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Biomedical subjects

A Freitas

Publications and source records attributed to A Freitas.

At least 37 records · Page 2Linked to original sources
PubMed1997

Cladophialophora bantiana (Previously Cladosporium trichoides): First Report of a Case in Brazil.

Cladophialophora bantiana (Cladosporium trichoides) is a black fungus recorded rarely as a cause of brain abscess. Only 21 cases have been reported in the literature world-wide. We describe the first case seen in Brazil. A 30 year old, previously healthy female, HIV negative, came to the hospital with a clinical diagnosis of brain tumor. After biopsy and culture of the lesion, it was found that she had an abscess due to Cladosporium trichoides. During the following five months, the patient underwent three more surgical brain interventions to totally remove the area of compromised tissue. In addition to surgery, amphotericin B, both intravenously and intrathecally, was used followed by itraconazole orally, without success. Six months after the first surgical intervention, the patient died. The worldwide experience with diagnosis and treatment of patients with this diseases is reviewed.

Journal Article↗
PubMed1996

Murine acariasis. II. Immunological dysfunction and evidence for chronic activation of Th-2 lymphocytes.

The authors describe the immunological profile of BALB/c mice with Mite-Associated Ulcerative Dermatitis (MAUD)-like disease, due to Myocoptes musculinus (Koch 1844) infestation. The disease probably involves allergic mechanisms and is characterized by erythematous and pruritic skin lesions, widespread hair loss, lymphadenopathy, lymphocytopenia, granulocytosis and wasting. Affected individuals had much reduced numbers of pre-B and B cells in bone marrow and B cells in blood; decreased T-cell numbers in peripheral lymphoid organs and blood; hypergammaglobulinaemia with selective increases of IgG1, IgE and IgA, and depletion on IgM and IgG3, the same isotype distribution being detected in splenic plasmocytes; qualitative modifications of the serum antibody reactivity pattern; and increased production of IL-4 with decreased IL-2 production after in vitro polyclonal stimulation of T cells. Taken together, these results suggest that infestation by M. musculinus in BALB/c mice leads to a significant immunological disorder resulting in a T-helper-2 (Th-2) type response, with marked systemic consequences. This pathological condition may thus provide a useful model system for the immunobiological perturbation associated with chronic allergic disease.

Animals↗
PubMed1996

Gift-giving among gay men: the reification of social relations.

Previous work on gift-giving has shown the economic and social importance of this activity, ways in which it may reflect social relations, and characteristics of good and bad gift exchanges. This study examined gay gift-giving experiences to determine whether some of the propositions based almost exclusively on heterosexual data needed reinterpretation to be relevant to the homosexual community. It was found that, compared to previous research on gift-giving between heterosexual partners, gay males devoted more attention to selection or creation of gifts and they were also more concerned about the recipient's appreciation and utilization of the gift. On the other hand, they were less concerned with economic equity in the exchange process. These findings have implications for products offered as gifts as well as gift promotions that would be most suitable for this market.

Adolescent↗
PubMed1996

Communities, commodities, cultural space, and style.

This article explores the interconnections between queer communities and cultural space(s) in the context of style. Visibility issues and politics have become important to gay communities in the U.S. Gays and lesbians use clothing and appearance style to signal membership in or separation from specific cultures or communities. Within commodity capital, the heuristic categories of 'subculture' and 'target market' describe space or spaces that gays and lesbians occupy, and often occupy differently, based on self positionality within gay cultures, within commodity capital, and in relation to gender-specific discourse. Based on in-depth interviews with 60 lesbians and gays, this paper illuminates the ambivalences gays and lesbians express in embracing 'subculture' and 'target market' as categories to establish differences and fashion identities within the current cultural economy.

Culture↗
PubMed1994

Heart rate variability in 24-hour Holter recordings. Comparative study between short- and long-term time- and frequency-domain analyses.

Mean hourly parameters obtained from all beats (long series) were compared with those obtained from a sample of 512 beats extracted each hour (short series) in nine presumably normal subjects. For both the short and long series, the spectral components, very low frequency, (VLF), low frequency (LF), and high frequency (HF), and time-domain indices (such as the Ewing statistic [PNN50] and RR standard deviation [SD-RR]), have been estimated. The spectral components LF and HF, estimated from the short and long series, were not significantly different, whereas significant differences were found between VLF, SD--RR, and PNN50. In both the short and long series, a strong correlation was found between LF and SD-RR and between HF and PNN50. The results suggest that, over a period of 24 hours, hourly LF and HF spectral components can be obtained using a single series of 512 beats every hour, with a great advantage over the evaluation of the mean hourly parameters. This method would be particularly useful in the study of circadian heart rate spectral analysis in Holter recordings with multiple artifacts or ectopic beats, and in general, when analysis of the entire 24-hour series is not feasible.

Adult↗
PubMed1993

Analysis of VH gene utilisation in the non-obese diabetic mouse.

The immunoglobulin (Ig) heavy chain variable (VH) gene complexity and the VH gene utilisation pattern of the non-obese diabetic (NOD) mouse were investigated. We found that the NOD mouse displays a VH gene complexity which appears to be identical to that of the C57BL/6 mouse. Thus, Southern hybridisation using probes specific for 9 of the murine VH gene families revealed identical restriction fragment length polymorphism (RFLP) patterns in both mouse strains. As indicated by immunofluorescence analysis using allotype specific monoclonal antibodies the NOD mice were also found to carry the IgCH-1b allele. Collectively, these data suggest that the NOD mice carry an IgVH locus identical to that carried by C57BL/6. In contrast to the apparent identity at the level of germline VH gene repertoires, the pattern of VH gene utilisation differed considerably between these two mouse strains. Thus, in NOD mice the neonatal preference of D-proximal VH genes was found to be more pronounced than in C57BL/6 mice. Moreover, in contrast to adult C57BL/6 mice a D-proximal bias was evident also in adult NOD mice. On the basis of these findings we discuss the possibility that the distorted development of B cell repertoires in the NOD mouse could be directly or indirectly related to the T cell mediated, autoimmune process in the NOD mouse.

Alleles↗
PubMed1993

The physiology of bcl-2 expression in murine B lymphocytes.

Quantitation of bcl-2 gene expression in B-lineage lymphocytes from normal adult mice allows the identification of four cell populations, characterized by successive three- to fivefold increases in average mRNA levels: bone marrow pre-B cells, bone marrow B cells, splenic B cells and long-lived splenic B cells. Thus, in line with previous experiments using overexpression systems, a correlation between longevity and levels of bcl-2 mRNA exists also in the physiology of B-lineage cells. The data are compatible with a quantitative regulation of expression, possibly determined at selective differentiation steps. No difference in bcl-2 expression was detected by comparing splenic IgD+ with IgD- B cells, while distinctly low levels of bcl-2 mRNA were scored in peritoneal CD5+ and CD5- B cells. These observations indicate that the reported persistence of peritoneal B cells may be controlled by mechanisms other than bcl-2 gene expression.

Animals↗
PubMed1993

[Cardiological changes in candidates for sports].

OBJECTIVES: To evaluate the incidence and the clinical significance of the cardiologic abnormalities detected in candidates to competitive sports. DESIGN: Retrospective study of candidates to competitive sports who were evaluated for heart fitness. SETTING: Out patient cardiologic clinic in a Center of Sports Medicine in Lisbon. PATIENTS AND METHODS: 420 subjects out of a population of 6795 were followed up for one year. They underwent clinical evaluation with ECHO (M mode, 2D, Doppler), 24 hours Holter monitoring and Exercise Tests as indicated for decision concerning fitness and adequacy for the practice of competitive sports. RESULTS: Main reason for observation was the assessment of the significance of cardiac murmur (265; 6.3%). 14 cases of organic heart disease were diagnosed: 9 bicuspid aortic valves (2 with systolic gradient over 40 mmHg), 2 with atrial septal defects, 2 significant mitral valve prolapse and 1 ventricular septal defect. 86 patients were evaluated because of ECG abnormalities; 26 out of these presented ventricular ectopic beats, 6 had delayed AV conduction (PQ > 0.24 sec), 44 developed non specific STT changes and 16 a pre-excitation (WPW) tracing. Holter studies demonstrated 8 cases of complex ventricular premature beats and one case of paroxysmal atrial tachycardia. Arterial hypertension was the reason for evaluation of 20 athletes, 5 of whom were considered unfit due to hypertensive response to effort and/or systemic involvement. CONCLUSIONS: The evaluation of heart murmurs was the principal reason to evaluate candidates to the practice of sports. The large majority were considered innocent murmurs. Ventricular premature beats, non specific repolarization changes and pre-excitation (WPW) were the predominant electrocardiographic abnormalities. There was a remarkably low incidence of organic heart disease in the latter group. The most common reasons to declare unfitness for competitive sports practice were repetitive ventricular ectopic beats and arterial hypertension.

Adolescent↗
PubMed1992

On the origin of natural IgM in immunoglobulin transgenic mice.

Surface transgenic IgM was expressed by > 95% of small resting splenic B cells but only by 50% of CD5+ and CD5- peritoneal B cells from the mu-transgenic mouse line M54. Transgenic male M54 were crossed with female CBA/N mice carrying the Xid defect. Offspring F1 animals carrying the transgene were analysed for the presence of transgenic and endogenous IgM expressed both in the serum as well as on the surface of splenic and peritoneal B cells. We found that the levels of serum IgM coded for by the transgene were similar in both F1 male, which lack CD5 B cells, and female transgenic mice, which have CD5 B cells. Thus, the Xid defect does not influence the expression of the transgene at the level of naturally activated plasma cells, a finding substantiated by the fact that both male and female naturally activated splenic plasma cells express the transgene at the same frequency. F1 hybrid mice, like transgenic C57BI/6 M54 mice, have naturally activated splenic plasma cells that overexpress endogenous IgM coded for by the VH gene family Q52. The data indicate that normal serum IgM is not derived from CD5+ B cells and that the serum IgM coded for by the mu-transgene from M54 is produced at normal levels even in the male F1 mouse which lacks CD5+ B cells.

Animals↗
PubMed1992

[Functional and anatomic involvement of the right ventricle in arterial hypertension].

The early cardiac involvement is well known in arterial hypertension, particulary the diastolic and left ventricular hypertrophy. The right ventricle and pulmonary circulation may likewise be affected early in the course of disease. Scarce though it is, studies on the right repercussion of hypertension have shown an increase in pulmonary resistance and right-sided pressures in hypertensive patients. In spite of the limitations arising from the complex geometry of the right ventricule, echocardiography may be the most important non-invasive technique in the evaluation of the structural and functional repercussion of hypertension on the right ventricle. Our studies have revealed an increase in the diastolic thickness of the right ventricular free wall in hypertensive patients, as well as a good correlation between the diastolic thickness of the free walls of both ventricles. Most studies suggest a functional relationship between both ventricles. Structural alterations may occur in the right ventricle, along with hemodynamic alterations, thus suggesting structural and functional similarity of both ventricles, regarding cardiac response to arterial hypertension.

Cardiomegaly↗
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

Normal serum immunoglobulins influence the numbers of bone marrow pre-B and B cells.

The homeostatic mechanisms controlling B lymphocyte output from bone marrow are not well understood. The present experiments evaluated putative influences of circulating immunoglobulins (Ig) on bone marrow (BM) pre-B and B cell populations. Injections into normal mice of Ig isolated from normal mouse serum, resulted in a dose-dependent and reversible reduction in numbers of BM B lineage cells, in particular of small B220+ surface IgM- cells. Maximal effects were observed upon injection of isologous polyclonal Ig and were independent of mature T cells. These results suggest a feedback modulation of peripheral Ig on cellular activities in BM B lineage compartments, mediated by mechanisms that seem to involve the variable regions of the Ig molecule.

Animals↗
PubMed1991

Clonal persistence of B lymphocytes in normal mice is determined by variable region-dependent selection.

Many adult splenic B cells die within 1 week in the spleen of adoptive adult recipient mice; in contrast, the cellular environment of newborn recipients allows for their expansion and persistence for several weeks. In the present study, we show that the local environment of adult peritoneal cavity also allows adult splenic B cells to persist for over 2 weeks after intraperitoneal transfer. In order to determine whether the persistence of donor B cells in newborn hosts and in the peritoneum of adult recipients results from a selection process involving the clonal specificities expressed, the variation in time of VH gene family repertoires of donor B cells was analyzed in the hosts. At different times after the transfer of splenic cells from lipopolysaccharide (LPS)-reactive mice into LPS-non responder histocompatible recipients, mRNA colony blot assays were performed. The results show that among the donor adult LPS-reactive B cells, the VH genes are differently used by the expanding or persisting B cells, in both kinds of recipients. Thus, cells expressing J558 or VH11 gene families are, in particular, positively selected, while those expressing D-proximal or J606 and 36-30 VH gene families are less selected. These findings demonstrate that the propensity of B cells to persist and expand is determined by their selection through their immunoglobulin variable regions, rather than by genetic properties linked to particular B cell subsets.

Animals↗
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↗