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Biomedical subjects

C Rocha

Publications and source records attributed to C Rocha.

At least 19 recordsLinked to original sources

The occurrence of different Bs in Cestrum intermedium and C. strigilatum (Solanaceae) evidenced by chromosome banding.

In this study, we examine the morphology, mitotic stability, meiotic behavior and the composition of heterochromatin of B chromosomes in Cestrum intermedium and C. strigilatum. The results showed that B chromosome number shows intraindividual variation in the root meristem, which seems to lead to a slight rate of B elimination in this somatic tissue. B chromosomes in both species were similar in size and shape, but differed with regard to the type, size and distribution of heterochromatin. Possible evolutionary pathways for B chromosome origin in Cestrum are discussed.

Cestrum↗

A comparison of organic and inorganic carbon controls over biological denitrification in aquaria.

In aquaria and rearing tanks, nitrate accumulation as a result of organic matter degradation is inevitable and has two major negative side effects: direct toxicity to organisms, specially invertebrates, and the introduction of a reducing environment by oxygen consumption. The aim of this study was to compare two alternate methods of removing nitrogen compounds from closed systems, autotrophic columnar denitrification (ACD) and heterotrophic columnar denitrification (HCD) by following end product concentrations as reaction progressed. A pilot plant consisting of two series of 50 dm3 recirculating flow systems (each in triplicate) was used to test both methods. Absence of pH control was also useful in autotrophic denitrification systems in order to follow effects over reaction rates and pathways. Concentrations of NO(3-), NO2- and NH(4+) were followed throughout the experiment, as well as pH, temperature and salinity. Under different flow conditions results show that higher nitrate reduction rates were possible in the autotrophic systems (35.1+/-4.7 microM/day without pH control until reversal of the process and 20.6+/-7.3 microM/day after reestablishment of pH control) in comparison with heterotrophic (9.9+/-1.3 microM/day). However, pH control through calcium bicarbonate addition was found to be crucial in maintaining constant levels of total denitrification in ACD systems, just as it was necessary to closely maintain organic carbon addition to HCD systems.

Aquaculture↗

[Topiramate: an experience in children with partial epilepsy].

Topiramate (TPM) is a new drug currently used in Brazil. We verified the clinical responses to TPM in children under 15 years-old. We started with 12.5 mg/day (1-7 mg/kg/day) and the doses increased 12,5 mg each week. Eleven children were studied, 9 females and 2 males, from 3 to 14 years-old with partial epilepsy associated to different etiological factors. Only one patient had an intense abdominal pain. The patients had weekly or daily seizures and after began TPM 1 patient stayed free from seizures, 5 improved more than 75% in frequency, 1 patient improved more than 50% and 3 had no control. A good control of seizures was achieved with a low dose of TPM as monotherapy and add-on therapy with carbamazepine even in severe cases.

Adolescent↗

RS-127445: a selective, high affinity, orally bioavailable 5-HT2B receptor antagonist.

Efforts to define precisely the role of 5-HT2B receptors in normal and disease processes have been hindered by the absence of selective antagonists. To address this deficiency, we developed a series of naphthylpyrimidines as potentially useful 5-HT2B receptor antagonists. RS-127445 (2-amino-4-(4-fluoronaphth-1-yl)-6-isopropylpyrimidine) was found to have nanomolar affinity for the 5-HT2B receptor (pKi = 9.5+/-0.1) and 1,000 fold selectivity for this receptor as compared to numerous other receptor and ion channel binding sites. In cells expressing human recombinant 5-HT2B receptors, RS-127445 potently antagonized 5-HT-evoked formation of inositol phosphates (pK(B) = 9.5+/-0.1) and 5-HT-evoked increases in intracellular calcium (pIC50 = 10.4+/-0.1). RS-127445 also blocked 5-HT-evoked contraction of rat isolated stomach fundus (pA2 = 9.5+/-1.1) and (+/-)alpha-methyl-5-HT-mediated relaxation of the rat jugular vein (pA2 = 9.9+/-0.3). RS-127445 had no detectable intrinsic activity in these assays. In rats, the fraction of RS-127445 that was bioavailable via the oral or intraperitoneal routes was 14 and 60% respectively. Intraperitoneal administration of RS-127445 (5 mg kg(-1)) produced plasma concentrations predicted to fully saturate accessible 5-HT2B receptors for at least 4 h. In conclusion, RS-127445 is a selective, high affinity 5-HT2B receptor antagonist suitable for use is vivo. The therapeutic potential of this molecule is being further evaluated.

Animals↗

Mouse adenovirus (MAV-1) expression in primary human endothelial cells and generation of a full-length infectious plasmid.

Using RT-PCR, we show that mouse adenovirus type I (MAV-1) is capable of infecting and expressing in various cell types, specifically human endothelial cells. The capability of MAV-1 to infect and express in human endothelial cells makes it a potentially useful alternative to the use of human adenoviruses type 2/5 (Ad2/5) in virus-based gene therapy, although presently MAV-1 can only be produced at lower titers than Ad2/5. In this report, we present methods for the purification of MAV-1 DNA and use of this DNA along with a modified bacteria-based homologous recombination protocol to generate a full-length plasmid clone of MAV-1 DNA. Using various transfection procedures, we show that this plasmid MAV-1 DNA can generate plaques of MAV-1 virus, albeit at low efficiencies (about 0. 2 p.f.u./microg DNA). Furthermore, the construction of an MAV-1 plasmid along with its capability to express in human cells justifies the full development of MAV-1 into a system of gene therapy.

Adenoviridae↗

[Clinical and neuroradiologic aspects of pseudohypoparathyroidism. Case report].

The authors describe the case of a 18-year-old man with short stature, epilepsy, mental deficiency and basal ganglia and central nervous system calcifications. The clinical and laboratorial findings have suggested pseudohypoparathyroidism which is a rare pathology with a peripheral resistance to parathormone, neuromuscular hyperexcitability, short stature and various clinical findings. This paper reviews the clinical form and treatment of pseudohypoparathyroidism and the neuroradiologic aspects of calcifications.

Adolescent↗

Chiral kinetics and dynamics of ketorolac.

It has been shown that the analgesic and cyclooxygenase inhibitor activity of ketorolac tromethamine (KT), which is marketed as the racemic mixture of (-)S and (+)R enantiomers, resides primarily with (-)S ketorolac and that the ulcerogenic activity of this agent also resides in (-)S ketorolac. Resolution of individual enantiomers for analysis in plasma samples has been accomplished by two methods: derivatization to form diastereomers that are separated by HPLC, or direct HPLC using a chiral phase column. When mice and rats were given oral solutions of (-)S and (+) KT, it was found that the kinetics and interconversion of the enantiomers were species and dose dependent. Interconversion was higher in mice than in rats; when (-)S KT was administered, 71% of the area under the concentration-time curve (AUC) was due to (+)R ketorolac in mice, compared with 12% in rats. More interconversion was observed at higher doses; the percent of AUC due to (-)S ketorolac when (+)R KT was administered increased from 12% to 25% in mice and from 2% to 8% in rats. In general, more interconversion occurred from (-)S to (+)R ketorolac in the animal studies. Human subjects were given single oral solution doses of racemic KT (30 mg), (-)S KT (15 mg), and (+)R KT (15 mg). The plasma concentrations of (-)S ketorolac were lower than (+)R ketorolac at all sample times after racemic KT (22% of the AUC was due to (-)S ketorolac). When (+)R KT was administered, (-)S ketorolac was not detectable and interconversion was essentially 0%. When (-)S KT was administered, significant levels of (+)R ketorolac were detectable and interconversion was 6.5%. After all doses, plasma half-life was shorter and clearance greater for (-)S ketorolac than for (+)R ketorolac. Thus, in humans very little or no interconversion of (+)R to (-)S was observed, and interconversion of (-)S to (+)R was minimal (6.5%). These data demonstrate that the kinetics and interconversion of the enantiomers of ketorolac is different in animals and humans as well as from most other NSAIDs. This may be due to more rapid excretion or metabolism of (-)S ketorolac and a different mechanism of interconversion.

Animals↗

An indirect (derivatization) and a direct HPLC method for the determination of the enantiomers of ketorolac in plasma.

An indirect and a direct HPLC method for the quantification of the (R) and (S) enantiomers of ketorolac are described here. The indirect method employs the chiral amine (+)-R-1-(1-naphthyl)ethylamine to form disastereomeric amides; separation of the disastereomeric derivates is achieved by normal-phase HPLC with a mobile phase of ethyl acetate-hexane. The direct method uses a C18 solid-phase extraction column to extract ketorolac enantiomers from plasma; the reconstituted extract is then injected onto an alpha 1-acid glycoprotein chiral column using a mobile phase of isopropanol-phosphate buffer (0.05 M; pH 5.5). Both methods are reproducible, accurate, and stereospecific, and both have equivalent quantification limits (0.02 microgram ml-1 of plasma for each enantiomer), ranges (0.02-2.0 micrograms per aliquot of plasma), precision (% relative standard deviations of < or = 10.5% and < or = 10.8% for (R)- and (S)-ketorolac respectively), and accuracy (mean recoveries of 88.4-110% and 90.1-110% for (R)- and (S)-ketorolac respectively). Results of analyses of clinical samples by the two methods showed excellent agreement (slope near 1.0 and coefficients of correlation between 0.9740 and 0.9864 for both enantiomers).

Analgesics, Non-Narcotic↗

Schistosomiasis and vascular alterations of the colonic mucosa.

The diagnosis of schistosomiasis is made by identification of Schistosoma in stool and urine, or by colonic or hepatic biopsies. The authors demonstrate in this paper, however, that it is also possible to suspect this disease by colonoscopy, i.e., by macroscopic observation of the vascular alterations in the mucous membrane of parasite infected patients. Out of 33 patients -21 with schistosomiasis and 12 with other intestinal parasitoses--the endoscopist correctly diagnosed Schistosomiasis in 18 (85.7%) patients, although he had no previous experience of the diagnosis. Since this infection is widespread throughout the world, these endoscopic findings are important; they may help the physician correctly diagnosis schistosomiasis in non-endemic areas where the diagnosis may not be suspected.

Adult↗

The first field trials of the chemically synthesized malaria vaccine SPf66: safety, immunogenicity and protectivity.

This paper reports the results of the first field study performed to assess the safety, immunogenicity and protectivity of the synthetic malaria vaccine SPf66 directed against the asexual blood stages of Plasmodium falciparum. Clinical and laboratory tests were performed on all volunteers prior to and after each immunization, demonstrating that no detectable alteration was induced by the immunization process. The vaccines were grouped as high, intermediate or low responders according to their antibody titres directed against the SPf66 molecule. Two of the 185 (1.08%) SPf66-vaccinated and nine of the 214 (4.20%) placebo-vaccinated volunteers developed P. falciparum malaria. The efficacy of the vaccine was calculated as 82.3% against P. falciparum and 60.6% against Plasmodium vivax.

Amino Acid Sequence↗

Correlation between EEG spectral parameters and an educational evaluation.

EEG spectral parameters were computed in a group of children with different degrees of difficulty in learning to read and write. For statistical analyses, Z-transformed values according to normative age-regression equations were used to control the age effects. Canonical Correlation Analysis between absolute power in different bands and the categories of the educational evaluation (good, regular, poor and very poor) showed that more delta was probably related to a poor evaluation and more alpha in occipital areas to a good one. MONOVA also showed highly significant differences in the absolute power in many leads between children with different evaluations. As children with a poor evaluation very frequently had antecedents of risk factors related to brain damage and were from a low socioeconomic status, and both factors have been shown to affect absolute power, it may be that the differences observed were due to these causes. However, relative power correlated more with the learning problems. Children with minor difficulties, with no antecedents and with good socioeconomic status had more theta in almost all leads than children with a good evaluation and with the same characteristics. Children with a poor, or very poor, evaluation had more delta in left frontal and temporal areas (F3, F7 and T3) which may reflect underlying cerebral dysfunction of these regions directly involved in reading and writing processes.

Child↗

The influence of nutritional status on skin anergy in experimental cancer.

Malignant tumours as well as severe malnutrition can interfere with carcass weight, serum albumin and delayed hypersensitivity tests. In order to identify the separate effects of these two phenomena, Wistar rats were submitted to various nutritional manipulations prior to Walker-256 carcinosarcoma inoculation (TU). Six groups of well-nourished rats with positive response to the Keyhole Limpet Haemocyanin (KLH) test were studied. Three TU-bearing groups were established, [1] protein-deprived before and after TU (group DDT), [2] protein deprived before TU and later brought back to normal chow (group DNT), and [3] those receiving a complete diet throughout the experiment (group NNT). Identical control groups without TU, sham-injected, were called DDC, DNC and NNC. Tumour size and body weight were measured daily. KLH tests were done sequentially and serum albumin was determined at sacrifice. Results indicated that cancer produced marked changes in immune response. Malnutrition was responsible for anergy and weight loss, and further aberrations tended to occur when both conditions were present. Feeding was able to restore body weight and KLH response in tumour-bearing as well as in control rats, but subsequent deterioration occurred in cancer bearing rats after the first week of tumour development. It is concluded that cancer potentiates the effects of malnutrition, on body weight and immune response, but temporary recovery could be demonstrated after adequate refeeding.

Journal Article↗

Detection and characterization of monoclonal antibodies specific to IgE receptors on human lymphocytes by flow cytometry.

BALB/c mice were immunized with human lymphoblastoid cells (RPMI 8866 cells) expressing surface receptors for IgE (Fc epsilon R). Spleen cells from animals displaying high titres of anti-Fc epsilon R antibodies were fused with HGPRT-deficient NSI myeloma cells. Anti-Fc epsilon R antibodies were identified by a flow cytometric assay based on their ability to block the binding of IgE-coated fluorescent latex particles to Fc epsilon R-positive cells. Fourteen monoclonal hybridoma cell lines secreting antibody of the required specificity were amplified in tissue culture and then grown in the peritoneal cavity of BALB/c mice in order to obtain ascitic fluids with high antibody titres. The specificity of each monoclonal antibody (Mab) to lymphocyte Fc epsilon R was shown by the following observations: (i) the intact monoclonal antibody molecule or, in some cases, its F(ab')2 fragments blocked the binding of IgE to several Fc epsilon R(+) cell lines different from that employed for the initial immunization; (ii) the Mab bound directly to all the Fc epsilon R(+) cell lines tested, but not to several Fc epsilon R(-) cells as determined by indirect immunofluorescence; (iii) the binding of Mab to Fc epsilon R(+) cells was selectively blocked by IgE, but not by the other classes of Ig; and (iv) Mab had no effect on the binding of IgG to Fc gamma R on normal human peripheral blood mononuclear cells (PBMC).

Animals↗

Characterization of cellular infiltrates in skin lesions of atopic eczema by means of monoclonal antibodies.

Frozen skin biopsies from 3 acute and 3 chronic lesions of atopic dermatitis were examined by means of various ortho-monoclonal antibodies (OKT3, 4] not equal to----4, OKT6, OKT8; OKIa and OKM1) in an indirect immunofluorescence technique. The results show that both T helper (T4) and T suppressor cytotoxic (T8) lymphocytes are present in the inflammatory infiltration which predominantly contained Ia mononuclear cells. Despite the absence of double staining procedure, the observations suggest that T4 cells predominate over T8 cells in the acute lesions whereas the reverse tendency is noted in the chronic lesions. T8 cells are found mainly in the superficial dermis or even in the epidermis; by contrast, T4 cells tend to be more deeply located in the dermis. The lesions are characterized by a dramatic increase in the number of Langerhans cells (OKT6, OKIa+) that are found not only in the epidermis but also in the dermis.

Adolescent↗

Wavelet analysis of EEG for three-dimensional mapping of epileptic events.

This paper is aimed at understanding epileptic patient disorders through the analysis of surface electroencephalograms (EEG). It deals with the detection of spikes or spike-waves based on a nonorthogonal wavelet transform. A multilevel structure is described that locates the temporal segments where abnormal events occur. These events are then visually interpreted by means of a 3D mapping technique. This 3D display makes use of a ray tracing scheme and combines both the functional (the EEG but also its wavelet representation) and the morphological data (acquired from computed tomography [CT] or magnetic resonance imaging [MRI] devices). The results show that a significant reduction of the clinical workload is obtained while the most important episodes are better reviewed and analyzed.

Algorithms↗

[Data analysis and quality control in radioimmunoanalysis. II. Evaluation of the internal and external quality in the quantification of pituitary gonadotropins].

The procedures for a systematic evaluation of the quality control of radioimmunoassay in general were described previously. In this report we present the parameters of quality control and their application to the radioimmunoassay (RIA) of pituitary gonadotrophic hormones, luteinizing hormone (LH) and follicle stimulating hormone (FSH) in serum. We present the results obtained in the intra-assay variation for the measurement of the pituitary gonadotrophic hormones in serum (LH and FSH) from 1983 to 1989. The results on bias and the inter-laboratory assessment through an external quality control scheme during the same period are also presented.

Bias↗

[Detection of TEM-beta-lactamase in strains of Haemophilus influenzae resistant to ampicillin using the polymerase chain reaction (PCR)].

With the purpose of determining the type of beta-lactamases that mediate ampicillin resistance to in Haemophilus influenzae strains in the Hospital Infantil de México "Federico Gómez", we determined the minimum inhibitory concentration of 180 strains, isolated from different sources, to ampicillin, amoxicillin-clavulanic acid and ampicillin-sulbactam. All ampicillin resistant strains (29) were beta-lactamase positive as determined by nitrocephin hydrolysis. Using PCR with the primers from pBR322, we detected the presence of the gene for the TEM-beta-lactamase in 100% of the ampicillin resistant strains.

Ampicillin Resistance↗