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Biomedical subjects

L Acosta

Publications and source records attributed to L Acosta.

15 recordsLinked to original sources
PubMed1997

Odor learning, recall, and recognition memory in young and elderly adults.

use of an odor learning test and the California Verbal Learning Test in young and elderly adults enabled comparison of age-related effects on recall and recognition memory. Assessment of odor identification further enabled study of which odor function (recall, identification, recognition) is most affected by aging, the odor functions' interrelationships, and predictors of odor recall. Results suggested that both recall and recognition were significantly affected by aging and that the odor-recall decline cannot simply be referred to poor identification. Very similar age-related effect sizes were found for the 3 types of odor functions. Finally, the combined ability to encode, store, and retrieve odors appears to predict overall recall performance (including its identification component) better than do identification and recognition.

Adolescent↗
PubMed1997

Rainbow Universal CPG: a versatile solid support for oligonucleotide synthesis.

We have developed a universal solid support, termed Rainbow Universal CPG, for use in automated oligonucleotide synthesis. The universal solid support allows any oligodeoxyribonucleotide sequence to be synthesized from a single type of controlled pore glass (CPG) support. Deprotection of oligodeoxyribonucleotides was optimized using 0.5 M LiCl in concentrated ammonium hydroxide. PCR experiments using three different sets of primers proved that the 3'-hydroxyl function of oligodeoxyribonucleotides synthesized from Rainbow Universal CPG was retained. This universal solid support shows promise for replacing the standard nucleoside CPG supports.

Automation↗
PubMed1997

[A study of cerebral maturity by means of quantitative analysis of the electroencephalogram].

INTRODUCTION AND OBJECTIVE: The objective of this study is to evaluate cerebral maturity by means of quantitative analysis techniques applied to the electroencephalogram (EEG). MATERIAL AND METHODS: A transversal study of cerebral maturity was carried out in 403 persons who had undergone an EEG. A previous pilot study had been carried out of 103 persons. A series of spectral parameters of the EEG were selected so that all those studied were in the most similar conditions possible. Different frequency bands were analyzed choosing the one with best discrimination of the maturity aspect. Classification of the different levels of cerebral maturity was done with the help of multivariant analysis. The value of the median of the frequencies and the spectrum of relative potencies at the moment when a frequency band is at a maximum are the parameters which evolve best with age and best discriminate maturity Spectral analysis allows selection of the frequency bands most suitable to the problem. Working with two frequency bands is sufficient to evaluate cerebral maturity. RESULTS: The variables obtained in the occipital channels were sufficient for evaluation of cerebral maturity. Those of the right hemisphere were more significant for diagnosis. The occipital channels are the most relevant in the study of cerebral maturity. CONCLUSIONS: The neuronal network is the most efficient classifier for classification of different groups of maturity The next most efficient method is by quadratic discriminant analysis. Consideration of the variables, taking into account the factors of stability and regularity of the EEG signals improves discrimination with respect to the average of those recorded during the entire procedure.

Adolescent↗
PubMed1996

Paramyosin: a candidate vaccine antigen against Schistosoma japonicum.

Paramyosin, a 97 kDa myofibrillar protein, is a candidate vaccine antigen for prevention of infection with the human parasite Schistosoma mansoni. To determine if paramyosin would also induce protection against Schistosoma japonicum, paramyosin was biochemically purified from S. japonicum adult worms. SDS-PAGE demonstrated a single protein with a molecular weight of 97 kDa. In four separate experiments, vaccination of mice with S. japonicum paramyosin without adjuvant induced significant resistance (62%-86%, P < 0.001) against cercarial challenge as compared to controls. These data suggest that S. japonicum paramyosin may represent a candidate vaccine for immunization against schistosomiasis japonica.

Animals↗
PubMed1995

Brain maturation estimation using neural classifier.

Quantitative electroencephalographic (EEG) signal analysis has revealed itself as an important diagnostic tool in the last few years. Through the use of signal processing techniques, new quantitative representations of EEG data are obtained. To automate the diagnosis, a problem of supervised classification must be solved on these. Artificial Neural Networks provide an alternative to more traditional classifier systems for this task. The objective of this paper is to perform a comparison between several classifiers in a particular problem, the brain maturation prediction. The data preprocessing/feature extraction process and the methodology for making the comparison are described. Performance of the methods is evaluated in terms of estimated percentage of correctly classified subjects.

Adolescent↗
PubMed1994

Hydrolaparoscopy in the rabbit: a fine model for the development of operative fetoscopy.

OBJECTIVE: Our goal was to become adept at performing laparoscopic procedures within a fluid medium and at using miniature instruments in a small animal model. STUDY DESIGN: Adult female New Zealand rabbits underwent carbon dioxide laparoscopy while they were under general anesthesia with the use of 2 mm instruments. The abdominal cavity was filled with lactated Ringer's solution. Visualization of the intraabdominal organs and surgical procedures were performed below the fluid level. RESULTS: Excellent visualization of the abdominal organs below the fluid level was obtained. Several surgical tasks were accomplished, including cutting and coagulation of the uterine horns with monopolar electrocautery, creation of a defect in the mesovarium and mesometrium, extracorporeal knot tying, and intraabdominal cutting of suture material. Relatively high amounts of energy were needed during electrocautery within the liquid medium (> 25 W). Occasional fluid and gas leakage through the skin punctures was prevented with accessory clamps. CONCLUSION: Hydrolaparoscopy can be performed in the rabbit with miniature instruments. As it simulates the human intraamniotic environment, it is a useful model for the development of operative fetoscopy.

Abdomen↗
PubMed1994

Macrophage inflammatory protein-1 alpha in term and preterm parturition: effect of microbial invasion of the amniotic cavity.

PROBLEM: This study was conducted to determine whether: (1) gestational age, parturition, and microbial invasion of the amniotic cavity (MIAC) are associated with changes in amniotic fluid concentrations of immunoreactive macrophage inflammatory protein-1 alpha; (2) amniotic fluid concentrations of macrophage inflammatory protein-1 alpha are correlated with the white blood cell count and the concentrations of interleukin-8 in amniotic fluid. METHOD: Amniotic fluid was retrieved by amniocentesis from 126 patients; 54 women with preterm labor and intact membranes (no MIAC-delivery at term, N = 21; no MIAC-preterm delivery, N = 16; MIAC-preterm delivery, N = 17); 62 patients at term (no labor, N = 19; labor-no MIAC, N = 20; labor-MIAC, N = 23); and 10 patients in the midtrimester of pregnancy. Amniotic fluid was cultured for aerobic, anaerobic and Mycoplasma species. Determinations of amniotic fluid macrophage inflammatory protein-1 alpha and interleukin-8 were performed with immunoassays validated for amniotic fluid (sensitivity: 14.2 pg/ml and 0.3 ng/ml, respectively). Kruskal-Wallis analysis of variance (ANOVA) for censored data, Mann-Whitney U test and Spearman's rank correlation were performed for analysis. RESULTS: 1) Amniotic fluid macrophage inflammatory protein-1 alpha was present in only 31.0% (9/29) of patients not in labor (midtrimester and term). 2) Patients with preterm labor and MIAC had higher amniotic fluid concentrations of macrophage inflammatory protein-1 alpha than those without MIAC (no MIAC-delivery at term: median 0.0 pg/ml, range 0.0-221.2; no MIAC-preterm delivery: median 37.4 pg/ml, range 0.0-494.6; MIAC-preterm delivery: median 7171.0 pg/ml, range 402.5-37994.0; P < 0.00001). 3) Among patients at term, MIAC was associated with higher concentrations of amniotic fluid macrophage inflammatory protein-1 alpha than patients without MIAC (no labor: median 0.0 pg/ml, range 0.0-25.6; labor-no MIAC: median 16.7 pg/ml, range 0.0-161.6; labor-MIAC: median 103.8 pg/ml, range 0.0-4349.0, P < 0.001). 4) Among patients in preterm labor, a strong correlation was found between amniotic fluid concentrations of macrophage inflammatory protein-1 alpha and interleukin-8 (r = 0.9, P < 0.00001) and between amniotic fluid macrophage inflammatory protein-1 alpha concentrations and amniotic fluid white blood cell count (r = 0.6, P < 0.0001). CONCLUSIONS: (1) Macrophage inflammatory protein-1 alpha is undetectable in most amniotic fluid samples from patients in the midtrimester of pregnancy and at term not in labor. (2) Microbial invasion of the amniotic cavity is associated with increased concentrations of immunoreactive amniotic fluid macrophage inflammatory protein-1 alpha in both term and preterm gestations. (3) Amniotic fluid macrophage inflammatory protein-1 alpha concentrations significantly correlate with interleukin-8 levels and white blood cell count in amniotic fluid. Our data strongly suggest a role for macrophage inflammatory protein-1 alpha in the mechanisms responsible for the recruitment of leukocytes into the amniotic cavity during the course of intrauterine infection.

Amnion↗
PubMed1994

Quantitative diagnosis of Schistosoma infections by measurement of circulating antigens in serum and urine.

Recent research on the detection of the schistosome circulating antigens, circulating anodic antigen (CAA) and circulating cathodic antigen (CCA), has greatly expanded the scope of applications. In the present paper aspects of assay development, in particular of highly sensitive assays and of field-applicable assays, are discussed. The progress in the use of CAA- and CCA-detection for diagnosis, follow-up of chemotherapy and sero-epidemiological studies is evaluated.

Animals↗
PubMed1991

Trypanosomatid isolates from Honduras: differentiation between Trypanosoma cruzi and Trypanosoma rangeli.

With the aim of identifying and differentiating Trypanosoma cruzi from Trypanosoma rangeli, culture epimastigotes from 30 Honduran trypanosomatid isolates were analyzed by susceptibility to complement lysis, reactivity to lectins, reactivity to monoclonal antibodies specific for T. cruzi, and isoenzymatic electrophoretic patterns. Using these four methodologies, 27 of the 30 trypanosomatid isolates, as well as 5 clones, were identified as T. cruzi, whereas the remaining three isolates were classified as T. rangeli. None of the isolates presented mixed trypanosome species. Results indicate that both trypanosomatid species circulate in Honduras and that any of the four methods employed may be used to reliably differentiate T. cruzi from T. rangeli.

Agglutination Tests↗
PubMed1987

Incorporation of [3H]fucose in rat hippocampal structures after conditioning by perforant path stimulation and after LTP-producing tetanization.

The contribution of glycoprotein synthesis to functional synaptic changes and to the formation of memory traces was investigated by autoradiographic determination of the incorporation of [3H]fucose into the hippocampal structures of rats. In the first experiment, the fucose incorporation was measured after induction of post-tetanic long-term potentiation (LTP) in granular cell synapses by repeated tetanization (200 cps) of the perforant path, and after stimulation of this hippocampal input by the same number of impulses with very low frequency (0.2 cps) not producing LTP. In the second experiment, the incorporation of fucose was determined after an active avoidance training using the stimulation of the perforant path by impulse trains of 15 cps as conditioning stimuli, and after a session of corresponding unpaired stimulations of the perforant path. Unstimulated animals were used in both experiments to measure the basal glycosylation. LTP-producing tetanization resulted only in a slight increase of incorporation into the ipsilateral hippocampal structures without significant differences to similar changes after the corresponding control stimulation with single impulses. After a session of unpaired stimulation of the perforant path with impulse trains of 15 cps only slight and inconsistent changes of incorporation occurred in the hippocampus too. However, after conditioning by the corresponding perforant path stimulation as conditioned stimulus, considerable increases of incorporation were observed in all structures of the ipsilateral hippocampus, when compared to the unpaired control stimulation. An enhanced labeling occurred also in some structures of the contralateral hippocampus mainly receiving commissural inputs. The results suggest again, that the activation of one single hippocampal afferent, even if producing LTP, would not be sufficient to induce an increased glycosylation of neuronal proteins. The increase of glycoprotein formation seems to require the convergence of several inputs, which can be assumed to occur during learning. Therefore, LTP of a single synaptic population seems not to represent the complete long-lasting memory trace, but only one of its components, or a preceding transient storage mechanism.

Animals↗
PubMed1987

Fiber-type composition of selected hindlimb muscles of a primate (cynomolgus monkey).

The distribution of fiber types in selected leg and thigh muscles of three male Cynomolgus monkeys were determined. Almost all fibers could be classified as fast-glycolytic (FG), fast-oxidative glycolytic (FOG), or slow-oxidative (SO) according to the qualitative histochemical staining scheme described by Peter et al. (1972). Most muscles showed regional variations in fiber-type distributions, i.e., the percent SO was higher and the percent FG was lower in the deep, compared to the superficial, regions of the muscle. Exceptions were the soleus and plantaris muscles, which contained similar distributions of fiber types throughout their cross sections. In the extensor compartment of the leg, a layering of fiber types from deep to superficial were evident in the triceps surae and plantaris complex with the deepest muscle, the soleus, having primarily SO fibers. A similar layering arrangement was observed in the extensor compartment of the thigh, with the deepest muscle, the vastus intermedius, having a much larger proportion of SO fibers than the other muscles in the quadriceps complex. These results indicate that Cynomolgus monkey hindlimb muscles, unlike human leg muscles (Saltin and Gollnick: Handbook of Physiology, L.D. Peachey, ed. American Physiological Society, MD, pp. 55-631, 1983) have a regional distribution of fiber types similar to that observed in many subprimate mammals. Further, the presence of compartmentalization of fiber types within the cross section of several of the muscles studied is suggestive of structure-function interrelationships related to motor control.

Animals↗
PubMed1986

Fiber type and fiber size changes in selected thigh muscles six months after low thoracic spinal cord transection in adult cats: exercise effects.

The effects of low thoracic spinal cord transection on muscle weights, fiber type compositions and, fiber cross-sectional areas of selected hind limb muscles were studied. Adult cats were spinalized at T12 and maintained for approximately 6 months. Some spinalized cats were exercised on a treadmill 30 min/day, 5 days/week to determine the role of weight support in maintaining the muscle properties. Spinalization resulted in a significant decrease in the weights of most extensors, whereas the flexors or those that act as both flexors and extensors were maintained near control values. All muscles showed a significant increase in the percentage of fast-twitch fibers and decrease in slow oxidative fibers following spinalization. In addition, the predominant fast fiber type in each muscle tended to have the largest decrease in cross-sectional area in the spinalized cats. The atrophic and fiber type adaptations were less pronounced in the exercised cats. In contrast, the relative cross-sectional area of high oxidative fibers generally was similar among the three groups. These results demonstrated that the muscles below the level of the lesion became more "fast-like" histochemically following spinal cord transection, whereas the oxidative properties were relatively unaffected. Further, daily exercise involving weight support appeared to be an important deterrent to these atrophic responses, particularly in the muscles that normally have a postural function (i.e., the slow extensors).

Animals↗
PubMed1978

Free amino acid levels in amyotrophic lateral sclerosis.

To evaluate reports of abnormal levels of free amino acids (AA) in patients with amyotrophic lateral sclerosis (ALS), we studied serum, cerebrospinal fluid, and urine AA in 12 patients with ALS and 12 controls matched for age, sex, and severity of disability. ALS patients had statistically significant elevations in serum levels of tyrosine, total aromatic AA, and total basic AA. ALS patients also had statistically significant elevations in cerebrospinal fluid of total basic AA, lysine, essential AA, and leucine. The severity of ALS correlated inversely with acidic AA (glutamate and aspartate) and O-phosphoserine in cerebrospinal fluid. Activity of ALS correlated directly with serum aspartate and cerebrospinal fluid alanine. We conclude that subtle abnormalities of AA levels are present in ALS and that these are not due to age, sex, or disability. The pattern of distribution of AA levels differs from that in hepatic or renal disease and suggests defective membrane transport or poor cellular utilization of basic and essential AA in the central nervous system.

Adult↗