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Biomedical subjects

D Silva

Publications and source records attributed to D Silva.

At least 37 records · Page 2Linked to original sources
PubMed1998

Transdermal nicotine effects on attention.

Nicotine has been shown to improve attentiveness in smokers and attenuate attentional deficits in Alzheimer's disease patients, schizophrenics and adults with attention-deficit/hyperactivity disorder (ADHD). The current study was conducted to determine whether nicotine administered via transdermal patches would improve attentiveness in non-smoking adults without attentional deficits. The subjects underwent the nicotine and placebo exposure in a counterbalanced double-blind manner. Measures of treatment effect included the Profile of Mood States (POMS), Conners' computerized Continuous Performance Test (CPT) of attentiveness and a computerized interval-timing task. The subjects were administered a 7 mg/day nicotine transdermal patch for 4.5 h during a morning session. Nicotine significantly increased self-perceived vigor as measured by the POMS test. On the CPT, nicotine significantly decreased the number of errors of omission without causing increases in either errors of commission or correct hit reaction time. Nicotine also significantly decreased the variance of hit reaction time and the composite measure of attentiveness. This study shows that, in addition to reducing attentional impairment, nicotine administered via transdermal patches can improve attentiveness in normal adult non-smokers.

Administration, Cutaneous↗
PubMed1998

Endoscopic management of colloid cysts.

OBJECTIVE: Several surgical approaches have been proposed for the treatment of colloid cysts, which still remains controversial. The most recent technique used is endoscopy. By its nature, endoscopy cannot offer complete removal, as compared to microsurgical techniques, but can do more than puncture. To evaluate the usefulness of endoscopy for colloid cyst surgery, a series of 15 patients who were operated on for colloid cysts under endoscopic control since 1994 was reviewed. METHODS: The presenting symptoms of our patients (10 men and 5 women) were intermittent headache (10 patients), nausea (3 patients), short-term memory loss (4 patients), coma (2 patients), gait disturbance (3 patients), blurred vision (2 patients), and mental status changes (3 patients). The sizes of the cysts ranged from 4 to 50 mm (median, 22.93 mm). Depending on the radiological appearance, the procedure was performed via a right (10 patients) or left (5 patients) precoronal burr hole. A rigid neuroendoscope was used. Initial stereotactic placement of the neuroendoscope was used in two patients who had moderate hydrocephalus. In the other patients, hand-guided endoscopy was performed using an articulated arm. The cysts were perforated with a needle. The opening was enlarged with microscissors. The cyst material was aspirated, and the remaining capsule was coagulated. RESULTS: The average follow-up was 15.26 months (range, 1-28 mo). Total aspiration of the cysts was achieved in 12 patients, as revealed by normal postoperative magnetic resonance imaging. Control magnetic resonance imaging revealed residual cysts in three patients. One patient presented with an asymptomatic recurrence at 1 year. Resolution of the symptoms was obtained in all patients except for two of the four patients with preoperative memory deficit (improvement without complete recovery). There was no mortality or morbidity. CONCLUSION: These results show that endoscopy is a safe and promising percutaneous technique for the treatment of colloid cysts of the third ventricle. Longer follow-up is, however, still required.

Adult↗
PubMed1997

Genetic and environmental factors regulating blood pressure in childhood: prospective study from 0 to 3 years.

OBJECTIVES: Blood pressure (BP) regulation depends on the interaction between multiple environmental and genetic factors. Of these, BP sensitivity to dietary sodium intake has been one that has been investigated in adults but not in children. The aim of the present study was to investigate, prospectively, the BP profile in relation to different genetic and hormonal factors, in the first 3 years of life. POPULATION AND METHODS: Thirty-nine children born at term following normal pregnancies, with uncomplicated neonatal periods, were randomly selected to take part in the study. BP, weight and length were evaluated every 3 months from birth to 3 years. At the age of 12 months, haptoglobin phenotypes and plasma active renin concentration were determined as well as random urine evaluation of aldosterone, cAMP, dopamine and digoxin-like immunoreactive substances (DLIS). Family history of cardio-vascular diseases was also recorded. RESULTS: Systolic BP (SBP) demonstrated a gradual increase until the age of 6 months with little variation up to 36 months. Tracking of SBP values was also observed from the first year as infants with high values (above the 75 percentile) maintained this tendency up to, at least, the age of 36 months. The comparison between SBP and diastolic BP (DBP) according haptoglobin phenotypes demonstrated that SBP was systematically higher in allele 1, with apparently an increasing tendency with age, although the differences did not have statistical significance. The comparative study between haptoglobin phenotypes, with correction for the covariates fractional excretion of sodium and potassium, showed that allele 1 carriers had significantly lower plasma renin and urine aldosterone and cAMP concentrations than allele 2, but dopamine excretion was found to be higher in allele 1 than in allele 2. There were no differences among variables relating to family history of cardiovascular disease. CONCLUSIONS: There was an early tracking process of BP values from the first 6 months of life which persists through, at least, to the age of 36 months. Differences in sodium handling between haptoglobin 1 and 2 phenotypes were already present in early childhood, although no significant repercussion in BP values could be demonstrated in the 3-year duration of this study.

Age Factors↗
PubMed1995

[Alcohol consumption and glomerulonephritis caused by IgA mesangial deposits. (Berger's disease)].

Alcohol ingestion is considered as a possible pathogenic agent for Berger's disease, since Iga mesangial deposits have been described in liver cirrhosis. Aiming to assess this issue, 28 patients with Berger's disease (BD) and 40 patients with other glomerulopathies (NBD) were subjected to an enquiry about alcohol ingestion. Data was corroborated with 21 close relatives of BD patients and 34 relatives of NBD patients. No differences were observed in reported alcohol intake between BD patients and their relatives, however relatives of NBD patients underestimated their alcohol intake. No differences in alcohol intake, either self-reported or reported by relatives, were observed between BD and NBD patients. It is concluded that no differences in alcohol intake were observed between patients with Berger's disease and subjects with other glomerulopathies.

Adolescent↗
PubMed1994

Capacity management: get the level of detail right.

The objective of this article is to outline the three main stages of manufacturing planning where capacity analysis is employed and to highlight the differences in approach and level of detail required for capacity analysis at each stage. Capacity management is not a single discipline or function. Rather, the term takes on meaning within the context of the planning job it is supporting. There are significant differences between the objectives and output of each planning stage and consequently, there is a need to adjust the approach and level of detail employed in capacity analysis and scheduling depending on the stage. In effect, the typical manufacturing company doesn't have one planning or capacity management challenge; it has several. Thus, when seeking solutions to planning or capacity problems, a company must first decide which problem it wants to attack and then select the peopl/tool combination best suited to handle the level of detail involved.

Industry↗
PubMed1992

[Hypertensive cardiopathy. Functional evaluation during isometric effort after regression of left ventricular hypertrophy].

OBJECTIVE: Echocardiographic evaluation of the response to isometric exercise of hypertensive patients with and without left ventricular hypertrophy. PARTICIPANTS: 28 patients with severe arterial hypertension on long-term follow-up with or without regression of left ventricular hypertrophy on medical therapy; a control group of 10 healthy volunteers. METHODS: Two groups were considered: Group A persistent left ventricular hypertrophy and group B normalization of the left ventricular wall thickness and mass index. The arterial blood pressure and heart rate were evaluated and an echocardiographic record was obtained both at rest and after isometric exercise (maximal effort for 1 to 1.5 minutes). The following echocardiographic data were obtained: left ventricular diameters and thickness of septum and posterior wall during systole and diastole. Volumes, shortening and ejection fractions, cardiac output and index, mass index, end-systolic stress, contractility index and periferal resistance were calculated as usual. RESULTS: During isometric exercise there was a rise in systolic, diastolic and mean arterial pressures and heart rate. Systolic function was normal in all groups at rest. The shortening fraction was not altered in normotensive individuals with isometric exercise. Hypertensive patients showed a significant reduction within normal limits, however. End-systolic stress increased significantly in all groups although the rise was greater in hypertensive patients. The cardiac index rose significantly only in normotensives and hypertensive patients without left ventricular hypertrophy (group B). On the contrary the periferal resistance rose significantly only in hypertensive patients with left ventricular hypertrophy (group A). The contractility index (end-systolic stress/end-systolic volume index) increased significantly only in normotensive and hypertensive patients without left ventricular hypertrophy. CONCLUSIONS: There are functional alterations in hypertensive heart disease which although not evident at rest, can be revealed by isometric exercise. The regression of left ventricular hypertrophy back to normal, sets a trend for normalization of function and cardiac inotropic reserve, suggesting the importance of a complete regression of ventricular hypertrophy.

Adult↗
PubMed1991

[Arterial hypertension and the right heart. A hemodynamic and echocardiographic study].

OBJECTIVE: To evaluate the effects of arterial hypertension on the pulmonary circulation and the right heart. SETTING: Coronary Care Unit (UTIC Arsénio Cordeiro) Hemodynamics Laboratory and Medicine I Echocardiography Laboratory-Santa Maria Hospital. PARTICIPANTS: 38 hypertensive patients separated in two groups: 24 with thickened septum and left ventricular posterior wall (10 with hemodynamic evaluation)--Group A--and 14 without thickening--Group B; a control group of 12 healthy volunteers--Group C. RESULTS: The hypertensive patients with hemodynamic evaluation had normal pulmonary capillary wedge pressure the average pulmonary resistance (135.29 +/- 63.47 dyn.cm.5), pulmonary systolic (31.30 +/- 10.01 mmHg) and mean pressures (18.23 +/- 8.21 mmHg) were raised, but the diastolic pulmonary pressure was normal. The right ventricle systolic pressure was raised (32.10 +/- 9.12 mmHg) and there was no modification of the right atrial or ventricular telediastolic pressures. On echocardiography there was a diastolic thickening of the right ventricular free wall in both group A (7.08 +/- 1.41 mm) and B (4.07 +/- 1.00 mm) as compared to group C (3.08 +/- 0.51 mm); there were similar findings regarding systolic thickness with statistical significance in group A (p less than 0.001). The right ventricular ejection fraction was normal in both groups. There was a positive correlation between the diastolic thickness of left ventricular posterior wall and right ventricular free wall in hypertensive patients and normotensive volunteers (r = 0.7754; p less than 0.001). CONCLUSIONS: The findings suggest an anatomic an functional relationship between both ventricles regarding the cardiac repercussions of arterial hypertension.

Adult↗
PubMed1990

New refractive method for laser thermal keratoplasty with the Co:MgF2 laser.

We have observed corneal curvature changes from laser thermal keratoplasty with a Co:MgF2 laser. We studied corneal curvature changes in rabbits and have identified specific treatment patterns and laser parameters that can correct myopia and astigmatism. These corneal changes, some as large as 8 diopters, have been stable for at least one year, and slitlamp examination demonstrates clear central corneas with normal appearance.

Animals↗
PubMed1989

Overcoming laryngospasm by electrical stimulation of the posterior cricoarytenoid muscle.

The intent of this study was to demonstrate that the technique of transmucosal electrical stimulation of laryngeal muscles may be of clinical use in airway management. Specifically, its ability to overcome laryngospasm was evaluated. Laryngospasm was induced in eight tracheotomized dogs by hyperventilating each dog, and then applying 0.1 M ammonia to the laryngeal mucosa while administering continuous positive airway pressure (CPAP). Laryngospasm was defined by steady apposition of the vocal cords, massive electromyographic activity in the laryngeal adductor muscles, absence of such activity in the posterior cricoarytenoid muscle (PCA), and intraglottic pressure greater than 80 mm Hg. Upon transmucosal application of 10 mAmp current to the PCA bilaterally, the vocal cords abducted for the duration of the stimulus. We theorize that overcoming laryngospasm by electrostimulation involves a reflexive inhibition of the laryngeal adductors. This study provides an objective model for laryngospasm, and demonstrates that electrical manipulation of the vocal cords may have clinical relevance.

Animals↗
PubMed1989

[Experience and results with a lactate dehydrogenase marker in vaginal secretions of women at high risk for endometrial cancer].

The authors present and discuss the results obtained with 202 Gynaegnost experiments in 161 women, between 45 and 65 years, nulliparous, or having experienced a late pregnancy, with menopause occurring after the age of 52 and undergoing or not estrogen-therapy after menopause, and presenting high blood pressure, obesity or diabetes. The purpose of this multicenter study, to be continued, was to demonstrate the efficacy of this tumor marker, in the early diagnosis of endometrial carcinoma, in high-risk women.

Aged↗
PubMed1987

Isolation and characterization of a novel nonheme chloroperoxidase.

Chloroperoxidase, purified from the fermentation of Curvularia inaequalis, had a molecular weight of approximately 240,000 and was composed of 4 subunits of identical molecular weight (Mr 66,000). The enzyme was specific for I-, Br- and Cl-, and inactive toward F-. The optimum pH of the enzyme was centered around 5.0. X-ray fluorescence revealed that the enzyme contained 2.2 atoms of zinc and 0.7 atom of Fe per molecule of protein. The enzyme had no heme-like compound as a prosthetic group, making it the first nonheme chloroperoxidase to be reported. Under oxidative conditions that rapidly inactivated other haloperoxidases, this enzyme was remarkably stable.

Chloride Peroxidase↗
PubMed1985

Synthesis of bovine growth hormone in primates by using a herpesvirus vector.

A strain of herpesvirus saimiri containing a bovine growth hormone (bGH) gene under the control of the simian virus 40 (SV40) late-region promoter was constructed. This strain, bGH-Z20, was replication competent and stably harbored the bGH gene upon serial passage. Nonpermissive marmoset T cells persistently infected with bGH-Z20 produced a 0.9-kilobase RNA which contained all of the bGH exon sequences and appeared to initiate within the SV40 promoter region. However, in permissively infected owl monkey kidney cells, RNAs containing growth hormone sequences appeared to initiate from herpesvirus saimiri promoters positioned upstream from the SV40-growth hormone gene. Persistently infected T cells in culture secreted 500 ng of bGH protein per 10(6) cells per 24 h during the several months of testing. The secreted protein was 21 kilodaltons, the size of authentic bGH. New World primates experimentally infected with bGH-Z20 produced circulating bGH and developed immunoglobulin G antibodies directed against bGH. Because herpesviruses characteristically remain latent in the infected host, these observations suggest a means for replacing gene products missing or defective in hereditary genetic disorders.

Animals↗
PubMed1981

[Pure cutaneous cryptococcosis].

The authors present one case of cutaneous cryptococcosis, which diagnosis was confirmed by histopathologic and mycologic procedures. As there has not been systemic dissemination, this case must be considered uncommon. The lesions healed completely after treatment by amphotericin-B.

Amphotericin B↗