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Biomedical subjects

A Campos

Publications and source records attributed to A Campos.

At least 109 records · Page 6Linked to original sources

[Etiological and clinical evaluation of low acute respiratory infections in children].

Viral laboratory diagnosis was correlated with clinical and epidemiological data from 80 hospitalized children with acute lower respiratory infection (ALRI). They all were less than 5 years-old and were studied from May to September 1993. Fifteen percent of them were malnourished and 75% had some unsatisfied basic necessity. Nasopharingeal aspirates were obtained the first day of hospitalization, and diagnosis for respiratory viruses was performed by the immunofluorescence test with monoclonal antibodies. Routine laboratory determinations, x-ray studies, and clinical data were not conclusive to determine viral etiology. Forty-one percent of the children had a positive viral diagnosis: the most important agent was Respiratory Syncytial Virus (78.7%) followed by Adenovirus (9.1%), Influenza A (6.1%) and Parainfluenza (3%). The peak of incidence was observed in June and the majority of the patients remained hospitalized less than 10 days. Six children died: two of them had viral pneumonia and could not receive mechanical respiratory assistance. The percentage of children who received antibiotics was high, 61.2%, in spite of the fact that 34.7% of these patients had a laboratory confirmed viral etiology. The availability of rapid laboratory viral diagnosis may contribute to decrease the use of antibiotics and improve the management of patients.

Acute Disease↗

Shape, F-actin, and surface morphology changes during chemotactic peptide-induced polarity in human neutrophils.

BACKGROUND: The exposure of human neutrophils to uniform concentrations of chemoattractants, such as N-formyl peptides, induces morphological cell polarization. In this study we report the temporal sequence of changes in cell shape, F-actin, and cell surface morphology during cellular polarization induced by N-formylmethionyl-leucyl-phenylalanine (fMLP) in human neutrophils in suspension. METHODS: Neutrophil shape changes induced by 10(-8) M fMLP were observed with DIC microscopy. Size and cellular granularity were analyzed by flow cytometry measuring their forward and side scattered light. To visualize F-actin distribution, neutrophils were labeled with the fluorescence probe FITC-phalloidin, and were examined with fluorescence and confocal laser scanning microscopy. Cell surface morphology was assessed with scanning electron microscopy (SEM). RESULTS: The stimulation of round-smooth neutrophils with nanomolar concentrations (10(-8) M) of fMLP in suspension induced a temporal sequence of morphological changes during cell polarization, characterized by 1) increase in size as determined by forward angle scattered light, 2) rapid redistribution of F-actin from a diffuse cytoplasmic localization to the cell periphery, and 3) rapid reorganization of cell surface morphological features, with accumulation of plasma membrane in the front of polar cells. Four cell shapes were identified with SEM after stimulation of round-smooth neutrophils: round-ridged, round-ruffled, nonpolar ruffled, and polar cells. These cell shapes were correlated with a cortical localization, focal aggregates, and multipolar distribution of F-actin. In polar neutrophils, F-actin became concentrated in the front of the cell. CONCLUSIONS: These findings show the relation between reorganization of the microfilamentous cytoskeleton and modifications in cell shape and surface features during cell polarization induced after fMLP activation in neutrophils. This approach offers a powerful tool for further analysis of receptor distribution in polarized, motile neutrophils.

Actins↗

Dynamic reorganization of the alkaline phosphatase-containing compartment during chemotactic peptide stimulation of human neutrophils imaged by backscattered electrons.

Scanning electron microscopy (EM) and cytochemical techniques were used to examine the alkaline phosphatase-containing compartment in human neutrophils after stimulation with nanomolar concentrations of N-formylmethionyl-leucyl-phenylalanine (10(-8) M fMLP). Alkaline phosphatase (AlkPase) activity was demonstrated with a lead-based metal capture cytochemical method. The reaction product was visualized with the backscattered electron imaging mode of scanning EM, and analyzed by electron probe X-ray microanalysis. Alkaline phosphatase activity was detected only in fMLP-stimulated neutrophils; unstimulated neutrophils displayed no activity. Stimulation of human neutrophils with 10(-8) M fMLP induced a time-dependent intracellular redistribution of irregular round or tubular granules containing alkaline phosphatase activity, as seen by backscattering. The intracellular redistribution of alkaline phosphatase activity was accompanied by increased cytochemical activity on the cell surface. The reaction product was localized preferentially on ridges and folds of polar neutrophils. Reorganization of the AlkPase-containing compartment correlated with changes induced by fMLP in cell shape, ie, membrane ruffling and front-tail polarity, as observed with the secondary electron image mode of scanning EM. These findings demonstrate the intracellular reorganization, increase, and asymmetric distribution of alkaline phosphatase activity on the plasma membrane of human neutrophils after stimulation by chemotactic peptides.

Alkaline Phosphatase↗

MRI changes in the central nervous system in a child with lupus erythematosus.

We report on a 10-year-old girl with systemic lupus erythematosus who presented in status epilepticus as the only manifestation of central nervous system involvement. MRI of the brain showed diffuse gray and white matter lesions which almost completely resolved after treatment with methylprednisolone. MRI findings in this child are similar to those in adults with diffuse clinical manifestations. The study is essential in the initial evaluation of patients suspected of central nervous system lupus.

Brain↗

X-ray biological dosimetry performed by selective painting of human chromosomes 1 and 2.

Fluorescence in situ hybridization with a cocktail of whole-chromosome probes, specific for human chromosomes 1 and 2, was performed to analyze the induction of translocations and dicentrics in human peripheral blood lymphocytes exposed to 100 KVp X-rays and cultured for 48 h. The dose-response curves for both aberration types were linear-quadratic, with similar coefficients, and after correction for genome content were a little lower than the dose-response curve for dicentrics established by conventional analysis. Three doses were also assessed after 76-h culture. The dicentric yield at 76 h was reduced compared with that at 48 h because of the existence of second and third division metaphases. The translocation yield did not reduce except at 4 Gy. The frequency of cells containing both dicentrics and translocations suggested that their occurrence is not correlated. The importance of stating the scoring criteria and of specifying the different types of aberrations is stressed.

Cells, Cultured↗

Difference in constitutive heterochromatin behaviour between human amniocytes and lymphocytes detected by a sequential in situ exonuclease III digestion-random primer extension procedure.

Fixed chromosomes from human amniotic fluid cells and peripheral blood lymphocytes were digested in situ with exonuclease III and the single stranded DNA obtained was used as template for an in situ random primer extension. Under these conditions an R banding pattern, more evident in lymphocytes than in amniocytes, was obtained. Nevertheless, constitutive heterochromatin of chromosomes 1, 16, Yq, and mainly the pericentromeric region of chromosome 9 was far more intensely labelled in amniocytes than in lymphocytes. Fluorescence in situ hybridisation with a specific classical satellite DNA probe, showed that this differential labelling was dependent on a greater sensitivity of chromosome 9 constitutive heterochromatin to exonuclease III digestion in amniocytes than in lymphocytes, thus indicating qualitative differences in this region between both human cellular materials.

Adolescent↗

Hypoglossal nerve conduction study by transcranial magnetic stimulation in normal subjects.

The introduction of transcranial magnetic stimulation has allowed the study of conduction in the proximal portions and central pathways of the cranial nerves. A study is made of cranial nerve XII with transcranial magnetic stimulation at two levels, cortical and cisternal, registering the motor evoked potential by means of surface electrodes in contact with the upper face of the tongue. Motor evoked potentials were constantly observed on cortical stimulation, in a painless, easy, and reproducible way, with mean values of 10.84 +/- 1.14 milliseconds (latency) and 7.81 +/- 1.14 mV (amplitude). Motor evoked potentials were unconstant and showed reduced amplitudes on cisternal stimulation, with mean values of 4.72 +/- 0.62 milliseconds and 0.83 +/- 1.26 mV. The magnetic stimulation technique allows the study of the entire motor pathway of cranial nerve XII (motor cortex-medulla, motoneuron-muscle). The method is efficient, noninvasive, painless, and easily reproduced, and it comes close to being an ideal clinical conduction study technique for this cranial nerve.

Adult↗

Imagery, concreteness, emotionality, meaningfulness, and pleasantness of words.

This account of the literature on the relationships among imagery, concreteness, emotionality, meaningfulness, and pleasantness shows high test-retest reliability for all five attributes which are stable for subjects of both genders and of several nationalities. Gender differences and the influence of attributes on other attributes are also examined.

Adolescent↗

Total intravenous anesthesia with propofol vs. propofol/midazolam in oncology patients.

The goal of this study was to determine dose requirements of propofol vs. propofol/midazolam in oncology patients during total intravenous anesthesia. The design of the study was a controlled clinical trial. The setting was the Oncology Hospital, National Medical Center, IMSS, located in Mexico City. Sixty patients were allocated randomly into two groups, patients in control group received propofol and fentanyl to induced and to maintain the anesthesia. Twenty nine patients in the experimental group received propofol and midazolam to induce anesthesia and to maintain propofol and fentanyl. The combination of propofol and midazolam to induce general anesthesia in oncology patients reduced the requirements in propofol and fentanyl in total intravenous anesthesia.

Adult↗

[Prevalence of digestive symptoms in normal adult women and its association with cholelithiasis].

The aim of this work was to study the prevalence of biliary diseases and digestive symptoms in normal adult women. Four hundred nineteen women were chosen; of these 145 were discarded due to previous gastrointestinal diseases (20), previous gastrointestinal complaints (38) and previous cholecystectomy (85). Two hundred seventy six women were subjected to abdominal ultrasound examination; of these 53 had cholelithiasis and in three a gallbladder cancer was suspected (and confirmed by surgery). Considering women with previous cholecystectomy, cholelithiasis and gallbladder cancer, a 33.6% prevalence of biliary diseases can be inferred. An interrogation about gastrointestinal symptoms was performed to women subjected to ultrasound examinations, by 2 professionals unaware of ultrasound results. A high frequency of pyrosis, food intolerance and constipation was found, not observing differences between women with or without cholelithiasis. However, these last women had a higher frequency of upper abdominal pain. Both groups had also a high rate of previous surgical procedures.

Adult↗

Cutaneous sarcoidosis and foreign bodies. An electron probe roentgenographic microanalytic study.

A 60-year-old woman had extensive and recurrent foreign-body granulomatous inflammation of her forehead. The granulomata contained double refractile crystalline material. Electron probe roentgenographic microanalysis identified silicon, calcium, aluminum, potassium, and sulphur in the crystalline material. Silicon-rich particles are generally considered exogenous. A diagnosis of sarcoidosis was confirmed by the presence of bilateral hilar and mediastinal lymphadenopathy due to biopsy-proven nodal replacement by noninfectious noncaseating granulomata. We conclude that foreign matter may operate as a nidus for the formation of granuloma in sarcoidosis and that the presence of polarizable matter in a sarcoid granuloma does not rule out sarcoidosis.

Aluminum↗

Surface expression and distribution of Fc receptor III (CD16 molecule) on human natural killer cells and polymorphonuclear neutrophils.

Human natural killer cells and polymorphonuclear neutrophils constitutively express the low-affinity IgG Fc receptor (Fc gamma RIII, CD16 molecule). To investigate cell surface morphology, antigenic receptor density, and topographical distribution of Fc gamma RIII on the plasma membrane of natural killer cells and polymorphonuclear neutrophils, conventional scanning electron microscopy (SEM), flow cytometry, and immunoscanning electron microscopy were used. Fc gamma RIII was detected with an indirect immunogold labeling procedure, and receptors were visualized in the backscattered and secondary electron imaging mode of SEM. Natural killer cells showed a cell surface morphology compatible with lymphocytic differentiation characterized by microvilli and microridges. Polymorphonuclear neutrophils showed surface features characterized by ridges with folds and scattered short microvilli. Natural killer cells displayed a lower cell labeling density, whereas polymorphonuclear neutrophils showed a high level of expression of Fc gamma RIII on the plasma membrane by quantitative analysis with SEM in the backscattered electron imaging mode. Flow cytometry analysis confirmed these findings. Analysis of the topographical distribution of Fc gamma RIII antigenic receptor sites by SEM in the backscattered and secondary electron imaging modes showed that Fc gamma RIII on natural killer cells are randomly distributed, whereas Fc gamma RIII are located on ridges and folds of the plasma membrane of polymorphonuclear neutrophils. These observations suggest that natural killer cells and polymorphonuclear neutrophils differ in their levels of expression and topographic distribution of Fc gamma RIII on the plasma membrane. This different spatial distribution of Fc gamma RIII would provide morphological evidence of certain cellular functions mediated by natural killer cells and polymorphonuclear neutrophils.

Cell Count↗

Electron probe microanalysis of gentamicin-induced changes on ionic composition of the vestibular gelatinous membrane.

Gentamicin-induced changes in ionic composition in the otolithic membrane of adult OF1 mice were evaluated in the gelatinous layers of the saccule and utricle by quantitative electron probe X-ray microanalysis. The otolithic membranes were plunge-frozen and freeze-dried to prevent the redistribution of elements. Quantitative analysis was carried out with an energy dispersive detector using the peak-to-background (P/B) ratio method and different salts dissolved in dextran as standards to calibrate the P/B ratio against the concentration of the elements P, S and K in the microprobe. Gentamicin selectively decreased the concentrations of P (P < 0.001) and S (P < 0.01) in the gelatinous membrane of the saccule, and had no effect in the utricle. The concentration of K also increased in the utricular gelatinous membrane (P < 0.05). The mechanism of ototoxicity in the gelatinous membrane is unknown, but the ability of aminoglycosides to block calcium channels may induce disturbances in the ionic equilibrium of the endolymphatic fluid, and thus affect the biochemical composition of the gelatinous membrane. This technique can be useful to evaluate the distribution of ions in the process of drug-induced ototoxicity.

Animals↗