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Biomedical subjects

L Carvalho

Publications and source records attributed to L Carvalho.

At least 19 recordsLinked to original sources
PubMed2001

Detection and localization of non-HLA-ABC antigenic sites relevant to kidney rejection on endothelial cells.

Immunological rejection of kidney allografts is usually attributed to presensitization to HLA antigens. However, data on HLA identical transplant rejections indicate that non-HLA antigens may also be involved, and it has been suggested that vascular endothelium represents the main target cell. The purpose of the present study is to describe a method of detecting non-HLA antibodies immunocytochemically. We showed the molecular independence between HLA-ABC molecules identified by the monoclonal antibody w6/32, and antigenic sites identified by a kidney rejection patient serum, previously characterized, on cultured endothelial cells isolated from human umbilical cords by collagenase digestion. Single immunofluorescence staining indicated the molecular independence between these antigenic sites, as the first serum showed a granular pattern, diffused throughout the cytoplasm and the other a reticular pattern restricted to the same cytoplasmic region. This result was confirmed by double labeling. Immunoelectronmicroscopy study also confirmed site independence, showing labeling patterns with different intensities and distinct localizations, using 10- and 20-nm colloidal gold particles to reveal HLA-ABC and non-HLA-ABC determinants, respectively. In conclusion, cultured endothelial cells may be used immunocytochemically to detect non-HLA-ABC determinants of antibody reactivity in renal graft recipients, and the indirect immunofluorescence may be the methodology of choice, since it is easy, reliable and low cost.

Adult↗
PubMed2001

Prophylactic donor lymphocyte infusions after moderately ablative chemotherapy and stem cell transplantation for hematological malignancies: high remission rate among poor prognosis patients at the expense of graft-versus-host disease.

We investigated the use of 'prophylactic' donor lymphocyte infusions (DLI) containing 1 x 107 CD3+ cells, given at 30, 60 and 90 days post-allogeneic blood and marrow transplantation (BMT), following conditioning with fludarabine 30 mg/m(2)/4 days and melphalan 70 mg/m(2)/2 days. GVHD prophylaxis consisted of cyclosporin A (CsA) 2 mg/kg daily with early tapering by day 60. Our goals were the rapid achievement of chimerism and disease control, providing an immunological platform for DLIs to treat refractory patients with hematological malignancies. Twelve heavily pre-treated patients with life expectancy less than 6 months were studied; none were in remission. Diagnoses were AML (n = 4), MDS (n = 1), ALL (n = 3), CML (n = 3) and multiple myeloma (n = 1). Response rate was 75%. Three patients are alive at a median of 450 days (range, 450-540). Two patients are in remission of CML in blast crisis and AML for more than 14 months. Median survival is 116 days (range, 25-648). Six patients received 12 DLIs; three patients developed acute GVHD after the first infusion and were excluded from further DLIs, but no GVHD occurred among patients receiving subsequent DLIs. One patient with CML in blast crisis went into CR after the first DLI. The overall incidence of acute GVHD was 70%. Primary causes of death were infections (n = 3), acute GVHD (n = 3), chronic GVHD (n = 1) and disease relapse (n = 2). We observed high response and chimerism rates at the expense of an excessive incidence of GVHD. DLI given at day +30 post BMT caused GVHD in 50% of the patients, and its role in this setting remains unclear.

Adolescent↗
PubMed2001

Do microtubules around the Toxoplasma gondii-containing parasitophorous vacuole in skeletal muscle cells form a barrier for the phagolysosomal fusion?

The intracellular fate of Toxoplasma gondii was studied in primary cultures of skeletal muscle cells (SMC). The labelling of secondary lysosomes with BSA-Au particles showed no phagolysosomal fusion with the vacuole containing the parasite. After internalization of the parasites, the parasitophorous vacuole became involved by closely apposed endoplasmic reticulum (ER) and mitochondria; within 18 h of interaction, microtubules were visualized in association with the parasitophorous vacuole, suggesting that they could form a barrier for the phagolysosomal fusion.

Animals↗
PubMed2001

Ultrastructural study of expression of adhesion molecules between blood monocytes and alveolar macrophages from patients with pulmonary sarcoidosis.

Pulmonary sarcoidosis is a chronic inflammatory disorder characterized by the presence of activated T cells and alveolar macrophages at sites of inflammation. These cells are recovered from bronchoalveolar lavage (BAL) from sarcoid patients in order to evaluate the expression of various markers on cell surfaces that should determine the diagnosis in sarcoidosis. In this work we compared the expression of VLA-4, VLA-5, Mac-1, ICAM-1 and VCAM- 1 adhesion molecules, at ultrastructural level, between blood monocytes and alveolar macrophages obtained from BAL, from patients with pulmonary sarcoidosis. Cells obtained from blood and BAL were fixed, embedded in LRWhite and then ultrathin sections were incubated with monoclonal antibodies against VLA-4, VLA-5, Mac-1, ICAM-1 and VCAM-1. The results showed a more evident labelling of all adhesion molecules on alveolar macrophages when compared to blood monocytes. The labelling was seen at cell surface, at cytoplasm and small vacuoles. The differences on adhesion molecule distributions from blood monocytes to alveolar macrophages suggest that changes in the expression of these molecules occur during pulmonary inflammatory response. Lymphocytes from BAL or blood had a weak label for these molecules.

Bronchoalveolar Lavage↗
PubMed1999

Preliminary tests and construction of a computerized quantitative surgical keratometer.

PURPOSE: To construct a simple, computer-based, quantitative surgical keratometer to measure a 3.0 to 4.0 mm central region of the corneal surface. SETTING: Laboratorio de Optica Oftalmica, Instituto de Física de São Carlos (IFSC-USP), São Paulo, Brazil. METHODS: A high-intensity fiber-optic-illuminated ring pattern (Placido disk) is projected on the cornea. Reflected images are captured by a charge-coupled device camera mounted on a Zeiss microscope beam splitter and then digitized by a frame grabber installed on an IBM-compatible personal computer. Simple algorithms based on image-processing techniques were implemented for border detection. A calibrating curve based on 4 spherical surfaces was used to calculate diopter values at 360 points at each examination. Results were plotted on the computer monitor using diopter value versus angle (1 through 360 degrees) graphs. Preliminary measurements of 14 healthy corneas were compared with the equivalent radial distance points measured on an EyeSys corneal topographer. RESULTS: Mean deviation was 0.05 mm for radius of curvature, 0.24 diopter for power, and 5 degrees for cylinder. CONCLUSION: The keratometer provided precise measurements for corneal shape control during surgery.

Adult↗
PubMed1999

Ultrastructural localization of anionic sites and lectin-binding sites in sarcoid human alveolar macrophages during interaction with T-lymphocytes.

Sarcoidosis alveolitis is caused by an unknown stimulus activating alveolar macrophages (AM) and T-lymphocytes. During antigen presentation, the complex HLA class II molecule/processed peptide, on the surface of sarcoid AM, induces the T-lymphocyte to proliferate. Altered glycosylation patterns of cell surface glycoproteins such as class II molecules in inflammatory states, may enhance the antigen-presenting capability of AM. In order to know if anionic sites and lectin-binding sites take part in the process of antigen presentation by alveolar macrophages, cells obtained from bronchoalveolar lavage of patients with pulmonary sarcoidosis were incubated with cationized ferritin (CF) and colloidal gold complexed lectins (BSL-I-A4; RCA-I; RCA-II; WGA) for 30 min at 4 degrees C. After incubation, the cells were fixed with 4% paraformaldehyde, 2% glutaraldehyde, postfixed, and Epon embedded. The CF particles were uniformly distributed over the entire cell surface of the lymphocyte, and formed clusters on the surface of the macrophage mainly at the adhesion region between the AM and the lymphocytes. We found enhanced binding of BSL-I-A4 by AM, while WGA and RCA were poorly taken up by these cells. Gold-BSL-I-A4 was distributed randomly on the plasma membrane of the AM, and clustered in the adhesion region with lymphocytes. These results suggest that anionic sites and alpha-D-N-acetyl-galactosamine residues labeled with gold-BSL-I-A4 may be involved in the process of antigen presentation by sarcoid alveolar macrophages.

Anions↗
PubMed1998

Lipid peroxidation in lung tissue after chest trauma and correlation with the duration of the post-trauma survival period.

Blunt chest trauma is a frequently encountered cause of death in forensic pathology and one of the organs most likely to be affected are the lungs. Assuming that the victim survives the initial trauma, reperfusion processes take place, free radicals are formed and lipid peroxidation occurs. The aim of this study was to ascertain whether the length of the survival time is correlated with the extent of lipid peroxidation in the lung tissue following such ischaemia-reperfusion processes. A study of 470 samples taken from all five pulmonary lobes from 94 cadavers was carried out. Cases were allocated to different groups according to whether there was chest trauma and/or a known survival period. Lipid peroxidation was investigated by determining malondialdehyde (MDA) levels. The lowest mean level of peroxidation was found in control cases showing no evidence of chest trauma at autopsy and no apparent survival period. Our results suggest that the level of lipid peroxidation in lung tissue can be a reliable indicator of survival processes.

Adult↗
PubMed1998

Toxic Shock Syndrome in a neonate?

Toxic Shock Syndrome is an acute multisystemic disease, characterized by high fever, hypotension and involvement of the skin and mucous membrane, associated with multisystem dysfunction. It is a rare condition in the paediatric population. We describe a newborn child with asphyxia and meconium aspiration, who developed a temperature of > or =38.9 degrees C, severe hypotension and rash with desquamation, associated with evidence of coagulopathy and renal and muscular dysfunction. Strict CDC criteria of toxic shock syndrome were fulfilled in our patient, with all major criteria verified. These criteria have never been validated in neonates, but in this case some symptoms favour a diagnosis of toxic shock syndrome since they are not associated with birth asphyxia, viral intrauterine infection or other disease. We believe a probable intrapartum transmission occurred through ingestion or aspiration of contaminated amniotic fluid. The patient described in this report is, to our knowledge, one of the youngest described to fulfil all of the strict CDC criteria for Toxic Shock Syndrome.

Diagnosis, Differential↗
PubMed1998

Amphotericin B use in a community hospital, with special emphasis on side effects.

The purpose of this study was to analyze the usage of amphotericin B desoxycholate in a small community hospital, with special emphasis on its side effects and need for premedication. We performed a retrospective chart review for patients who received intravenous amphotericin B from January 1993 to May 1996. Temperature elevation, clinical symptoms during infusion, need for premedication, and fluctuations in serum potassium and creatinine values were especially noted. Statistical analysis showed that toxicity indicated by laboratory values (laboratory toxicity) increased with increasing amphotericin B dose, but clinical side-effects decreased with advancing age. Clinical side effects were not associated with total amphotericin B dosage; laboratory toxicity in our study was not more prevalent in elderly patients. The main finding of this study was that most patients tolerate amphotericin B well and only 23% of patients needed premedication. Our fungal cure rate was 83%. New, expensive preparations of amphotericin B should be reserved for the small subset of patients who either are intolerant of amphotericin B desoxycholate or need high doses for systemic fungal infections.

Adult↗
PubMed1998

[Cellular immune response to mycobacterial antigens].

The authors studied the immunological response before and after beginning anti-tuberculous therapy, of a previously health, HIV negative, 22 year old black male, from the Republic of Cape Verde. The patient had multiple vertebral bony lesions associated to subcutaneous abscesses. As immunological markers of antigen recognition, we measured blastogenic and cytotoxic responses and gamma-IFN secretion towards 30 kD, 65 kD, filtrate proteins of M. tuberculosis, M. tuberculosis (H37Rv) and PPD cultures. To characterise the role of cytokines during infection, expression of mRNA for gamma-IFN, IL-4 and IL-10 was also analysed. A slight increase of lymphocyte proliferation and gamma-IFN production was seen in response to purified protein derivative (PPD) and short term culture filtrate proteins (ST-CFP), after one month of therapy. More significant, was the increase in M. tuberculosis and PPD-specific cytolytic T lymphocyte response after one one month of treatment. After 6 months of treatment, blastogenic and cytotoxic responses and gamma-IFN production were considerably higher toward the antigen panel. The CD4/CD8 ratio increased from 0.7 to 1.4 after treatment. We observed that ST-CFP and MT-CFP induced increasingly higher lymphoproliferation and gamma-IFN production, confirming their role in the protective immune responses to M. tuberculosis. The reduced immune responses in the peripheral blood of this patient probably reflect a high activity in the local sites of infection. This case of disseminated tuberculosis infection maybe related to nutritional or social factors or may represent an example of reduced in ate resistance against tuberculosis infection.

Adult↗
PubMed1997

Squamous cell carcinoma of the cervix metastatic to the spleen--case report.

Squamous cell carcinoma of the cervix metastatic to the spleen is an uncommon occurrence which has only been reported in small numbers in autopsy series. We present a case of a 47-year-old patient with a Stage IIb carcinoma of the cervix, treated with radiotherapy in 1990. Four years after completion of primary treatment she presented with a voluminous left hypochondrium and epigastrium mass. An exploratory laparotomy was performed and a splenic cyst 19 cm in diameter was found. The pathological examination revealed metastatic squamous cell carcinoma of the cervix in the spleen. Peritoneal washings were positive for malignant cells, due to incidental rupture of the cyst capsule. The patient received six courses of chemotherapy with a palliative intent and is alive, without further evidence of disease, 15 months posttreatment. To our knowledge this is the only case reported in the literature of squamous cell carcinoma of the uterine cervix metastatic to the spleen, diagnosed clinically as the only site of distant spread.

Carcinoma, Squamous Cell↗
PubMed1997

Prophylactic use of ivermectin against cattle myiasis caused by Cochliomyia hominivorax (Coquerel, 1858).

The prophylactic efficacy of ivermectin against navel or scrotal myiasis in calves was evaluated in eight trials in Argentina and Brazil. In two trials, calves were injected subcutaneously with ivermectin at a dosage of at least 200 microg kg(-1) within 24 h of birth. In the other six trials, two with two-month-old calves and four with four-month-old or older calves, all calves were treated with ivermectin at a dosage of at least 200 microg kg(-1) immediately after castration. In all trials, calves were maintained together on pasture and naturally exposed to Cochliomyia hominivorax. Navel and scrotal wounds were examined for myiasis daily for at least 14 days. Incidence of navel and scrotal myiasis was significantly lower (P < 0.01) in treated calves than in control calves.

Animals↗
PubMed1997

A collaborative approach to the diagnosis of a lethal short limb skeletal dysplasia.

We report a male infant with a lethal short limb Skeletal Dysplasia, born in a District Hospital in the South of Portugal. Local paediatricians investigated clinical and radiographical data. At the Perinatal Pathology Unit of the Egas Moniz hospital the diagnosis of Atelosteogenesis type II was proposed by the Clinical Geneticist and was supported by histopathological findings. Only a collaborative approach turned possible the diagnosis of this unusual entity. Atelosteogenesis type II and Diastrophic Dysplasia are closely related diseases, with similarities in phenotypic and histopathological presentation. Recently, these similarities were extended to molecular levels. The DNA analysis, in progress, will be able to establish a final diagnosis for this affected family.

Abnormalities, Multiple↗
PubMed1995

[Primary lymphoma of the lung].

Primary lymphomas of the lung are rare neoplasias that can be easily diagnosed when enough tissue is available, but are easily mistaken for lung carcinomas or mesotheliomas on clinical evaluation. Two surgical cases are described with reference made to their morphological and immunohistochemical characteristics.

Adult↗
PubMed1994

[Pancytopenia as the first manifestation of connective tissue disease].

We report a case of a 25-year-old women admitted to the emergency room of Santa Maria Hospital with pancytopenia and fever. We describe the diagnostic work-up, laboratory findings, therapy, outcome and follow-up after discharge Lastly, we discuss aplastic anemia as a rare systemic lupus erythematosus complication, with only ten cases reported to date.

Adult↗
PubMed1990

[Aneurysm of the abdominal aorta. Is arterial hypertension a risk factor?].

OBJECTIVE: the purpose of this study was to measure ecographically and ascertain the characteristics of the abdominal aorta in a sample of the male population over sixty years, and try to correlate the findings with some so-called "risk factors" most currently quoted in the medical press, such as arterial hypertension, diabetes mellitus, tobacco consumption and coronary or cerebrovascular diseases. MATERIAL AND METHODS: this is a preliminary note of the results obtained in the first forty patients in a prospective study (still ongoing). They were choose randomly from all those admitted to the general medicine ward of Medicine I Hosp. St. Maria or attended at the Medicine or Cardiology/Hypertension outpatient clinics at the same hospital. Pearson's linear correlation, Student's t test for not paired samples and chi-square tests were used to analyze the results. MEASUREMENTS AND MAIN RESULTS: the medium value obtained for the abdominal aorta diameter (daa) was 28.8 mm (SD. +/- 3.6). In this sample there was no correlation between the age and daa (r:0.03), nor any statistical difference (chi-square) in the daa between the subgroups creating regarding the existence of hypertension no hypertension, active smoking/no smoking habits, or the association of all these so-called risk factors added to diabetes as opposed to their absence (the number of patients is still insufficient to reach statistical significance). CONCLUSIONS: in this study no risk factor/marker of the aneurysm of the abdominal aorta was so far detected in a population of aged male patients, but in some groups (as in the association of multiple factors) the number of patients was insufficient to reach any significant statistical conclusion.

Aged↗
PubMed1990

Growth modulation effects of synthetic steroids on rat prostatic adenocarcinoma and human breast adenocarcinoma cells in vitro.

Treatment of carcinoma of the reproductive organs using both an antiproliferative agent to inhibit cell growth and a cytotoxic agent to kill the neoplastic cells represents an attractive approach to therapy. By using steroids to achieve both effects, it may be possible to avoid some of the dose-limiting side effects of conventional antiproliferative or cytotoxic agents. We screened in vitro 23 selected steroids against four rat prostatic carcinoma cell lines and one human breast carcinoma cell line. Effects of the steroids were measured using a tritiated thymidine uptake assay to assess antiproliferative activity and a colorimetric enzyme-based assay to assess cytotoxicity. Several of the steroids had marked cytostatic and cytotoxic properties rendering them worthy of further evaluation, both separately and in combination.

Animals↗