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Biomedical subjects

S Barbosa

Publications and source records attributed to S Barbosa.

12 recordsLinked to original sources
PubMed2000

Short-term ventricular volume changes on serial MRI in multiple sclerosis.

Axonal loss is likely to be an important component of atrophy and the pathological substrate for the fixed disability of MS. To estimate the rate of central white matter reduction we investigated ventricular volume change and disease activity on monthly MRI in 19 patients over 6 months. At baseline, ventricular volumes were largest in primary progressive MS and smallest in relapsing-remitting MS. Over the study period ventricular volumes increased overall by 0.2% (F= 2.75, P = 0.02), but the percentage changes in relapsing-remitting MS were much larger (median increase 14.9%). Lesion volumes were also highest at baseline in relapsing-remitting MS, but serial changes in ventricular volumes were not correlated with serial changes in lesions. This study shows that ventricular enlargement in MS may occur over short epochs, particularly in relapsing-remitting cases. However, the loss of central white matter volume observed in any brief period may be related to inflammatory activity that occurred in a preceding or earlier epoch, a delayed post-inflammatory degenerative process, or most likely, a combination of both.

Adult↗
PubMed1999

Parental attachment and identity in Portuguese late adolescents.

Based on a life-span attachment perspective and on identity status paradigm, this study investigated the relationship between attachment and identity in a sample of 361 Portuguese late adolescents as a function of parental and adolescent gender. The results indicated gender differences in the association between attachment variables and identity foreclosure. Although adolescents tended to report close emotional bonds with both parents, relationships with mothers seemed to play an important role in the tendency for foreclosure identity in boys. Adolescents who were in diffusion reported the least secure parental attachment and experienced the least separation anxiety. Parental inhibition of exploration and individuality, as perceived by adolescents, did not correlate with the identity dimensions.

Adolescent↗
PubMed1996

Retinal venous sheathing and the blood-retinal barrier in multiple sclerosis.

OBJECTIVE: To assess the temporal relations among retinal appearance, disruption of the blood-retinal barrier, clinical subgroup, disease course, and disruption of the blood-brain barrier in multiple sclerosis. DESIGN: A 6-month prospective study involving monthly clinical ocular examinations, color fundus photography, fundus fluorescein angiograms, and magnetic resonance brain scans with gadolinium-diethylenetriamine-pentaacetic acid (Gd-DPTA) enhancement. SETTING: University-based ophthalmology and neurology departments. PATIENTS: Twenty-three patients with relapsing-remitting, primary-progressive, or secondary-progressive multiple sclerosis. RESULTS: Retinal venous sheathing was seen in six patients. The appearances observed included focal venous sheathing, diffuse venous sheathing, sheathing centered on sites of arteriovenous crossover, and focal perivenous hemorrhage. Arteriolar sheathing was also observed in one patient. Venous leakage on fundus fluorescein angiogram was detected in three patients, all of whom also had sheathing. The following three patterns of disruption of the blood-retinal barrier were seen on fundus fluorescein angiogram: focal leakage, extensive leakage, and very late wall staining. In one patient, the leakage was transitory. No correlations were observed between ophthalmologic features and multiple sclerosis clinical subgroup, disease course, or the number of new (Gd-DTPA-enhancing) lesions on magnetic resonance imaging. CONCLUSIONS: Disruption of the blood-retinal barrier, like the more frequent disruption of the blood-brain barrier seen on magnetic resonance imaging, is often unrelated to clinical neurologic relapses and occurs with apparently similar frequency in different patients independent of clinical disease course.

Adult↗
PubMed1994

Magnetic resonance relaxation time mapping in multiple sclerosis: normal appearing white matter and the "invisible" lesion load.

Prolonged T1 and/or T2 relaxation times (RT) in the normal appearing white matter (NAWM) of patients with multiple sclerosis (MS) have been attributed either to a diffuse abnormality, or to "small lesions" undetected by visual inspection of conventional MR images. In a comparison of brain slices from five MS patients and five healthy control subjects, we have confirmed that the average T1 and T2 RTs obtained from NAWM in patients with MS are significantly prolonged (p < .04). Quantitative pixel-by-pixel mapping shows that this overall prolongation is due to the averaging of RTs from two subfractions of NAWM. In all patients a proportion (average 54% for T1 and 63% for T2) of the total white matter pixel sample from each MR brain slice had RT values indistinguishable from those found in the white matter of matched healthy control subjects (i.e., "normal normal appearing white matter," NNAWM). Scattered throughout the NAWM were multiple small areas, often of only one or two pixels, with abnormal RT values. These lesions, which were revealed only by pixel-by-pixel mapping of RT, made up a significant proportion (average 47% for T1 or 57% for T2 estimates) of the total (visible plus "invisible") lesion load per slice, and of the NAWM (average 36% for T1, 27% for T2), with wide interpatient variability. Further studies of these minute lesions are required to determine their total volume in the brain, their precise nature, evolution and relevance to the functional deficit in MS.

Brain↗
PubMed1993

Histologic and histometric responses to polymeric composite grafts.

The present study was designed to determine whether a polymeric composite promotes new attachment in artificially-induced bony defects in the dog model. HTR, hard tissue replacement, is a non-resorbable calcium-layered polymer of polymethyl-methacrylate and hydroxyethyl-methacrylate. It has been reported to be clinically non-inflammatory, osteophilic, and osteoconductive. For the study, 4 beagle dogs, 4 to 6 years old with no periodontal disease were used. Mucoperiosteal flaps were raised including the 2nd, 3rd, and 4th maxillary premolars. Buccal Class II furcation defects were created on these premolars. Reference notches were placed in the roots at the level of the bony defects. Test quadrants were selected by the toss of a coin, and furcations were filled with the polymeric composite particles wetted with sterile saline. Following grafting, the flaps were approximated and sutured. The contralateral side, serving as control, was treated by flap debridement only. Sutures were removed 7 days after surgery. Dogs were sacrificed 4 months following surgery. Mesio-distal histological sections were evaluated by descriptive histology. In addition, surface area determinations (in mm2) of the furcal tissues were carried out using the microscope attached to a digitizer and a computer. In 8 mesio-distal serial sections cut 30 microns apart in both experimental and control teeth, surface area determinations relative to the furcations were made evaluating: 1) the total fill of the furcation; 2) the area filled with alveolar bone; 3) the area occupied by connective tissue; 4) the area occupied by new deposited cementum; and 5) the area filled by epithelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Bone Loss↗
PubMed1989

Qualitative and quantitative defects of thyroglobulin resulting in congenital goiter. Absence of gross gene deletion of coding sequences in the TG gene structure.

Seven subjects belonging to three families (ME, MA, MO), with congenital goiter and various degrees of thyroid hypofunction, were investigated from the standpoints of clinical, biochemical, and molecular biology. In two of these families (ME, MA), 6 individuals had low serum levels of Tg-related antigens with a minor increase after bovine TSH (bTSH) stimulation. A large proportion of the tracer was incorporated into serum albumin, and Tg antigens in the thyroid extracts were barely detectable by RIA. (0.19 mg/g tissue; normal, 70-90 mg/g). Gel filtration (CL6B Sepharose gel) showed absence of a normal Tg peak, and SDS agarose gel electrophoresis indicated complete absence of Tg dimer and monomer. Immunoelectrophoresis confirmed the absence of Tg-related antigens. Thus, in these patients a quantitative defect of Tg gene expression was characterized. By contrast, in the MO family a high basal serum concentration of immunoreactive Tg was present, with an exaggerated response to bTSH. Thyroid extracts revealed elevated TPO activity and normal levels of Tg-related antigens. Tg was also eluted in the gel filtration columns with the same mobility as standard 19S Tg. Immunoelectrophoresis against rabbit and human Tg was abnormal, with two precipitin arcs being detected. The Tg molecule after hydrolysis yielded only DIT and MIT, with poor formation of iodothyronines. Microscopic studies revealed a pronounced lack of colloid in the follicular lumina, and overdistended endoplasmic reticulum cisternae.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Genitourinary tuberculosis. A study of 1117 cases over a period of 34 years.

One thousand one hundred and seventeen patients with genitourinary tuberculosis who were treated over a period of 34 years have been reviewed. During this time various regimens of treatment were used and have been evaluated. Emphasis is placed on the results of the group on short-course chemotherapy which has been in use since 1970 and is now standard practice. This group has been carefully studied, as the chemotherapeutic combinations are important to developing countries. The clinical response, sterilisation of urine, urinary reversion, drug toxicity and the place of surgery in relation to modern chemotherapy have been discussed and assessed. They show that the results of short-course chemotherapy are satisfactory and confirm that there is no need to extend chemotherapy beyond 4 months, except in unusual circumstances.

Adult↗
PubMed1975

Persistent atrial standstill.

The authors present a case of permanent atrial standstill with syncopal attacks, in a patient with chronic Chagas' Heart Disease. The recognition of this dysrhythmia was based upon the conventional and intracavity electrocardiographic tracings in addition to phonomecanographic and hemodynamic data. The recording of the His Bundle electrogram demonstrated the absence of atrial activity, with the His potential preceding all ventricular complexes and an advanced conduction defect distal to the bundle of His. A diffuse type of atrial involvement was suggested by the lack of response to pacemaker stimulation. An increase in ventricular rate following intravenous atropine administration, led to the diagnosis of an a-v junctional rhythm with a widened QRS complex due to an associated right bundle branch block. Following the implantation of an epicardial ventricular pacemaker, the patient became completely asymptomatic despite the persistence of electrical and mechanical atrial standstill.

Adult↗
PubMedDate not supplied

Weber's syndrome and sixth nerve palsy secondary to decompression illness: a case report.

We describe the first case of Weber's Syndrome to present as a manifestation of decompression illness in a recreational scuba diver. Weber's Syndrome is characterized by the presence of an oculomotor nerve palsy and contralateral hemiparesis. The patient was a 55 year-old male with a past medical history of a pulmonary cyst, in whom symptoms developed after a multilevel drift dive to a depth of 89 feet for 53 minutes, exceeding no-decompression limits. Symptom onset was within 30 minutes of surfacing and included the Weber's Syndrome, a sixth nerve palsy, dizziness, nausea, sensory loss, and ataxia. The patient received four U.S. Navy Treatment Tables with complete resolution of all neurological signs and symptoms. The mechanism of injury remains unclear, but may involve aspects of both air gas embolism and decompression sickness. Individuals with pre-existing pulmonary cysts may be at increased risk for dive-related complications.

Abducens Nerve Diseases↗