[Primary lymphomas of the brain not related to immunodeficiency]

Primary brain lymphoma (PBL) is a rare disease, the study of which is based on small series and case reports. The AA review new cases of PBL not associated to immunodeficiency at the Portuguese Institute of Oncology of Porto since 1978. Five male patients were found with lymphoma primarily located in the brain, with aggressive histology, IE staging, detected by CAT, NMR or brain scintigraphy and with histologic material collected by stereotaxic biopsy (3 cases) or by craniotomy (2 cases). Three patients were in complete remission (25,5 and 1 year) and 2 were dead with a survival of 12 and 17 months. The cases and literature are discussed.

Cerebral toxoplasmosis after renal transplantation. Case report and review

Infection caused by Toxoplasma gondii is a frequent event in Portugal. When this occurs in immunocompetent individuals, it is rarely a matter of concern; the contrary occurs with immunosuppressed patients or in pregnancy. Transplant patients are treated with immunosuppressive drugs which mainly disturb their mechanisms of cellular immunity, and that opens the way to infections by opportunistic intracellular microorganisms. We recently treated a renal transplant patient who suffered from cerebral toxoplasmosis, and this provided an opportunity for a review of the other 20 patients reported in medical literature to date.

A model for gene evolution of the ets-1/ets-2 transcription factors based on structural and functional homologies

The chicken c-ets-1 locus encodes two transcription factors, p54c-ets-1 and p68c-ets-1 that differ in their N-termini, encoded respectively by the I54 and alpha beta exons. p68c-ets-1 equivalents are only found in birds and reptiles while p54c-ets-1 is widely conserved in vertebrates, from amphibians to mammals. Thus, the classical view concerning the evolution of the c-ets-1 gene has been to consider that I54 is of ancient origin whereas alpha and beta, which provide an additional activating domain in p68c-ets-1, would have been acquired much more recently. Sequencing the alpha and beta exons in various species pinpointed a highly conserved region of 13 amino acids which is rich in acidic and hydrophobic residues, a feature of some other transactivating domains. Strikingly, this subdomain is also present in the otherwise unrelated N-terminal activating region of p58c-ets-2 and was thus named BEC for Ets-1-beta/Ets-2-Conserved sequence. Moreover, the two N-termini share the BEC sequence at a homologous position in their highly similar genomic organization indicating a common origin. This structural homology underlies a functional similarity since fusion of the heterologous GAL4 DNA-binding domain with either of the two isolated domains demonstrates that BEC is essential in both cases for the transactivating activity. The function of the alpha beta domain in the context of p68c-ets-1 also strictly depends on the presence of the BEC sequence. Finally, the whole N-terminus of p58c-ets-2 can functionally substitute for its counterpart in p68c-ets-1 further demonstrating that p68c-ets-1 and p58c-ets-2 are structurally and functionally more closely related than previously thought. Besides, we also found BEC in the N-terminus of the Drosophila pointed gene which may be considered as closely related to the uncommitted 'ets1/2' common ancestor. These data demonstrate that the alpha and beta exons are not a recent and specific acquisition but stem, like the p58c-ets-2 N-terminus, from the invertebrate unduplicated 'ets 1/2' gene. This work unravels a new model for the ets-1/ets-2 gene's evolution, based for the first time on both structural and functional evidences. Accordingly, p68c-ets-1 and p58c-ets-2 are the direct descendants of the ancestral 'ets1/2' gene whereas I54 may have been acquired as a second promoter in the c-ets-1 gene after the duplication. Indeed, I54 is not found in the Drosophila pointed gene. The high degree of similarity, and hence of functional redundancy, between p68c-ets-1 and p58c-ets-2 may have led to the rapid divergence (and even loss in mammals) of alpha and beta during evolution whereas I54, which provided a novel function unique to c-ets-1, was maintained within the presently widespread p54c-ets-1 version.

Identification and analysis of the chicken c-mil promoter: possible involvement of Sp1- and Ets-related proteins

We have determined the exon organization in the 5' region of the chicken c-mil gene and identified its promoter. A 0.44-kb fragment containing the 5' terminus of the c-mil gene showed strong promoter activity when placed upstream of the bacterial chloramphenicol acetyltransferase gene and transfected into chicken embryo fibroblasts (CEF). By primer extension analysis, multiple transcriptional start sites were detected within the promoter region. Nucleotide sequence analysis revealed that the c-mil promoter had a high G + C content (71.8%) and contained multiple GC box-like sequences, but no TATA or CAAT boxes. Deletion analysis of 5' upstream sequences showed that the minimal region required for maximal promoter activity in CEF resides in the 99 bp located immediately upstream of the major initiation site. This region contains two putative Sp1 binding sites and one PU box/PEA3 motif, defined as a recognition element for members of the Ets gene family. These sequences bound proteins present in nuclear extracts of CEF as well as in vitro synthesized Ets-related proteins, suggesting that the binding of Sp1 or related proteins and of Ets-related proteins within the promoter is important for modulation of the mil gene.

[Cerebral toxoplasmosis in a kidney transplant patient. A clinical case and review of the literature]

Infection caused by Toxoplasma gondii is a frequent event in Portugal. When this occurs in immunocompetent individuals it is rarely a matter of concern; the contrary occurs with immunosuppressed patients or in pregnancy. Transplant patients are treated with immunosuppressive drugs which mainly disturb their mechanisms of cellular immunity, and that opens the way to infections by opportunistic intracellular microorganisms. We recently treated a renal transplant patient who suffered from cerebral toxoplasmosis, and this provided an opportunity for a review of the other 20 patients reported in medical literature to date.

[Resistance to antibiotics of vibrio cholerae strains isolated in Angola]

Among 87 strains of Vibrio choleare (78 Ogawa serotype and 9 Inaba serotype strains) isolated in Angola in 1987-1990, 86% exhibited multiple resistance to antimicrobials. Eighty-four to 86% of strains were resistant to ampicillin with beta-lactamase production (MIC greater than or equal to 512 mg/l), streptomycin (MIC greater than or equal to 64 mg/l), spectinomycin (MIC greater than or equal to 1,024 mg/l), and trimethoprime-sulfisoxazole (MIC greater than 1,024 mg/l). Seventy-four per cent of strains were resistant to kanamycin (MIC = 512 mg/l), 26% to chloramphenicol (MIC = 32 mg/l), 10% to tetracycline (MIC = 16 mg/l), and 10% to gentamycin (MIC greater than or equal to 32 mg/l). Transfer to E. coli K12 was associated with a substantial increase in expression of resistance to tetracycline and chloramphenicol (CAT type I), with MICs in the 128-512 mg/l range. Transfer rates to E. coli K12 of plasmids for the various resistance phenotypes were 10(-6)/10(-8). The size of the isolated plasmids was 100 Md in diameter and belonged to the incompatibility group inc 6-C.

[The pathogen spectrum and its resistance behavior in children with urinary tract infections in Angola]

In 225 children (135 boys, 90 girls) suffering from clinical relevant urinary tract infection the bacterial spectrum and resistance behaviour to routinely used antibiotics were evaluated. In 65.4% of the patients a significant bacteriuria was found: E. coli (34.6%), proteus (22.3%), klebsiella (14.6%), citrobacter (9.2%), enterobacter (5.4%) and pseudomonas (5.4%). In testing a high resistance of bacterias to trimethoprim/sulfamethoxazol, ampicillin, and gentamycin was found, whereas good susceptibility was found to nitrofurantoin and nalidixin acid.

[Primary antiphospholipid syndrome: clinical experience of 6 patients]

Recently, the association between anti-phospholipid antibodies (false positive VDRL, lupus anticoagulant or anti-cardiolipin antibody) and diverse clinical manifestations has been termed antiphospholipid syndrome. We report 6 female patients with "primary" antiphospholipid syndrome, not related to connective tissue disorders. Their age ranged from 23 to 66 years and they were followed from 1 to 27 years (mean 9.2). Venous occlusion developed in 4, arterial occlusion in 4 (TIA, convulsive episode and cutaneous thrombotic microangiopathy). Three of 5 had fetal loss and 3/6 developed thrombocytopenia. Leg ulcer, migraine and mitral valvulopathy and peripheral facial paralysis were isolated manifestations in different patients. High titers for type IgG anticardiolipin antibodies were present in all patients. Low titers for IgM antibodies were present in 2. The pathogenesis of this syndrome is discussed.

An alternatively spliced c-mil/raf mRNA is predominantly expressed in chicken muscular tissues and conserved among vertebrate species

The chicken c-mil gene produces two mRNA species generated by an alternative splicing mechanism. These two transcripts differ at least by the presence or absence of a 60 nucleotide exon (E7a) localized at the splice junction of c-mil exons 7 and 8. By using RNAase protection assays, we have analysed the pattern of expression of these two mRNA species in several chicken tissues. Here we report that the two c-mil mRNAs are differentially expressed in chicken tissues: the mRNA lacking E7a is detected in all tissues tested, while the mRNA containing E7a is detected only in the skeletal muscle, heart and brain. Sequences homologous to E7a have also been detected in DNAs from quail, mouse and human cells and their sequencing revealed that the alternative E7a is structurally preserved in these species. By PCR analyses performed on RNAs extracted from muscular tissues of these species, we also show that the alternative splicing mechanism described in chicken also occurs in these species.

Hereditary protein C deficiency and portal-vein thrombosis

Inherited defects of the natural coagulation inhibitors predispose patients to thrombosis. These disorders have similar clinical presentations with a strong family history of thrombosis, episodes of recurrent venous thromboembolism, beginning in early adulthood. We report a case of upper gastrointestinal bleeding in a patient with portal hypertension due to portal-vein thrombosis secondary to hereditary protein C deficiency, an association that has seldom been reported.

[Hereditary protein C deficiency and portal vein thrombosis]

Inherited defects of the natural coagulation inhibitors predispose patients to thrombosis. These disorders have similar clinical presentations with a strong family of thrombosis, episodes of recurrent venous thromboembolism, beginning in early adulthood. We report a case of upper gastrointestinal bleeding in a patient with portal hypertension due to portal-vein thrombosis secondary to hereditary protein C deficiency, an association that has seldom been reported. We conclude that protein C deficiency should be investigated in thrombotic states, namely after more frequent causes have been excluded.

[Hemodynamic profile of patients with normal coronary cineangiography]

The authors reviewed 1474 consecutive selective coronary arteriograms performed on patients with suspected coronary insufficiency for the diagnosis of obstructive coronary disease and found 281 (19.1%) cases of apparently normal coronary arteries. These patients presented mean age of 47 +/- 10 years; they were 135 (48%) males and 146 (52%) females. The objective of this study was to obtain the hemodynamic profile of these patients for the following parameters: a) aortic and left ventricular pressures; b) volumes, ejection fraction, segmentary contraction, wall thickness and mass of left ventricle; c) morphology, mobility and competence of the mitral valve. Eight groups of patients were selected: 1) without hemodynamic alterations - 18.9%; 2) with systemic arterial hypertension - 48.7%; 3) with abnormal myocardial contraction - 16.7%; 4) with idiopathic left ventricular hypertrophy - 6.4%; 5) with mitral valve prolapse - 2.5%; 7) with myocardial bridge of the left anterior descending coronary artery - 1.8%; 8) with coronary arterial microfistula of the left ventricle - 0.4%. It is desirable to determine before situations of cardiac emergencies, whether provoked ischemia, as detected by noninvasive stress testing, is present before the performing coronary arteriography in patients, specially females, with systemic arterial hypertension, left ventricular hypertrophy, disorders of ventricular contraction or mitral valve prolapse.

Cardiomyopathy in Cebus apella monkeys experimentally infected with Trypanosoma cruzi

Twenty four Cebus apella monkeys were studied as a biological model for the cardiac chronic form of Chagas' disease. Twelve were inoculated with Trypanosoma cruzi trypomastigotes, seven with the Brazilian Y strain and five with the Argentinian RA strain. Twelve monkeys were uninfected controls. The following parameters were studied: body weight, body temperature, direct parasitemia, xenodiagnosis, specific antibodies by IFA, clinical chemistry, hematology, ECG and chest X-ray. Three monkeys infected with Y strain were sacrificed at 4 months and 4 monkeys at 12 months after inoculation. Monkeys inoculated with RA strain were sacrificed at 48 months. Direct parasitemia was positive within a week after inoculation in all monkeys. Xenodiagnosis was positive until 49.0 +/- 3.0 and 79.0 +/- 6.0 weeks p.i. for Y and RA strains, respectively. In all inoculated monkeys an increase in antibody titers was detected within 3 weeks after inoculation. In all monkeys inoculated with the Y strain and 3/5 with the RA strain abnormal ECGs were observed within 1 or 2 weeks p.i., becoming more severe in the chronic phase. Y strain inoculated monkeys sacrificed at 4 months presented only a slight concentric hypertrophy of the heart left ventricle. Those sacrificed at 12 months had concentric left ventricle hypertrophy and 3/4 had an aneurism of the apex. Four out of 5 RA strain inoculated monkeys had an enlarged, flaccid heart; 3/5 aneurism of the apex and 2/5 concentric hypertrophy of the left ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and partial characterization of rhoptries and micronemes from Eimeria nieschulzi zoites (Sporozoa, Coccidia)

Homogenization and subcellular fractionation of sporozoites of Eimeria nieschulzi have allowed the recovery of highly enriched fractions of rhoptries and micronemes. The isolated organelles kept their in situ morphological characteristics. Their apparent densities in sucrose solutions were approximately 1.18 g/cm3 for rhoptries and 1.14 g/cm3 for micronemes. When subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the microneme fraction showed two major polypeptides at 220 and 94 kDa. The rhoptry fraction contained at least three predominant peptides at 200, 150, and 63 kDa. Micronemes were also isolated from third-generation merozoites of the same species; their characteristics were identical to those of the organelles isolated from sporozoites.

The HLA polymorphism in five Brazilian populations

A total of 977 White individuals living in five Brazilian cities, as well as 173 Black individuals from two of these cities have been studied in relation to HLA-A and HLA-B. Allele frequency similarities among these populations are much more impressive than dissimilarities, and the differences, considering putative ancestors, are not remarkable. This limited variability can be only partially explained in terms of racial admixture, estimates of the latter using different alleles in the various populations showing disparate results. Linkage disequilibrium values vary between groups, that for A1-B8 being the most consistent, independent of sample or race. But four other haplotypes observed to be in significant disequilibrium in Portugal showed the same pattern in at least one of the five Brazilian White samples.

Immunoelectron microscopic demonstration of the exocytosis of dense granule contents into the secondary parasitophorous vacuole of Sarcocystis muris (Protozoa, Apicomplexa)

Merozoites of the parasitic protozoon Sarcocystis muris (Apicomplexa) possess three types of characteristic organelles with electron dense contents named rhoptries, micronemes, and dense granules, which are supposed to be involved in the parasite-host cell interactions during and after invasion. Dense granules were purified from a merozoite homogenate by centrifugation on a sucrose density gradient. It was shown by SDS polyacrylamide gel electrophoresis that they contain a major protein of 21 kDa. Polyclonal antibodies raised against this protein were applied to ultrathin frozen and Lowicryl-K4M-embedded sections of the parasite before and after host cell invasion. Dense granules were distinctly labeled by immunogold before and after invasion. After host cell invasion the parasite is enclosed in a secondary parasitophorous vacuole which contains an electron-dense material. This deposition was heavily labeled by anti 21 kDa antibodies which clearly demonstrated that the dense granule contents is released into the secondary parasitophorous vacuole.

Bone marrow transplantation in Brazil

The first program of bone marrow transplantation in Latin America was started 5 years ago at the Federal University Hospital, Curitiba, Paraná. The results of 62 patients who underwent bone marrow transplantation are presented and discussed.

Toxoplasma gondii: redistribution of monoclonal antibodies on tachyzoites during host cell invasion

Immunodetection of protein P30, a major surface antigen of Toxoplasma gondii tachyzoites, by a specific monoclonal antibody has demonstrated a homogenous distribution of this antigen on the surface of intra- and extracellular tachyzoites at all stages of their endodyogenic development. On living zoites, no redistribution of anti-P30 was obtained, contrasting with the capping obtained with antiserum to T. gondii. Upon invasion of a host cell, however, most of the coat of anti-P30 was shed from preincubated zoites at the level of the moving junction governing the entry of the parasite into the host cell.

Quantitative evaluation of antibody-dependent lymphocyte-mediated lysis of human red cells

The ability of lymphocytes to lyse human red cells coated with anti-D antibody was assessed by measuring 51 Cr release from labeled red cells incubated with peripheral blood leukocyte suspensions from 12 normal donors. Mixed mononuclear cell suspensions (containing monocytes and lymphocytes) from all donors produced lysis of sensitized red cells. Treatment with carbonyl iron reduced monocyte concentration to less than 1.2% in all donors, as measured by morphologic criteria, esterase staining and ingestion of latex particles. Lysis of red cells following monocyte depletion was markedly reduced in 8 of the 12 donors. Despite depletion of monocytes, unchanged or increased lysis was noticed with the leukocytes of the remaining 4 donors. This lysis was due to lymphocytes, not to residual monocytes. If target red cells were treated with papain or trypsin prior to sensitization, marked lysis occurred with lymphocytes of all donors, including those which did not lyse unmodified red cells. Direct cytolysis of sensitized red cells during contact with small lymphocytes was recorded using microcinematography, which confirmed the role of lymphocytes in mediating lysis. Lymphocyte-mediated lysis of red cells increased with mounting levels of antibody sensitization regardless to prior treatment with papain. Papain increased antibody coating per red cell, yet lysis per molecule of antibody bound was also increased. Lysis was inhibited by IgG1 and IgG3 in the fluid phase but not by IgG2 or IgG4. At an equivalent level of antibody sensitization lysis was augmented by concurrent coating of the red cells with C3b, C3d and/or C4b, though these components could not produce lysis in the absence of antibody coating.

Heterogeneity of lymphocyte subpopulations in severe combined immunodeficiency. Evidence against a stem cell defect

Surface markers typical of T and B lymphocytes were present on varying proportions of peripheral blood lymphocytes from three infants with severe combined immunodeficiency disease. Despite this, functions mediated by T and B cells were either absent or very minimal in all three, including cell-mediated responses in vivo; the in vitro proliferative response to mitogens, allogeneic cells, or antigens; effector cell function in lymphocyte-antibody lymphocytolytic interaction assays; and in vitro synthesis of IgG, IgA, and IgM. In contrast, mononuclear cells from one of the infants were tested and found capable of lysing both human and chicken antibody-coated erythrocyte targets normally. Co-cultivation experiments with unrelated normal control lymphocytes failed to demonstrate suppressor cell activity for immunoglobulin synthesis in these infants. Augmentations of immunoglobulin production from 310 to 560% over that expected on the basis of individual culture data were noted in co-cultures of one of the infants' cells with two different unrelated normal control cells. These findings suggest that that infant may have had a T helper cell defect or that his T cells were unable to produce soluble factors necessary for B cell differentiation. The finding of cells with differentiation markers characteristic of T and B lymphocytes in each of these patients, though in variable quantities, is further evidence for heterogeneity among patients with the clinical syndrome of severe combined immunodeficiency and argues against the concept that their immunodeficiency was due to a stem cell defect.

Evora district as a new focus for canine leishmaniasis in Portugal

On the basis of information acquired from local health authorities in Evora district of Portugal on cases of visceral leishmaniasis (VL), an epidemiology survey study was conducted. To determine the prevalence of anti-Leishmania antibodies in the local human and canine populations residing in Evora town and 14 adjacent villages, blood samples collected from 885 children and 3,614 dogs were tested in a direct agglutination test (DAT). Seropositivity for Leishmania parasite obtained by DAT in both endemic populations was further confirmed by an enzyme-linked immunosorbent assay (ELISA) and immunofluorescence test (IFAT). For identification of the responsible sandfly vector, 79 biotopes within the study areas were surveyed. In the infantile population assessed, none of the children screened showed an antibody level indicative (titer, > = 1:3200) of visceral leishmaniasis in the DAT. However, agglutinating antibody rates ranging from 0.7% to 6.9% were obtained in dogs residing in Evora and 11 adjacent villages. Concordant seropositivity of 94.04% was obtained by ELISA and IFAT in the same canine population (141) identified by DAT. Of the 159 sandflies captured, 67 were identified as Phlebotomus sergenti; 15, as P. ariasi; 58, as P. perniciosus; and 19, as Sergentomyia minuta. Unlike the results previously reported in Alto-Douro and Algarve districts of Portugal, as compared with the other three species, P. sergenti appears to be more abundant in Evora district.(ABSTRACT TRUNCATED AT 250 WORDS)