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Biomedical subjects

M Lema

Publications and source records attributed to M Lema.

At least 37 records · Page 2Linked to original sources
PubMed1995

Genetic markers: association study in migraine.

Eleven genetic markers were typed in 112 unrelated patients with migraine (50 with aura, 62 without aura) and compared with a random sample of healthy individuals. No significant differences were found for the ABO and Rh systems, acid phosphatase 1, phosphoglucomutase 1, adenosine deaminase, haptoglobin, transferrin, alpha-1-antitrypsin, and D1S80. Strong associations between the group of patients with migraine and group-specific component GC 1F-1F and esterase-D ESD 2-2 phenotypes were observed. These associations raise the possibility that a molecular genetic factor for migraine may exist in or near the Group Component (chromosome 4) and Esterase D (chromosome 13) loci, and represent a first comprehensive step in the eventual localization and isolation of the migraine genes.

Adolescent↗
PubMed1994

Plasma monoamines in tension-type headache.

Clinical and pharmacological data suggest a derangement of central monoaminergic systems in tension-type headache. Biochemical evidence has been rarely recognized. These findings may relate with pathophysiological mechanisms of headache or with underlying depression. We measured platelet-rich plasma serotonin and plasma catecholamines (norepinephrine, epinephrine, and dopamine) in 30 patients with tension-type headache and in 20 healthy controls, using High-Pressure Liquid Chromatography. We studied differences between groups and the relation between biochemical parameters and clinical indices evaluating duration and severity of headache and depression. Platelet serotonin levels in tension headache patients were higher than in controls (P < 0.001). Plasma catecholamine levels were lower in patients than in controls (P < 0.001 for epinephrine and dopamine, and P < 0.05 for norepinephrine). There was a positive correlation between dopamine levels and duration of history of headache (r = 0.55, P < 0.05). A negative correlation between epinephrine levels and severity of headache was observed (r = 51, P < 0.01). No correlations were found between monoamine levels and severity of depression. Our results add to the evidence of alterations of monoaminergic central systems in tension-type headache patients. These alterations seem to be independent from the underlying depression and related to the pathophysiologic mechanisms of headache.

Adult↗
PubMed1994

[Changes in neuroexcitatory amino acids during and between migraine attacks].

We studied changes in plasma levels of neuroexcitatory amino acids during and between migraine attacks in 16 patients with migraine without aura, 11 with aura and 21 controls. Glutamic acid levels between attacks were 1.027 +/- 0.60 and 0.890 +/- 0.41 mg/dl in migraine patients without and with aura, respectively; during attacks the levels were 0.535 +/- 0.23 and 0.601 +/- 0.20 for the same patients. The concentration of glutamic acid in the control group was 0.980 +/- 0.64 mg/dl. Aspartic acid levels between attacks in patients without and with aura were 0.179 +/- 0.04 and 0.167 +/- 0.03 mg/dl. Concentrations during attacks were 0.129 +/- 0.02 and 0.119 +/- 0.02 mg/dl for the same patients. Plasma levels of aspartic acid for controls were 0.146 +/- 0.03 mg/dl. We found no significant variations in neuroexcitatory amino acids between migraine attacks in patients with an without aura; changes took place only during attacks, possibly related to the mechanisms of the spreading depression process.

Adult↗
PubMed1993

Taurine levels in plasma and cerebrospinal fluid in migraine patients.

Taurine is the amino acid with the highest concentration in the human body. Its physiologic functions are not yet well understood. As a neurotransmitter or neuromodulator it may display inhibitory functions. We have measured taurine levels in plasma and cerebrospinal fluid of migraine patients during attacks, comparing them with controls. Patients with migraine had significantly higher concentrations than controls. No sex or age influence over the amino acid levels were observed. Plasma taurine levels in patients with classic migraine correlated negatively with severity of headache. Central taurine liberation during migraine crisis may be due to spontaneous depolarization or a defensive reaction in the context of cerebral homeostatic processes.

Adolescent↗
PubMed1993

Catecholamine levels in plasma and CSF in migraine.

There is clinical and pharmacological evidence of the existence of sympathetic dysfunction in migraine. Adrenaline and noradrenaline concentrations were determined in plasma and CSF of patients during attacks of common or classic migraine, comparing them with controls suffering from stress. Plasma noradrenaline levels were significantly lower in the patients with common migraine than in controls (p < 0.05). Other catecholamine levels in plasma and CSF in both migraine groups were only slightly lower than in controls. Our results suggest that central sympathetic dysfunction exists in patients with migraine.

Adult↗
PubMed1993

Controlled ruminal infusion of sodium bicarbonate. 3. Influence of infusion dose on systemic acid-base status, minerals, and ruminal milieu.

Four ruminally cannulated, lactating Holstein cows were assigned to a 4 x 4 Latin square to monitor effects of intraruminal NaHCO3 infusion on temporal changes in ruminal and systemic acid-base status and mineral metabolism. Twice daily from 2 to 4 h postfeeding, cows were infused with 0, 110, 220, or 330 g of NaHCO3 dissolved in 3.8 L of water. All cows had access to their TMR of sorghum silage and concentrate (35: 65, DM basis) for 2 h twice daily. Ruminal fluid, blood, and urine were collected at feeding and every 30 min postfeeding for 12 h on the last day of each 14-d period. Total urine volume also was measured during this interval. Infusion of buffer increased ruminal fluid buffering capacity transiently at 4.5 h postfeeding but otherwise did not markedly affect ruminal fluid acid-base status. Systemic acid-base status was unaffected by the buffer primarily because renal excretion of base successfully reduced systemic base load. Urine volume increased in response to NaHCO3 infusion. Buffer infusion increased urinary excretion of Na, Mg, and K but decreased Ca excretion for 12 h postfeeding; Cl excretion was not affected. Buffer infusion tended to increase total VFA in ruminal fluid. Our data indicate that homeostatic mechanisms can eliminate exogenous base via the kidneys; hence, acid-base status was not perturbed by infusion of NaHCO3. The increased excretion of Mg and K with buffer infusion indicates that the dietary requirements for these minerals may be increased by NaHCO3. Although loss of Ca through the urine was reduced by buffer infusion, this reduction may indicate reduced availability of Ca to the cow. The diuresis accompanying large doses of NaHCO3 may increase dietary requirements for some minerals.

Acid-Base Equilibrium↗
PubMed1993

Influence of dietary buffer value index on the ruminal milieu of lactating dairy cows fed sorghum silage and grain.

The objective of this study was to evaluate the influence of dietary buffer value index on ruminal fluid pH, buffering capacity, and buffer value index in lactating cows. Three Holstein cows averaging 18 +/- 10 DIM were used in a 3 x 3 Latin square with 3-wk experimental periods. Diets contained grain:sorghum silage DM ratios of 50:50, 60:40, and 70:30. By analysis, these diets had buffer value indexes of -74, -41, and -7. The analyzed dietary buffer value index of the total diets was higher than the index that was calculated from the buffer value index of individual ingredients. Although milk fat content tended to be highest for milk from cows fed the 50:50 concentrate to forage diet and although milk protein production was highest for cows fed the 70:30 concentrate to forage diet, milk yield, 4% FCM, milk fat yield, protein content, and milk fat content were not significantly affected by dietary buffer value index. Dietary buffer equivalents were calculated to be 11% of total buffering equivalents available to the cow, and dietary acid equivalents were 15% of total acid production in the rumen. Compared with ruminal acid production and salivary buffering in the rumen, dietary acid and dietary buffer contributions to the acid-base balance of the cow are minor quantitatively. Ruminal fluid pH, hydrogen ion concentration, buffer value index, buffering capacity, and total VFA were not affected significantly by dietary buffer value index. Hence, dietary acid-base status alone is inadequate as a predictor of the need for buffers in the diet of lactating cows.

Animal Feed↗
PubMed1992

Pineal and plasma melatonin as determined by high-performance liquid chromatography with electrochemical detection.

A rapid and sensitive method for the routine quantitative determination of melatonin in pineal and plasma is described. The assay used reversed-phase high-performance liquid chromatography (RP-HPLC) separation combined with either amperometric (system A) or coulometric (system B) detection. The method gave satisfactory reproducibility and accuracy, and detection limits for melatonin were as low as 8.5 pg (system A) and 1 pg (system B). This high sensitivity, together with the short analysis time (less than 10 min), and the simplicity of sample procedure make the present RP-HPLC method suitable for a wide range of studies concerning melatonin measurements. Melatonin values obtained in this study from both rat pineal and human plasma agree with those reported previously, and clearly determined a circadian pattern.

Animals↗
PubMed1992

A buffer value index to evaluate effects of buffers on ruminal milieu in cows fed high or low concentrate, silage, or hay diets.

Our objective was to develop a buffer value index that would incorporate alterations in both ruminal fluid pH and buffering capacity as indicators of the influence of dietary buffering and alkalinizing agents on ruminal acid-base status. This index was evaluated using ruminal fluid from four lactating Holstein cows fed either sorghum silage or alfalfa hay in high or low concentrate diets. Ruminal fluid was incubated in vitro for 1, 2, 3, 4, or 5 h with no buffer or with 7.1 g of either NaHCO3, sodium sesquicarbonate, or a multielement buffer added per liter of ruminal fluid. Ruminal fluid pH was lower for diets based on high concentrate or alfalfa; buffering capacity between pH 5 and 7 was greater for high concentrate diets but was not affected by forage type. Ruminal fluid pH was higher for sesquicarbonate than for NaHCO3, the multielement buffer, or the control; however, ruminal fluid H+ concentration was similar between sesquicarbonate and NaHCO3, and both were lower than for the multielement buffer. Hydrogen ion concentration for the multielement buffer was lower than for the control. Buffering capacity was highest for NaHCO3, followed by sesquicarbonate, the multielement buffer, and the control. The buffer value index, which accounted for alterations in both H+ concentration and buffering capacity, was highest for NaCHO3, followed by sesquicarbonate, the multielement buffer, and the control. The poor response to the multielement buffer may be attributable to our relatively short incubation interval (less than 5 h). Dietary buffers increase both ruminal fluid pH and buffering capacity; both of these responses are beneficial.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1992

Evaluation of a system for rating edema in dairy cattle.

Our objective was to evaluate a subjective edema rating system to quantitate edema severity. Edema was evaluated with 20 nulliparous Holstein heifers from 3 wk before their expected calving date until 3 wk postpartum. Severity of udder edema was evaluated independently daily by five people throughout the 68-d experiment; a 10-point rating system (0 = no edema, 10 = severe edema) was used. One of the people developing the scoring system served as the official scorer. The accuracy of the rating system, defined as the closeness of test evaluator scores to official scores, was highest for scores 2 to 8. The precision of the system, identified by the standard error of the mean, was similar for each score in the rating system. The largest disagreement between official and test evaluator scores was evident postpartum. The large number of defined points in this rating system and the similarity between official and test scores in this study indicate the usefulness of this tool to evaluate precisely the severity of edema in dairy cattle.

Animals↗
PubMed1992

Influence of calcium chloride fed prepartum on severity of edema and lactational performance of dairy heifers.

Twenty Holstein heifers in a completely randomized design were used to evaluate the effects of prepartum dietary CaCl2 on the development and regression of edema and on subsequent lactational performance. Heifers were assigned to diets containing either 2.17% limestone or 1.5% CaCl2 (DM basis) at 3 wk before expected calving date. Except for the Ca sources, diets were identical. Test diets were only fed prepartum; at calving, all heifers were offered a lactation diet for 3 wk. Severity of edema was evaluated independently by five people daily throughout the experiment; a 10-point rating system was utilized to quantify the severity of edema. Calcium chloride reduced the severity of edema, although this response was most evident during the 1st wk that this salt was fed. The beneficial effects of CaCl2 on edema prepartum disappeared postpartum, when CaCl2 was removed from the diet. Indeed, edema was higher for heifers fed CaCl2 than for those fed limestone at 2 wk postpartum. Calcium chloride reduced DMI prepartum, but, following parturition, a compensatory increase in feed intake occurred. Postpartum daily DMI averaged 1.3 kg higher for heifers fed CaCl2 than for those fed the limestone diet prepartum. Milk yield and composition were somewhat lower for heifers fed CaCl2, although this response was most evident at 1 wk postpartum. Feeding CaCl2 prepartum to prevent milk fever also may reduce the severity of udder edema prepartum and increase feed intake during early lactation.

Animals↗
PubMed1992

Influence of dietary fiber and buffer value index on the ruminal milieu of lactating dairy cows.

The influence of dietary buffer value index and dietary ADF content on ruminal fluid pH, buffering capacity, and buffer value index was measured. Four lactating Holstein cows (two primiparous) averaging 72 +/- 60 DIM were used in a 4 x 4 Latin square with 3-wk experimental periods. Treatments were a 2 x 2 factorial arrangement of TMR containing two ADF concentrations (16 and 21% of DM) and two buffer value indexes (calculated from analysis of individual dietary ingredients to be -200 and 0). Milk fat content and milk fat yield tended to be increased by high ADF, and protein yield tended to increase with low buffer value index and low ADF. Although the high ADF diets increased ruminal fluid pH, they reduced buffering capacity; because the magnitude of the pH increase was greater than the reduction in buffering capacity, ruminal fluid buffer value index was increased by added ADF. The high buffer value index diets reduced ruminal fluid pH and increased ruminal fluid buffering capacity; effects on pH outweighed those on buffering capacity so that the ruminal fluid index paradoxically decreased as the dietary index increased. Ruminal fluid acetate increased and propionate decreased as ADF increased. We conclude that ruminal fluid buffer value index increases with dietary ADF, likely because of reduced ruminal concentrations of fermentation acids. Because diets with the highest index produced the lowest ruminal indexes, dietary buffer value index must be studied further before it can be included in any model purporting to predict the need for supplemental dietary buffers.

Acetates↗
PubMed1992

Sodium bicarbonate or multielement buffer via diet or rumen: effects on performance and acid-base status of lactating cows.

Our objective was to compare the influence of dietary NaHCO3 and a multielement buffer on ruminal acid-base status and lactation performance of dairy cows. Five ruminally fistulated, primiparous and multiparous lactating Holstein cows averaging 123 +/- 21 d postpartum were assigned randomly to treatments in a 5 x 5 Latin square with 3-wk experimental periods. Treatments were a basal diet without supplemental buffers, with 1.5% NaHCO3 or 1.5% multielement buffer, or with NaHCO3 or multielement buffer solutions poured into the rumen via cannula at 2 h postfeeding. Addition of either buffer to the diet reduced ruminal fluid hydrogen ion concentration from 0 to 6 h postfeeding; only NaHCO3 reduced ruminal fluid acidity when dosed via the cannula. Addition of buffers via ruminal cannula appeared to retard the reduction in ruminal fluid acidity that normally occurs from 6 to 12 h postfeeding; this may have been related to a feedback mechanism inhibiting salivary buffer secretion. Buffering capacity of ruminal fluid tended to increase with buffer addition; the increase was greatest during infusion of NaHCO3. The ruminal fluid buffer value index increased by 4 units for control cows from early (0 to 6 h) to late (6 to 12) postfeeding; smaller increases were noted for addition of multielement buffer. This index was not different for NaHCO3 during these two intervals. Milk yield and DMI were not affected by buffer addition. Although milk fat content tended to be higher with the multielement buffer than with NaHCO3, it was not accompanied by the expected alterations in ruminal acid-base status. Therefore, this increase may be related to systemic effects of specific minerals in the multielement buffer rather than to a more stable ruminal environment. Based on the ruminal fluid buffer value index, NaHCO3 tended to maintain the most stable ruminal acid-base status.

Acetates↗
PubMed1992

[The results of drug holiday in Parkinson's disease].

The transitory suppression of L-dopa in patients with advanced Parkinson's disease improves motor response upon reintroduction of the drug although this improvement is not constant. The degree and duration of clinical improvement obtained following L-dopa drug holiday were studied and the factors which may intervene in the result of 32 patients with Parkinson's disease were analyzed. Improvement was found in 100% (24.9 +/- 6.7%) with significant differences being observed in the degree of disability (p < 0.05) and the final decrease of the doses of L-dopa (p < 0.05). Improvement was maintained during 10.3 +/- 7.9 weeks. Linear regression studies did not show any relation between the length of the drug holiday, longer than 4 days, and the degree and maintenance of improvement or final decrease of the doses of L-dopa. The authors consider this procedure useful in patients with important fluctuations in treatment response or with important refractory side effects to other measures.

Adult↗
PubMed1992

[Rhombencephalitis caused by Listeria monocytogenes].

The observation of an abscess in the brain stem and cerebellum due to Listeria monocytogenes is presented. The patient was a 55 year old diabetic, alcoholic, gastrectomized male in whom a febrile and meningeal syndrome developed. Three days later he had a progressive unilateral dysfunction of the cranial nerves. The cerebrospinal fluid showed pleocytosis of the polymorphonuclear cells, an increase in proteins and low glucose in relation with the glycemia. No parenchymatous lesion was observed upon emergency computerized tomography. Magnetic resonance imaging showed a hyper-signal lesion in the brain stem and cerebellum with a contrast enhancement in ring. Following antibiotic treatment the clinical evolution of the patient was favorable with slight focal sequelae persistent at discharge. A review of the epidemiology, clinical manifestations and treatment of this infection is carried out.

Encephalitis↗
PubMed1992

[Biologic markers in multiple sclerosis (and II). Neurophysiologic and imaging correlations].

The relation between the results of 7 biological markers (cells, total protein, albumin, IgG, IgG ratio, Tibbling ratio, and Tourtellotte's formula) and 4 paraclinical tests (PEV, PEATC, CT and MR) in 236 patients with multiple sclerosis (MS) not selected by the localization of symptoms were studied. One hundred forty-one had clinically defined MS, 22 had defined MS supported by a laboratory and 68 had clinically probable MS. The existence of a relation between PEV and MRI abnormality and the increase in the concentration and the ratios of intrathecal IgG synthesis and the degree of certainty of disease diagnosis was demonstrated. The most sensitive test was MRI (93%) followed by VEP (83%) and BAEP (60%) and the sensitivity of the study with high resolution CT including 59 patients explored by double enhancement and delayed cut off was very low (33%). It was considered that for the lack of a specific diagnostic test the use of biological markers PEV and MR constituted a necessary aid in the diagnosis of MS.

Adult↗
PubMed1991

Two-parameter mobile phase optimization for the simultaneous high-performance liquid chromatographic determination of dopamine, serotonin and related compounds in microdissected rat brain nuclei.

A new high-pressure liquid chromatography method with electrochemical detection is described that allows the simultaneous determination of dopamine, serotonin, 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylacetic acid, 5-hydroxytryptophan and 5-hydroxyindoleacetic acid in microdissected nuclei from individual rat brains. No sample pre-treatment steps are required. Resolution and analysis time were optimized by a simple limited optimization procedure, involving two-parameter factorial design.

3,4-Dihydroxyphenylacetic Acid↗