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Biomedical subjects

C Lopes

Publications and source records attributed to C Lopes.

At least 19 recordsLinked to original sources
PubMed2000

Characterization of a novel gene, C21orf6, mapping to a critical region of chromosome 21q22.1 involved in the monosomy 21 phenotype and of its murine ortholog, orf5.

Phenotypic and molecular analyses of patients with partial chromosome 21 monosomy enabled us to define a region, spanning 2.4 Mb between D21S190 and D21S226, associated with arthrogryposis, mental retardation, hypertonia, and several facial anomalies. The markers of the region were used to screen a total human PAC library (Ioannou, RZPD). We isolated 57 PACs, which formed primary contigs. EST clusters (UNIGENE collection) located in a 6-Mb interval, between D21S260 and D21S263, were mapped in individual bacterial clones. We mapped the WI-17843 cluster to the PAC clone J12100, which contains the two anchor markers LB10T and LA329. The open reading frame extends over 960 bp, with three putative start codons. The 1695-bp cDNA containing a polyadenylation signal should correspond to the full-length cDNA. From the genomic sequence, we deduced that the gene contained five exons and that there was a putative promoter sequence upstream from exon 1. In silico screening of DNA databases revealed similarity with a murine EST. The corresponding cDNA (1757 bp) sequence was very similar (>85%) to the human cDNA and had an open reading frame of 876 nucleotides. Somatic hybrid mapping localized the cDNA to mouse chromosome 16. EST analyses and RT-PCR indicated that the third exon in the human gene (exon 2 in the mouse) undergoes alternative splicing. Northern blot hybridization showed that the gene was ubiquitously expressed in humans and mice. The longest mouse clone was used to generate riboprobes, which were hybridized to murine embryos at stages E-9.5, E-10.5, E-12.5, E-13.5, and E-14.5-15, to study the pattern of expression during development. Ubiquitous labeling was observed, with strong signals restricted to limited areas of the telencephalon, the mesencephalon, and the interrhombomeric regions in the central nervous system, and other regions of the body such as the limb buds, branchial arches, and somites.

Amino Acid Sequence↗
PubMed2000

Regional and cellular specificity of the expression of TPRD, the tetratricopeptide Down syndrome gene, during human embryonic development.

The TPRD gene (tetratricopeptide (TPR) containing Down syndrome gene) is one of the candidate genes in the Down syndrome chromosomal region-1. Duplication of this gene may be the cause of major phenotypic features of Down syndrome. Here we show that the TPRD expression is developmentally regulated during human embryogenesis. At the earliest stages of development (Carnegie 8-12) TPRD expression is ubiquitous. At later developmental stages (Carnegie stages 14, 16 and 18), it becomes restricted to the nervous system, as is the case for the mtprd gene during mouse development. We extended our analysis of TPRD expression during fetal development of the human nervous system (13, 22 and 24 weeks). A new oblique illumination technique was used to compare signal intensity and cell density. Some regions of the nervous system such as the external cortical layers of the brain, and the inner neuroblastic layer of the eye, strongly express the TPRD gene.

Cerebral Cortex↗
PubMed2000

Central nervous system (CNS) tuberculosis following allogeneic stem cell transplantation.

Tuberculosis is an uncommon infectious complication after stem cell transplantation. We report a patient who presented with a brain mass, 3 months after pulmonary tuberculosis had been diagnosed and while he was receiving triple antituberculous therapy. He had extensive chronic GVHD. The diagnosis was made after biopsy of the lesion. The cerebral mass was excised, antituberculous treatment was maintained and the patient made a complete neurologic recovery. Six months later, he died of gram-negative septic shock. Mycobacterial infections should be considered in allograft recipients with chronic GVHD and solid lesions in the brain. Bone Marrow Transplantation (2000) 25, 567-569.

Brain↗
PubMed1999

Dynamic expression pattern of Ca(2+)/calmodulin-dependent protein kinase II gene in the central nervous system of Drosophila throughout development.

Calcium/calmodulin-dependent protein kinase II (CaM KII) is thought to be involved in the majority of the neuronal functions mediated by intracellular free Ca(2+), and has been implicated in long-term potentiation, learning, and memory. In this work, we have examined in detail the RNA expression pattern for the Drosophila CaM KII gene by in situ hybridization, during embryonic, larval, pupal, and adult stages. Our results indicate that expression of CaM KII was homogeneous in early embryos, but that during development the gene transcription rapidly became restricted to neuroblasts and their progeny in the nervous system. This predominant expression in the nervous system is maintained during late embryogenesis and post-embryonic development. A signal compartmentalization appeared in the larval central nervous system, where the CaM KII expression became progressively concentrated in the anterior ganglia. In the adult brain, a specific expression was more abundant in a subset of neurons around the central brain, particularly the mushroom bodies and the central complex, structures that play an important role in learning and memory.

Animals↗
PubMed1999

Mutations in the essential spindle checkpoint gene bub1 cause chromosome missegregation and fail to block apoptosis in Drosophila.

We have characterized the Drosophila mitotic checkpoint control protein Bub1 and obtained mutations in the bub1 gene. Drosophila Bub1 localizes strongly to the centromere/kinetochore of mitotic and meiotic chromosomes that have not yet reached the metaphase plate. Animals homozygous for P-element-induced, near-null mutations of bub1 die during late larval/pupal stages due to severe mitotic abnormalities indicative of a bypass of checkpoint function. These abnormalities include accelerated exit from metaphase and chromosome missegregation and fragmentation. Chromosome fragmentation possibly leads to the significantly elevated levels of apoptosis seen in mutants. We have also investigated the relationship between Bub1 and other kinetochore components. We show that Bub1 kinase activity is not required for phosphorylation of 3F3/2 epitopes at prophase/prometaphase, but is needed for 3F3/2 dephosphorylation at metaphase. Neither 3F3/2 dephosphorylation nor loss of Bub1 from the kinetochore is a prerequisite for anaphase entry. Bub1's localization to the kinetochore does not depend on the products of the genes zw10, rod, polo, or fizzy, indicating that the kinetochore is constructed from several independent subassemblies.

Animals↗
PubMed1999

In vitro transformation of cell lines from human salivary gland tumors.

Explanted cells from salivary gland tumors are particularly difficult to propagate in vitro and not efficiently immortalized by agents such as simian virus 40. Human papillomavirus 16 (HPV16) has been widely used to transform cells of epithelial origin, but its use for salivary gland cell transformation has not been described. In this study, we employed viral constructs containing the E6/E7 genes of HPV16 to infect and stably transform 9 salivary gland tumor cell cultures. Four of the tumor cell cultures were derived from benign tumors and 5 from malignant tumors. All of the original cell cultures were diploid; however, 6 contained subpopulations of cells with structural abnormalities. All 9 cell cultures were successfully transformed, and 8 were immortalized. The resulting cell lines have decreased serum requirements, exhibit a high proliferation rate, are E6/E7-positive and form colonies in soft agar. Immuno-histochemical and molecular studies confirmed that the transformed cells were indeed epithelial/myoepithelial in origin. All of the transformed cell lines had a diploid or near-diploid karyotype, and 2 contained the original translocated chromosomes in all cells. Our report represents a new application of the E6/E7 system in immortalizing salivary gland cell cultures, resulting in retention of the cellular features found in the native tissue without a general destabilization of the karyotype. These types of tissue culture resources should prove useful for positional cloning and functional studies of genes involved in salivary gland oncogenesis.

Antigens, Differentiation↗
PubMed1999

Developmentally regulated expression of mtprd, the murine ortholog of tprd, a gene from the Down syndrome chromosomal region 1.

The gene tprd, which contains three tetratricopeptide domains, has been recently localized in the Down syndrome (DS) chromosomal region 1. We have cloned a cDNA encoding part of the murine ortholog of tprd and used it to characterize the expression pattern of this gene during development and at the adult stage. At E8.5 the expression is uniform. In the later stages of embryogenesis, although expression remains ubiquitous, a pattern of tissues with particularly high expression develops: the strong expression is restricted to non proliferating zones of the nervous system such as the external layer of the cortex, the spinal cord, the cranial and root ganglia and the nerves. In the brain of adult mouse the strongest signals are observed in layers II-III and V-VI of the cortex, in the hippocampus and in the cerebellum, which correspond to the abnormal brain regions seen in DS patients.

Animals↗
PubMed1999

Pleomorphic adenoma gene 1 is expressed in cultured benign and malignant salivary gland tumor cells.

The pleomorphic adenoma gene 1 (PLAG1) is activated by reciprocal chromosomal translocations involving 8q12 in a subset of salivary gland pleomorphic adenomas. PLAG1 encodes a zinc finger protein and was initially reported to be expressed in placenta and fetal tissues, with no detectable expression in other normal adult tissues. By Northern blotting we have detected PLAG1 expression in a wide set of normal adult tissues, including heart, placenta, spleen, prostate, testis, ovary, and small intestine. We have performed reverse transcriptase-PCR and Northern blot analyses to study the expression of PLAG1 in normal salivary gland tissues and in primary cultures and cell lines derived from salivary gland tumors. PLAG1 was expressed in all tumor-derived primary cultures and cell lines, irrespective of their histological type or the presence of genomic rearrangements involving PLAG1, but was not detected by our assays in normal salivary glands. Our data indicate that the presence or absence of PLAG1 expression is not an unequivocal marker for the differential diagnosis of benign versus malignant salivary gland tumors, and that a simple de novo activation of this gene does not fully explain the involvement of this gene in salivary gland tumors.

Adenoma, Pleomorphic↗
PubMed1998

Expression of the mnb (dyrk) protein in adult and embryonic mouse tissues.

Mnb is a human homologue of the Drosophila minibrain gene which encodes a serine/threonine protein kinase that is required in distinct neuroblast proliferation centers during postembryonic neurogenesis. The high degree of homology of the human gene to the murine gene (dyrk) allowed us to use a human polyclonal anti-mnb antibody to study the expression pattern of the protein in adult and embryonic mouse tissues. Western blot analysis and immunohistochemical methods were used to define the detailed distribution of mnb in adult brain and 17 days mouse embryos. The results show a high expression in the cerebral cortex, the cerebellum, the hippocampus which is in accordance with previous reports of in situ hybridization studies using mRNA probes but also a very strong expression in the epithelial layers of the skin, the retina, the tongue, the intestine and the kidney which has not been described before. Since epithelial cells are highly mitotic cells and since mnb shares sequence similarities with the cdk kinases involved in the regulation of cell division, this result may indicate a important role of mnb in the cell cycle control.

Aging↗
PubMed1998

Transcriptional map of the 2.5-Mb CBR-ERG region of chromosome 21 involved in Down syndrome.

The region of chromosome 21 between genes CBR and ERG (CBR-ERG region), which spans 2.5 Mb on 21q22.2, has been defined by analysis of patients with partial trisomy 21. It contributes significantly to the pathogenesis of many characteristics of Down syndrome, including morphological features, hypotonia, and mental retardation. Cosmid contigs covering 80% of the region were constructed and EcoRI maps produced. These cosmids were used for exon trapping and cDNA selection from three cDNA libraries (fetal brain, fetal liver, and adult skeletal muscle). Isolated exons and cDNAs were mapped on the EcoRI map, organized into contigs, sequenced, and used as probes for Northern blot analysis of RNA from fetal and adult tissues. We identified 27 genuine or highly probable transcriptional units evenly distributed along the CBR-ERG region. Eight of the transcriptional units are known genes.

Chromosome Mapping↗
PubMed1998

Intracystic (encysted) papillary carcinoma of the breast: a clinical, pathological, and immunohistochemical study.

Intracystic papillary carcinoma (IPC) of the breast is a rare tumor with predilection for elderly women and distinctive pathological features that must be distinguished from ductal carcinoma in situ (DCIS) of papillary type and from invasive papillary carcinoma. The clinical, radiological, and pathological features of 29 cases of IPC are reported. The cases were divided into three groups (IPC alone, associated with DCIS, or associated with invasive carcinoma) and studied in terms of their size, predominant architectural pattern, nuclear grade, and presence of necrosis. Immunohistochemical studies were performed to evaluate the c-erbB2 oncoprotein, estrogen receptors, and ki-67 antigen expression. The median age of the patients was 75 years. Microscopically, nine tumors (31.0%) were IPC alone, nine (31.0%) had IPC associated with DCIS, and 11 (38.0%) were IPC associated with invasive carcinoma. Most of the IPC cases had low or intermediate nuclear grade, no necrosis, strongly expressed estrogen receptor, and was negative for c-erbB-2. Nuclear grade 3 and necrosis were found only in cases of IPC associated with invasive carcinoma. The median Ki-67 antigen expression was 10.6%. One patient with IPC alone had a recurrence 5 years later. Lymph node metastases were found in one patient who had the tumor with the biggest invasive area. IPC is a low-grade carcinoma with overall good prognosis. However, there is a high frequency of DCIS or invasive carcinoma associated with it, and the prognosis of these cases is related to the type, grade, and size of the associated lesions.

Aged↗
PubMed1998

Nitric oxide synthase activity and L-arginine metabolism in the retinas from streptozotocin-induced diabetic rats.

1. Nitric oxide synthase (NOS) activity was studied in the retinas from normal rats and in the retinas from two groups of streptozotocin-induced (8 days and 4 months) diabetic rats. In each animal group, the NOS activity was correlated to the concentration of amino acids related to L-arginine metabolism and to L-arginine uptake. 2. Retinas from both groups of streptozotocin-induced diabetes (8 days and 4 months) showed an increased NOS activity compared with the NOS activity in retinas from normal rats. In retinas lysate from normal rats, the NOS activity was most potently inhibited by NO-Arg (1 mM), whereas, in both groups of streptozotocin-induced diabetes, the NOS activity was most potently inhibited by the NOS inhibitor aminoguanidine (0.5 mM). 3. The basal levels of the amino acids related to L-arginine metabolism-namely, L-arginine, L-citrulline, L-ornithine and L-glutamine-in retinas from both groups of rats with streptozotocin-induced diabetes were decreased compared with the amino acid levels in retinas from normal rats. 4. The uptake of L-[3H]arginine in retinas from both groups of rats with streptozotocin-induced diabetes was increased compared with the uptake of of L-[3H]arginine in retinas from normal rats.

Animals↗
PubMed1998

[The clustering of cardiovascular risk factors in the urban population of Porto].

The aim of the study was to assess the total prevalence of obesity, non-insulin-dependent diabetes mellitus (NIDDM), hypertension, hypertriglyceridemia, hypercholesterolemia and central fat distribution, in a population-based survey. Two-hundred and ten individuals from the community were selected by random digit dialing. Obesity was defined as a body mass index > or = 25 kg/m2, central distribution of fat if the waist-to-hip ratio > 0.80 in women and 1.0 in men, diabetes was diagnosed if fasting plasma glucose levels > or = 140 mg/dl and/or currently under treatment, hypertension was defined as a systolic blood pressure > or = 140 mm Hg and/or diastolic blood pressure > 90 mm Hg and/or currently taking antihypertensive medications, hypertriglyceridemia was defined as a fasting serum triglyceride concentration > or = 200 mg/kg and hypercholesterolemia as a fasting serum cholesterol level > or = 200 mg/dl and/or currently taking specific medication. Prevalence rates of obesity, NIDDM, hypertension, hypertriglyceridemia, hypercholesterolemia and central fat distribution were 54.3%, 8.0%, 60.0%, 13.9%, 67.0% and 46.7% respectively. The prevalence of each of these conditions in its isolated form was 2.8% for obesity, 0.0% for diabetes, 3.8% for hypertension, 0.5% for hypertriglyceridaemia, 12.0% for hypercholesterolemia and 0.1% for the central fat distribution pattern. The large differences in prevalence between isolated and combined forms in the six disorders analyzed indicate a great overlap between these cardiovascular risk factors, and give epidemiologic support to a proposed metabolic syndrome.

Adult↗
PubMed1998

[Diet and risk of myocardial infarction. A case-control community-based study].

OBJECTIVE: To evaluate diet as a risk factor for myocardial infarction. DESIGN: Community based case-control study. SETTING: University Hospital, Oporto. PARTICIPANTS: First time consecutive cases of acute myocardial infarction (n = 100) and 198 community controls, older than 39 years and living in Oporto, were compared. METHODS: Data were collected by trained interviewers using a structured questionnaire designed to obtain information on socio-demographic, medical and behavioural aspects, emphasising the description of diet and food habits (using a semi-quantitative food frequency questionnaire). Controls were selected by random digit dialing with a participation rate of 70%. Odds ratios and 95% confidence intervals (CI) according to quartiles of nutrient ingestion were calculated using unconditional logistic regression. RESULTS: Female controls presented significantly higher mean intakes of protein, omega-3 fatty acids, fiber, cholesterol and vitamin C. Male controls had a significantly higher mean daily intake of fiber, vitamin C, vitamin E, and carotenes. After adjusting for age, sex, education, body mass index, ethanol, smoking and total energy intake, there was a protective effect of vitamin C (OR = 0.2, 95% CI: 0.1-0.6, for the 4th quartile), vitamin E (OR = 0.3, 95% CI: 0.1-0.9 for the 4th quartile) and total fiber (OR = 0.3, 95% CI: 0.1-0.9) for the 4th quartile). No significant effect was found for trans-fatty acids, but there was a higher risk with increased energy intake. CONCLUSIONS: This study showed that diet has an important independent effect on myocardial infarction, a protective independent role for anti-oxidant vitamin C and E was verified.

Adult↗
PubMed1998

[Gliosarcomas].

Gliosarcomas are rare tumors of the central nervous system with a poor prognosis. Histologically these tumors are characterized by an admixture of neoplastic glial cells and sarcomatous elements. Due to the scarcity of data in literature, the diagnosis is often missed and treatment is difficult. The authors report three cases of cerebral gliosarcomas and review the literature on this subject.

Adult↗
PubMed1998

[Acute eosinophilic pneumonia. Possible role of chloroquine].

We report the case of a patient aged 49 who presented with a picture of an acute respiratory distress syndrome developing over several days after the preventative treatment of a burn using chloroquine (Nivaquine). The combination of clinical data, radiological and clinical as well as the broncho-alveolar lavage, enabled a diagnosis of acute eosinophilic pneumonia to be made according to Allen's criteria. The outcome after stopping the cloroquine and treating with corticosteroids was rapidly favourable and without any relapse. Based on this observation, we recall the characteristics of acute eosinophilic pneumonia as well as the causes which are currently established. Their potentially serious nature should encourage people to report similar cases to ours because even if we have not made identical observations to other cases. Chloroquine seems to us responsible for the clinical picture presented by our patient.

Acute Disease↗
PubMed1997

Angiomatoid fibrous histiocytoma of the arm treated by radiotherapy for local recurrence--case report.

The Angiomatoid Fibrous Histiocytoma is a rare tumor of soft tissues, which occurs mainly in children and young adults, with low malignancy grade. It has the capacity of local recurrence, but rarely metastizes. It is frequently difficult to differentiate this from vascular tumors, namely hemangioendotheliomas and angiosarcomas, or simply organized hematomas. The authors present a case of a patient with an angiomatoid fibrous histiocytoma of the arm, treated with radiotherapy after three postsurgical recurrences.

Arm↗