Search PubMed⌕ Search

Biomedical subjects

S Miranda

Publications and source records attributed to S Miranda.

34 records · Page 2Linked to original sources
PubMed1995

Differences between nuclear run-off and mRNA levels for multidrug resistance gene expression in the cephalocaudal axis of the mouse intestine.

P-glycoprotein is a multidrug transporter encoded by the mdr3 gene in the mouse intestinal epithelium. The aims of this study were to characterize the mdr3 gene expression in the cephalocaudal axis of the intestine in adult animals and during perinatal development, and to define the molecular mechanism responsible for the heterogeneous expression of the gene along the cephalocaudal axis. RNA extracted from stomach, duodenum, jejunum, ileum, cecum and colon was hybridized by slot blot and Northern blot using a mdr3 cDNA probe. The regulation of gene expression was investigated examining the rate of transcription by nuclear run-off analysis. Transport studies of rhodamine 123, a substrate of P-glycoprotein, were performed in everted jejunum and ileum. The level of mdr3 mRNA and P-glycoprotein found in ileum was 6-fold higher than the level found in duodenum. The regional pattern of mdr3 gene expression is established in the intestine of 10-day-old animals. Similar mdr3 hybridization signal in nuclear run-off assay was found in nuclei of enterocytes isolated from jejunum and ileum, suggesting that the heterogeneous expression of the mdr3 gene in the cephalocaudal axis of the small bowel may be predominantly regulated at the post-transcriptional level. Transport rate of rhodamine 123 from the serosal to mucosal side in everted ileum was higher than the rate of transport found in jejunum. These results indicate that enterocytes of the ileum may be more actively involved in the P-glycoprotein-mediated transport of xenobiotics into the intestinal lumen.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Vowel identification in mixed-speaker silent-center syllables.

Strange [J. Acoust. Soc. Am. 85, 2135-2153 (1989b)] has demonstrated that there is sufficient information in the onsets and offsets of syllables, spoken in sentence context, to provide accurate identification of the vowel in the syllable. Verbrugge and Rakerd [Language Speech 29, 39-57 (1986)] and Andruski and Nearey [J. Acoust. Soc. Am. 91, 390-490 (1992)] have shown that such information is present in citation-form syllables even when the syllables begin with one speaker and end with another. These studies of "hybrid syllables," however, reported relatively high error rates. In a perceptual experiment using /dVd/ syllables spoken in sentence context by a male and a female speaker, relatively low error rates were obtained for both "silent-center" syllables and "hybrid silent-center" syllables. It was concluded that the information specified over syllable onsets and offsets together for identification of vowels is speaker independent and that it was sufficient in most cases to specify the vowel. The acoustic patterns, represented as functions of log (F2/F1) over time, revealed potentially useful dynamic acoustic characteristics of co-articulated vowels.

Adult↗
PubMed1992

The proportion of symmetric and asymmetric IgG antibody molecules synthesized by a cellular clone (hybridoma) can be regulated by placental culture supernatants.

The purpose of the present work was to establish whether the placenta is producing factors favoring an increased synthesis of asymmetric IgG antibodies which are known to assume a protective effect upon paternal antigens to which they largely are specific. In this way they can contribute to fetal survival in the maternal uterine environment. The hybridoma cell lines OKT8 (anti-CD8) and 112B4 (anti-DNP) were used in this respect since they synthesized both symmetric and asymmetric molecules of the IgG2a and IgG1 subclasses, respectively, murine isotypes in which anti-paternal antibodies have been detected. The cells were cultured in RPMI 1640 medium supplemented with 10% BCS and different amounts (5, 10, and 20%) of human placental supernatant. After incubation for 3 days at 37 degrees C in a humid chamber containing 5% CO2 the cells were centrifuged and the antibodies were obtained from the culture medium by a purification procedure involving precipitation at 50% ammonium sulfate saturation followed by DEAE-cellulose chromatography. Symmetric and asymmetric antibodies were separated by Con A-Sepharose affinity chromatography, the latter lectin retaining selectively only asymmetric IgG molecules. Both OKT8 and 112B4 hybridomas presenting a stable background synthesis of 15-17% of asymmetric antibodies have shown an increased level reaching 27-28% of these molecules in the presence of 5-10% placental supernatant added to the RPMI 1640 culture medium. These results clearly show that placental factors can up-regulate efficiently the synthesis of asymmetric IgG molecules of different isotypes secreted by plasma cells.

Animals↗
PubMed1992

Preferential synthesis of asymmetric antibodies in rats immunized with paternal particulate antigens. Effect on pregnancy.

The effect of immunization of female Fischer rats with particulate (spleen cells) (group I) or soluble (supernatant of disintegrated spleen cells) (group II) paternal antigens previous to mating with Buffalo rats was investigated. The percentage of asymmetric IgG molecules in the serum of rats inoculated with particulate antigens was 38% while in those injected with soluble antigens it was 29% and 28% in non-immunized animals. These percentages further increased during pregnancy to 45%, 38% and 37%, respectively. The antipaternal antibody titres, as determined by indirect immunofluorescence (IIF), was much higher in the animals immunized with particulate antigens but the effector activity, judged by complement fixation, was similar in both groups. The same values were observed at the time of mating (after 3 months of immunization) and at day 17 of pregnancy. Fetus and placenta weights and offspring survival were equally greater in group I than in group II or non-immunized rats (group III). The results obtained indicate the preferential synthesis of antipaternal IgG asymmetric antibodies in rats injected with particulate antigens previous to mating and suggests a beneficial effect of these antibodies in pregnancy.

Animals↗
PubMed1992

Asymmetric non-precipitating antibodies in commercial hyperimmune gamma-globulin for therapeutic use.

The presence of asymmetric (non-precipitating or co-precipitating) antibodies has been studied in three commercial preparations of antitetanus gamma-globulin. It was found that 27% of the specific antibodies are of asymmetric type, a value two to three times higher than that found in normal IgG. In toxicity tests in mice with tetanus toxin, the asymmetric antibodies were 2.7 times less effective than the symmetric ones. It is concluded that the protection capacity of the tetanus gamma-globulin preparations is dependent on the ratio of symmetric to asymmetric antibodies. The high content of asymmetric antibodies is probably due to the fact that immunization is performed with the antigen in a particulate form.

Animals↗
PubMed1991

Quality of life and longterm survival after intensive care discharge.

From 1st January 1986 till 31st December 1986; 273 patients were treated in the Intensive Care Ward. The mortality in the Intensive Care Unit was 24.5%, mortality of patients 60 years and above was 35%. Of 187 patients who had survived, only 105 (56.2%) responded to the questionnaire, 39 (20.9%) did not respond and 43 (23.0%) could not be traced. Of the total discharged alive, 95 (51.9%) survived two years and eight (4.6%) died over the two years. Forty (41%) have returned to normal routine and are satisfied with their life style; 57 (59%) were not satisfied with their life style for various reasons, ill health being one. As regards patients above 60 years; 21 (53.8%) are alive and 10 (47.6%) are happy and satisfied with their life style.

Adolescent↗
PubMed1987

Ultrasound-guided brain abscess aspiration in neonates.

Four cases of brain abscess in neonates are described, diagnosed by ultrasonography and CT. All abscesses were confirmed surgically. One patient was operated on 5 weeks after diagnosis because of initial parental refusal. The etiology in all cases was meningitis superimposed on an hypoxic-ischemic insult. Two cases had a single abscess while the other two had multiple lesions. All cases were operated on with intraoperative ultrasound examination through the fontanelle. The case with delayed aspiration showed complete evolution from localized cerebritis to complete capsule formation with mass effect. One abscess was sterile, and in the others grew Klebsiella pneumoniae and Enterobacter aerogenes. The microorganism initially isolated from the lumbar CSF was also found in the abscess. Even after sterilization of the lumbar CSF, all abscesses were still present. Ultrasound examination and CT are compared.

Brain Abscess↗
PubMed1981

Ring chromosome 14: a distinct clinical entity.

An infant girl with ring chromosome 14 is presented. The findings in this patient and in six previously reported cases of a ring 14 suggest that a characteristic clinical syndrome is associated with this chromosome aberration. The major features of the ring chromosome 14 syndrome include mental retardation, a disorder of skin pigmentation, seizures, and dysmorphic features, including flat occiput, epicanthal folds, downward slanting eyes, flat nasal bridge, upturned nostrils, short neck, and large low set ears.

Abnormalities, Multiple↗
PubMed1981

Experimental neurogenic pulmonary edema. Part 1: The role of systemic hypertension.

Neurogenic pulmonary edema (NPE) was produced consistently in normal cats by increasing intracranial pressure with an intraventricular infusion of mock cerebrospinal fluid. The usual elevation of systemic arterial pressure (SAP) that follows severe intracranial hypertension (the "Cushing response") was controlled by blood withdrawal at variable rates to achieve and maintain constant cerebral perfusion pressure (CPP) in three groups of cats of 50, 20, and 0 mm Hg, respectively, for 30 minutes. In this model, NPE occurs in the absence of increased SAP and in the presence of decreasing CPP. These results indicate that systemic arterial hypertension is not an essential stimulus for the development of NPE, and suggest that the lungs are directly affected by the intense sympathetic discharge evoked by severe intracranial hypertension.

Animals↗
PubMed1981

Experimental neurogenic pulmonary edema Part 2: The role of cardiopulmonary pressure change.

Pressure changes in the aorta, left atrium, and main pulmonary artery were measured before, during, and after inducing increased intracranial pressure in cats. By selectively controlling each of the three pressures, it was concluded that pulmonary arterial hypertension is the single most important precursor of experimental neurogenic pulmonary edema. An earlier observation that neurogenic pulmonary edema may develop in the absence of systemic arterial hypertension was confirmed.

Animals↗
PubMed1979

Development of nystagmus in response to vestibular stimulation in infants.

Nystagmus in response to perotatory stimulation by torsion swing or ice-cold caloric (ICC) irrigation of the ear canals was studied in 276 infants from birth to 12 months of age. The percentage of positive responses to perotatory stimulation correlated with gestational age and weight at birth during the first 3 months of life and became comparable among groups by 6 months of age. The quality of perotatory nystagmus did not differ among groups. A direct correlation between the caloric-induced intensity and duration of nystagmus with gestational age and weight at birth was noted during the first 3 months of life. Premature infants showed the weakest responses, and term-delivered, large for gestational age children the strongest responses. ICC-induced nystagmus reached comparable levels for all groups by 6 months except for premature infants, in whom comparable responses were attainedby 9 months of age. Vestibular responses mature over time, with patterns that correlate with gestational age and weight at birth.

Age Factors↗
PubMed1978

Primary carcinoid tumor of the testis: case report, ultrastructure and review of the literature.

A case of primary pure carcinoid tumor of the testis which occurred in a 71-year-old male is reported. The patient was treated by radical orchiectomy and remains well and symptom free 10 months after operation. Histologically as well as ultrastructurally the tumor showed typical appearances of carcinoid tumor of midgut derivation. 23 cases of carcinoid tumors of the testis were discovered in the literature. Of these 17 were primary testicular carcinoids, and 6 were metastatic to the testis. Of the 17 cases of primary carcinoid tumors, 14 were pure carcinoids and only 3 were associated with teratoma. None of the primary testicular carcinoids were associated with metastases and the prognosis after orchiectomy was excellent, thus indicating that no further therapy is necessary. The prognosis of patients with carcinoid metastatic to the testis is poor. In view of this it is very important to determine whether the tumor is primary or metastatic.

Aged↗