Biomedical subjects
Publications and source records attributed to S R Silva.
The prenatal diagnosis of wormian bones has not been made previously. We report four fetuses with wormian bones but none of the associated anomalies. The diagnosis, differential diagnosis, associated anomalies, and prognosis of this entity are discussed.
CONTEXT: Intrauterine closure of exposed spinal cord tissue prevents secondary neurologic injury in animals with a surgically created spinal defect; however, whether in utero repair of myelomeningocele improves neurologic outcome in infants with spina bifida is not known. OBJECTIVE: To determine whether intrauterine repair of myelomeningocele improves patient outcomes compared with standard care. DESIGN: Single-institution, nonrandomized observational study conducted between January 1990 and February 1999. SETTING: Tertiary care medical center. PARTICIPANTS: A sample of 29 study patients with isolated fetal myelomeningocele referred for intrauterine repair that was performed between 24 and 30 gestational weeks and 23 controls matched to cases for diagnosis, level of lesion, practice parameters, and calendar time. All infants were followed up for a minimum of 6 months after delivery. MAIN OUTCOME MEASURES: Requirement for ventriculoperitoneal shunt placement, obstetrical complications, gestational age at delivery, and birth weight for study vs control subjects. RESULTS: The requirement for ventriculoperitoneal shunt placement for decompression of hydrocephalus was significantly decreased among study infants (59% vs 91%; P = .01). The median age at shunt placement was also older among study infants (50 vs 5 days; P = .006). This may be explained by the reduced incidence of hindbrain herniation among study infants (38% vs 95%; P<.001). Following hysterotomy, study patients had an increased risk of oligohydramnios (48% vs 4%; P = .001) and admission to the hospital for preterm uterine contractions (50% vs 9%; P = .002). The estimated gestational age at delivery was earlier for study patients (33.2 vs 37.0 weeks; P<.001), and the birth weight of study neonates was less (2171 vs 3075 g; P<.001). CONCLUSIONS: Our study suggests that intrauterine repair of myelomeningocele decreases the incidence of hindbrain herniation and shunt-dependent hydrocephalus in infants with spina bifida, but increases the incidence of premature delivery.
This work presents a Neo-Fuzzy-Neuron algorithm for the identification of nonlinear dynamic systems at the point of view of a rotor flux observer. The algorithm training is on-line, has low computational cost, does not require previous training and its convergence in one step is proved. The gradient descent method is used for its weights adjustment. Simulation and experimental results demonstrate the effectiveness of the algorithm for flux observer of induction motor drive system.
The effects of intracisternal (i.c.) application of the 5-HT3 receptor antagonist granisetron (0.016-0.16 microg kg-1) and the agonist phenylbiguanide (0.3-3 microg kg-1) on reflex bradycardia evoked by injection of phenylbiguanide (i.v.; 10 microg kg-1) were investigated in urethane anesthetized atenolol-pretreated rats. The effect of bilateral microinjection of granisetron (10 nmol per side, 100 nl) into the nucleus tractus solitarius (NTS) on the reflex was also investigated. Intracisternal administration of granisetron dose-dependently (0.016-0.16 microg kg-1) and significantly attenuated the reflex bradycardia whilst the highest dose given i.v. had no significant effect on the reflex bradycardia. Phenylbiguanide given i.c. only caused significant potentiation at the middle dose (1 microg kg-1), having no significant effects at the other doses. Neither granisetron nor phenylbiguanide given i.c. affected resting heart rate or blood pressure. Granisetron microinjected bilaterally into the NTS also significantly attenuated both reflex bradycardia and hypotension. It is concluded that excitation of cardiac vagal motoneurones evoked by cardiopulmonary afferents involves activation of 5-HT3 receptors located in the nucleus tractus solitarius and other brainstem areas.
Hair mercury concentration, as an indicator of mercury body load, was studied in 251 samples of indigenous women and children living in selected areas of the Amazonian region. The mothers or women of child-bearing age, either non-Indians or Indians, and their children were sampled along the Madeira River and in the Kayapó reservation (Fresco River), respectively. Among the sampled individuals there were mothers with infants less than 2 years old. Total mercury in hair was determined by cold vapor atomic absorption spectrometry after alkaline digestion. The distribution of hair mercury concentration greater than 10 microg/g occurred in 67.4% of non-Indian women and 25% of Indian women; overall only 1% of non-Indian women had concentrations of hair mercury above 50 microg/g. In women of child-bearing age, the median and range of hair mercury concentration was 14.08 microg/g, and 0.8-94.7 microg/g for non-Indians, and 8.30 microg/g, and 0.8-13.3 microg/g for Indians. The correlation between maternal hair mercury and mercury in hair of infants (less than 2 years of age) still breast-feeding, was statistically significant only for non-Indians (r = 0.555 p < 0. 001). The correlation between length of breast-feeding and mercury concentration in infant's hair was significant for Indian children (r = 0.512; p = 0.029) but not for non-Indian children (r = 0.025; p = 0.832). A subsampling of 30 mothers had segmented hair analysis that showed a mean decrease of 20% in body burden during pregnancy, thus indicating the extent of placental transference of mercury to fetuses.
BACKGROUND AND AIM OF THE STUDY: A bovine pericardial conduit processed in glutaraldehyde was designed, incorporating the principle of crimping used for synthetic vascular prostheses. The crimping process did not affect the integrity of collagen fibers and tissue structure. This conduit, designed for aortic reconstruction, is available in different sizes, with or without a biological valve. METHODS: Between October 1989 and May 1997, 40 patients with aortic dissection, aortic aneurysm, aortic coarctation or aortoiliac occlusive disease underwent aortic reconstruction using this vascular substitute. Procedures included total reconstruction of the ascending aorta and aortic valve with reimplantation of coronary arteries (nine patients), single ascending thoracic aorta (six), descending thoracic aorta (two), aortic arch (one) and thoracoabdominal aorta (one); the abdominal aorta was reconstructed in 21 cases, including those undergoing aortoiliac or aortofemoral bypass. RESULTS: The hospital mortality rate was 20% (eight patients); causes of deaths were low cardiac output, recurrence of aortic dissection, multiple organ failure and bleeding. Mean follow up was 3.6 years; total follow up was 114 patient-years. Late conduit-related complications occurred in four patients, including a limb obstruction in one patient subjected to aortofemoral bypass and infection of three resulting in pseudoaneurysm (incidence of 3.5 +/- 1.8% per patient-year). All underwent reoperation. There were four late deaths due to sudden death, coronary artery disease, pneumonia and metabolic complications of diabetes and renal failure (incidence of 3.5 +/- 1.8% per patient year). The eight-year actuarial survival rate was 63.7 +/- 11.6%, including hospital mortality, and the eight-year actuarial freedom from conduit failure due to primary tissue structural degeneration was 100%. CONCLUSIONS: The crimping design provides a circular tube which makes construction of the anastomosis easier, retains its shape with bending, and avoids kinking. The material is very soft, easy to handle and suture, coapts nicely to suture lines resulting in a hemostatic anastomosis. The eight-year follow up demonstrated a satisfactory performance without report of fibrosis, calcification or aneurysmal dilation.
PURPOSE: To evaluate the diagnosis value of exercise testing for silent myocardial ischemia in systolic hypertension of the elderly. METHODS: We compared 110 patients with systolic hypertension (group A) with 104 patients without hypertension (group B). They were submitted to an exercise test according to the Bruce protocol, between January/91 to December/94. Exercise was discontinued if target heart rate was achieved, or fatigue, dyspnea, severe arrhythmia, hypotension or significant ST segment depression > or = 2 mm/0.2 mV developed. RESULTS: Exercise testing showed ischemic ST depression in 22 (20%) of the elderly patients with hypertension systolic and 12 (11.5%) of control elderly patients. The exercise time was shorter in the hypertensives 7.1 +/- 2.9 min vs 8.8 +/- 2.5 min. The ST depression was greater in the hypertensives than the control group: 2.5 +/- 0.8 min vs 1.9 +/- 0.4 min. Also the duration or ischemic ST depression was longer in the hypertensive patients than the control group 5.4 +/- 2.8 min vs 3.4 +/- 1.9 min. CONCLUSION: Elderly hypertensive patients with systolic hypertension have more silent myocardial ischemia than elderly without hypertension. Among the elderly hypertensive patients there was a prevalence of silent ischemia that was 1.7 times higher than in the normotensive elderlies (20% vs 11.5% P < 0.003).
OBJECTIVE: To determine if caretakers of young children with IDDM could consistently reproduce small incremental measurements of insulin (U100). RESEARCH DESIGN AND METHODS: Fifteen caretakers of children with IDDM were asked to deliver repeated small doses of insulin, including doses separated by only 0.25 U of insulin. A sensitive gravimetric technique was used to determine the error in measurement of these low doses of insulin. Statistical analysis was used to evaluate accuracy and internal consistency of each caretaker at each dose. RESULTS: The means +/- SD at each dose level were as follows: 2.75 +/- 0.13 U at 2.5 U, 3.19 +/- 0.13 U at 3.0 U, 3.55 +/- 0.13 U at 3.25 U, and 3.70 +/- 0.11 U at 3.5 U. All doses were biased toward overadministration. There was as statistically significant difference in the dose delivered when the target doses were varied by only 0.25 U. The average differences and standard errors between 2.5 U and 3.0 U, 3.0 U and 3.25 U, and 3.25 U and 3.5 U were 0.44 +/- 0.20 U, 0.36 +/- 0.018 U, and 0.15 +/- 0.017 U, respectively. CONCLUSIONS: Participants were not accurate in measuring small insulin doses, consistently overdrawing insulin by an average of 0.22 U. Caretakers are reasonably internally consistent with a given dose, since participants were able to measure statistically significant differences in 0.25 U dose changes. The error in insulin measurement does not vary with the intended dose level. Caretakers in the same family deliver insulin doses as variable from each other as they are from the population as a whole; however, when two or more individuals are responsible for one insulin dose in a child with IDDM, they have a combined variability that is approximately 40% greater than a single individual's variability.
A 17 year-old boy was admitted to the hospital because of severe hypertension (200/130 mmHg), headache, irritability, and sweating. Initial biochemical tests suggested pheochromocytoma, being treated with nifedipine, clonidine and propranolol. However, with report of exposure to mercury vapor, twenty-four-hour urine screening and measurement of blood mercury confirmed intoxication. The patient underwent courses of chelation therapy with dimercaprol (BAL) and penicillamine with remission of symptoms and normalization of blood pressure after 2 months. This case has relevance for current practice reflecting similarity between mercury intoxication and hypertension secondary to pheochromocytoma.
Neuroleptic-induced catalepsy remains a useful method to study central dopaminergic function in rodents. Evidence obtained in several studies indicates that this phenomenon can be modified by cholinergic, histaminergic and serotonergic manipulation. Angiotensin II is a central neurotransmitter acting through AT1 and AT2 receptors. There are few data on the effect of angiotensinergic drugs on dopaminergic transmission. We investigated the effect of losartan, a nonpeptide antagonist of central and peripheral AT1 receptors, on neuroleptic-induced catalepsy. Adult male albino mice, 26-35 g, were used. Catalepsy was induced with haloperidol (H; 1 mg/kg, ip) and measured at 30-min intervals by means of a bar test. Losartan (10 or 100 ng/kg) or saline (control; 0.13 ml) was injected intraperitoneally 20 min before H, with each animal (7 per group) being used only once. Losartan (10 and 100 ng/kg) significantly (P < 0.05) potentiated the cataleptic effect of H in comparison to the control group (e.g. 264 +/- 26 and 299 +/- 68 sec, respectively, vs 89 +/- 24 sec for the control group, 90 min after H). No differences were demonstrable 120, 150 or 180 min after H. Considering the high selectivity and the pharmacokinetic properties of losartan, these data suggest that central angiotensin AT1 receptors play a role in neuroleptic-induced catalepsy. However, further studies are necessary to confirm this hypothesis and to clarify the mechanism(s) involved in this process.
The relation between cocaine use and cardiovascular disease has been well documented including coronary artery vasoconstriction, coronary thrombosis, accelerated atherosclerosis, myocarditis, cardiomyopathies and endocarditis. Cocaine use has reached epidemic proportions. Cocaine is the most commonly abused drug among young patients. We report the case of a 32-year-old male admitted to the emergency department with myocardial infarction secondary to an overdose of cocaine.
Electrocardiographic changes, left ventricular wall motion abnormalities, myocardial ischemia, myocytolysis and arrhythmias have been well documented in patients with cerebral bleed. These complications may be related to stimulation of autonomic nervous system and central nervous system. We report a case of a 38-year-old back woman without previous heart disease, taken to emergency unit with headache and subarachnoid Haemorrhage. One day after, she complained of retroesternal pain. An electrocardiographic tracing showed significant and diffuse ST-T wave abnormalities. The patient remained stable with no neurologic or cardiac deficits. She was treated with bed rest, nimodipine, isossorbide propranolol and is symptomless six months of follow-up.
Typical neuroleptics (e.g. haloperidol) can induce a cataleptic state in rodents by means of striatal DA receptor blockade. It has been shown that drugs which influence central serotonergic (5-HTergic) mechanisms can modify neuroleptic-induced catalepsy, suggesting that dopaminergic transmission is under 5-HTergic modulation. The aim of this study was to examine the effects of bemesetron and granisetron, two selective 5-HT3 receptor antagonists, on this catalepsy in mice. Catalepsy was induced with haloperidol (1.5 mg/kg, i.p.) and measured at 30-min intervals by means of a bar test. Drugs (or saline, for the controls) were injected i.p. 20 min before haloperidol, with each animal used only once. Bemesetron significantly reduced catalepsy at a dose of 1 mg/kg, whilst 10 mg/kg potentiated the phenomenon and 0.1 mg/kg was found to be without effect. Granisetron inhibited catalepsy at doses of 0.04 and 0.1 mg/kg while 4 mg/kg of the antagonist significantly increased the duration of catalepsy. These data suggest that 5-HT3 receptors play a role in neuroleptic-induced catalepsy. Considering the high affinities of both antagonists for 5-HT3 receptors, it is tempting to speculate that the potentiation of catalepsy by high doses of them is due to non 5-HT3 receptor mechanisms.
Our observation that thalidomide administration to a dialysis patient with leprosy alleviated his pruritus led us to conduct this short-term study to assess the efficacy of the drug in this regard. From 210 hemodialysis patients, 29 cases of refractory uremic pruritus were entered into the study. Patients were instructed to score their symptoms from 0 to 3, three times a day and assigned to receive thalidomide or placebo at bed time for 7 days. After a washout period of 7 days, drugs were crossed over. Response was defined as a reduction of at least 50% in the pruritus scoring. Eighteen patients finished the study. In the first phase, 55% of patients responded showing a mean reduction in their pruritus scoring of 78% (p < 0.05 vs. placebo); no response to placebo was observed. A similar proportion of patients responded to thalidomide in the second phase with a mean reduction in their pruritus scoring of 81%. In conclusion, thalidomide can be a precious tool in the handling of uremic pruritus unresponsive to available therapy.
Considerable experimental evidence suggests that central dopaminergic (DA) transmission is under serotonergic (5-HTergic) modulation. For instance, neuroleptic-induced catalepsy (NIC) in rodents, a behavior mainly due to blockade of DA receptors in the striatum, can be affected by 5-HTergic manipulation. It has been shown that ligands of 5-HT1A receptors (e.g. buspirone, gepirone) reduce NIC, while 5-HT2 receptor antagonists (e.g. ritanserin) do not affect this phenomenon. However, the role of 5-HT2 receptors in the modulation of NIC is still controversial and there is evidence from behavioral models other than NIC suggesting the existence of functional interaction between the two subtypes of 5-HT receptors. The present study was designed to evaluate the effect of ICI 170,809 (a selective 5-HT2 receptor antagonist) on NIC and to test the possible effect of this drug on the anticataleptic effect of gepirone (GP). Male Wistar rats weighing 300-350 g were used, and each animal (7 per group, 4 groups) was used only once. Catalepsy was induced with haloperidol (H; 1 mg/kg, i.p.) and measured at 30-min intervals by means of a bar test. Animals received either ICI 170,809 (3 mg/kg, i.p.) or 0.9% saline (SL; 0.8 ml, i.p.) 30 min before H. At 110 min after H, the rats received GP (1 mg/kg, i.p.) or SL (0.8 ml, i.p.). GP significantly attenuated NIC (e.g. 739 +/- 106 s vs 1009 +/- 85 s for controls, at 150 min after H), while ICI 170,809 did not significantly affect the phenomenon (e.g. 978 +/-89 s vs 1009 +/- 85 s for controls, at 150 min after H). Pretreatment with ICI 170,809 did not significantly modify the anticataleptic effect of GP (e.g. 617 +/- 90 s vs 739 +/- 106 s for SL-pretreated animals, at 150 min after H). These results confirm reports of the anticataleptic effect of GP and the lack of effect of 5-HT2 receptor antagonists on NIC. Moreover, these data also suggest the absence of functional interactions between central 5-HT1A and 5-HT2 receptors in this model of DA transmission.
The research reported was carried out to assess the prevalence of caries and dental care status in schoolchildren from urban and rural areas in Araraquara, SP, Brazil. Schoolchildren from an urban area (1,472) and from a rural area (355), aged 7-12 years were examined by two examiners previously trained using the DMFT index. The results showed that the DMFT index was similar in both areas. At 12 years-of-age, the DMFT was 3.8 in urban schoolchildren and 4.0 in rural schoolchildren, considered moderate according to WHO classification. The dental care status was different in the urban and rural areas. In the urban area, 82.9 per cent of the decayed teeth were filled and in the rural area, only 22.1 per cent. The moderate prevalence of dental caries and the high proportion of filled teeth in the urban area suggest that the implementation of primary prevention programmes is necessary, in both, urban and rural populations.
Catalepsy induced by neuroleptics in rats can be modified by 5-hydroxytryptaminergic (5-HTergic) manipulation. For example, buspirone (BUS) and other central 5-HT1A receptor ligands reduce neuroleptic-induced catalepsy (NIC). The dorsal (DRN) and median (MRN) raphe nuclei are reported to be important sources of 5-HTergic projections to the basal ganglia, the site of action of neuroleptics in producing NIC. A previous study showed that lesion of DRN did not affect NIC or the anticataleptic effect of BUS. The present study was designed to evaluate the participation of MRN in NIC and in the anti-NIC effect of BUS. Twenty-four male Wistar rats (N = 6/group) weighing 220-250 g were used. Electrolytic lesion of MRN was carried out in anesthetized rats along with sham operations (electrode inserted but no current applied). Ten days later, the rats were injected with BUS (5 mg/kg, ip) or saline (1 ml, ip). Catalepsy was induced 20 min later with haloperidol (H; 1 mg/kg, ip) and measured at 30-min intervals by means of a bar test. The Costall & Naylor method of scoring (range 0-5 points) was used. Saline-injected MRN-lesioned rats displayed significantly lower catalepsy scores than sham-lesioned rats (1.5 +/- 0.2 vs 3.8 +/- 0.3 at 90 min after H). In sham-lesioned rats, BUS significantly reduced the catalepsy scores in comparison with saline-treated animals (1.3 +/- 0.2 vs 3.8 +/- 0.3 at 90 min after H). However, BUS was not able to further reduce NIC in the MRN-lesioned animals.(ABSTRACT TRUNCATED AT 250 WORDS)