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Biomedical subjects

A S Carvalho

Publications and source records attributed to A S Carvalho.

16 recordsLinked to original sources
PubMed2005

Effect of the pH of growth on the survival of Lactobacillus delbrueckii subsp. bulgaricus to stress conditions during spray-drying.

AIMS: The aim of this study was to optimize survival of Lactobacillus delbrueckii subsp. bulgaricus during spray-drying and subsequent storage through optimizing the pH of growth conditions. METHODS AND RESULTS: Cell concentrates previously grown without or with pH controlled were spray-dried and stored at 20 degrees C and heat treated at 57 degrees C. Cells grown under noncontrolled pH were more resistant to both drying and heating than cells grown under controlled pH but no significant differences were observed during storage. The intracellular proteins profile of cells grown under both conditions was studied by two-dimensional SDS-polyacrylamide gel electrophoresis. Eight proteins were identified using automated mass spectrometry (MS) and tandem mass spectrometry (MS/MS) data acquisition. Of the identified proteins, only cochaperonin GroES corresponded to a known heat shock protein (HSP). The other proteins identified are proteins involved in glycolysis. For cells grown under noncontrolled pH the expression of the Hsp70, GroES and GroEL, measured by Western blotting, was enhanced. CONCLUSIONS: The higher resistance of cells grown under noncontrolled pH correlates with the enhanced production of heat shock proteins. SIGNIFICANCE AND IMPACT OF THE STUDY: Growth of L. bulgaricus under controlled pH (commonly used by the starter cultures production industry) results in cells more sensitive to stresses frequently encountered by the cells during starter cultures preparation/storage/utilization.

Bacterial Proteins↗
PubMed2003

Effect of various growth media upon survival during storage of freeze-dried Enterococcus faecalis and Enterococcus durans.

AIMS: The effects of three different growth media (MRS, M17 and Lee's) on survival during freeze-drying and subsequent storage of six strains of Enterococcus faecalis and two strains of E. durans were investigated. METHODS AND RESULTS: Distinct Enterococcus spp. strains were grown on M17, MRS and Lee's broth, freeze-dried and stored at 20 degrees C in air under darkness. At regular intervals throughout storage, freeze-dried samples were rehydrated and then plated on M17 agar. CONCLUSIONS: A higher survival rate during storage of dried E. durans was obtained when growth occurred in MRS. The same effect was not observed, however, for the majority of E. faecalis strains, which clearly survived better in the dried state when this organism had been grown in M17 or Lee's medium. SIGNIFICANCE AND IMPACT OF STUDY: The survival of the dried Enterococcus spp. tested during storage was shown to be strain-specific and dependent on the growth medium.

Culture Media↗
PubMed2002

Ethical guidance on human embryonic and fetal tissue transplantation: a European overview.

This article presents an overview of regulations, guidelines and societal debates in eight member states of the EC about a) embryonic and fetal tissue transplantation (EFTT), and b) the use of human embryonic stem cells (hES cells) for research into cell therapy, including 'therapeutic' cloning. There appears to be a broad acceptance of EFTT in these countries. In most countries guidance has been developed. There is a 'strong' consensus about some of the central conditions for 'good clinical practice' regarding EFTT. International differences concern, amongst others, some of the informed consent issues involved, and the questions whether an intermediary organisation is necessary, whether the methods of abortion may be influenced by the possible use of EFT, and whether EFTT should only be used for the experimental treatment of rare disorders. The potential use of hES cells for research into cell therapy has given a new impetus to the debate about (human) embryo research. The therapeutic prospects with regard to the retrieval and research use of hES cells appear to function as a catalyst for the introduction of less restrictive regulations concerning research with spare embryos, at least in some European countries. It remains to be seen whether the prospect of treating patients suffering from serious disorders with transplants produced by therapeutic cloning will decrease the societal and moral resistance to allowing the generation of embryos for 'instrumental' use.

Bioethics↗
PubMed2002

Bacteriocin production by spray-dried lactic acid bacteria.

AIMS: Cell survival and antagonistic activity against Listeria innocua, Listeria monocytogenes and Staphylococcus aureus were investigated after spray-drying three bacteriocin-producing strains of lactic acid bacteria: Carnobacterium divergens, Lactobacillus salivarius and Lactobacillus sakei. METHODS AND RESULTS: Bacterial cell concentrates were spray-dried and stored at 4 degrees C and 18 degrees C and 0.3% ERH (equilibrium relative humidity). Enumeration and antagonistic activity were evaluated before and after spray-drying and at regular intervals during storage. CONCLUSIONS: A higher survival rate was obtained when survival was performed at 4 degrees C. With the exception of Carnobacterium divergens which lost the inhibitory activity against Staph. aureus after drying, antagonistic production was not affected by the process nor by the storage. Of the three species studied, Lact. salivarius showed the highest resistance to the spray-drying and storage processes. SIGNIFICANCE AND IMPACT OF THE STUDY: Spray-drying is a potentially useful process for large scale production of dried powders containing viable organisms with antagonistic activity against pathogens.

Aerosols↗
PubMed2001

Novel nitroimidazoles with trypanocidal and cell growth inhibition activities.

Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, affects 18 million people in Latin America and is an important cause of heart disease. Although transmission has been reduced, an effective therapy for the infected population is lacking. New nitroimidazoles were designed and synthesized aimed at the development of a trypanocidal drug. The coupling of nitroimidazoles with heterocyclic N-trifluoromethyltriazolyl and pyrazolyl groups, 5-[N-(3-(5-trifluoromethyl)-1H-1,2,4-triazolyl)]amino-1-methyl-4-nitroimidazole (compound 4) and 5-N-(1-pyrazolyl)-1-methyl-4-nitroimidazole (compound 5). The in vitro trypanocidal effects of compounds 4 and 5 were evaluated. The results demonstrated that compound 5 was the most active compound, killing about 100% and 64% of the parasites in 0.3 mg/ml and 0.003 mg/ml concentrations, respectively. Interestingly, compound 4 also inhibited myeloma cell growth in a dose-dependent manner.

Animals↗
PubMed2000

Factors associated with Helicobacter pylori infection by a cagA-positive strain in children.

Although infection with a cagA-positive Helicobacter pylori strain is considered a risk factor for the development of duodenal peptic ulcer in adults, this association has not been demonstrated in children. The presence of cagA was investigated by polymerase chain reaction in H. pylori strains isolated from 27 children with duodenal ulcer and 53 without duodenal ulcer. All patients (100%) with duodenal ulcer and 33 (62.3%) without ulcer were colonized by a cagA-positive strain (P=.00007). A cagA-positive status was also associated with a more marked macroscopic gastritis, with a greater inflammatory infiltrate of both mononuclear and polymorphonuclear cells in the antral and oxyntic gastric mucosae and degenerative and regenerative changes of the gastric mucosa. Increased cagA positivity was also associated with increased age, but no association between cagA-positive status and sex was observed.

Adolescent↗
PubMed2000

Immunoblot analysis of humoral immune response to Helicobacter pylori in children with and without duodenal ulcer.

Several studies have demonstrated that enzyme-linked immunosorbent assay is not a sensitive and specific method to diagnose Helicobacter pylori infection in children, especially in the younger ones. Since serum immune response can also be determined by immunoblotting and it permits the detection of antibodies to virulence factors such as CagA and VacA, we evaluated the accuracy of a commercial immunoblotting test to diagnose H. pylori infection and to assess the humoral immune response to different H. pylori antigens in 122 children who underwent upper gastrointestinal endoscopy. The presence of H. pylori was determined in antral biopsy specimens by culture, preformed urease test, and histological analysis. H. pylori was identified by microbiological and histopathological methods in 66 children (including all of the 21 who had duodenal ulcer). Antibodies to H. pylori were detected in 63 infected children and in 8 noninfected ones. The sensitivity, specificity, and positive and negative predictive values of the immunoblotting test were 95.5, 85.7, 88.7, and 94.1%, respectively. The number of immunoreactive bands increased with age (P = 0.003), and the bands of 35 kDa (P = 0.013); 89 kDa, the VacA antigen (P = 0.001); and 116 kDa, the CagA antigen (P = 0.00004) were more frequently observed in older children. The frequency of the bands of 89 kDa (P = 0.001) and 116 kDa (P = 0.03) was higher in children with duodenal ulcer than in H. pylori-positive children without the disease. In conclusion, the immunoblotting test appears to be useful for the diagnosis of H. pylori infection in children, even in the younger ones.

Adolescent↗
PubMed2000

[Peptic ulcer]

OBJECTIVE: To present a current review about pathogenesis, pathophysiology, diagnosis, and treatment of peptic ulcer disease in children, based on the reviewed publications and the author personal experience. METHODS: We revised the most relevant articles about peptic ulcer in children, published from the last 20 years. RESULTS: The gastroduodenal peptic ulcer is very common in adults, mostly in the developing countries. Although it is less frequent in children, the optical fibroendoscopy has improved the number of diagnosed cases. The peptic ulcer is classified as its etiology in primary and secondary. The secondary peptic ulcer is related to a subjacent disease or use of drugs, while the primary ulcer happens in the absence of underlying systemic diseases The primary duodenal ulcer is the most common presentation, and there are strong evidences of the H. pylori association in the etiology. Clinical presentation changes with age and ulcer type. Secondary ulcers are mostly acute and sometimes dramatic, while the primary ones have a chronic evolution mostly similar to patients with functional recurrent abdominal pain, but the presence of epigastric pain, feeding-related pain, vomiting, bleeding, familiar history for peptic ulcer, nocturnal pain, and male gender are strongly related to peptic ulcer. The acid antisecretory agents have great efficacy on relieving symptoms and solving ulcerate lesion, although the H. pylori eradication itself prevents primary duodenal ulcer recurrence. CONCLUSIONS: The primary peptic ulcer involve many factors in Its etiopathogenesis, being H. pylori the most important of them Although there isn t yet a ideal therapeutic course. The antibiotics play an important role in peptic ulcer and the H. pylori research must be done for na accurate diagnosis and treatment.

Journal Article↗
PubMed1991

Differences in distribution and severity of Helicobacter pylori gastritis in children and adults with duodenal ulcer disease.

The presence of Helicobacter pylori and the gastric mucosa histology were investigated in 15 children and 15 adults with duodenal ulcer. The microorganism was isolated from antral and oxyntic mucosa in 100% of patients, both adults and children. The results of Gram stain and preformed urease test were compared with those of culture and there was no difference in sensitivity among the tests. Antral chronic gastritis was observed in all patients. However, children presented oxyntic gastritis more frequently than adults. It was also observed that the endoscopic aspects were different in the two groups of patients. The results here observed strongly support the idea that, as well as in adults, H. pylori is the causative agent of the gastritis seen in children with duodenal ulceration. On the other hand, the histological findings of oxyntic mucosa of children with duodenal ulcer were different from those of adults.

Adolescent↗
PubMed1991

Histamine concentration of gastric mucosa in Helicobacter pylori positive and negative children.

The histamine concentration was determined by enzymatic isotopic method in biopsy specimens of oxyntic mucosa from 37 children. Nineteen of the 37 had Helicobacter pylori associated gastritis (9 with duodenal ulcer). The histamine concentration in the H pylori negative group was mean (SD) 54.1 (23.1) micrograms/g fresh weight, and that in the H pylori positive group was 26.3 (14.2) micrograms/g (p less than 0.01). There was also a significant difference between H pylori positive patients with duodenal ulcer (19.8 (6.3) micrograms/g) and those without ulcer (31.4 (17.9) micrograms/g) (p less than 0.05). These results suggest that H pylori positive patients, especially those with duodenal ulcer, have reduced 'stored' histamine, perhaps because of increased histamine liberation.

Adolescent↗
PubMed1991

Diagnosis and distribution of Helicobacter pylori in the gastric mucosa of symptomatic children.

1. The demonstration of the association of H. pylori with gastritis and peptic ulcer has been of increasing interest to gastroenterologists, microbiologists, and histopathologists. 2. In this study, the presence of H. pylori in the gastric mucosa of children was investigated by culture, preformed urease test, and carbolfuchsin staining of biopsy smears. 3. The organism was detected in 44.9% of the children studied, and found to be distributed equally on the antral and fundic mucosa. 4. Compared to culture, the urease test and carbolfuchsin staining proved to be of higher sensitivity and specificity in detecting H. pylori.

Adolescent↗
PubMed1989

Chronic calcifying pancreatitis in children: a report of six cases.

1. A study of six patients with Chronic Calcifying Pancreatitis (CCP) occurring over a 10 year period, representing an incidence rate of approximately 1:1,000 of the inpatients in the children's ward of a general hospital in central Brazil, is reported. 2. Major clinical manifestations as well as therapeutic management are described. 3. The possible relationship between CCP and primary protein-calorie malnutrition is discussed and the importance of a CCP diagnosis when dealing with malnourished children who do not respond satisfactorily to common therapy is emphasized.

Calcinosis↗
PubMedDate not supplied

Fluoride release from some dental materials in different solutions.

Most of the data reported on release of fluoride from dental materials are based upon measurements made in deionized water and artificial saliva, which do not simulate the dynamics of caries development. So, the purpose of this study was to determine the level of fluoride released from different restorative materials in storage solutions, considering the caries process (pH-cycling). Six cylindrical samples of each material (Chelon-Fil, Dyract, Variglass, Vitremer, and Tetric) were prepared and suspended individually in 2.0 mL of each studied solution. The studied media were deionized water, artificial saliva, and solutions for pH-cycling (demineralizing solution--pH 4.3 and remineralizing solution--pH 7.0). All solutions were changed daily over 15 days. Fluoride release was determined after buffering the solutions with an equal volume of TISAB. The fluoride release was higher in pH-cycling than in the other solutions (P < 0.05), and changes of the rank order of fluoride release from the studied materials occurred when the different media were considered (P < 0.05). The data suggest that the comparison of fluoride released from dental materials is dependent on the medium used in the evaluation.

Acrylic Resins↗
PubMedDate not supplied

T and B lymphocytes, total serum IgE and peripheral eosinophils in bronchial asthma.

Absolute T and B lymphocytes, assayed by E and EAC rosette techniques, serum IgE levels, total eosinophil counts and delayed hypersensitivity cutaneous reactions were studied in 39 asthmatic subjects (19 extrinsic asthmas and 20 intrinsic asthmas) and in 15 age-matched control subjects. The mean value of T lymphocytes was 1753 +/- 709 mm.3 in the extrinsic group, 1511 +/- +/- 530 mm.3 in the intrinsic, and 1609 +/- 451 mm.3 in the controls. There was no statistical difference between the two groups of patients and the controls (P > 0.05). There was also no statistical difference of B lymphocytes between the two groups of patients and the controls. Serum IgE was elevated in 8 extrinsic asthmatics (42.1%), in one intrinsic (5%), and in none of the control population. The mean value of eosinophils ws significantly higher (P < 0.01) in the extrinsic group as compared to the controls. The same was true of the intrinsic group, but not so significantly (P congruent to 0.02). No correlation was observed between the number of T lymphocytes and the skin tests, serum IgE and total eosinophil counts.

Adolescent↗