seizures. Twelve percent of the group of patients stopped their treatment because of side-effects.When the results of our study are evaluated and compared with those published in the literature, it may be seen that gabapentin is a safe, effective drug which is well tolerated when used as monotherapy for the treatment of patients with partial seizures.

Myasthenia Gravis is an infrequent disease. Diagnosis and treatment must be done early to avoid high morbidity that can compromise patients lives. Nine cases were identified during the eight year 1990-1997 at the Santo Tomas Hospital of Panama city but one had to be excluded because he refused treatment. Most of the patients (7/8) had symptoms for more than 3 months. The diagnosis of Myasthenia Gravis requires a high index of suspicion and the clinical impressión must be confirmed by various diagnostic studies that include the edrophonium test, the repetitive stimulation test, the therapeutic test with pyridostigmine, the determination of acetylcholine anti-receptor antibodies and a CT Scan of the thorax. Medical treatment consists mainly of anticholinesterase agents and surgical treatment consists of thymectomy by means of an extended transternal ablation. Operative results were excellent, seven out of eight improved.

The Human T-Cell lymphotropic virus type I (HTLV-I) is endemic in the Caribbean basin, Japan, Central Africa and South Pacific. It as been associated to Lymphoma-Leukemia of Adult T-Cells (ATLL) and a progressive spastic paraparesis (TSP/HAM). The nationwide seroprevalence of Panama is of 1-2%. We report a case of a 73 year old male, albino, single, patient, Panamanian descendent from Jamaican immigrants who presented a skin disorder which started 1 year ago, characterized by the appearance of infiltrative, intensely pruritic papules, nodules and a non exfoliative erythroderna involving face, neck, trunk and extremities. He also had painless enlarged cervical lymph nodes, non tender hepatomegaly. Laboratory studies revealed a keukocyte count of 128,000/ml wit 67% atypical lymphocytes, serum calcium was 12.5 mg/dl, DL in 583 UNI, "flower cells" and atypical lymphocytes with hyperlobulated nuclear contour was observed in the peripheral blood smear, seropositivity to TLV-I detected by enzyme-linked immunosorbent assay (Elisa) and confirmed by Western blot assay. The skin biopsy shows a bandlike dermal infiltrates of atypical lymphoid cells with epidermotropism and Pautrier's microabscesses. Once the treatment was initiated with prednisone, cyclophosphamide, and systemic antibiotics for a bronchopneumonic process most of the cutaneous lesions cleared up although the clinical condition of our patient became progressively worse and died after a acute renal failure and a lower gastrointestinal bleeding. In 1986, the tree first cases of ATLL were identified in Panama, there has not been apparently new cases reported until now.

Cerebellar symptoms at onset are unusual in HTLV-I/II-associated tropical spastic paraparesis (TSP). A prospective study of neurological disorders in Panama (1985-1990) revealed 13 patients with TSP and 3 with HTLV-I/II-associated spinocerebellar syndrome (HSCS) presenting at onset loss of balance, wide-based stance and gait, truncal instability, and mild leg ataxia (vermian cerebellar syndrome), with absent upper limb dysmetria but with postural tremor, downbeat nystagmus, and dysarthria. In 4-5 years, spinal cord manifestations of TSP developed, including spastic paraparesis, pyramidal signs, bladder and sphincter disturbances. Two patients were infected with HTLV-I and another one, a Guaymi Amerindian woman, with HTLV-II. Magnetic resonance imaging (MRI) demonstrated cerebellar atrophy involving predominantly the superior vermis. Mild axonal peripheral neuropathy in the lower limbs, dorsal column involvement and inflammatory myopathy were found by neurophysiology studies. There are 14 similar cases reported in Japan and Canada, but to our knowledge these are the first documented cases of HSCS in the tropics. A cerebellar syndrome constitutes another form of presentation of HTLV-I/II infection of the nervous system.

Lymphomas of the central nervous system include primary and secondary lymphomas of Hodgkin and non-Hodgkin types. For a long time central nervous system involvement during the course of systemic non-Hodgkin lymphoma has been considered unusual, to occur late on in the disease process and usually to be located in the meninges.We describe the case of a 27 year old man initially diagnosed as having a primary cerebral lymphoma after having had repeated convulsive crises. Two months later he was found to have a retroperitoneal mass. On anatomopathological study of the mass, a peripheral T lymphoma was confirmed.Dissemination of systemic lymphomas to the central nervous system is usually seen in persons with advanced systemic disease. It is atypical to find a peripheral T lymphoma with initial clinical findings that were neurological, and even less frequent that these neurological findings were due to an intraparenchymatous lesion. In this article we describe a patient with these characteristics, and conclude that it is necessary to study patients with a diagnosis of primary cerebral lymphoma very fully to establish where the primary focus is.

Dystonia is a neurologic disease characterized by involuntary repetitive muscular contractions which frequently causes torsion, spasmodic movements or abnormal postures. Pharmacologic and surgical treatment had been unsatisfactory in the majority of the cases. Intramuscular botulinic toxin application in focal dystonia disorders, achieve relief in approximately 90% of the cases by quimiodenervation. We included 35 patients with focal dystonia treated between November 1994 through June 1996: 14 facial hemispasm, nine blepharospasm, five cervical dystonia, two writer's cramps, one oromandibular dystonia and four patients with mixed focal dystonia. Improvement between 50-90% was observed in 32/34 (94%) of the patients; one case (2.8%) with therapeutic failure and one case (2.8%) never returned to quantify the response. Actually, botulinic toxin is the first choice treatment of focal dystonia and other diseases related to involuntary muscle spasm.

The importance of cerebrovascular pathology demands the most exact and complete diagnosis possible, by general physical and neurological examination and complementary techniques including computerized tomography (CT). Without CT, diagnosis may be delayed, for which reason such authors as Allen have put forward scales which by means of diagnostic scoring distinguish between stroke types.To validate the Allen scale as opposed to CT scan in a series of patients suffering from haemorrhagic and ischaemic stroke.Sixty-two consecutive hospitalized patients suffering from stroke were studied, who all underwent CT scan within fifteen days of admission.The group consisted of 62 patients, 33 males (53%) and 29 females (47%) having an average of 70.2 +/- 11.2 years. The most frequent type of stroke was ischaemic (63%) as opposed to haemorrhagic (37%). Globally for all strokes we obtained the following results: Sensitivity (S) = 61%, Specificity (Sp) = 40%, positive predictive value ( + PV) = 84% and negative predictive value (-PV) = 17%. For ischaemic stroke the results were as follows: S = 76%, Sp = 66%; +PV = 67% and -PV = 76%. Finally for haemorrhagic stroke the results were S = 43%; Sp = 100%; +PV = 100% and -PV = 75%.The Allen scale has not proved to be a valid instrument in stroke diagnosis due to its low sensitivity and specificity especially in cases of haemorrhagic stroke.

We describe the expression of the transcription factor GHF-1/PIT-1 in adult porcine adenohypophysis by a nonradioactive in situ hybridization (ISH) method using a digoxigenin-labeled cDNA probe corresponding to the entire coding region of rat GHF-1. GHF-1 transcripts were found in 71.7% of adenohypophyseal cells. We also report the simultaneous detection of GHF-1 mRNA and pituitary hormones by combined ISH and immunocytochemistry (IC) in dispersed adenohypophyseal cells, detected with an alkaline phosphatase-NBT/BCIP technique and with an immunoperoxidase-3-amino-9-ethylcarbazole (AEC) method, respectively. The combination of the two techniques neither abolished nor diminished their sensitivity or specificity. GHF-1 is expressed in all five of the cell types in the adult porcine adenohypophysis, showing that this method is suitable for simultaneous detection of transcripts and proteins at the single-cell level.

A patient suffering from Faconi's anemia presented multifocal neurologic complications, initially with an exacerbating-remitting clinical presentation, next followed by chronic progressive course. Both as a nosologic association or as neurologic complication of Fanconi's anemia, this case is un unpublished observation, to our knowledge.

We studied the clinical and histopathology findings of the first proved case of Creutzfeldt-Jakob disease in Panama. A sixty-five-years-old female patient referred from Santiago de Veraguas was admitted to Santo Tomás Hospital with a progressive clinical picture of dementia, incoordination and generalized myoclonia. The electroencephalogram showed periodic paroxysmal activity. The patient died eight months after initiated the disease. The cerebral histopathologic study was characteristic of Creutzfeldt-Jakob disease: status spongiform, neuronal loss and non-inflammatory gliosis was found.

Studies of the prevalence of the human T-cell lymphotropic virus (HTLV-1) in 1984 to 1986 in the Republic of Panama revealed a national seroprevalence of 1 to 2%. Since 1985 clinical epidemiological studies of neurological diseases associated to HTLV-1 are being done. Two hundred and fitly six clinical cases of thirty eight different neurological diseases of unknown etiology studied in the Neurology Services of the Santo Tomas Hospital and the Social Security Metropolitan Hospital Complex have been associated in some way to the HTLV-1. Twelve cases of progressive spastic paraparesis were identified and related to HLTV-1 as an etiologic agent. The ratio of men to women was maintained at 1:1 with the average age at onset at 44 years and without racial preference. There are important doubts about the association of this virus to multiple sclerosis. The seroprevalence of the HTLV-1 virus in Panama is found to be similar to that reported in neighboring countries and the association of tropical spastic paraparesis to THLV-1 infection is identified.

The authors have studied the influence of certain meteorological factors (air temperature, atmospheric pressure and humidity) on the onset of acute cerebrovascular disorders. The investigations related to 232 persons of both sexes affected by stroke. The case material was subjected to detailed statistical analysis. On the basis of their investigations the authors conclude that there is some parallelism between the particular meteorological factors examined and development of strokes.

In this case study, lithium carbonate, used to control bipolar disorders, is postulated to be the cause of downbeat nystagmus; the degree of nystagmus could be correlated with the dosage and serum level of the drug. All tests for anatomic lesion were negative, including metrizamide cisternography.