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J C Sousa

Publications and source records attributed to J C Sousa.

At least 37 records · Page 2Linked to original sources
PubMed1998

Typing of Helicobacter pylori vacA gene and detection of cagA gene by PCR and reverse hybridization.

The present report describes an analysis of two virulence genes of Helicobacter pylori. Parts of the cagA gene, as well as parts from the signal (s) and middle (m) regions of the mosaic vacA gene, were amplified with biotin-labelled PCR primers and the products were subsequently analyzed by a single-step reverse hybridization line probe assay (LiPA). This assay comprises a strip containing multiple specific probes for the vacA s region (sla, slb, and s2 alleles), the vacA m region (ml and m2 alleles), and the cagA gene. A total of 103 H. pylori-positive materials, including cultured isolates, gastric biopsy specimens, and surgical specimens from patients living in Portugal (n = 55) and The Netherlands (n = 48) were tested by the PCR-LiPA. cagA was detected in 84 and 73% of the Portuguese and Dutch patients, respectively. vacA typing results, as determined by reverse hybridization, were completely concordant with those of sequence analysis. Most Portuguese patients (72%) contained type slb, whereas most Dutch patients (61%) contained type sla (P < 0.001). The method is also very effective at detecting the presence of multiple genotypes in a single biopsy specimen. The prevalence of multiple strains in Portuguese patient samples was significantly higher (29%) than that in Dutch patient samples (8%) (P = 0.001). There was a significant association between the presence of ulcers or gastric carcinoma and the presence of vacA type sl (sla or slb; P = 0.008) and cagA (P = 0.003) genes.

Antigens, Bacterial↗
PubMed1998

[Myocardial morphometric study in protein-energy malnourished adults].

PURPOSE: To compare cardiac muscle cells width and cardiomyocyte lipofuscin pigment presence between malnourished and non-malnourished necropsied adults. METHODS: Out of 315 necropsy protocols of adults randomly chosen, those with edema, ascitis, systemic arterial hypertension, chronic liver disease, and heart disease were excluded. Malnutrition was defined by body mass index (BMI) < 17 kg/m2. Cardiomyocytes morphometry study and lipofuscin pigment counts were performed. RESULTS: Malnourished (n = 8) and controls (n = 4), respectively, showed statistical differences in relation to BMI (14.86 +/- 1.13 vs 22.02 +/- 0.9 kg/m2), heart weight/body weight ratio (0.68 +/- 0.09 vs 0.54 +/- 0.07%), cardiomyocytes width (10.91 +/- 0.77 vs 12.90 +/- 1.82 microns) and lipofuscin pigment presence (39.1 vs 54.4%). CONCLUSION: When compared with controls, necropsied malnourished adults showed decreased myocardial fibers diameters and lower lipofuscin pigment presence. These findings might reflect altered metabolism, and would be associated with harmful clinical effects in terminally ill patients.

Adult↗
PubMed1993

Blood-retinal barrier permeability and its relation to progression of retinopathy in patients with type 2 diabetes. A four-year follow-up study.

Forty patients with late-onset diabetes (age at diagnosis 30 years or more) and minimal retinopathy as found by fundus photography were followed prospectively by repeated examination (baseline, 1 year, and 4 years). The study shows that early retinopathy changes are not permanent or invariably progressive. In the 1st year of follow-up microaneurysms worsened in 25%, improved in 10%, and remained stabilized in 65%. Vitreous fluorometry was able to detect an overall increase of 0.84 +/- 1.06 x 10(-6) min-1 in blood-retinal barrier (BRB) penetration ratios. After 4 years, 16 of the 40 patients had undergone photocoagulation (focal photo-coagulation in 11 and pan retinal photocoagulation in 5). The eyes that needed photocoagulation were the eyes that had higher fluorometry penetration ratios at the patient's entry into the study and showed a higher rate of deterioration during the 1st year of the study (5.54 +/- 1.97 vs 3.11 +/- 1.22 x 10(-6) min-1, P < 0.001, initial values; 1.52 +/- 0.76 vs 0.45 +/- 0.99 x 10(-6) min-1, P < 0.001, annual increase in leakage). The eyes that did not need photocoagulation, 24 out of 40, showed stable fluorometry readings within the 4-year period of follow-up (+0.02 +/- 0.98 10(-6) min-1). Abnormally high vitreous fluorometry values and their rapid increase over time appear to be good indicators of rapid progression and worsening of the retinopathy.

Adult↗
PubMed1991

Characterization of beta-lactamases encoded by pathogenic strains of Escherichia coli from Portugal.

A survey of 2036 strains of Escherichia coli was conducted in Oporto, Portugal, to establish the prevalence of resistance to beta-lactam antibiotics. Isolates were from hospital and clinical practice patients, and were further divided into urinary and non-urinary pathogens. A high level of resistance to aminopenicillins (55.3%) was observed. Further examination of the resistant strains showed that the frequencies of occurrence of known beta-lactamases were as follows: TEM-1 (78.2% of resistant strains); SHV-1 (7.9%); TEM-2 (0.45%); OXA-1 (1.5%); HMS-1 (0.18%); TEM-1 + SHV-1 (4.2%). Other pairs of beta-lactamases were also identified in less than 2% of the resistant strains. In addition, 4.7% of the resistant strains produced elevated levels of a presumed chromosomal cephalosporinase, while 0.9% produced a ceftazimidase of pI 5.8-5.9 which was similar to TEM-6.

Anti-Bacterial Agents↗
PubMed1983

Developmental guidelines for children with myelodysplasia.

A new inventory of 166 milestones and developmental tasks was designed and given to parents of 173 children with myelodysplasia to use over a 2 1/2-year period to record their children's development. The inventory included items in the categories of self-help (including independent toileting), personal-social development, and gross motor development. The children were placed in one of four subgroups according to their level of paralysis. For each motor-level group, the percentage of those performing each item at various ages was calculated. The ages of routine performance of selected self-help and personal-social items are reported for 20, 50, and 80 percent achievement for the children for whom the data were known. There was a tendency for the less paralyzed children to learn skills more quickly than their more paralyzed peers. However, the wide age ranges within groups for learning individual skills indicate that factors other than the level of paralysis affect the rate of development, and these factors need to be identified. The data provided represent a reasonable estimate of when children with varying degrees of paralysis can first be expected to perform developmental tasks. The tables can be used to establish learning objectives and programs so that more children with myelodysplasia can learn independence at an earlier age.

Activities of Daily Living↗
PubMed1979

A Bacillus subtilis mutant requiring dipicolinic acid for the development of heat-resistant spores.

A Bacillus subtilis mutant is described which forms heat-resistant spores only in the presence of external dipicolinic acid (DPA). The mutation, dpa-1, is localized in a new sporulation locus, linked to pyrA. The dpa-1 strain is unable to synthesize DPA but can incorporate external DPA. The amount of DPA incorporated, the frequency of heat-resistant spores and their degree of resistance are all dependent on the concentration of external DPA. Spores of dpa- 1 strains exhibit normal resistance to most chemicals, including octanol and chloroform, but not to ethanol, pyridine, phenol and trichloroacetic acid. Complete resistance to the latter group depends on DPA. DPA incorporation is slow and apparently requires an energy supply but not protein synthesis. Direct involvement of DPA in the heat-resistance of the spores is suggested. Thin sections of DPA-less spores exhibit clearly visible cytoplasmic membranes and ribosomes. These structures are absent or less visible in the core of spores obtained with added DPA.

Bacillus subtilis↗
PubMed1979

Decadent sporulation mutants of Bacillus subtilis.

In decadent sporulation mutants, sporulating populations are heterogeneous: the cells reach successive chemical and physical resistances with progressively decreasing frequencies. Each decadent mutant can be characterized by the shape and slope of the curve describing the frequency of cells resistant to various agents ('the resistance spectrum'). In some mutants the resistance spectrum decreases progressively from xylene resistance to heat resistance; in other mutants it decreases rapidly between octanol resistance and chloroform resistance. Electron microscopy showed that in two mutants the majority of the cells are blocked at stages III and IV; the number of cells that develop further to reach successive morphological stages falls off progressively. In two other mutants most cells reach stage V. Cortexless spores are also frequent. One of the decadent mutations, SpoL1, was localized between aroD and acf. The phenotype of decadent mutants is discussed in terms of sequential gene activation.

Bacillus subtilis↗
PubMed1979

Genetic instability of sporulation-associated characters in a Bacillus subtilis mutant: relationship between sporulation, segregation and the synthesis of extracellular enzymes (kinetic studies).

In the genetically unstable, protease-overproducing 'medusa (M) strains of Bacillus subtilis, segregation of stable, wild-type-like B cells occurred mainly during sporulation. After the end of the exponential growth phase, a small fraction of M cells sporulated quickly and formed M spores, while the majority of the cells, after a 'critical period', gave rise to B segregants which sporulated after a delay. Segregation occurred without cell division. Delayed sporulation, segregation and protease overproduction are related. Similar but more complex results were obtained with the highly unstable TD strains. Sporulation and the kinetics of protease overproduction were also followed in several stable segregants. Depending on the strain, either the rate of protease production or both the rate and time course were affected. The results are interpreted in terms of sequential activation and de-activation of sporulation genes. The production of the alkaline and the neutral proteases was, in general, under common genetic control. In some strains alpha-amylase was also overproduced.

Alleles↗
PubMed1979

Effects of local anesthetics on bacterial cells.

The membrane effects of chlorpromazine, nupercain, tetracain, and procain were studied using Bacillus cereus, B. megaterium, B. subtilis, and Streptococcus faecalis, protoplasts from S. faecalis, and isolated membranes from B. subtilis. Chlorpromazin, nupercain, and tetracain produced characteristic micromorphological alterations after treatment for 5 to 30 min at pH 7.0 and 20 degrees C; the membrane staining pattern changed from asymmetric to symmetric, complex mesosome-like structures appeared, and membrane fractures and solubilization occurred. Procain at concentrations up to 100 mM did not induce detectable alterations. Protoplasts were quickly lysed by 10 mM tetracain. A rapid and extensive leakage of K+ was induced by chlorpromazin, nupercain, and tetracain. Procain (100 mM) induced a slight K+ leakage. The membrane respiratory activity of intact B. cereus cells (as measured by the triphenyl tetrazolium reduction) and the succinic dehydrogenase activity of B. subtilis isolated membranes were found to be inhibited by the four local anesthetics. The concentrations that produced 50% inhibition of those activities are correlated with the hydrophobicities of the anesthetic molecules.

Anesthetics, Local↗
PubMed1978

Ultrastructure and development of an exosporium-like outer spore envelope in Bacillus subtilis.

An exosporium-like outermost envelope is occasionally observed in thin sections of Bacillus subtilis spores. Treatment of the mature spores with urea and mercaptoethanol (sometimes completed by sodium dodecyl sulfate) or with NaOH, disorganizes and partially solubilizes the outer spore coat. This treatment permits a clear visualization of the exosporium in all spores of several B. subtilis strains. Exosporium appears either as a single sheet, 8-9 nm thick, or with a triple-layered unit membrane-like profile. Frequently it exhibits a crystal-like periodic pattern. The exosporium primordium appears first at stage IV, and its development is apparently independent of the formation of the cortex and of the spore coats. No morphological relationship was found between the outer forespore membrane and the exosporium.

Bacillus subtilis↗
PubMed1978

Ultrastructural effects of chemical agents and moist heat on Bacillus subtilis. I--Effects on vegetative cells.

The ultrastructural alterations induced by treatment of vegetative Bacillus subtilis cells with organic solvents, trichloroacetic acid (TCA) and moist heat were examined by electron microscopy. Organic solvents disorganize the membrane and change the asymmetric unit membrane profile to a symmetric profile. They also lead to partial solubilization of the membrane and produce small or extensive gaps. Membrane damaging activity increases in the following order: xylene = toluene less than octanol less than choroform. TCA coagulates the cytoplasm which shows large, electron-dense, pronase-sensitive blocks. Moist heat alters both the membrane and the cytoplasm.

Bacillus subtilis↗
PubMed1978

Ultrastructural effects of the chemical agents and moist heat on bacillus subtilis. II.--Effects on sporulating cells.

When sporulating cells are treated with the organic solvents (xylene, toluene, octanol and chloroform), with TCA or with moist heat (10 min at 80 degree C), the sporangial cells exhibit the same ultrastructural changes as do the vegetative cells. The forespores undergo similar changes after early but not after late treatment. Resistance toward the killing effect and toward ultrastructural alterations appear in the same order. One could correlate the appearance of resistances with precise ultrastructural events as follows:--xylene resistance: cortex formation (stage IV);--resistance to toluene, octanol and chloroform: coat development and cortex maturation (respectively early, middle and late stage V);--TCA and heat resistance: spore maturation (stage VI). The possible mechanisms of the chemical resistances are discussed.

Bacillus subtilis↗
PubMed1976

Bacterial mesosomes. Real structures or artifacts?

The ultrastructural study of membrane organization in gram-positive bacteria related to the OSO4 fixation conditions revealed that large, complex mesosomes are observed only when the bacteria are subjected to an initial fixation with 0.1%OSO4 in the culture broth, as in the prefixation step of the Ryter-Kellenberger procedure. Evidence was obtained suggesting that the large mesosomes are produced by this prefization. The kinetic study of the membrane morphological alterations occurring during the prefixation of Bacillus cereus with 0.1%OSO4 in the culture broth showed that the amount of mesosome material increases linearly from zero to a maximum observed at 1.7 min of prefixation and that at about this time a maximum is reached for the number of mesosomes per unity of cell area and for the average individual mesosome area. The large mesosomes observed in gram-positives fixed by the complete Ryter-Kellenberger procedure would be the result of the membrane-damaging action of 0.1%OSO4. Such damaging action was deduced from the observation thay 0.1%OSO4 quickly lyses protoplasts and induces a quick and extensive leakage of intracellular K+ from B. cereus and Streptococcus faecalis. In support of that interpretation is the observation that in bacteria subjected to several membrane-damaging treatments, mesosome-like structures are seen after three different fixation procedures. In bacteria initially fixed with 1% OSO4, 4% OSO4 or 2.5% glutaraldehyde, no large complex mesosomes are observed, small and simple invaginations of the cytoplasmic membrane being present. The size of these minute mesosomes is inversely proportional that causes of fixation. Uranyl acetate was found among the studied fixatives the one to the rate the least damage to bacterial membranes. This fixative satisfactorily preserves protoplasts. In bacteria initially fixed with uranyl acetate no mesosomes were found. The results of the present work throw serious doubts on the existence of mesosomes, both large and small, as real structures of bacterial cells. It is proposed that a continuous cytoplasmic membrane without infoldings (mesosomes) would be the real pattern of membrane organization in gram-positives.

Bacillus cereus↗
PubMed1976

Assessing the development of daily living skills in patients with spina bifida.

The development of independence in daily living skills of 256 patients with spina bifida was assessed by means of a new Functional Activities scoring system. The score was derived from nine categories of activity; five are to do with self-care, three with locomotion and one with social interaction. The reasons for the variation in achievement between individuals with the same degree of paralysis are discussed, as are the differences in learning curves for single activities. The scoring system enables a quantitative assessment to be made of the current status of an individual patient, and enables more realistic therapeutic goals to be set.

Activities of Daily Living↗
PubMed1976

Effects of phenethyl alcohol on Bacillus and Streptococcus.

The activity of phenethyl alcohol (PEA) on Bacillus cereus, B. megaterium, and Streptococcus faecalis was studied by electron microscopy of thin sections and by the assay of intracellular K+ leakage. S. faecalis was unaffected by PEA at concentrations up to 0.5%, B. cereus was severely damaged by 0.5% PEA, and B. megaterium behaved intermediately. Important membrane ultrastructural alterations were observed in B. cereus cells treated with 0.5% PEA, namely the change in the geometry of the membrane profile from asymmetric to symmetric, the occurrence of prominent, complex mesosome-like structures, and membrane fracturing and solubilization. Protoplasts from B. megaterium were found to be quickly lysed by 0.5% PEA due to the disruption of the cytoplasmic membrane. The electron microscopic observations, together with the results of the study of the K+ efflux from B. cereus and B. megaterium, indicate that PEA primarily and directly damages the cytoplasmic membrane of sensitive bacteria. The breakdown of the permeability barrier probably is responsible for the observed bactericidal action of 0.5% PEA on B. cereus.

Bacillus cereus↗