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Biomedical subjects

S Rubio

Publications and source records attributed to S Rubio.

At least 37 records · Page 2Linked to original sources
PubMed1997

Isolation and characterization of surfactant-like particles in rat and human colon.

The source of a phospholipid-rich layer recovered from the surface of the mammalian colon has been obscure. This report describes the isolation of a low-density membrane from the surface of rat and human colons (d = 1.07-1.08 g/ml), with a low cholesterol-to-phospholipid ratio and phosphatidylcholine as its major phospholipid. Electron microscopy shows unilamellar and partially coiled membranes. Compared with microvillous membranes isolated from underlying mucosa, this extracellular membrane is enriched for tissue-unspecific alkaline phosphatase and surfactant protein A. It does not contain small intestinal marker proteins (intestinal alkaline phosphatase and sucrase-isomaltase). The human membrane contains only traces of the colonic microvillous membrane marker, carcinoembryonic antigen. Antiserum against the rat colonic membrane does not recognize colonic microvillous membrane or small intestinal surfactant-like particle proteins. Antiserum against human colonic membrane identifies one protein in the surfactant-like particle from the adjacent small intestine and two proteins in the colonic microvillous membrane. These data show that the colonocyte microvillous membrane is covered by another membrane with a different protein composition. Enrichment for surfactant protein A suggests that this colonic membrane is another example of a surfactant-like particle sharing proteins with pulmonary surfactant.

Alkaline Phosphatase↗
PubMed1996

Antibody against pulmonary surfactant protein A recognizes proteins in intestine and swim bladder of the freshwater fish, carp.

An antibody raised against rat pulmonary surfactant protein A (SP-A) bound on Western blots to proteins present in intestinal mucosa and in swim bladder, but not in gills of the carp. The fish protein(s) revealed by the antibody exhibited an electrophoretical behavior similar to that of rat SP-A with a characteristic triplet in the 30- to 35-kDa range. It therefore appears that proteins immunologically very close to mammalian SP-A are present in modern fish which evolved from ancestors that never possessed lungs. The association of SP-A with phospholipid-rich surfactant-like materials appears as a phylogenetically old feature.

Air Sacs↗
PubMed1996

Behaviour laterality in male rats: influence of practice and stress.

During recent decades, the existence of cerebral and behavioural asymmetries has been manifested in many different animal species. In this work, the asymmetric spatial preference recorded in the water T-maze has been analysed. Fifty-five male rats were tested in this maze for 8 consecutive days. Spatial preference, the number of times each arm was chosen, and the percentages of animals that showed right, left, or no spatial preference were calculated. The results show the evolution of this asymmetric behaviour. Most of the animals tested preferred the right arm (populational laterality). Recently, the influence of factors such as stress and practice in the process of acquiring this behaviour has been investigated. We used 40 male rats divided into two groups with two different stress levels: water temperature at 21 degrees C and 14 degrees C. Our results, based on these two criteria, hypothesize that both variables, stress and practice, are involved in the acquisition of spatial preference behaviour.

Animals↗
PubMed1996

Ethanol- and diazepam-induced cytochrome oxidase activity in mammillary bodies.

This study aims to analyze the effect of the administration of diazepam and alcohol on cytochrome c oxidase activity (COX) in the mammillary bodies (MB) with a quantitative densitometry method. The histochemical reaction of the COX is used as a reflection of energy consumption. Our results show an increase in the COX activity after treatment with diazepam in the different nuclei of MB: medial medial nucleus (MMNm), lateral medial nucleus (MMN1), and lateral nucleus (LMN) of the MB, the MMNm and LMN being significantly more active compared to the MMN1. Furthermore, the consequences of administering these drugs become manifest in spatial learning (water T maze). The performance in a spatial discrimination task did not prove to be impaired.

Animals↗
PubMed1996

Simultaneous spectrophotometric determination of o-cresol and m-cresol in urine by use of the kinetic wavelength-pair method.

The kinetic wavelength-pair method was applied to the simultaneous determination of o-cresol and m-cresol, based on their oxidative coupling with aniline in the presence of hypochlorite as oxidant and nitroprusside as catalyst. The benzoquinoneanils produced exhibited severe spectral overlap. Resolution of this isomer mixture by using discrete wavelengths was subject to a high degree of error for the determination of m-cresol since the ratios vo-cresol/vm-cresol (where v denotes initial rate for the oxidative coupling reaction) and epsilon o-cresol/epsilon m-cresol (where epsilon is the absorptivity of reaction products) were greater than unity at any given wavelength. Selectivity in the resolution was achieved by measuring the initial rate difference at the wavelength pair 666-566 nm where the contribution of o-cresol was removed, o-Cresol and m-cresol were simultaneously determined at mass ratios between 5:1 and 1:5 at concentrations from 1 to 5 micrograms ml-1, with relative standard deviations of less than 3%. The proposed method was applied to the determination of o-cresol and m-cresol in urine samples, with analytical recoveries ranging between 95 and 105%.

Aniline Compounds↗
PubMed1995

Pulmonary surfactant protein A (SP-A) is expressed by epithelial cells of small and large intestine.

Surfactant protein A (SP-A) is the most abundant protein associated with phospholipids in pulmonary surfactant. There are several lines of evidence that pulmonary and gastrointestinal epithelium produce closely related surface-active materials, although the presence of SP-A in gastrointestinal tract has so far not been reported. Indirect immunofluorescence experiments using different antibodies raised against rat pulmonary SP-A showed that some jejunal and colonic but not gastric epithelial cells positively stained for SP-A. Analysis of the proteins in cell lysates from rat small intestine and colon studied by Western blot revealed several immuno-reactive bands, including the characteristic triplet of 26-, 32-, and 38-kDa monomeric proteins, less strongly labeled than in lung cells, and higher molecular mass forms of 66 and 120 kDa also present in lung cells. The 66- and 120-kDa bands displayed the expected isoelectric pH of SP-A after two-dimensional electrophoresis. Alkylation induced conversion of the 120-kDa form (almost completely) and the 66-kDa form (partly) into the 26-38-kDa monomeric species. The presence of SP-A mRNA in rat stomach, small intestine, and colon was then searched for by conventional cDNA/reverse transcriptase-polymerase chain reaction. Products of appropriate size (372 base pairs) identical to that of pulmonary tissue were amplified in small intestine and colon but not in stomach or in other tissues used as controls. Cloning and sequencing of rat colon SP-A cDNA revealed the same sequence as the one reported for rat lung SP-A. Furthermore, analysis of the transcriptional initiation site of SP-A gene in colon by anchored-polymerase chain reaction showed that transcription was initiated at the same site in both colon and lung. These data, which demonstrate that small intestine and colon express SP-A constitutively and that this protein is present in some epithelial cells, extend the concept of intestinal surfactant and underline its close relationships to pulmonary surfactant.

Animals↗
PubMed1995

[Surfactants in the digestive tube].

Epithelia of the gastrointestinal tract both synthesize and secrete surfactant-like materials. Like the pulmonary surfactant, these materials contain not only phospholipids, but also surfactant apoproteins, regarded until recently as specific products of the bronchoalveolar epithelium. Presented here are the various roles, most of them still speculative, of these phospholipids-containing products in the gastro-intestinal tract.

Animals↗
PubMed1995

Immunoreactive substance P and calcitonin-gene-related peptide (CGRP) in rat milk and in human milk and infant formulas.

This study examined the presence of substance P and calcitonin-gene-related peptide (CGRP) immunoreactivities in various milks and infant formulas. Rat milk was obtained from lactating dams between parturition and weaning (0, 2, 5, 10, 15, and 20 d postpartum). Samples of human milk were obtained from seven multiparous, nonsmoking white women, and newborn infant formulas were purchased from local stores. Substance P and CGRP were measured by competitive enzyme immunoassay using acetylcholinesterase-peptide conjugates as tracers. In rats, substance P and CGRP were below detectable concentrations in amniotic fluid from the last day of gestation. In contrast, in milk the concentrations of substance P and CGRP-like immunoreactivities were high on the first day of lactation (3.1 +/- 0.2 and 23.1 +/- 1.5 micrograms/L, respectively), then dropped after day 2 (1.6 +/- 0.7 and 7.5 +/- 0.4 microgram/L, respectively) and remained fairly constant until weaning. Significant concentrations of substance P and CGRP were found in human milk (129.2 +/- 27 ng/L and 4.5 +/- 0.7 microgram/L, respectively, at 15 wk), but substance P or CGRP could not be detected in any of the formulas tested. These data show that milk contains high concentrations of immunoreactive substance P and CGRP. In rats the absence of peptides in amniotic fluid suggests that there is a flood of peptides into the gastrointestinal tract of neonates when suckling is initiated. Significant concentrations of substance P and CGRP in human milk but not in infant formulas may therefore have physiologic implications for neonatal nutrition.

Amniotic Fluid↗
PubMed1995

Neonatal nosocomial respiratory infection with coronavirus: a prospective study in a neonatal intensive care unit.

The aim of this prospective study was to evaluate the incidence of viral respiratory infection in hospitalized premature newborn infants and to assess the role of coronaviruses. All hospitalized premature infants with a gestational age less than or equal to 32 weeks were included. Tracheal or nasopharyngal specimens were studied by immunofluorescence for coronaviruses, respiratory syncytial virus, adenoviruses, influenza and parainfluenza viruses. Forty premature infants were included; 13 samples were positive in 10 newborns (coronaviruses n = 10; influenza 1 n = 2; adenovirus n = 1). None was positive at admission. All premature infants infected with coronaviruses had symptoms of bradycardia, apnea, hypoxemia, fever or abdominal distension. Chest X-ray revealed diffuse infiltrates in two cases. However, no significant difference was observed between infected and non-infected premature infants for gestational age, birth weight, duration of ventilation, age at discharge, incidence of apnea or bradycardia. Nosocomial respiratory tract infection with coronaviruses appears to be frequent. The clinical consequences should be evaluated in a larger population.

Body Fluids↗
PubMed1994

Use of the triiodide-cetylpyridinium chloride micellar system for the determination of benzoyl peroxide in pharmaceutical preparations.

A kinetic spectrophotometric method for the determination of benzoyl peroxide in acne preparations is proposed. The method is based on the reduction of benzoyl peroxide by iodide in the cationic micellar medium provided by cetylpyridinium chloride (CPC). The triiodide ion produced associates with CPC micelles, which gives rise to an absorption maximum at 500 nm in addition to substantially increased absorptivity and stability constant for the triiodide complex. Acne preparations can be analyzed directly after dissolution of the samples in ethanol. The detection limit thus achieved is 0.033 microgram.mL-1, so the proposed method surpasses existing alternative methods in sensitivity. The relative standard deviation for 0.25 microgram.mL-1 is 2.1%.

Acne Vulgaris↗
PubMed1994

[Pathogen role of coronavirus in pediatric intensive care: retrospective analysis of 19 positive samples with indirect immunofluorescence].

BACKGROUND: Coronaviruses (CV) are ARN-containing agents that are responsible for mild upper respiratory tract infections in adults and children. Their pathogenicity in neonates is not wellknown. POPULATION AND METHODS: Eighty five samples of tracheal or nasopharyngeal secretions were obtained from January to October 1991 from 53 children (29 less than 1 month of age; 19 from 1 month to 1 year; five older than 1 year). They were examined for respiratory syncytial virus, adenovirus, myxovirus influenza and parainfluenza and coronavirus by immunofluorescence (IF). RESULTS: Nineteen samples from nine newborns and three infants were positive for coronavirus. The mean birth weight of the nine neonates was 2100 +/- 840 g; their mean gestational age was 34 +/- 5 weeks and their mean age at diagnosis was 21 +/- 9 days. Apnea and bradycardia were the main symptoms in this group. Blood C-reactive protein was not elevated and blood cultures were sterile. One infant was admitted for near-miss; the two others were admitted at birth because they suffered from chronic lung disease (pulmonary hypoplasia and bronchopulmonary dysplasia). An acute episode of pulmonary deterioration occurred at the time of coronavirus infection. Both died one at 4 months and the other at 10 months. CONCLUSION: Coronaviruses seem to be responsible for respiratory tract infections in hospitalized neonates and chronically ventilated infants.

Apnea↗
PubMed1993

Spine and femur density and broadband ultrasound attenuation of the calcaneus in normal Spanish women.

Bone density of the spine and femoral neck and broadband ultrasound attenuation of the calcaneus were measured in 111 normal Spanish women between the ages of 30 and 70 years. The cross-sectional study showed that spine and hip density decreased by 36 and 29%, respectively, and the ultrasound attenuation value decreased by 32% between 30 and 70 years of age. The rate of bone loss at the three sites was significant in women over age 50 and in postmenopausal women. These normative data will be helpful in assessing bone mass in Spanish women suspected of having osteoporosis.

Adult↗
PubMed1993

[Cerebral intraventricular and/or intraparenchymal hemorrhages in full-term newborn infants. Long-term outcome].

BACKGROUND: Intraventricular and parenchymal hemorrhages are rare in full-term neonates. Their prognosis is still under discussion. POPULATION AND METHODS: 6 full-term newborns admitted between January 1985 and December 1988 developed intracranial hemorrhage: 3 had intraventricular hemorrhage and 3 parenchymal without intraventricular hemorrhage. The study includes the results of a questionnaire on the pregnancy and delivery, clinical, ultrasonographic and CT scan data. The long-term neuro-developmental outcome was assessed when the children were 4 to 7 year-old. RESULTS: All the patients were given phenobarbitone for 1 month to 1 year (one patient was given phenobarbitone plus phenytoin). One patient, aged 1 month, required insertion of a valve, because hydrocephalus developed. One patient had difficulties at school with developmental retardation; another patient developed minor difficulties. The 4 other patients had normal motor and mental development with good scholastic performances. CONCLUSIONS: The prognosis for intraventricular and parenchymal hemorrhage seems better in full-term than in pre-term infants.

Cerebral Hemorrhage↗
PubMed1993

[Fulminant pneumococcal septicemia in a splenectomized child despite vaccination and chemoprophylaxis: necessity for education of the entourage].

A splenectomized three-year-old developed fulminant pneumococcal septicemia despite immunization and chemoprophylaxis. The course was rapidly fatal. Fulminant pneumococcal septicemia mainly affects splenectomized individuals and is associated with very substantial mortality. Immunization prior to splenectomy and daily prophylactic oral penicillin have partial preventive efficacy. Other useful measures include carrying a health status card and inpatient antimicrobial therapy in the event of fever. The need for these precautions should be repeatedly discussed with the child's parents and physician.

Bacteremia↗