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Biomedical subjects

J Santos

Publications and source records attributed to J Santos.

At least 91 records · Page 5Linked to original sources
PubMed1998

[Fungemia in patients with HIV infection].

OBJECTIVE: To make an analysis of fungemia in HIV-infected patients in our hospital. PATIENTS AND METHODS: We retrospectively (1989-1997) studied all HIV-infected patients with positive blood cultures for Candida sp., Cryptococcus neoformans or any other fungal infection. RESULTS: C. neoformans was isolated in 11 patients (10 men and 1 woman): Six were treated with amphotericin B and 5 with fluconazole. 2 patients died during the acute phase and the infection relapsed in 3. Blood culture for Candida sp. were positive in 9 (8 men and 1 woman): only a case was nosocomial. Seven patients were intravenous drug users and the presenting manifestations were autolimited candidemia in 3, aortic and tricuspid endocarditis in 1 and 2 cases respectively and pneumonia in another one. Six C. albicans, 2 C. krusei and 1 C. glabrata were isolated. 3 patients received amphotericin B and 3 received fluconazole. 2 patients suffering from endocarditis died and so did the patient with C. glabrata infection. A patient, who denied having travelled to endemic areas, developed histoplasmosis; blood culture was positive for H. capsulatum. He initially had a good response to amphotericin B and itraconazole. CONCLUSIONS: Fungemia is not frequent in HIV-infected patients. Cryptococcosis and histoplasmosis occur in advanced HIV-patients and candidemia is fundamentally associated with intravenous drug use.

Adult↗
PubMed1998

[An increase in renal dopamine production after the administration of radiographic contrast agents].

Renal vasoconstriction and anti-natriuresis conditioned by radiographic contrast agents (CA) may be antagonised by the administration of exogenous dopamine. However, the influence of CA on the activity of renal synthesis of dopamine has not been studied. This study assessed the daily urinary excretion of dopamine, its precursor. L-3, 4-dihydroxyphenylaline (L-DOPA), and its metabolites (acid 3, 4-dihydroxyphenylacetic, DOPAC; homovanillic acid, HVA) 24 hours before and 48 hours following administration of a non ionic and hyposmolar (lopromide) CA in patients (n = 10; average age 61.3 +/- 4.3 years) submitted to coronary angiography. Urinary excretion of noradrenalin, a marker of sympathetic activity, was also assessed during the same period. The deputation of creatinine (Ccr) and the urinary excretion of sodium (UNa+) lowered after the administration of the CA (Ccr, 79.2 +/- 10.2 vs 72.2 +/- 9.6 ml/min/1.73 m2, p < 0.05; UNa+, 112.8 +/- 9.6 vs 61.7 +/- 25.1 mmol/24 h, p < 0.05). On the contrary, the urinary excretion of potassium increased in the period of 24 h following the administration of the AC (31.7 +/- 5.2 vs 103.8 +/- 10.8 mmol/24 h, p < 0.05). There was an increase in the urinary excretion of dopamine as well as noradrelalin during the 24 hour period following the administration of the CA (dopamine, 1260.2 +/- 196.8 vs 1571.5 +/- 170.2 mmol/24 h p < 0.5; noradrenalin, 186 +/- 36.6 mmol/24 h, p < 0.05). On the contrary, the urinary excretion of L-DOPA lowered after the administration of the CA (115.4 +/- 25.5 vs 80.5 +/- 13.2 mmol/24 h, p < 0.05). These results conditioned an increase in the dopamine/L-DOPA ratio in the urine, after the administration of the CA (12.2 +/- 1.5 vs 22.2 +/- 4.5 mmol/24 h, p < 0.05). In conclusion, the administration of CA is accompanied by an increase in the renal production of dopamine which, in these conditions, may act as a compensatory natriuretic hormone.

Adult↗
PubMed1997

Frequent allelic losses of 9p21 markers and low incidence of mutations at p16(CDKN2) gene in non-Hodgkin lymphomas of B-cell lineage.

We present an allelotype analysis of 35 cases of non-Hodgkin lymphomas and normal pairs using four microsatellite markers that flank the region occupied by the CDKN2 gene locus at 9p21. Frequent allelic losses (LOH) were detected in B-cell lineage NHLs, including Burkitt lymphoma (33.3% of total, if we only consider high grade tumors). In five of these tumors LOH did not include the CDKN2 gene. Mutational analysis of exon 1 and 2 of CDKN2 (SSGP and sequencing of abnormal bands) revealed a nonsense mutation (Arg72Ter) in one tumor (case 10), where the second hit of the Knudson's model consisted of the elimination of the wild type allele. In view of these results, the hypothesis of two different candidate tumor suppressor gene regions around the CDKN2 locus remains an intriguing possibility.

Alleles↗
PubMed1997

Inactivation of the cyclin-dependent kinase inhibitor p15INK4b by deletion and de novo methylation with independence of p16INK4a alterations in murine primary T-cell lymphomas.

A wide panel of murine induced T-cell lymphomas have been analysed for p16INK4a or p15INK4b alterations. Only one gamma-radiation-induced lymphoma showed p16INK4a homozygous deletion and no other intragenic mutations were found in these INK4 genes. However, de novo methylation of the 5' CpG islands of the murine p15INK4b and p16INK4a genes was found to be highly frequent. While p16INK4a hypermethylation was found in 36% of the neutron-radiation-induced lymphomas and 15% of the gamma-radiation-induced lymphomas, de novo methylation of p15INK4b occurs in 88% and 42% of these tumors respectively, correlating with deficient expression of the corresponding mRNA and allelic losses in the p15INK4b and p16INK4a chromosome location. These data represent, to our knowledge, the first report on the significant involvement of hypermethylation of these INK4 genes in murine primary tumors. Moreover, they show the importance of allelic losses and CpG island methylation of p15INK4b gene inactivation and support a tumor suppressor role for p15INK4b in T-cell lymphomas independent of p16INK4a.

Animals↗
PubMed1997

D1-D2 dopamine receptor interaction: an in vivo single unit electrophysiological study.

After intrastriatal administration of selective dopamine receptor agonists only a small percentage of substantia nigra pars reticulata single units showed changes in firing rate (23% after SKF38393 and 17% after quinpirole). After their intrastriatal co-administration, however, or after the application of the non-selective dopamine receptor agonist apomorphine, 72% and 69% of units responded, respectively. This result confirms the participation of the striatum in the phenomenon of D1-D2 receptor interaction, and show that co-activation of both receptor subtypes produced a maximal effect on basal ganglia output nuclei.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1997

Enantioselective determination of the hydroxylated metabolites of mexiletine in human plasma.

Pre-column derivatization with o-phthaldialdehyde and N-acetyl-l-cysteine was used for liquid-chromatographic diastereomeric resolution of p-hydroxymexiletine (PHM) and hydroxymethylmexiletine (HMM), metabolites of mexiletine formed by aromatic and aliphatic hydroxylation, respectively. The resulting diastereomeric derivatives were resolved on a C18 column and monitored by fluorescence detection. The diastereomeric elution order for both metabolites was determined on the basis of the circular dichroism spectra of each eluted fraction. Plasma samples (500 microliters) showed recoveries greater than 75% for both the metabolites. Calibration curves in plasma samples were linear over the concentration ranges 10-500 and 20-1,000 ng/ml for each enantiomer of PHM and HMM, respectively. The limits of quantitation were found to be 10.0 and 5.0 ng/ml for both enantiomers of PHM and HMM. The within-day and between-day coefficients of variation were less than 10%. The assay was shown to be suitable for a pharmacokinetic study performed in a patient with ventricular arrhythmias following the short-term oral treatment of 200 mg t.i.d. of racemic mexiletine hydrochloride.

Anti-Arrhythmia Agents↗
PubMed1997

Absolute Line Intensities in the 2nu3 Band of 16O12C32S

The strengths of 100 lines in the 2nu3 band of 16O12C32S have been measured at high resolution in the spectral range 4069-4118 cm-1, using a tunable difference-frequency laser spectrometer. These intensities were obtained by fitting Voigt profiles to the measured shapes of the lines. The vibrational transition moment [(2.141 &plusmn; 0.020) x 10(-2) D] and the absolute intensity (16.19 &plusmn; 0.24 cm-2 atm-1 at 296 K) of the 2nu3 band of 16O12C32S are determined from these linestrength measurements. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1997

The Stimulated Raman Spectrum of Cyanogen

The Raman spectrum of cyanogen 12C214N2 has been investigated at nearly Doppler resolution by means of the Stimulated Raman technique. The regions around the Q branches of the nu1 (2330 cm-1) and nu2 (845 cm-1) vibrations have been recorded. Besides the fundamentals, hot bands arising from v5 = 1, v5 = 2, and v4 = 1 have been observed. The spectra have been analyzed, and rotational constants for the excited states have been obtained. Computer simulations of the Raman contours have been carried out as a test of the assignments. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1997

Liver cell atypias: a comparative study in cirrhosis with and without hepatocellular carcinoma.

Various criteria have been proposed for the identification of early neoplastic changes in the setting of both small hepatocellular carcinomas and macroregenerative nodules. In this study we have applied those criteria to cases of liver cirrhosis without tumour (group I) and hepatocellular-carcinoma-associated cirrhosis (group II) to assess their discriminatory value in these two situations. Group I included 50 liver biopsies with uncomplicated cirrhosis while group II encompassed 48 liver biopsies of cirrhotic nodules adjacent to hepatocellular carcinomas. The histological changes sought were large cell dysplasia, small cell dysplasia, cytoplasmic basophilia, small microacinar structures, peripheral distribution of nuclei, nuclear irregularities and thickened liver cell plates. These changes were also assessed in macroregenerative nodules (nine in group I and seven in group II). None of these changes was useful to discriminate between group I and group II cirrhotic nodules when assessed separately. On the other hand, cirrhotic nodules showing three or fewer changes were never associated with malignancy, whereas those exhibiting four or more alterations were often located in the vicinity of a tumour. Acinar structures, thickened cell trabeculae, peripheral distribution of nuclei and nuclear irregularities seem to be the most specific indicators of proximity to a hepatocellular carcinoma. Similar results were obtained for macroregenerative nodules. These results may be helpful as guidelines to the probability of having a hepatocellular carcinoma elsewhere in livers containing atypical cirrhotic nodules, and may also prove valuable in the selection of appropriate material for investigating early molecular events in hepatic carcinogenesis.

Biopsy↗
PubMed1997

Instability of the D4Mit12 microsatellite marker in C57BL/6J x BALB/cJF1 hybrid mice is independent of the tumor phenotype.

We examined the stability of different types of DNA microsatellite markers in gamma-radiation-induced thymic lymphomas as well as normal, nontumorous tissues of F1 hybrid mice derived from the parental strains C57BL/6J, RF/J, and BALB/cJ. Surprisingly, the D4Mit12 microsatellite showed genomic instability in a significant fraction of DNAs of the (C57BL/6J x BALB/cJ) F1 hybrids with independence of the tumor phenotype. This instability was not found in the reciprocal F1 DNAs, in DNAs of the parental strains, or in DNAs of (C57BL/6J x RF/J) F1 hybrid mice. These results suggest that the instability of the D4Mit 12 microsatellite is dependent on its repeat length, the genetic background of F1 hybrids, and the maternal origin of the C57BL/6J allele.

Animals↗
PubMed1997

Determination of malonaldehyde in Alzheimer's disease: a comparative study of high-performance liquid chromatography and thiobarbituric acid test.

The concentration of malonaldehyde (MDA) was measured in human erythrocytes obtained from subjects suffering from senile dementia of the Alzheimer type (SDAT), non-demented elderly subjects, and from young controls by two methods: high-performance liquid chromatography (HPLC) and the thiobarbituric acid (TBA) test. The MDA concentration measured by HPLC showed significant differences between SDAT and young control groups (p < 0.01) and between SDAT and non-demented elderly groups (p < 0.01), respectively. Nevertheless, significant differences were not exhibited between young control and non-demented elderly. Moreover, the rate of accumulation of TBA-reactive substances was not significantly different among the three groups. Our results indicate that the HPLC method is highly specific and accurate and distinguishes between true MDA and other aldehydes that may react with TBA. Significant increases in the concentration of MDA of SDAT subjects were found in comparison with the two other groups, indicating that the measurement of MDA in erythrocytes could be used as a marker of oxidative damage in Alzheimer's disease.

Adult↗
PubMed1997

Comparison of barley and sorghum grain processed at different densities for lactating dairy cows.

To vary ruminally degradable starch, sorghum grain was dry-rolled or steam-flaked to different densities and compared with dry-rolled barley in total mixed diets fed to 40 lactating cows (111 d of lactation) assigned to five dietary treatments. Diets contained (percentage of dry matter) 35% alfalfa hay, 4.1% cottonseed hulls, 10% whole cottonseed, 2% fish meal, 4% soybean meal, and 4.9% of a molasses, mineral, and vitamin supplement. Treatments were 40% sorghum grain either dry-rolled or steam-processed at flake densities of 437, 360, and 283 g/L. A fifth diet containing 42% dry-rolled barley was fed. Cows were blocked according to pretreatment (14 d) milk yield and received experimental diets for 56 d. Increasing ruminal starch degradability by including steam-flaked sorghum grain or barley in the diet did not increase milk yield or milk protein percentage and yield, as was shown in eight previous studies. Steam-flaked sorghum or dry-rolled barley in the diet decreased dry matter intake, resulting in a 10 to 19% higher efficiency of conversion of feed dry matter to milk than that for dry-rolled sorghum. Milk urea N was decreased, and milk casein yield tended to be increased, by steam-flaking sorghum at the moderate density compared with dry-rolling or fine flaking. Dietary protein was more efficiently converted to milk protein and casein from flaked sorghum and dry-rolled barley than from dry-rolled sorghum. In this study, increasing ruminal starch degradability resulted in higher feed efficiency and lower feed intakes, bu optimal flake densities for steam-processed sorghum gain to maximize milk and milk protein yield were not clarified.

Animal Feed↗
PubMed1997

[Surgery of the elongated styloid syndrome].

The symptomatology sometimes due to a giant styloid process can be very troublesome and at the same time unspecific, raising differential diagnosis problems with a large group of pathologies. We report a clinical case of elongated styloid syndrome, stylalgia or Eagle's syndrome, that forced our team to the exeresis of the anomalous process. We emphasizes the relative simplicity of the diagnosis and its treatment as well, especially when the intrabucal approach is followed.

Abnormalities, Multiple↗
PubMed1997

[Fibrous diaphragm of the nasopharynx].

A case of nasopharyngeal fibrous diaphragm of unknown origin is reported. In view of the scarcity of publications about this disorder, this new case is interesting. A differential diagnosis is made with choanal atresia and nasopharyngeal stenosis. Aspects of the etiology, clinical manifestations, and treatment are discussed.

Diagnosis, Differential↗