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Biomedical subjects

G Santos

Publications and source records attributed to G Santos.

At least 19 recordsLinked to original sources
PubMed2003

Monitoring the active sessile-colonisation of two drinking water distribution systems based on the protein contents in native biofilm samples.

Biofilms are present to a greater or lesser degree in virtually all drinking water distribution systems. In order to investigate the relative intensity and the spatial and temporal distributions of the active sessile-colonization, protein was determined in native biofilm samples from the Oeiras-Amadora (OADS) and the Almada (ADS) distribution systems in Portugal. Samples (25 cm2) were taken from lengths of asbestos cement pipes of different ages and diameters. Protein was detected at levels from 0.3 to 68 microg/cm2 in samples from all analysed pipe diameters and ages. At OADS, protein was found at 0.3 to 1 mg/cm2 in 99% of the samples. At ADS, protein was only found in 30% of the samples, but at significantly higher levels (0.3 to 68 mg/cm2). In addition to displaying a more intense and scattered active colonization, ADS's oldest-pipes (in use for over 30 years) solely exhibited protein at the highest levels found (> 19 mg/cm2), in contrast with the younger pipes where protein levels ranged from 0.3 to 19 mg/cm2. Observed results suggest that the spatial and temporal distribution patterns of the active biofilm colonization may vary significantly among drinking water networks and may have a rather slow evolution, possibly at the decades scale.

Biofilms↗
PubMed2001

Community-based controlled trial of dietary management of children with persistent diarrhea: sustained beneficial effect on ponderal and linear growth.

BACKGROUND: Uncontrolled hospital-based studies in developing countries have reported promising results of dietary rehabilitation of children with persistent diarrhea. OBJECTIVE: The objective was to determine the immediate and long-term effects of a dietary supplement and micronutrients given to children with persistent diarrhea during the episode and for 1 wk during convalescence. DESIGN: The study was open, controlled, and community-based and was conducted in a periurban area in Guinea-BISSAU: Children <3 y of age with persistent diarrhea were identified during weekly household visits. The children randomly assigned to the treatment and control groups were examined by a physician and all medical conditions were treated. The children in the treatment group were offered home-based dietary treatment consisting of locally available foods and micronutrient supplements. RESULTS: There were 141 episodes of persistent diarrhea during the study: 70 in the treatment group (in 58 children) and 71 in the control group (in 62 children). During the intervention period (median: 17 d), weight gain in the treatment group exceeded that of the control group by 61.5 g/wk (95% CI: 49.2, 73.8), whereas there was no significant difference in linear growth on the basis of knee-heel length. At a median follow-up period of 6.6 mo after the intervention was stopped, weight gain in the treatment group exceeded that of the control group by 12.5 g/wk (95% CI: 7.7, 17.3); knee-heel length was 7.5 mm/y (4.8, 10.2) greater and total length was 0.65 cm/y (0.11, 1.19) greater in the treatment group. CONCLUSION: Therapeutic feeding and micronutrient supplementation had an immediate and sustained beneficial effect on growth in children with persistent diarrhea.

Administration, Oral↗
PubMed2000

Potency of a genetically detoxified mucosal adjuvant derived from the heat-labile enterotoxin of Escherichia coli (LTK63) is not adversely affected by the presence of preexisting immunity to the adjuvant.

The objective of the current studies was to evaluate whether the potency of a genetically detoxified mucosal adjuvant, derived from heat-labile enterotoxin of Escherichia coli (LTK63), was adversely affected by preexisting immunity. Studies of mice and pigs have involved consecutive intranasal immunization with LTK63 and 2 different vaccines (influenza virus hemagglutinin and a protein-polysaccharide conjugate of Neisseria meningitidis group C). The antibody responses to the vaccines plus LTK63 in naive animals were compared with the responses achieved in animals that previously had been immunized with the alternate vaccine plus LTK63. The data showed that the responses of both animal models to intranasal immunization were not adversely affected by the presence of preexisting immunity to the LTK63 adjuvant.

Adjuvants, Immunologic↗
PubMed1999

Purification and characterization of the hemagglutinin-neuraminidase of Porcine rubulavirus LPMV.

The Hemagglutinin-Neuraminidase (HN) from the LPMV strain of Porcine rubulavirus was purified from virions by ultracentrifugation in a continuous 20-60% sucrose gradient and by ion exchange chromatography. The HN is a glycoprotein of 66 kDa constituted by 50.5, 13.3 and 13.6% of non polar, uncharged polar, and charged polar amino acids, respectively. The HN contains 4% of carbohydrates, its glycannic portion is constituted by Man, Gal, GlcNAc, GalNAc, and Neu5Ac in 3:3:4:1:1 molar ratios. The HN possesses hemagglutinating activity in the presence of erythrocytes from several animal species, including human ABO, and treating the erythrocytes with neuraminidase or pronase abolishes this activity. The binding specificity of the purified HN was determined by hapten inhibition assays, indicating that the hemagglutinating activity of the HN is specific for sialic acid and Neu5Acalpha2,3Gal-containing structures.

Animals↗
PubMed1999

Community-based randomized controlled trial of reduced osmolarity oral rehydration solution in acute childhood diarrhea.

OBJECTIVE: The standard oral rehydration solution (ORS) recommended by WHO and UNICEF does not reduce the volume or frequency of stools or the length of the episode. Hospital-based studies from developing and developed countries and intestinal perfusion studies suggest a beneficial effect on water and sodium absorption with reduced osmolarity ORS as compared with standard ORS. We conducted a community-based study comparing the efficacy of reduced osmolarity ORS (224 mmol/l) with standard ORS (311 mmol/l) in acute childhood diarrhea in a West African community. METHODS: Infants and toddlers age 0 to 30 months having 738 episodes of diarrhea identified by weekly household visits were randomly assigned to treatment with either standard ORS (n = 376) or reduced osmolarity ORS (n = 362). The children were followed by daily home visits to assess ORS intake and clinical characteristics. Duration of diarrhea was compared by proportional hazards regression analysis, the hazard ratio being interpreted as the relative recovery rate between the children receiving the two types of ORS. Because earlier reports have suggested that weaning status might be an important modifier for the performance of reduced osmolarity ORS, the effect was assessed overall and as an interaction between type of ORS and weaning status and age. Maternal satisfaction was assessed in a paired analysis among mothers whose children participated at least twice in the study. RESULTS: In the overall analysis reduced osmolarity ORS was as efficacious as standard ORS as assessed by duration of diarrheal episode and total number of stool evacuations on Days 1 and 2. Non-breast-fed toddlers (i.e. children ages 12 to 30 months) treated with reduced osmolarity ORS had significantly shorter diarrheal episodes [1.14 days vs. 1.78 days with standard ORS; hazard ratio, 1.50; 95% confidence interval (CI), 1.07 to 2.09] and lower total number of stool evacuations on Days 1 and 2 (3.9 stool evacuations vs. 5.0 stool evacuations with standard ORS; ratio of geometric means, 0.77; 95% CI 0.60 to 1.01). No significant difference was found for breast-fed toddlers or for infants. There was no statistically significant difference in the ORS intake between the two treatment groups. The odds ratio for the mother preferring reduced osmolarity ORS to standard ORS was 1.92 (95% CI 0.97 to 3.85). CONCLUSIONS: Reduced osmolarity ORS was as efficacious as standard ORS. Non-breast-fed children treated with reduced osmolarity ORS had significantly shorter diarrheal episodes and a tendency toward lower stool frequency. These findings may be of importance, especially in developing countries where early weaning is common.

Acute Disease↗
PubMed1994

Geometric reconstruction in left ventricular aneurysm. Surgical aspects and early results.

The early results of 79 patients who underwent left ventricular aneurysmectomy with geometric and circular reconstruction in a seven-year experience are analyzed. The most common indication for operation was congestive heart failure (78.4%), either isolated (25.3%) or with angina (53.1%). Sixty patients (76%) were in NYHA class III and 10 (12.6%) in NYHA class IV at the time of surgery. Fifty-eight (73.4%) underwent coronary artery by-pass graft surgery. Hospital mortality was 5.1%, in patients older than 60 (12%), in NYHA class IV (20%), with poor left ventricular function (EF < 0.30-20% and LVED > 25) (14%), and with extensive coronary artery disease (10%) were under increased risk. Low cardiac output and use of intra-aortic balloon pump were also associated risk factors. Other risk factors mentioned in the literature are discussed. There were no deaths from isolated left ventricular aneurysmectomy. The early results of this study and the early and late results of others using the same technique are better than the results obtained in previous studies of different types of correction, suggesting that this is the procedure of choice for treating left ventricular aneurysm.

Adult↗
PubMed1994

[Physician-patient communication in oncology].

The authors analyse the problems of doctor/patient communication in Oncology with a particular incidence on the matter of diagnosis information. In a short theoretical review on the subject are debated the reasons that lead to an unbalanced power in doctor/patient relation, ships. It is pointed a general view of medical attitude along the last 25 years in several countries concerning diagnosis information and cultural differences, among other aspects. The AA seek to foresee reasons that may lead to a change on this matter. The medical class has been questioned about it's attitude on the diagnosis information of cancer. For that purpose a questionnaire was made and 80 doctors of HUC and CHC were interviewed. From the results the AA consider it is to be noted the following: 59% of the colleagues interviewed usually don't reveal the whole truth about the diagnosis; -Fear of patient's emotional reactions, is the most frequent reason to not to inform; There's the feeling among doctors that the knowledge of the truth has commonly a positive effect on doctor/patient relations.

Adult↗
PubMed1993

Bone marrow transplantation and cataract development.

OBJECTIVES: To evaluate risk factors for the development of posterior subcapsular cataract following bone marrow transplantation (BMT) and the results of patients undergoing cataract extraction. DESIGN: Retrospective case-control study. SETTING: Tertiary referral center. PATIENTS: Three hundred sixty-six patients (59% male, 41% female) undergoing BMT at one institution who survived for at least 1 month and underwent full ophthalmologic examination. Risk factors were then compared between patients who developed posterior subcapsular cataract and those who did not. INTERVENTION: Cataract surgery in six eyes of four patients. MAIN OUTCOME MEASURE: Formation of posterior subcapsular cataract. Data were obtained on all patients for type of BMT, pretransplantation regimen, underlying malignancy, demographic background, complications of BMT, and medications. RESULTS: Forty (10.9%) of 366 patients developed posterior subcapsular cataract. By univariate analysis, cataract formation was associated with total body irradiation, chronic graft-vs-host disease, the use of allogeneic bone marrow, and the total dose and duration of corticosteroid therapy. Multivariate analysis revealed that the total dose and duration of corticosteroid therapy were the most important risk factors, while total body irradiation was not a statistically significant risk factor. Cataract surgery was performed in six eyes of four patients, all of whom developed visual acuities of 20/40 or better. CONCLUSION: Posterior subcapsular cataract following BMT is uncommon and rarely requires surgery. Total dose and duration of corticosteroid therapy are the most important risk factors for development of cataract, but total body irradiation is not a statistically significant risk factor.

Adolescent↗
PubMed1993

Long-term results of large-dose, single-session phenol injection sclerotherapy for hemorrhoids.

PURPOSE: The aim of our study was to assess the medium to long-term outcome following single session large dose injection sclerotherapy for symptomatic hemorrhoids. METHODS: One hundred eighty-nine patients (male = 106, female = 83, median age, 51; range, 20-85 years) were assessed following single-session, large-dose (3 x 5 ml) phenol injection therapy. The most frequent complaint was bleeding (100 percent). RESULTS: At four-year follow-up, 53 patients (28.0 percent) were cured, 26 (13.7 percent) were improved, 35 (18.5 percent) remained unchanged, 59 (31.2 percent) deteriorated, and 16 (8.5 percent) required surgical intervention. Among the patients who were not cured, symptoms were minimal in 50 percent. Sclerotherapy was associated with a reduced incidence of bleeding (P < 0.05) but an increase in difficulty in perineal cleaning was observed (P < 0.05). CONCLUSION: Large-dose, single-session sclerotherapy provides only short-term benefits in the majority of patients with symptomatic hemorrhoids.

Adult↗
PubMed1993

Chromosome abnormalities in patients treated with 4-hydroperoxycyclophosphamide-purged autologous bone marrow transplantation.

Autologous bone marrow transplantation (ABMT) offers potentially curative therapy for patients with acute leukemia and lymphoma, yet little information exists about the chromosome abnormalities observed in ABMT recipients. Clonal abnormalities of chromosome 1 were reported by van den Akker. We report the cytogenetic results of 55 patients who underwent ABMT between November 1987 and July 1990: acute nonlymphocytic leukemia (ANLL, 22), acute lymphocytic leukemia (ALL, eight), Hodgkin's disease (seven), lymphoma (16), other (two). ANLL patients received busulfan and cytoxan, and the others received cytoxan and total body irradiation as their preparative regimen before transplant. BM was purged ex vivo with 4-hydroperoxycyclophosphamide (4-HC) at 30-100 micrograms/ml before reinfusion to kill tumor cells. Cytogenetic analysis was performed before and after transplant. Between one and four posttransplant specimens of BM were analyzed per patient (range 36-921 days). Chromosome abnormalities were observed in 14 of 55 patients after transplant. Seven had clonal abnormalities; all were in leukemic relapse, and one karyotype had complex rearrangements. Clonal abnormalities of chromosome 1 were not observed. Seven patients had nonclonal changes, and three of these have had overt clinical relapse. Our data suggest that clonal abnormalities observed posttransplant are best explained by clinical relapse of tumor and that ex vivo marrow purging with 4-HC is not likely to induce clonal chromosome abnormalities in normal cells. Long-term observation of these patients will be required to answer that question definitively, however.

Adolescent↗
PubMed1992

Karyotype at relapse following allogeneic bone marrow transplantation for chronic myelogenous leukemia.

Eighty-four patients underwent allogeneic or syngeneic bone marrow transplantation as therapy for chronic myelogenous leukemia (CML) during a 5-year period at The Johns Hopkins Oncology Center. We describe the karyotype at relapse in 19 patients who were Ph chromosome positive (Ph+) at diagnosis. Eighty-four percent of patients demonstrated clonal and/or nonclonal chromosome abnormalities in addition to the t(9;22)(q34;q11) at first detection of relapse or later during relapse. These abnormalities included: Ph plus additional clonal abnormalities (three patients), Ph plus nonclonal abnormalities (five patients), Ph plus additional clonal and nonclonal abnormalities (eight patients). Three patients had only the original Ph+ clone. The additional chromosome abnormalities were primarily structural, and entirely different from those most frequently observed during karyotypic evolution in conventionally treated CML. Chromosome 1 was most frequently involved, with 1q32 being the location of three clonal and two nonclonal abnormalities. Other sites included 6p21-22 (the site of two clonal abnormalities), 7p21-22, and 10q21 (the site of two clonal and one nonclonal abnormality each). Chromosomes 5 and 7q, regions of frequent involvement in acute nonlymphocytic leukemia that follows chemotherapy for other malignancies, were infrequently involved. The clinical significance of these additional abnormalities remains undetermined at this time.

Adult↗
PubMed1991

Comparison of molecular and cytogenetic methods in the evaluation of engraftment following allogeneic bone marrow transplantation.

Cytogenetic evaluation of patients after bone marrow transplantation (BMT) has provided a standard method of documentation of hematopoietic engraftment. More recently, recombinant DNA technology has also been applied to determine engraftment status. In order to establish the relative utility of these methods in clinical practice we have directly compared the data from cytogenetic and recombinant DNA methods, evaluating engraftment status in 68 BMT recipients. Patients were evaluated pre-transplant, 30, 60, 90, and 180 days after BMT, and yearly thereafter for 1) the presence or absence of the Y chromosome in sex-mismatched allogeneic transplant recipients, 2) the presence or absence of the Philadelphia chromosome [t(9;22)] in patients transplanted for chronic myelogenous leukemia (CML), 3) restriction fragment length polymorphism (RFLP) profiles, and/or 4) clonal rearrangement of the bcr gene. Cytogenetic examination of unstimulated bone marrow and recombinant DNA tests of nucleated peripheral blood or bone marrow cells produce qualitatively similar data in the identification of patient and donor cells and/or normal and tumor cells. Differences in the results obtained by the two analytic methods were most often due to the restricted cell populations evaluable by cytogenetic studies of PHA-stimulated peripheral blood specimens. DNA analyses could frequently be applied at earlier intervals after transplantation and, in cases of graft rejection, when cell counts were low. Although recombinant DNA methods required fewer cells and demonstrated greater sensitivity in detection of minor cell populations in the majority of instances, the cytogenetic evaluation may complement the DNA studies and allow detection of additional chromosomal anomalies.

Bone Marrow Transplantation↗
PubMed1991

Optic disc edema after bone marrow transplantation. Possible role of cyclosporine toxicity.

Bone marrow transplantation has become widely used in the treatment of aplastic anemia and leukemia. Cyclosporine is used as prophylaxis against graft-versus-host disease. The authors report on eight cases of optic disc edema in patients taking cyclosporine after allogenic bone marrow transplant. Thorough evaluation revealed a possible alternate cause in two cases. In all cases, the optic disc edema resolved after discontinuing or decreasing the cyclosporine. Although cyclosporine has not previously been associated with optic disc edema, it has been implicated as the cause of a variety of neurologic side effects. Bone marrow transplant patients taking cyclosporine should be followed for the development of optic disc edema.

Adolescent↗
PubMed1990

Density-gradient separation for 4-hydroperoxycyclophosphamide purging of autologous bone marrow grafts.

We studied density-gradient separation of autologous bone marrow grafts in preparation for ex vivo 4-hydroperoxy-cyclophosphamide (4-HC) purging. A two-step procedure of buffy coat isolation followed by Ficoll-diatrizoate separation was used. Buffy-coat cells were isolated primarily either using the COBE 2991 Blood Cell Processor or Haemonetics 30 Cell Separator. All density-gradient separations were performed using the COBE 2991. The nucleated cell recoveries after buffy-coat isolation were 44.3 +/- 10.4% and 85.1 +/- 10.5% (+/- standard deviation, P less than 0.001) for the Haemonetics 30 and COBE 2991 isolated grafts, respectively. The final nucleated cell recoveries after density-gradient separation for these two buffy-coat techniques were 24.2 +/- 10.1% and 29.5 +/- 14.7% (p = 0.30). Compared to manual density-gradient separation, the techniques using the COBE 2991 recovered slightly higher numbers of nucleated cells and CFU-GM. The red blood cell concentration of the 4-HC incubation mixture was 1.0 +/- 0.6% and the CFU-GM survival after treatment was 2.4 +/- 2.6%. The variability in CFU-GM survival after 4-HC incubation of the density-gradient separated grafts appears less than previous experience treating buffy-coat cells. Density-gradient separation of autologous bone marrow appears to provide a more uniform treatment with 4-HC and may improve the clinical transplant course of the autograft recipient.

Bone Marrow↗