PubMed Health⌕ Search

Biomedical subjects

R M Pinto

Publications and source records attributed to R M Pinto.

At least 55 records · Page 3Linked to original sources
PubMed1993

Vitamin C load test in elderly subjects.

Ascorbic acid fasting serum levels and levels after a test dose were carried out in a group of elderly subjects: nine men with 70 +/- 6 years and six women 74 +/- 7 years old. They live in the same old folks home and ate similar food. Their ascorbic acid intake was found to be around 20 mg/day. Fasting serum levels found lower values in the women. A load test showed a small increase in the hourly samples, supporting low tissue reserves of the vitamin. Factors such as low intake, absorption, metabolism, body mass and/or excretion of the vitamin in elderly population could explain these results. A marginal vitamin C deficiency is believed to be present in the group and extra ascorbic acid food supply seems to be recommended for these subjects.

Aged↗
PubMed1992

Pretransplant conditioning with busulfan and cyclophosphamide in acute leukemia patients: neurological and electroencephalographic prospective study.

A neurological and electroencephalographic (EEG) prospective study was performed in 34 leukemic patients receiving busulfan (BU) plus cyclophosphamide (CY) before bone marrow autologous transplant. During BU treatment and briefly thereafter, all patients were given anticonvulsant prophylaxis with phenobarbital. Neurological evaluations were performed daily and EEGs, recorded one week before and soon after the end of the BU regimen, were re-evaluated two months later. Basal EEGs were normal in 23 of the 34 patients, focal abnormalities were detected in 9 cases, and generalized epileptic discharges were present in one (one subject was not studied). EEGs performed at the end of BU administration showed generalized spike/polyspike-and-wave discharges in 21 of the 34 patients, with associated myoclonic epilepsy in 10 subjects appearing on the 3rd or 4th day of treatment. Focal abnormalities were present in 6 patients and constant EEG normality in 7. It is known that myoclonic epilepsy can be induced by drugs. Oral administration of high-dose BU is followed by a high-dose cerebrospinal fluid concentration of the drug. Therefore, myoclonic epilepsy and/or paroxysmal epileptiform EEG discharges may be observed in leukemic patients undergoing high-dose BU therapy.

Acute Disease↗
PubMed1992

Description of Trichuris travassosi n. sp. (Nematoda: Trichurinae) from a Brazilian rodent, by light and scanning electron microscopy.

A new species of a trichurid nematode Trichuris travassosi n. sp., recovered from a wild rodent in the State of Rio Grande do Sul, Brazil, is described and compared to T. myocastoris (Enigk, 1933) and their differentiation was on the basis of a detailed morphometrical study. Oryzomys nigripes (Olfers, 1818) is a new host record for the genus. The denomination spicular prepuce is proposed to designate the structure previously named spicular sheath and, conversely, spicular sheath to indicate the cuticle that covers the spicule.

Animals↗
PubMed1992

Vaccination in murine schistosomiasis with adult worm derived antigens--II. Protective and immune response in inbred mice.

Previous work in our laboratory, mainly focused the prospects of achieving resistance against Schistosoma mansoni infection with adult worm-derived antigens in the form of a soluble extract (SE). This extract obtained by incubation of living adult schistosomes in saline, contains a large number of distinct molecules and was actually shown to be significantly protective in different outbred animals models such as Swiss mice and rabbits. It thus appeared worthwhile to investigate the potential protective activity of SE in different inbred strains of mice, known to be highly susceptible to the infection. Herein we present data showing that DBA/2 mice, once immunized with SE acquire significant levels of resistance to a S. mansoni cercarial challenge. In addition, preliminary studies on the immune system of immunized animals revealed that, injection of SE caused no general imbalance of B or T cell responses.

Animals↗
PubMed1991

Dinucleoside tetraphosphatase from human blood cells. Purification and characterization as a high specific activity enzyme recognized by an anti-rat tetraphosphatase antibody.

Dinucleoside tetraphosphatase (Np4Nase; EC 3.6.1.17) has been purified 170,000-fold from a 30-60% ammonium sulfate fraction of a human blood cell extract. Purification included a dye-ligand affinity elution step using the inhibitor adenosine 5'-tetraphosphate. Human blood Np4Nase resembled rat liver Np4Nase, including recognition by anti-rat Np4Nase, but differed from homogeneous human leukemia Np4Nase in the 1000-fold lower specific activity of the latter. The results are discussed in relation to the potential role of diadenosine tetraphosphate (Ap4A) in the control of cell division and the turnover of Ap4A in blood.

Acid Anhydride Hydrolases↗
PubMed1991

Location of dinucleoside triphosphatase in the matrix space of rat liver mitochondria.

The submitochondrial location of dinucleoside triphosphatase (EC 3.6.1.29), previously shown to be in part associated with mitochondria, has been studied in rat liver. The precipitability and latency of activity in organelle suspensions, and the profile of solubilization by digitonin, were like those of the matrix space marker glutamate dehydrogenase, and differed from those of other submitochondrial fractions. This, and the synthesis of diadenosine polyphosphates by mitochondrial aminoacyl-tRNA synthetases, suggest the occurrence of a pathway for the intramitochondrial turnover of diadenosine 5',5'''-P1,P3-triphosphate (Ap3A).

Acid Anhydride Hydrolases↗
PubMed1991

Vaccination in murine schistosomiasis with adult worm-derived antigens: variables influencing protection in outbred mice.

Previous studies have shown that both permissive (mouse) and partially permissive (rabbit) hosts develop high levels of resistance against Schistosoma mansoni infection after vaccination with a multiple antigen extract (SE) obtained by incubation of living adult worms in saline, plus bacterial adjuvant. To investigate variables influencing SE-induced protection in murine schistosomiasis, a series of distinct vaccination protocols were performed focussing on the immunization dose, carrier systems, route, site and amplitude of challenge infection, and time between immunization and challenge. In addition, a new approach was adopted to evaluate SE protective activity, by means of population analysis of worm burden frequency distributions in a large scale study of vaccination in outbred Swiss mice. Distinct curves of frequency and a drastic difference in worm burden distribution of frequencies from SE-vaccinated x non-vaccinated mice were found. It was shown that SE could generate 75% mean protection in outbred mice even in the absence of adjuvant. In addition SE immunization was also able to induce full protection against lethal infection. SE-induced protection could be modulated by such parameters as dose of SE immunization/challenge interval, and route of cercariae injection. These data show that SE yields very high protective activity in outbred mice, and may provide a further insight for rational design of a vaccine in experimental schistosomiasis.

Animals↗
PubMed1991

Schistosoma mansoni-New Zealand rabbit model: resistance induced by infection followed by active immunization with protective antigens.

In previous studies, rabbits immunized with adult worm antigens released from fresh adult schistosomes incubated in saline media showed a significant level of protection against challenge parasites. Focusing on the rabbit-Schistosoma mansoni model, concomitant immunity was investigated. A peculiar form of response to cercarial infection was observed: rabbits subjected to percutaneous infection and similar reinfections at different times after primary infection killed schistosomula from the challenge infection as well as established parasites from the primary infection. In this study the challenge infection stimulus was replaced by active immunization with an adult worm-derived protective antigenic mixture. The results show that immunization of New Zealand rabbits with an adult worm antigenic extract is capable of inducing a response that results in a significant reduction of the mean worm burden of the primary infection earlier than did homologous infection, as compared to worm reduction due to a second infection.

Animals↗
PubMed1990

Purification to homogeneity of rat liver dinucleoside tetraphosphatase by affinity elution with adenosine 5'-tetraphosphate.

Starting from a partially purified dinucleoside tetraphosphatase (Np4Nase; EC 3.6.1.17), we developed an affinity elution purification protocol involving the strong competitive inhibitor adenosine 5'-tetraphosphate. Np4Nase bound to Cibacron Blue F3G-A-Sepharose 4B or to Reactive Blue 2-Sepharose CL-6B was specifically eluted with 10 microM adenosine 5'-tetraphosphate and 5 mM MgCl2, but not by either of them separately. The final Np4Nase preparation was homogeneous by sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by Coomassie blue or silver staining. The protein band showed an apparent 18 kDa molecular mass. The specific activity of the homogeneous Np4Nase was about 150 units/mg, meaning a 45,000-fold increase and a 10% recovery with respect to the crude extract. After preparative polyacrylamide gel electrophoresis, protein visualization with KCl, fragmentation of the gel lane, and extraction, all the renatured Np4Nase activity was found associated to the 18 kDa band. The renatured enzyme showed the same Km value for diadenosine 5',5"'-P1,P4-tetraphosphate as the partially purified or the native homogeneous Np4Nase.

Acid Anhydride Hydrolases↗
PubMed1989

[Pneumonitis induced by amiodarone].

Fifteen patients, eleven males and four females, with amiodarone induced pulmonary disease were studied. Their ages ranged between 52 and 79 (mean = 64.0) years. 66% of the patients were taking a daily dose of 200 mg of amiodarone. The time elapsed between the initial dose and the diagnosis of the pneumonitis varied from 2 to 84 (mean = 23.3) months. Premature ventricular beats and recurrent episodes of paroxistic supra ventricular tachycardia were the most common indications for the use of the drug. The most frequent clinical complaints were progressive dyspnea and cough. Weight loss was observed in five patients, fever in six and chest pain in two. The most habitual thoracic physical sign was diffuse crepitation. Chest roentgenograms disclosed bilateral interstitial infiltrates in all patients, associated to pleural effusions in two. An increased diffuse uptake of 67 gallium citrate was observed in the nine patients to whom it was done. Lung function tests showed a pattern of restrictive ventilatory respiratory insufficiency and hypoxemia. Lung tissue specimens were obtained in ten patients, bronchoalveolar lavage in one and pleural fluid in one. The material was examined by light and electron microscopy. Amiodarone was discontinued in all patients and corticosteroids were introduced in thirteen. Five patients (33.3%) died, eight improved and two remained with radiographic scars.

Aged↗
PubMed1989

Curative and protective activity in rabbits after reinfection with Schistosoma mansoni: a new model of immunity?

New Zealand rabbits were infected on day 1 and challenged on days 15, 30, and 60 with 1,000 Schistosoma mansoni cercariae/animal/infection. Challenged and control rabbits were perfused 60 days after each infection, corresponding to days 75, 90, and 120 after the first exposure. No decrease in number of adult schistosomes occurred in animals reinfected 15 days after primary infection, but, when the rabbits were challenged 30 and 60 days after the first infection, worm burden reduction of 61.4% and 92.6%, respectively, was observed as compared to infection controls. These data indicate that rabbits submitted to reinfection are able to kill the worms from their primary infection, besides being protected against challenge parasites.

Animals↗
PubMed1988

Non-seasonal distribution of rotavirus in Barcelona raw sewage.

To ascertain the occurrence of a seasonal distribution of human rotavirus in Barcelona raw sewage, surveys of rotavirus levels in wastewater were undertaken in November 1985 and July 1986. A uniform distribution of rotaviruses was found to occur, which is consistent with the reported local frequencies of rotaviral diarrhoea, in contrast with the strict seasonability observed for rotavirus infections in temperate climates.

Humans↗
PubMed1987

Cytosol 5'-nucleotidase from Artemia embryos. Purification and properties.

Cytosol 5'-nucleotidase (EC 3.1.3.5) has been purified near homogeneity from Artemia embryos. The enzyme cleaves preferentially IMP and GMP, and to a lesser extent other 5'-mononucleotides. The substrate-velocity plot was hyperbolic with GMP and sigmoidal with AMP. The hydrolysis of GMP is stimulated both by ATP and beta, gamma-methyleneadenosine 5'-triphosphate with the same activation constant of around 0.6 mM. Both nucleotides decreased S0.5 without affecting V. The molecular mass of the native purified enzyme was 165 kDa, and one major band of 42 kDa was detected after sodium dodecyl sulphate polyacrylamide gel electrophoresis.

5'-Nucleotidase↗
PubMed1986

Diadenosine tetraphosphate activates cytosol 5'-nucleotidase.

The rate of hydrolysis of IMP (0.5 mM) by cytosol 5'-nucleotidase from Artemia embryos was increased up to 7-fold by concentrations of around 10 microM diadenosine tetraphosphate (Ap4A). Half maximal activation of the enzyme was accomplished with 5 microM Ap4A. The Km (S 0.5) values of the nucleotidase for IMP, GMP, AMP, XMP and CMP decreased about 10 fold in the presence of 10 microM Ap4A. Maximum velocity of the enzyme was not affected by Ap4A. ATP had been previously described as an activator of the enzyme. However, comparatively with Ap4A, concentrations of ATP two orders of magnitude higher are needed to elicit similar effects on the enzyme. Preliminary results indicate that Ap4A is also an activator of the cytosol 5'-nucleotidase from rat liver.

5'-Nucleotidase↗
PubMed1984

Adenosine deaminase isozymes in Artemia.

Three isozymes of adenosine deaminase, termed II, III and IV, have been detected in Artemia embryos. Their pI values, determined by chromatofocusing, were 4.9, 5.0 and 5.2, respectively. Upon development to larvae, a different isozyme (I) is induced, with a pI value of 4.2 as determined by isoelectric focusing.

Adenosine Deaminase↗