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M L Rodrigues

Publications and source records attributed to M L Rodrigues.

35 records · Page 2Linked to original sources
PubMed1995

Synthesis and beta-lactamase-mediated activation of a cephalosporin-taxol prodrug.

BACKGROUND: Enzyme-activatable prodrugs in conjunction with antibody-enzyme fusion proteins may enhance the anti-tumor efficacy of antibodies and reduce the toxic side effects of conventional chemotherapeutics. Cephalosporins have proven to be highly versatile triggers for the enzymatic activation of such prodrugs. RESULTS: A cephem prodrug of taxol (PROTAX) was synthesized by substituting the C-3' position of cephalothin with 2'-(gamma-aminobutyryl) taxol. Hydrolysis of PROTAX by beta-lactamase rapidly released 2'-(gamma-aminobutyryl) taxol (kcat/K(M) = (1.4 +/- 0.1) x 10(5) s-1 M-1), which yielded taxol following intramolecular displacement. PROTAX is inactive in a microtubule assembly assay in vitro but has similar activity to taxol following prolonged activation with beta-lactamase. PROTAX is approximately 10-fold less toxic than taxol against SK-BR-3 breast tumor cells in vitro but has activity approaching that of taxol following prolonged activation with a fusion protein comprising beta-lactamase fused to a tumor-targeting antibody fragment. CONCLUSIONS: Tubulin polymerization activity is abolished and cytotoxicity is reduced in the PROTAX prodrug compared to taxol. Activation of PROTAX by beta-lactamase followed by self-immolation restores the activity of PROTAX to that of free taxol.

Animals↗
PubMed1995

Relationship among sensitivity to adrenaline, plasma corticosterone level, and estrous cycle in rats.

The dose-response curves to the chronotropic effect of adrenaline obtained in right atria isolated from female rats indicated an order of increasing sensitivity to adrenaline, at the pD2 level, according to the estrous cycle, as follows: estrus < or = metestrus < or = diestrus < or = proestrus. Inhibition of neuronal and extraneuronal uptake shifted the dose-response curves to adrenaline to the left only in right atria isolated from rats during estrus or metestrus. Moreover, under these experimental conditions, right atria were subsensitive to adrenaline during proestrus, in contrast to metestrus. Plasma corticosterone levels were lower during estrus and higher at proestrus. There was a positive correlation between right atria sensitivity to adrenaline and plasma corticosterone levels and estrous cycle phases. Our results also suggest that in the rat atria during proestrus, as opposed to the other phases of the estrous cycle, there was an endogenous inhibition of extraneuronal uptake together with some alteration at the adrenoceptor level and (or) at intracellular mechanisms beyond receptors.

Animals↗
PubMed1995

[Cardiac weight in patients with chronic Chagas disease with Trypanosoma cruzi nests in the central vein of the adrenal glands].

PURPOSE: Comparative analysis of cardiac weight (CW) in patients with chronic Chagas disease, with or without parasitism by Trypanosoma cruzi in the central vein of the adrenal gland (CVAG). METHODS: The CW has been studied in 96 necropsied individuals with chronic Chagas disease. Among them, 48 of them had Trypanosoma cruzi nests on the wall of the CVAG and the other 48 patients did not have nests in the CVAG. Later, this sample was paired for sex, age and anatomo-clinical form, resulting in 60 patients. Among these patients, 30 of them had Trypanosoma cruzi nests on the walls of the CVAG and the other 30 did not have. RESULTS: The CW of Chagas patients which had nests of T. cruzi in the CVAG, was 484.8 +/- 146.0g, while in the ones that did not have the nests on the walls of the CVAG, the CW weight was 415.8 +/- 125.3g. This difference was statistically significant. In the first group it had a prevail of congestive heart failure. Subsequently to the pairing for sex, age and anatomo-clinical form, the CW was respectively 464.3 +/- 146.2g and 436.0 +/- 108.9g. This difference was not statistically significant. CONCLUSION: These data suggest that the parasitism in the central vein of the adrenal gland, combined with other possible events intrinsic to the chronic Chagas disease patients' hearts, carries a supporting role in the increasing of the cardiac weight and in the congestive cardiac insufficiency.

Adrenal Glands↗
PubMed1995

FARMACIN: a pharmacology database.

FARMACIN is a comprehensive pharmacology database that uses a Semantic DBMS engine. This paper discusses the implementation of this knowledge-base, the benefits it brought to the hospital, and it's acceptance by the users.

Clinical Pharmacy Information Systems↗
PubMed1993

Engineering Fab' fragments for efficient F(ab)2 formation in Escherichia coli and for improved in vivo stability.

We previously developed an efficient route to humanized F(ab')2 fragments by high level secretion of the Fab' arms from Escherichia coli followed by directed chemical coupling in vitro. Here the number and type of interchain linkages in F(ab')2 molecules has been modified to simplify their production and improve their serum stability. All F(ab')2 variants had comparable binding affinity for the p185HER2 Ag and antiproliferative activity against p185HER2-overexpressing tumor cells. This was anticipated since the modifications are distant from the Ag-binding loops. Replacement of a single disulfide bridge between Fab' arms with a more stable thioether bridge increased the serum permanence time in normal mice by threefold to 2.1 h. Removal of the disulfide bond between L and H chains in the thioether-bridged F(ab')2 did not affect the pharmacokinetics, suggesting that the L chain remains associated with the H chain. An additional Fab' variant containing three repeats of the motif, CysProPro, was constructed with the aim of promoting efficient formation of F(ab')2 in E. coli. This Fab' (CPP)3 variant was recovered predominantly (up to 70%) as F(ab')2 directly from fermentation cell pastes, thus circumventing the need for in vitro coupling. The F(ab')2 (CPP)3 variant has a similar serum pharmacokinetics to the thioether-bridged molecules. The improvements described here for deriving F(ab')2 fragments from E. coli should enhance the clinical potential of these molecules.

Amino Acid Sequence↗
PubMed1992

Development of humanized bispecific antibodies reactive with cytotoxic lymphocytes and tumor cells overexpressing the HER2 protooncogene.

The HER2 protooncogene encodes a 185-kD transmembrane phosphoglycoproteins, human epidermal growth factor receptor 2 (p185HER2), whose amplified expression on the cell surface can lead to malignant transformation. Overexpression of HER2/p185HER2 is strongly correlated with progression of human ovarian and breast carcinomas. Recent studies have shown that human T cells can be targeted with bispecific antibody to react against human tumor cells in vitro. We have developed a bispecific F(ab')2 antibody molecule consisting of a humanized arm with a specificity to p185HER2 linked to another arm derived from a murine anti-CD3 monoclonal antibody that we have cloned from UCHT1 hybridoma. The antigen-binding loops for the anti-CD3 were installed in the context of human variable region framework residues, thus forming a fully humanized BsF(ab')2 fragment. Additional variants were produced by replacement of amino acid residues located in light chain complementarity determining region 2 and heavy chain framework region 3 of the humanized anti-CD3 arm. Flow cytometry analysis showed that the bispecific F(ab')2 molecules can bind specifically to cells overexpressing p185HER2 and to normal human peripheral blood mononuclear cells bearing the CD3 surface marker. In additional experiments, the presence of bispecific F(ab')2 caused up to fourfold enhancement in the cytotoxic activities of human T cells against tumor cells overexpressing p185HER2 as determined by a 51Cr release assay. These bispecific molecules have a potential use as therapeutic agents for the treatment of cancer.

Amino Acid Sequence↗
PubMed1992

High level Escherichia coli expression and production of a bivalent humanized antibody fragment.

Many clinical uses of antibodies will require large quantities of fragments which are bivalent and humanized. We therefore attempted to generate humanized F(ab')2 fragments by secretion from E. coli. Titers of 1-2 g l-1 of soluble and functional Fab' fragments have been routinely achieved as judged by antigen-binding ELISA. Surprisingly, this high expression level of Fab' in the periplasmic space of E. coli does not drive dimerization. However, we have developed a protocol to directly and efficiently recover Fab' with the single hinge cysteine in the free thiol state, allowing F(ab')2 formation by chemically-directed coupling in vitro. The E. coli derived humanized F(ab')2 fragment is indistinguishable from F(ab')2 derived from limited proteolysis of intact antibody in its binding affinity for the antigen, p185HER2, and anti-proliferative activity against the human breast tumor cell line, SK-BR-3, which over-expresses p185HER2. This system makes E. coli expression of bivalent antibody fragments for human therapy (or other uses) practical.

Amino Acid Sequence↗
PubMed1992

Engineering a humanized bispecific F(ab')2 fragment for improved binding to T cells.

We recently constructed a humanized bispecific antibody (BsF(ab')2v1) by separate E. coli expression of each Fab' arm followed by directed chemical coupling in vitro. BsF(ab')2 v1 (anti-CD3/anti-p185HER2) was demonstrated to retarget the cytotoxic activity of human CD3+ CTL in vitro against the human breast-tumor cell line, SK-BR-3, which over-expresses the p185HER2 product of the proto-oncogene HER2. Our minimalistic humanization strategy is to install as few murine residues as possible into a human antibody in order to recruit antigen-binding affinity and biological properties comparable to that of the murine parent antibody. This strategy proved very successful for the anti-p185HER2 arm of BsF(ab')2 v1. In contrast BsF(ab')2 v1 binds to T cells via its anti-CD3 arm much less efficiently than does the chimeric BsF(ab')2 which contains the variable domains of the murine parent anti-CD3 antibody. Here we have constructed additional BsF(ab')2 fragments containing variant anti-CD3 arms with selected amino acid replacements in an attempt to improve antibody binding to T cells. One such variant, BsF(ab')2 v9, was created by replacing 6 residues in the second hypervariable loop of the anti-CD3 heavy chain variable domain of BsF(ab')2 v1 with their counterparts from the murine parent anti-CD3 antibody. BsF(ab')2 v9 binds to T cells (Jurkat) much more efficiently than does BsF(ab')2 v1 and almost as efficiently as the chimeric BsF(ab')2. This improvement in the efficiency of T-cell binding of the humanized BsF(ab')2 is an important step in its development as a potential therapeutic agent for the treatment of p185HER2 over-expressing cancers.

Amino Acid Sequence↗
PubMed1992

Protective effect of intradermal BCG against leprosy; a case-control study in central Brazil.

A case-control study was undertaken to evaluate the protective efficacy of intradermal BCG against leprosy in a high-endemic area of leprosy in central Brazil. Sixty-two cases and 186 controls were included in the study. Cases were all newly diagnosed leprosy patients under 16 years of age attending an outpatient health service, and all of them were schoolchildren. Three controls under 16 years old, frequency matched by sex and age group, were selected from schools geographically located in the area from which the cases came. The presence of BCG was negatively associated with leprosy, indicating a 5.3 risk of leprosy for those nonvaccinated and protective efficacy of 81%. Paucibacillary patients were more likely to have a BCG scar than multibacillary patients.

Adolescent↗
PubMed1990

Rapp-Hodgkin ectodermal dysplasia.

A rare case of ectodermal dysplasia--the Rapp-Hodgkin syndrome--is presented. Its diagnosis is discussed and the importance of a multidisciplinary management and genetic counselling outlined.

Child, Preschool↗
PubMed1982

Alcoholic liver diseases in Portugal. Clinical and laboratory picture, mortality, and survival.

Six main types of histopathological changes were found in 463 patients with chronic alcoholism admitted during the 10-year period from 1966 to 1975: group I, normal liver in 2.6%; group II, fatty liver in 8.4%; group III, acute alcoholic hepatitis (AAH) in 7.6%; group IV, cirrhosis with or without steatosis in 68.7%; group V, cirrhosis with AAH in 12.8%; group VI, liver cell carcinoma (LCC) in 1.9% (all of the latter patients were also included in group IV). Seventy-three % were males and 27% were females. Females tended to be older than males. Cirrhosis was found in 68% of the group between 21 and 30 yr and in 85% between 51 and 60 yr. Normal histology or steatosis was less frequent after the age of 50 yr. Ascites and jaundice were more frequent in patients with AAH than in patients with steatosis. The majority of patients had SGOT under 100 karmen units/ml; SGPT was normal in 80% of patients with cirrhosis and higher than 100 karmen units/ml in 10%. SGPT was higher than SGOT in only 11.9% of the patients. Mortality was 46.7% according to the followup until 1978. Survival was 38.4% at the end of the first year and decreased very slowly afterwards to 32.8% in males and 11.5% in females after a 5-yr period.

Adult↗
PubMedDate not supplied

Possible role of an adrenal parasite reservoir in the pathogenesis of chronic Trypanosoma cruzi myocarditis.

The possible contribution of parasitism of the central vein of the adrenal gland (CVAG) to chronic Trypanosoma cruzi myocarditis was assayed by comparing the occurrence of nests of amastigotes in the left ventricular myocardium (LVM) and determining the number and extent of areas of focal leucocyte exudate (FLE) in Chagas disease patients with and without CVAG parasitism. The frequency of occurrence of T. cruzi nests in the LVM, as well as the FLE number and area, were greater among patients with CVAG parasitism. We therefore suggest that CVAG parasitism plays a role in the onset and intensity of chronic T. cruzi myocarditis.

Adrenal Glands↗
PubMedDate not supplied

Nephrotoxicity attributed to meglumine antimoniate (Glucantime) in the treatment of generalized cutaneous leishmaniasis.

BACKGROUND: Pentavalent antimonials have became of basic importance for the treatment of leishmaniasis. Their most severe side effects have been reported to be increased hepatic enzyme levels and electrocardiographic abnormalities. Nephrotoxicity has been rarely related. OBSERVATIONS: We report a case of generalized cutaneous leishmaniasis involving a 50-year old male patient who was submitted to treatment with meglumine antimoniate (Glucantime). He developed acute renal failure (ARF) due to acute tubular necrosis (ATN), followed by death after receiving a total of 53 ampoules of Glucantime. CONCLUSIONS: The treatment with Glucantime was responsible by ARF diagnosed in this patient. The previous urine osmolarity and serum creatinine levels were normal and the autopsy showed ATN. It should be pointed out if ARF may also be explained by massive deposits of immunocomplexes by leishmania antibodies and antigens due to the antigenic break by the antimonial compound, since our patient presented countless lesions covering the entire tegument, similar to the Hexheimer phenomenon, but at the autopsy no glomerular alterations were seen.

Antiprotozoal Agents↗
PubMedDate not supplied

[Prevalence of intestinal parasitosis in feces collected during necropsies].

With the intention to verify the frequency of intestinal parasites, we have taken the inside digestive system material from three different parts of the intestinal tract while we were doing 135 complete necropsies. The stools were kept in MIF (Formol, iodine and merthiolate mixture) being studied in slides by the direct method. We have found intestinal parasites in 40 cases (29.6%), 11 (27.5%) with two or more kinds of parasites and 29 cases (72.5%) with only one kind of parasite. The most frequent parasites were: S. stercoralis (31,9%), E. hystolytica (23.4%), hook worm (19.1%) and A. lumbricoides (17%). The results are in according with epidemiological research made in this area. Thus, they prove that the parasitological exam made in feces taken during the necroscopy provides further evidence to enrich the anatomo-pathological diagnosis.

Adolescent↗