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Biomedical subjects

R M Pereira

Publications and source records attributed to R M Pereira.

At least 19 recordsLinked to original sources
PubMed2003

Mycobacterium simiae infection in a patient with acquired immunodeficiency syndrome.

Mycobacterium simiae is usually an environmental contaminant rarely associated with human disease. We report a fatal case of M.simiae infection in a 37 year old, HIV positive, male from whom the organism was isolated from blood culture. The identification of M.simiae was performed using DNA amplification followed by analysis on 3% agarose gel of the amplicon fragments after digestion by restriction endonucleases. The precise identification of mycobacterial isolates to the species level is important, with both epidemiological and therapeutic implications.

AIDS-Related Opportunistic Infections↗
PubMed2001

Viability and stability of biological control agents on cotton and snap bean seeds.

Cotton and snap bean were selected for a multi-year, multi-state regional (south-eastern USA) research project to evaluate the efficacy of both commercial and experimental bacterial and fungal biological control agents for the management of damping-off diseases. The goal for this portion of the project was to determine the viability and stability of biological agents after application to seed. The biological seed treatments used included: (1) Bacillaceae bacteria, (2) non-Bacillaceae bacteria, (3) the fungus Trichoderma and (4) the fungus Beauveria bassiana. Seed assays were conducted to evaluate the following application factors: short-term (< or = 3 months) stability after seed treatment; quality (i.e. isolate purity); compatibility with chemical pesticides and other biocontrol agents; application uniformity between years and plant species. For the bacterial treatments, the Bacillaceae genera (Bacillus and Paenibacillus) maintained the greatest population of bacteria per seed, the best viability over time and the best application uniformity across years and seed type. The non-Bacillaceae genera Burkholderia and Pseudomonas had the least viability and uniformity. Although Beauveria bassiana was only evaluated one year, the seed fungal populations were high and uniform. The seed fungal populations and uniformity for the Trichoderma isolates were more variable, except for the commercial product T-22. However, this product was contaminated with a Streptomyces isolate in both the years that it was evaluated. The study demonstrated that Bacillaceae can be mixed with Trichoderma isolates or with numerous pesticides to provide an integrated pest control/growth enhancement package.

Bacillaceae↗
PubMed2001

Effect of lipids and oleic acid on biomass development in anaerobic fixed-bed reactors. Part I: Biofilm growth and activity.

Two similar anaerobic fixed-bed bioreactors which allowed the biomass to be periodically withdrawn were run in parallel. After feeding each digester with synthetic dairy wastes of different lipid content (Period I), both digesters were fed with increasing sodium oleate concentrations with skim milk as co-substrate (Period II) and oleate as the sole carbon source (Period III). In Period I, the digester fed with lipids was more efficient and exhibited lower levels of volatile fatty acids than the digester fed without lipids. The biofilm built up in the presence of lipids was thinner, but more resistant to the presence of oleate than the biofilm formed in the absence of lipids, which lost 53% of its solids after contacting with oleic acid. The specific methanogenic activity with butyrate as substrate was enhanced in the presence of lipids, but no significant effect was detected on the acetoclastic and hydrogenophilic activities, which remained similar for both digesters along the trial period.

Anaerobiosis↗
PubMed2001

Effects of lipids and oleic acid on biomass development in anaerobic fixed-bed reactors. Part II: Oleic acid toxicity and biodegradability.

Oleic acid toxicity and biodegradability were followed during long-term operation of two similar anaerobic fixed-bed units. When treating an oleate based effluent, the sludge from the bioreactor that was acclimated with lipids during the first operation period, showed a higher tolerance to oleic acid toxicity (IC50 = 137 mg/l) compared with the sludge fed with a non-fat substrate (IC50 = 80 mg/l). This sludge showed also the highest biodegradation capacity of oleic acid, achieving maximum methane production rates between 33 and 46 mlCH4(STP)/gVS.day and maximum percentages of methanization between 85 and 98% for the range of concentrations between 500 and 900 mg oleate/l. When oleate was the sole carbon source fed to both digesters, the biomass became encapsulated with organic matter, possibly oleate or an intermediate of its degradation, e.g. stearate that was degraded at a maximum rate of 99 mlCH4(STP)/gVS.day. This suggests the possibility of using adsorption-degradation cycles for the treatment of LCFA based effluents. Both tolerance to toxicity and biodegradability of oleic acid were improved by acclimatization with lipids or oleate below a threshold concentration.

Biodegradation, Environmental↗
PubMed2001

Cortisol inhibits the differentiation and apoptosis of osteoblasts in culture.

Glucocorticoids decrease the replication of cells of the osteoblastic lineage and the function of the osteoblast. However, under certain conditions, they enhance the differentiation of osteoblastic cells, an effect that appears contradictory to their inhibitory actions on cell function. In this study we examine the effects of cortisol on the proliferation, differentiation, and fate of osteoblastic enriched cells from 22-day-old fetal rat calvariae (osteoblastic cells) in the absence and presence of beta-glycerophosphate. In the absence of beta-glycerophosphate, there was a progressive accumulation of DNA and cells, which was impaired by cortisol. In the presence of beta-glycerophosphate, there was an initial accumulation of DNA and cells followed by a marked decline that was prevented by cortisol. Despite the sustained number of cells, cortisol did not affect their mineralization, and inhibited Core binding factor a1 (Cbfa1), but not alkaline phosphatase, osteocalcin, or type I collagen transcripts. The decrease in cell number by cortisol observed in the absence of beta-glycerophosphate was due to a decrease in DNA synthesis, whereas the increase in cell number observed in the presence of beta-glycerophosphate was due to a relative increase in DNA synthesis and a decrease in apoptosis as determined by DNA fragmentation and acridine orange staining of the cells. This was correlated by a decrease in transcripts of proapoptotic genes and caspase 3 activity, and an increase of antiapoptotic genes. In conclusion, cortisol decreases the replication of cells of the osteoblastic lineage, but under conditions of differentiation/mineralization, cortisol prevents terminal differentiation of the cells and maintains an immature cell population.

Animals↗
PubMed2001

Effect of impact load and active load on bone metabolism and body composition of adolescent athletes.

PURPOSE: It is unclear whether adolescents involved in nonweight-bearing activities experience a delay in bone growth acquisition and sexual maturation. The purpose of this study was to compare bone mineral density (BMD), body composition, hormonal profile, and bone biochemical markers of adolescent athletes active in sports involved in impact load sports with those participating in active load sports. METHODS: Forty-five male Caucasian athletes aged 12--18 yr were divided into two groups according to type of skeleton loading, impact (N = 18), or active (N = 27). Twenty-four male Caucasian adolescents (12--18 yr) served as controls and only performed the activities included in their physical education classes. All subjects were assessed for bone mass, body composition, and bone age by dual x-ray absorptiometry (DXA). Serum calcium (Ca), phosphorus (P), bone-specific alkaline phosphatase (BAP), total testosterone, FSH, LH, urinary calcium to creatinine ratio (Ca/Cr), and urinary deoxypyridinoline crosslinks to creatinine ratio (DPD/Cr) were measured. RESULTS: The impact load group presented the highest BMD among the three groups for all studied sites. Lean mass and absolute weight were correlated with all of the bone mass measurements. BAP levels were significantly higher and testosterone levels significantly lower in the active load group compared with the impact group. CONCLUSION: High-impact load exercises have a beneficial effect on bone mass in male adolescents. There is also a positive correlation of weight and body composition with BMD. However, further longitudinal studies are necessary to determine whether there is a delay in bone growth acquisition among adolescents involved in a nonweight-bearing exercise regimen and its association with sex hormones.

Adolescent↗
PubMed2001

Growth hormone-releasing peptide-2 stimulates GH secretion in GH-deficient patients with mutated GH-releasing hormone receptor.

GH-releasing peptides (GHRPs) are synthetic peptides that bind to specific receptors and thereby stimulate the secretion of pituitary GH. In vivo it is uncertain whether these peptides act directly on somatotroph cells or indirectly via release of GHRH from the hypothalamus. In this study we compared the pituitary hormone response to GHRP-2 in 11 individuals with isolated GH deficiency (GHD) due to a homozygous mutation of the GHRH receptor (GHRH-R) gene and in 8 normal unrelated controls. Basal serum GH levels were lower in the GHD group compared with controls [0.11 +/- 0.11 (range, <0.04 to 0.38) vs. 0.59 +/- 0.76 microg/L (range, 0.04-2.12 microg/L); P = 0.052]. After GHRP-2 administration there was a 4.5-fold increase in serum GH relative to baseline values in the GHD group (0.49 +/- 0.41 vs. 0.11 +/- 0.11 microg/L; P = 0.002), which was significantly less than the 79-fold increase in the control group (46.8 +/- 17.6 vs. 0.59 +/- 0.76 microg/L; P = 0.008). Basal and post-GHRP-2 serum levels of ACTH, cortisol, and PRL were similar in both groups. Basal levels of serum TSH were significantly higher in the GHD group than in the control group (3.23 +/- 2.21 vs. 1.37 +/- 0.34 microIU/mL; P = 0.003). TSH levels in both groups did not change after GHRP-2 administration. These results suggest that an intact GHRH signaling system is not an absolute requirement for GHRP-2 action on GH secretion and that GHRP-2 has a GHRH-independent effect on pituitary somatotroph cells.

Adrenocorticotropic Hormone↗
PubMed2001

Effect of 17beta-estradiol or alendronate on the bone densitometry, bone histomorphometry and bone metabolism of ovariectomized rats.

The objective of the present study was to evaluate the effect of 17beta-estradiol or alendronate in preventing bone loss in 3-month-old ovariectomized Wistar rats. One group underwent sham ovariectomy (control, N = 10), and the remaining three underwent double ovariectomy. One ovariectomized group did not receive any treatment (OVX, N = 12). A second received subcutaneous 17beta-estradiol at a dose of 30 microg/kg for 6 weeks (OVX-E, N = 11) and a third, subcutaneous alendronate at a dose of 0.1 mg/kg for 6 weeks (OVX-A, N = 8). Histomorphometry, densitometry, osteocalcin and deoxypyridinoline measurements were applied to all groups. After 6 weeks there was a significant decrease in bone mineral density (BMD) at the trabecular site (distal femur) in OVX rats. Both alendronate and 17beta-estradiol increased the BMD of ovariectomized rats, with the BMD of the OVX-A group being higher than that of the OVX-E group. Histomorphometry of the distal femur showed a decrease in trabecular volume in the untreated group (OVX), and an increase in the two treated groups, principally in the alendronate group. In OVX-A there was a greater increase in trabecular number. An increase in trabecular thickness, however, was seen only in the OVX-E group. There was also a decrease in bone turnover in both OVX-E and OVX-A. The osteocalcin and deoxypyridinoline levels were decreased in both treated groups, mainly in OVX-A. Although both drugs were effective in inhibiting bone loss, alendronate proved to be more effective than estradiol at the doses used in increasing bone mass.

Alendronate↗
PubMed2000

Amplification of 9q34 in childhood adrenocortical tumors: a specific feature unrelated to ethnic origin or living conditions.

Adrenocortical tumors (ACT) in children under 15 years of age exhibit some clinical and biological features distinct from ACT in adults. Cell proliferation, hypertrophy and cell death in adrenal cortex during the last months of gestation and the immediate postnatal period seem to be critical for the origin of ACT in children. Studies with large numbers of patients with childhood ACT have indicated a median age at diagnosis of about 4 years. In our institution, the median age was 3 years and 5 months, while the median age for first signs and symptoms was 2 years and 5 months (N = 72). Using the comparative genomic hybridization technique, we have reported a high frequency of 9q34 amplification in adenomas and carcinomas. This finding has been confirmed more recently by investigators in England. The lower socioeconomic status, the distinctive ethnic groups and all the regional differences in Southern Brazil in relation to patients in England indicate that these differences are not important to determine 9q34 amplification. Candidate amplified genes mapped to this locus are currently being investigated and Southern blot results obtained so far have discarded amplification of the abl oncogene. Amplification of 9q34 has not been found to be related to tumor size, staging, or malignant histopathological features, nor does it seem to be responsible for the higher incidence of ACT observed in Southern Brazil, but could be related to an ACT from embryonic origin.

Adenoma↗
PubMed1998

Bone marrow findings in systemic lupus erythematosus patients with peripheral cytopenias.

We studied 21 bone marrow specimens from 21 patients with systemic lupus erythematosus (SLE) and peripheral cytopenias: anaemia (Hb < 10 g/dl), and/or leucopenia (white blood cell count < 4 x 10(9)/l), and/or thrombocytopenia (platelets < 150 x 10(9)/l). None of the patients had used immunosuppressive drugs in the 2 months before the study, and 11 (52.4%) had never used these drugs. The global and specific series cellularity, degree of fibrosis and necrosis were evaluated by bone marrow trephine; morphological abnormalities and iron stores were evaluated by cytological smears. The most important abnormalities viewed in bone marrow biopsies were: global hypocellularity (47.6%), increased reticulin proliferation (76.2%) with myelofibrosis in one patient, and necrosis (19.0%). The marrow aspirates were difficult to obtain in four patients, who showed an increased reticulin proliferation on histological analysis. Plasmocytosis was present in 26.7% of cases and in one there was a serum monoclonal component (IgG kappa). Iron stores were normal or increased in 26.7% of specimens and decreased or absent in 73.3%. The most frequent peripheral abnormality was leucopenia in 90.4% (19/21) and granulocytic hypoplasia was observed in 47.3% (9/19) of these patients. We conclude that the bone marrow may be a target organ in SLE with cytopenias.

Adolescent↗
PubMed1994

Psychiatric manifestations of systemic lupus erythematosus: clinical features, symptoms, and signs of central nervous system activity in 43 patients.

Forty-three female inpatients with active systemic lupus erythematosus (SLE) were studied by a multidisciplinary team to answer the following research questions: 1) What are the features of the psychopathology in patients with active SLE? and 2) In these patients, what is the relationship between psychiatric disorders and symptoms and signs suggesting activity of SLE in the CNS? Our a priori hypothesis was that, in patients with active SLE, those with psychiatric manifestations would have more symptoms and signs of CNS activity than those without psychiatric manifestations. Psychiatric evaluation consisted of standardized psychiatric instruments and diagnostic criteria. The assessment of SLE systemic and central nervous system (CNS) activity consisted of rheumatologic, neurologic, and ophthalmologic evaluations; serum and cerebral spinal fluid (CSF) analysis; brain computerized tomography (CT); and electroencephalogram (EEG). Twenty-seven patients (63%) presented psychiatric symptoms (Psychiatric Group), and 16 (37%) patients presented no current psychiatric diagnosis (Nonpsychiatric Group). These groups were compared in terms of the above variables. Depressive syndrome was the most frequent diagnosis (44%) followed by delirium (7%) and dementia (5%). Psychiatric symptoms were associated with subjective cognitive impairment (85%) and neurologic abnormality (85%). Widened cortical sulci was the most frequent CT alteration and was equally common in both groups. No statistical difference was found between the 2 groups regarding their general clinical evaluation, serum and CSF exams, or EEG alterations. To determine whether the severity of psychiatric symptoms was related to CNS activity, we divided the 27 patients with psychiatric manifestations into 2 groups: the Major Group--18 patients with major psychopathology, and the Minor Group--9 patients with mild depressive syndromes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Neutropenia associated with myelofibrosis in systemic lupus erythematosus.

Although myelofibrosis has been described in systemic lupus erythematosus (SLE), this coexistence must be rare since there are few reports showing this combination. The possible relationship between hematologic abnormalities and SLE remains unresolved. The authors describe a 39-year-old woman with persistent neutropenia and SLE in whom myelofibrosis was found. Unlike previously reported cases, myelofibrosis did not resolve with steroid therapy. In this report, the clinical course of the patient is compared with others described in the literature.

Adult↗
PubMed1993

Congenital malformation of the scalp and cranium after failed first trimester abortion attempt with misoprostol.

This study reports the occurrence of three cases of an unusual congenital malformation of the skull in neonates seen at a pediatric hospital during a five-month interval in Fortaleza, Brazil. The prenatal history focused on the mothers' exposure to drugs during pregnancy. It was found that all mothers had taken misoprostol orally and/or vaginally in the first trimester of pregnancy to induce abortion. Other drugs taken during pregnancy included iron, vitamins and tetanus toxoid. There was no evidence of a family history of malformations, consanguinity or clinical infective illnesses.

Abortion, Induced↗
PubMed1992

Pericardial tamponade in juvenile dermatomyositis.

Cardiac involvement in dermatomyositis has been well described; myocarditis and cardiac arrhythmias are the most frequent manifestations. An 8-year-old girl is presented, who developed pericardial tamponade in the course of the disease. It is the first time this association has been reported.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1992

Antiganglioside antibodies in patients with neuropsychiatric systemic lupus erythematosus.

Antiganglioside antibodies (AGA) were determined in sera and cerebrospinal fluids (CSF) from 50 systemic lupus erythematosus (SLE) patients, and age-matched normal controls. The SLE patients were subdivided according to the type of clinical manifestation into two groups: neuropsychiatric SLE and active SLE without neuropsychiatric manifestation. The presence of these antibodies showed a significant correlation between IgG AGA in the CSF and IgM AGA in the serum and neuropsychiatric SLE. Fifteen patients had this antibody in the CSF without detectable levels in the serum. No correlation was seen between anticardiolipin antibodies in the serum of CSF and neuropsychiatric SLE. The present work suggests that antibodies against gangliosides may be a marker for neuropsychiatric SLE and that intrathecal antibody production can result in the development of this manifestation.

Adolescent↗
PubMed1992

Arthritis as a manifestation of self-mutilation in childhood.

Traumatic arthritis resulting from self-aggression is rarely encountered in children. Differentiation from child abuse and common causes of childhood arthritis is difficult and rests upon a high level of suspicion. We describe a 10-year-old girl with hand deformities associated with joint pain and swelling managed as juvenile rheumatoid arthritis for 3 years. Reevaluation revealed both physical and radiographic evidence of recurrent trauma. Psychiatric assessment confirmed the diagnosis of autoaggression leading to self-mutilation and psychosocial rehabilitation was essential in successful management.

Arthritis↗
PubMed1990

Sonographic findings of adrenal cortical carcinomas in children.

Fourteen children with adrenal cortical carcinoma were evaluated by ultrasonography. The neoplasms, 2.5 cm-19 cm in maximum diameter, were all well circumscribed. The four smaller lesions were either homogeneously hypoechoic (2 patients) or generally hyperechoic (2 patients). In the 10 patients with larger tumors, a complex predominantly echogenic pattern was demonstrated, eight of which contained radiating linear echoes, the "scar sign". This finding, although not specific, when present in a large adrenal mass, is suggestive of a cortical carcinoma. Associated findings of vascular invasion or retroperitoneal adenopathy supported the diagnosis of a malignant adrenal neoplasm in 3 patients.

Adrenal Cortex Neoplasms↗