PubMed Health⌕ Search

Biomedical subjects

R Vieira

Publications and source records attributed to R Vieira.

At least 19 recordsLinked to original sources
PubMed2006

Identification and physical mapping of induced translocation breakpoints involving chromosome 1R in rye.

To obtain translocations involving specific chromosomes in rye, pollen of a line in which chromosome 1R has large C-bands on its two telomeres, but which lacks C-bands (or has very small ones) on the telomeres of the remaining chromosomes, was X-irradiated. All translocations involving the labelled chromosome (1R) could be easily recognized in C-banded mitotic metaphases. The non-labelled chromosome involved in each translocation was identified either from mitotic C-banding analysis or from the meiotic configurations observed in some specific progenies. A physical map including 40 translocation breakpoints has been developed by means of synaptonemal complex (SC) analysis of well-paired pachytene quadrivalents. The results agree with the hypothesis of chromosomes 2R to 7R having similar probabilities of participating in translocations with chromosome 1R. However, the locations of the breakpoints are not entirely random: an excess of translocation breakpoints located on the short arm of chromosome 1R was obtained, and the two acentric translocated segments of each translocation show a trend towards having similar sizes. The possible reasons for these two non-random situations are discussed.

Chromosome Banding↗
PubMed2006

Specific primers for rapid detection of Microsporum audouinii by PCR in clinical samples.

This report describes application of PCR fingerprinting to identify common species of dermatophytes using the microsatellite primers M13, (GACA)4, and (GTG)5. The initial PCR analysis rendered a specific DNA fragment for Microsporum audouinii, which was cloned and sequenced. Based on the sequencing data of this fragment, forward (MA_1F) and reverse (MA_1R) primers were designed and verified by PCR to establish their reliability in the diagnosis of M. audouinii. These primers produced a singular PCR band of 431 bp specific only to strains and isolates of M. audouinii, based on a global test of 182 strains/isolates belonging to 11 species of dermatophytes. These findings indicate these primers are reliable for diagnostic purposes, and we recommend their use in laboratory analysis.

Adolescent↗
PubMed2006

[Leishmania infantum/HIV co-infection: cutaneous lesions following treatment of visceral leishmaniasis].

BACKGROUND: The Mediterranean basin is an endemic region of leishmaniasis caused by Leishmania infantum. With the advent of human immunodeficiency virus (HIV) infection, the number of cases of visceral leishmaniasis has dramatically increased in this area over the last years, mainly in adults. Moreover, the presence of cutaneous lesions infested with Leishmania has been frequently reported in these patients. CASE-REPORT: A 35-year-old Portuguese woman, a former intravenous drug user HIV1-positive since 1997, developed visceral leishmaniasis in 2000, with several relapses in 2001 and 2002, treated successively with pentavalent antimonial salts (Glucantime), liposomal amphotericin B and Glucantime associated with itraconazole. Several weeks after therapy for the second relapse of visceral leishmaniasis, physical examination revealed asymptomatic erythematous papules on the face that later spread to the trunk and upper limbs. Histopathologic studies of a skin biopsy revealed a granulomatous infiltrate in the dermis with the presence of Leishmania amastigotes. After culture, the parasite was identified as L. infantum MON-1. In spite of improvement of the patient's visceral leishmaniasis with the above-mentioned treatment, the cutaneous lesions became increasingly numerous and infiltrated. After 2 months of therapy with intravenous pentamidine (4 mg/kg/3 times a week) and oral dapsone (100 mg b.i.d), the cutaneous lesions disappeared completely. Prevention with dapsone was successfully maintained for 6 months. Several weeks after discontinuation of treatment, further lesions appeared. The patient improved again on reintroduction of dapsone. DISCUSSION: This case confirmed the existence of a clinical form similar to post-kala-azar dermal leishmaniasis in a patient co-infected with L. infantum MON-1/HIV. The cutaneous lesions were resistant to classical antileishmanial drugs but disappeared on treatment with dapsone.

Adult↗
PubMed2003

Cutaneous infection due to Scedosporium apiospermum in an immunosuppressed patient.

Scedosporium apiospermum, the anamorphic form of Pseudallescheria boydii, is a filamentous fungus with low inherent virulence. Increasing numbers of cases of this infection have been reported probably related to the rising number of immunosuppressed persons. Apart from mycetoma, cutaneous and subcutaneous infection is rarely encountered in clinical practice. We describe a case of cutaneous infection caused by Scedosporium apiospermum in a subject with rheumatoid arthritis and diabetes mellitus who was submitted to long-term therapy with cyclosporin and corticosteroids. Histopathologic examination of a skin biopsy showed a granulomatous infiltrate with hyaline septate hyphae. Culture of two skin biopsies taken at two different observations of the woman, 3 weeks apart, allowed isolation of Scedosporium apiospermum. Therapy with itraconazole, 400 mg/day, for 3 months was effective in curing the infection.

Antifungal Agents↗
PubMed2002

New carbon nanofiber/graphite felt composite for use as a catalyst support for hydrazine catalytic decomposition.

Graphite felt supporting 40 nm diameter carbon nanofibers was synthesized and successfully used as a support for a high loaded iridium catalyst (30 wt%) in the decomposition of hydrazine; a strong mechanical resistance and a high thermal conductivity led to a very efficient and stable catalyst as compared to that used industrially, iridium supported on a high surface area alumina.

Journal Article↗
PubMed2002

Speed of particles ejected from animal skin by CO2 laser pulses, measured by laser Doppler velocimetry.

During ablation of tissue with laser pulses rapid sublimation of matter occurs and high pressures are exerted within the tissue, resulting in steam. smoke and particles being expelled. In this paper we report the speed of particles ejected from animal tissue exposed to CO2 laser pulses measured directly by laser Doppler velocimetry (LDV). Speeds recorded just above animal skin were in the range of 9 to 18 m s(-1) for laser pulses of 128 to 384 J cm(-2) respectively. Aerodynamic turbulence slowed the particles down to a critical speed Vc of 4 m s(-1) within a few millimetres above the laser ablation site. Once the particles reach this minimum speed, if no collisions occur, they will only decelerate by gravitational action and the residual kinetic energy will send the particles up to about 0.87 m from the skin surface. Since ejected particles may carry viable cells, acting as disease vectors during laser surgery, our results suggest that the LDV technique should be used to measure the speed of particles ejected from healthy or pathological human tissues, helping to establish safe conditions during laser surgery.

Animals↗
PubMed2000

Primary cutaneous CD30-positive large cell lymphoma.

Primary cutaneous CD30-positive large cell lymphoma is a recently described entity, recognized by immunohistochemical criteria. Spontaneous regression may occur and although relapses are frequent, most patients have a favourable prognosis. We describe a 83-year-old woman with a large ulcerated tumour on her right forearm, with 2 months evolution. Histological and immunohistochemical examination revealed a CD30-positive large cell lymphoma. Systemic involvement was not detected. The tumour regressed spontaneously. Cutaneous relapses occurred one year later, all with spontaneous regression. After a 2-year follow-up period, the patient is well, without concurrent extracutaneous disease. This case is in keeping with other reports of spontaneous regression and favourable outcome of this type of cutaneous lymphoma.

Aged↗
PubMed1997

A practical device for histological fixative procedures that limits formaldehyde deleterious effects in laboratory environments.

Formaldehyde vapor levels were evaluated in a histological fixative laboratory and environments where anatomical pieces treated with this fixative are stored or handled. Formaldehyde concentration in the air may reach values up to 9 times higher than that established (0.3 ppm) by the international official surveillance bureaus. These results emphasize the need to perform these activities in an environment with good exhaust conditions in view of the deleterious effects of formaldehyde. Therefore, we designed a practical modular mechanical device to carry out transcardiac fixative perfusion inside an exhaust hood. This device is coupled to accessories that help surgical procedures, animal head tissue cooling and collection of organic and chemical residues for posterior discharge or treatment. In addition, as it was designed to be readily assembled and disassembled it releases the hood for other tasks.

Air Pollutants↗
PubMed1997

Technetium-99m labelling of the IOR CEA 1 monoclonal antibody: evaluation of different methods.

AIM: The aim of this study was to investigate the in vivo and in vitro properties of 99mTc labelled monoclonal antibody, IOR CEA 1 when radiolabelled by different methods. METHODS: To achieve that purpose IOR CEA was directly radiolabelled via 2-mercaptoethanol (2-Me) and stannous ion (SnCl2) reduction and indirectly via the 2-iminothiolane (2-Im) conjugation. The resulting 99mTc-MoAbs were analysed for number of free sulfhydryl groups, chemical and radiochemical purity (checked by HPLC and SDS PAGE), immunoreactivity and biological distribution in mice. RESULTS: Experimental results indicated a similar radiochemical purity and immunoreactivity for direct labelling methods and a decrease of both for 2-Im method. 2-Me antibody reduction led to a high antibody fragmentation as indicated by non-denaturing SDS PAGE analysis. Nevertheless SnCl2 and 2-Im labels revealed lower in vivo stability. CONCLUSION: 99mTc-(2-Me) IOR CEA presented favorable in vitro and in vivo properties. Therefore this label was compared to 99mTc-monoclonal antibody BW 431/26. Similar characteristics were found. Clinical studies also revealed identical biodistribution profile.

Animals↗
PubMed1993

Colchicine alters lactate utilization in isolated hepatocytes of rats treated with CCl4 and ethanol.

Lactic acidosis has been described in patients with liver disease. Hyperlactacidaemia results from an imbalance in lactate production versus lactate utilization. It is estimated that the liver utilizes approximately 30 percent of the total lactate produced in the body under basal conditions, primarily by gluconeogenesis. The gluconeogenesis from lactate 10 mM and lactacidaemia were determined in order to investigate the effects of CCl4+ethanol administration in liver injury and, the possible effect of colchicine in our experimental fibrosis model. The tests were determined after 15, 30 or 45 days of treatment. The results indicate that the gluconeogenesis was significantly inhibited in both CCl4+ethanol groups and CCl4+ethanol+colchicine groups. By contrast, the lactacidaemia levels were much higher in the CCl4+ethanol groups than the colchicine groups. Summarising, we have documented that hyperlactacidaemia is due to the inhibition of lactate utilization by the isolated hepatocytes in experimental cirrhosis, and that the improvement in lactacidaemia caused by colchicine is not primarily due to an increase in hepatic lactate utilization.

Alcoholic Intoxication↗
PubMed1992

High-performance liquid chromatographic separation with electrochemical detection of amino acids focusing on neurochemical application.

Twenty-three amino acids and dipeptides, including compounds of neurochemical interest, are measured by high-performance liquid chromatography using electrochemical detection after precolumn derivatization with o-phthalaldehyde/beta-mercaptoethanol. The method uses a multistep polarity gradient system and the entire separation is performed in less than 23 min of analysis. The minimum detectable quantity was 0.66 pmol injected, corresponding to 50 nM concentration in the sample; the response was linear in the tested range of 1.33-1333 pmol (0.1-100 microM). Relative standard deviations ranged from 0.75 to 6.089% for area measurements (mean, 2.33) and from 0.209 to 0.779% for retention times (mean, 0.546). Examples of application of the method to analysis of biological samples such as rat brain homogenate and human cerebrospinal fluid are shown.

Amino Acids↗
PubMed1992

Pineal and plasma melatonin as determined by high-performance liquid chromatography with electrochemical detection.

A rapid and sensitive method for the routine quantitative determination of melatonin in pineal and plasma is described. The assay used reversed-phase high-performance liquid chromatography (RP-HPLC) separation combined with either amperometric (system A) or coulometric (system B) detection. The method gave satisfactory reproducibility and accuracy, and detection limits for melatonin were as low as 8.5 pg (system A) and 1 pg (system B). This high sensitivity, together with the short analysis time (less than 10 min), and the simplicity of sample procedure make the present RP-HPLC method suitable for a wide range of studies concerning melatonin measurements. Melatonin values obtained in this study from both rat pineal and human plasma agree with those reported previously, and clearly determined a circadian pattern.

Animals↗
PubMed1992

[Research in child psychiatry].

The research in child psychiatry faces general restrictions related to the observation and interpretation of child psychopathological phenomena. These restrictions are increased by the limits of the methodological credibility of the psychopathological and psychiatric research with adults. The specific form of the emergence of child psychological suffering lies in a great number of factors. These can be derived from the child itself, the interaction that the child has with adults or be related with the mental health of the adults themselves. The research in this field favours the detection of risk situations either individual or social. Assuming the preventive perspective, the early identification of these situations will allow an improvement in medical care. The authors intend to raise pertinent and suggestive questions on child psychiatry research by means of the introduction of update situations. Several areas, which are still being studied, are approached, namely the parental mental pathology and its association with pregnancy and post-delivery, parental drug and alcohol addiction and its relation to the child's development, recent fields of research such as fertilization in vitro and the acquired immunodeficiency syndrome and, lastly, family separation and human communication.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Decreased plasma benzylamine oxidase in a subgroup of schizophrenia.

Plasma benzylamine oxidase (BzAO) activity was analysed in a group of 40 schizophrenic patients and compared with that of healthy controls. Although plasma BzAO was significantly decreased in schizophrenics as a whole, when patients were divided into type I (favourable course) and type II (poor course) it was found that the reduced BzAO activity was only observed in type I. Several clinical features were associated with a low BzAO level. The clinical and biological significance of the identification of a biochemical alteration in a subgroup of schizophrenic patients is discussed, and we suggest that the possibility of BzAO being a marker for prognosis in schizophrenia should be further investigated.

Adolescent↗