Biomedical subjects

M T Antonio

Publications and source records attributed to M T Antonio.

16 recordsLinked to original sources

PubMed2002

Effects of maternal lead administration on monoaminergic, GABAergic and glutamatergic systems.

The effects of perinatal exposure to lead (300 mg/l) on the development of monoaminergic and aminoacidergic systems were evaluated in the striatum, cerebral cortex (Cx), dorsal hippocampus (d-Hipp) and basal-medial hypothalamus. Maternal exposure to lead produced regional alterations in monoamine content, with increases in dopamine and serotonin or their metabolites. Further, decreased glutamate levels were seen in all brain regions studied, while GABA content decreased only in the Cx. Together, these results show that lead causes alterations to neurotransmitter systems during development. These may be related to lead-induced neurobehavioral impairment.

Animals↗

PubMed2001

Endothelial dysfunction in salt-sensitive essential hypertension.

The aim of this study was to evaluate endothelium-dependent and -independent vasodilation, as well as endothelium biochemical markers, in a group of essential hypertensive patients classified on the basis of salt sensitivity. Changes in forearm blood flow in response to acetylcholine, sodium nitroprusside, and N(G)-monomethyl-L-arginine (L-NMMA) infusion were determined by means of strain-gauge plethysmography. Moreover, plasma and urinary concentrations of nitrates, cGMP, and endothelin were measured during low (50 mmol/d) and high (250 mmol/d) salt intake. Salt-sensitive hypertension was diagnosed in 26 patients who exhibited a significant increase in 24-hour mean blood pressure assessed by ambulatory blood pressure monitoring after 1 week of high salt intake. Nineteen patients were considered salt resistant. Compared with salt-resistant hypertensives, salt-sensitive patients presented a significant lower (P=0.005) maximal acetylcholine-induced vasodilation (21+/-6.3 versus 28+/-7.5 mL. 100 mL(-1). tissue. min(-1)). On the contrary, maximal sodium nitroprusside-induced vasodilation did not significantly differ between groups (22.4+/-4.5 versus 23.9+/-5.3 mL. 100 mL(-1). tissue. min(-1)). The decrease in maximal acetylcholine-induced vasodilation promoted by the coadministration of L-NMMA was significantly more pronounced in salt-resistant compared with salt-sensitive patients (P=0.003). Finally, high salt intake promoted a significant decrease in 24-hour urinary nitrate excretion in salt-sensitive patients (from 443+/-54 to 312+/-54 micromol/d; P=0.033) compared with salt-resistant hypertensives (from 341+/-50 to 378+/-54 micromol/d). We conclude that salt-sensitive hypertension is associated with endothelial dysfunction characterized by a defective endothelium-dependent vasodilation. Impairment of the L-arginine-nitric oxide pathway may be responsible for this abnormal endothelial response.

Acetylcholine↗

PubMed2001

Effect of salt intake on endothelium-derived factors in a group of patients with essential hypertension.

The aim of the present study was to evaluate the effects of the level of salt intake on endothelium-derived factors in a group of patients with essential hypertension. A group of 50 patients with essential hypertension who had never been treated for the condition were placed on a low-sodium (50 mmol/day), low-nitrate (400 micromol/day) diet, which was supplemented, in a single-blind fashion, with placebo tablets for the first 7 days and then with NaCl tablets (200 mmol/day) for a further 7 days (total sodium intake 250 mmol/day). At the end of both periods, 24-h ambulatory blood pressure monitoring was performed. In addition, plasma levels and 24-h urinary excretion of nitrites plus nitrates and cGMP were measured, along with plasma levels of endothelin. A high salt intake promoted significant decreases in plasma levels of nitrites plus nitrates (from 41.0+/-2.1 to 32.8+/-1.8 nmol/ml; P<0.001), 24-h urinary nitrate excretion (from 417+/-36 to 334+/-37 micromol/24 h; P=0.045) and plasma endothelin levels (from 5.6+/-0.3 to 4.6+/-0.3 pg/ml; P=0.007). The plasma concentration and 24-h urinary excretion of cGMP were not altered significantly by a high salt intake. We did not find any relationship between endothelium-derived products and 24-h mean blood pressure, at either low or high salt intakes, or between changes induced by the high-salt diet. A high salt intake also induced significant decreases in plasma renin activity, angiotensin II and aldosterone, and a significant increase in atrial natriuretic peptide. We conclude that a high salt intake decreases the plasma concentration and urinary excretion of nitrates and plasma levels of endothelin in patients with essential hypertension, suggesting that the level of salt intake may affect endothelial cell function. However, these alterations are not correlated with changes in blood pressure induced by the high salt intake.

Adult↗

PubMed2000

Study of the neurochemical alterations produced in discrete brain areas by perinatal low-level lead exposure.

Although the neurotoxic effects of Pb are well documented, the subcellular mechanisms of this action in the central nervous system are not fully understood. The present work examines some neurochemical parameters in discrete brain areas of pups whose mothers were intoxicated via drinking water with lead (300 mg/L), from day 1 of pregnancy until postnatal day 12. Lead intoxication produced a significant reduction in the activity of the enzymes alkaline phosphatase and ATP-ase in the brain. Furthermore, the levels of adenine nucleotides were significantly altered by treatment, the striatum being the area more affected, whereas lead did not vary the levels of ATP, ADP and AMP in the hypothalamus. On the other hand, there was a general decrease in neurotransmitter levels in all areas, specially in the hippocampus. These data suggest that gestational and lactational exposure to low dose of lead could produce neurochemical changes in discrete brain areas which can be responsible for the neurophysiological and behavioral changes described in lead-intoxicated animals.

Adenosine Triphosphatases↗

PubMed2000

Microalbuminuria in essential hypertension: clinical and biochemical profile.

This study aims to evaluate the clinical and biochemical profile associated with the presence of microalbuminuria in a group of essential hypertensive patients referred to a hypertension clinic. A total of 188 non-diabetic, untreated essential hypertensive patients (100 men, 88 women) aged 55.8 +/- 11.7 years are studied. Urinary albumin excretion was determined in two 24-h urine collections. Clinical and biochemical evaluations and 24-h ambulatory blood pressure (BP) monitoring were performed at baseline. Forty-two patients (22.3%) showed an increased urinary albumin excretion rate (20-200 micrograms/min). These patients showed significantly higher values (P < 0.01) for 24-h, daytime and night-time systolic and diastolic BP, compared with essential hypertensives with normal urinary albumin excretion. However, nocturnal reduction in BP did not differ between the groups. Furthermore, patients with microalbuminuria showed significantly higher (P < 0.01) creatinine, serum uric acid and triglycerides, as well as lower high-density lipoprotein (HDL)-cholesterol. In a multiple logistic regression analysis, a 24-h systolic BP > 140 mmHg (odds ratio: 3.19; 95% confidence interval [CI 95%]: 1.44-7.06) and a serum creatinine > 88 mumol/L (odds ratio: 3.08; CI 95%: 1.39-6.84) were the two factors associated independently with increased urinary albumin excretion. We conclude that, in essential hypertensive patients, the presence of microalbuminuria is associated with elevated BP, but not with its circadian pattern. Likewise, microalbuminuria is associated with the degree of renal impairment, and with increased uric acid and triglycerides and decreased HDL-cholesterol.

Adult↗

PubMed1999

[Study of mortality in a medical unit of emergency department: incidence, causes and consequences].

OBJECTIVES: To define the mortality pattern in a medical unit of emergency department (ED) and to know the satisfaction of relatives with ED provided care. PATIENTS AND METHODS: We computed the number of patients visited and dead from 1989 to 1996. From all patients dying during 1996, we recorded clinical and epidemiological data and we interviewed the patients' family to know their satisfaction with ED provided care. RESULTS: Whole mortality rate was 0.71 (0.15)% X (SD) with an annual increase of 10.4% (r = 0.78, p < 0.05). The clinical profile of patient dying at ED is an individual of advanced age, with a poor quality of life, and in whom the death was expected when arrived to ED. From the family interview, 61% of cases preferred that their relative was dying in the hospital, and 88% were satisfied with ED provided care. CONCLUSIONS: Although the annual mortality rate has progressively increased in ED, family satisfaction with the received care is good.

Age Factors↗

PubMed1999

Neurochemical changes in newborn rat's brain after gestational cadmium and lead exposure.

Gestational administration of cadmium (10 mg/l) and lead (300 mg/l) produced a strong decrease in proteins at birth (-17%) and on day 5 (-31%) as well as in brain lipid amount on both days (-11 and -23%, respectively). At day 5 postnatal the exposure also produced a marked decrease in DNA and RNA concentrations with respect to the control group. On the other hand, we found a significant increase of indoleamine content in all brain areas studied in the cadmium-lead group and so the dopamine and its metabolite in mesencephalon, whereas dopamine levels in metencephalon decreased significantly. This data suggests that gestational and early lactational exposure to low dose of cadmium and lead could produce alterations in monoaminergic metabolism that can place the exposed animal to a significant risk in adulthood.

Animals↗

PubMed1999

Decreased health care quality associated with emergency department overcrowding.

The objective of this study was to assess the influence of overcrowding on health care quality provided by emergency departments (ED). The study was carried out in an urban, university tertiary care hospital. All patients seen at the internal medicine unit (IMU) of the ED who returned during the following 72 hours, and those who died in the ED rooms were included in the study. During a consecutive period of 2 years (104 weeks), we prospectively quantified the number of weekly visits, revisits and deaths. We calculated revisit and mortality rates (in respect of percentage of all visited patients) for each week. Correlation between the number of weekly visits, and revisit and mortality rates was assessed using a simple linear regression model. We consigned 81,301 visits, 1137 revisits and 648 deaths; mean (+/- SD) number of weekly visits, revisits and deaths were 782 (68), 10.93 (3.97) and 6.23 (3.04) respectively; weekly revisit rate was 1.40% (0.48%) and weekly mortality rate was 0.79% (0.36%). We observed a significant, positive correlation between mortality rates and weekly number of visits (p = 0.01). Although a similar trend was also found for revisit rates, such an increase did not reach statistical significance (p = 0.06). It is concluded that since revisit and mortality rates constitute good health care quality markers, present data demonstrate that ED overcrowding implies a decrease in the health care quality provided by it.

Crowding↗

PubMed1999

The first report on human cases serologically diagnosed as Japanese encephalitis in Indonesia.

Although Japanese encephalitis (JE) virus was isolated from mosquitos in 1974, human JE cases have never been reported in Indonesia in spite of the prevalence of anti-JE antibodies among human and pig populations as well as abundant JE vector mosquitos. In this report, we describe serological diagnosis of JE cases in Bali. Indonesia. using IgM-capture ELISA both on serum and cerebrospinal fluid (CSF) of the patients. In the first series of our investigation (Series 1), we examined serum specimens from 12 patients with clinical diagnosis of viral encephalitis, meningitis or dengue hemorrhagic fever (DHF), and found 2 possible JE cases. In the next series (Series 2), we examined both serum and CSF from encephalitis patients and gave laboratory diagnosis of JE. One of them was suspected to have concomitant or recent infection with dengue virus, probably type 3. These results strongly indicated that JE has been prevalent in Bali, Indonesia.

Child, Preschool↗

PubMed1998

Study of alterations produced by cadmium and cadmium/lead administration during gestational and early lactation periods in the reproductive organs of the rat.

Administration of cadmium (10 mg/liter) and cadmium+lead (300 mg/liter) via drinking water to Wistar rats during gestation and early lactation until delivery and (5 days after parturition) damaged pup reproductive systems. The effects are additive in the decreased gonad weight and additive or even synergistic in the reduced DNA gonadal content. The effects on protein reduction are similar for both cations. In the testes, the effects of cadmium are more important in the reduction of seminiferous tubule diameter, whereas the effects of lead are more overt in the reduction of the number of prospermatogonia.

Animals↗

PubMed1998

Effect of metyrapone administration in pregnant rats on monoamine concentration in fetal brain.

Studies performed in our laboratory indicate that the adrenal deprivation during gestation can greatly influence the fetal catecholamines development in several cerebral areas. The present study was undertaken to determine whether the administration of metyrapone to pregnant rats affects the content of monoamines in fetal brain at term. To test wether the content of monoamines in fetal brain is regulated, at least in part, by endogenous glucocorticoids, pregnant rats were injected for 5 days prior to delivery with metyrapone, an adrenal 11-beta-steroid hidroxylase inhibitor which crosses the placenta and blocks endogenous glucocorticoid synthesis, or saline. On day 21 of gestation, delivery of all animals was accomplished by cesarean section. The encephalons were extracted and immediately dissected in metencephalon, mesencephalon, diencephalon and telencephalon. Monoamine determination was carried out using HPLC-ED. The results obtained indicate that the metyrapone treatment increases both DA and 5-HT and their metabolites in the brain studied areas.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1997

Maternal exposure to delta 9-tetrahydrocannabinol (delta 9-THC) alters indolamine levels and turnover in adult male and female rat brain regions.

Perinatal exposure to delta 9-THC has been shown to produce effects on brain development. In this study we evaluated the changes induced by maternal exposure to delta 9-THC (5 mg/kg per day) from gestational day 5 to postnatal day 24 in eight discrete brain areas on the central serotoninergic system in both adult male and female rats. These result show that maternal exposure to delta 9-THC from gestational day 5 to postnatal day 24 affects development of the various central indoleaminergic system of the offsprings brain. Perinatal exposure to delta 9-THC decreased the levels of 5-HT in hypothalamus and rostral neostriatum in exposed males, and also decreased the levels of 5-HT in ventral hippocampus, septum, and midbrain raphe nuclei in both exposed males and females. Perinatal exposure to delta 9-THC increased the levels of 5-HIAA in dorsal hippocampus, hypothalamus, septum, midbrain raphe nuclei, and rostral neostriatum in exposed males and females. We have also found differences between nonexposed males and females in several brain regions. Our results confirm a regional and sexual specificity in endogenous levels of indoleamine after perinatal delta 9-THC treatment, being the midbrain raphe nuclei the most affected area.

Animals↗

PubMed1992

Influence of amygdala catecholamines on ovarian and adrenal medullary secretion.

The amygdaloid complex participates in the modulation of endocrine functions, and contains measurable amounts of noradrenaline (NA) and dopamine (DA). This study examined the contribution of the amygdaloid catecholaminergic systems to the regulation of the adrenal medulla and the ovary. To accomplish this the neurotoxin 6-hydroxydopamine (6-OHDA) was bilaterally injected into the basolateral nucleus of the amygdala (ABL) in cycling rats. The contents of NA and DA in right and left amygdala decreased significantly in lesioned animals with respect to sham lesioned animals, but hypothalamic levels were not different between groups. Administration of 6-OHDA to rats increased the NA, DA and adrenaline (A) contents of the adrenals compared to vehicle treated rats. In addition, lesioned animals showed a significant increase of NA and DA contents in the ovary, although A levels did not differ between groups. Serum oestradiol (O) concentrations were significantly lower in lesioned animals than in controls. These data suggest that the amygdaloid catecholaminergic systems exert an inhibitory effect on catecholamine content of the adrenals and the ovary, and influence the ovarian oestradiol secretion mechanism.

Adrenal Medulla↗

PubMedDate not supplied

Neurotoxic effects of gestational administration of low-dose lead acetate.

Lead acetate (300 mg l-1) was administered to pregnant Wister rats from day 1 of pregnancy to day 0 postpartum or day 5 postpartum, via drinking water. On these days, pups were sacrificed, collecting the blood to determine the concentration of lead by graphite furnace atomic absorption spectrophotometry. Brains were used to determine the total content of nucleic acids, DNA/RNA ratio and the total amount of proteins, lipids and monoamines. We found a reduction in protein content on day 0 postpartum, and changes in monoamine concentration on day 0 postpartum and day 5 postpartum. These data suggest that prenatal and early lactational exposure to a relatively low dose of lead could produce alterations in monoaminergic metabolism.

3,4-Dihydroxyphenylacetic Acid↗

PubMedDate not supplied

Gestational administration of cadmium alters the neurotransmitter levels in newborn rat brains.

The effects of gestational and early lactational intoxication by cadmium (Cd) were studied in the brain of young Wistar rats. Pregnant rats were exposed to 10 mg of cadmium acetate per litre of drinking water, from initiation of pregnancy to parturition or until postnatal day 5. At birth or on postnatal day (PND) 5 the pups were weighed, sacrificed and brains were removed and frozen for later study. Protein, lipid and nucleic acid contents were measured and the brain Cd concentration was determined. Levels of dopamine (DA), 5-hydroxytryptamine (5-HT) and their respective metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5-HIAA) were measured in neonatal pup brain by higher performance liquid chromatography with electrochemical detection. The results from this experiment showed that Cd increased the 5-HT and 5-HIAA contents in all areas of the brain and the DA and DOPAC levels in mesencephalon, but decreased the DA and DOPAC levels in the metencephalon. On the other hand, Cd intoxication did not modify the other biochemical parameters measured, with the exception of a decrease in nucleic acids on PND 5.

Animals↗

PubMedDate not supplied

Testicular alterations in rats due to gestational and early lactational administration of lead.

A solution of lead acetate (300 mg/L) was administered via drinking water to pregnant Wistar rats from day 1 of pregnancy to delivery (Pb-treated day 0 group) or throughout gestation and early lactation (from day 1 to day 5 postnatal) (Pb-treated day 5 group). When the pups were born, four dams and their offspring in each group (control day 0, Pb-treated day 0, control day 5, and Pb-treated day 5) were sacrificed on day 0 (day 0 groups) or on day 5 (day 5 groups). Relative testicular weight and gross testicular structure were not altered by the treatment. The seminiferous tubule diameter and the number of prospermatogonia were reduced by the treatment. Determination of the n-ploidy stage of prospermatogonia indicates that these cells have more proliferative activity in Pb-treated rats than in control rats. On the other hand, the total DNA, RNA, and protein content of the testes in treated rats was significantly reduced, but the DNA: RNA ratio remained unaltered.

Animals↗