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Biomedical subjects

M A Reyes

Publications and source records attributed to M A Reyes.

17 recordsLinked to original sources
PubMed2002

Lambda(0) polarization in 800-GeV/cpp --> p(f)(Lambda0K+).

We report results from a study of Lambda(0) polarization in the exclusive reaction pp --> p(f)(Lambda0K+) at 800-GeV/c. We observe a dependence of the polarization on the Lambda0K+ invariant mass with large (+71%) positive polarization at small mass (1.63-GeV/c(2)) and large (-43%) negative polarization at large mass (2.75-GeV/c(2)). This observation confirms the result of the CERN ISR R608 experiment and extends the range over which the effect is observed. The strong dependence of the polarization on the Lambda0K+ invariant mass suggests that the origin of the polarization is closely related to the production dynamics of the diffractively produced Lambda0K+ system.

Journal Article↗
PubMed2001

Diffractively produced charm final states in 800-GeV/c pp collisions.

We report the first observation of diffractively produced open charm in 800-GeV/c pp collisions of the type pp-->pD*X. We measure cross sections of sigma(diff)(D*+) = (0.185+/-0.044+/-0.054) (mu)b and sigma(diff)(D(*-)) = (0.174+/-0.034+/-0.029) (mu)b. Our measurements are based on 4.3x10(9) events recorded by FNAL E690 in the fixed-target run of 1991. We compare our results with previous fixed-target charm experiments.

Journal Article↗
PubMed1997

Bilateral tonic-clonic epileptic seizures in non-benign familial neonatal convulsions.

We report an electroclinical pattern considered characteristic of benign familial neonatal convulsions (BFNC) in two neonates without BFNC. Both neonates were products of uncomplicated pregnancies, labor, and deliveries. The cause of the seizures was not established. There was no family history of seizures or epilepsy. Seizures started on the second and third days after birth. Ten seizures were captured by continuous video-EEG telemetry. The electroclinical events began with generalized tonic posturing coinciding with the appearance of diffuse attenuation of the EEG activity. After several seconds, bilateral clonic movements accompanied by bilateral repetitive sharp waves or spikes occurred in the EEG. One patient had normal development; the other became autistic. We conclude that the electroclinical pattern occurring in BFNC can occur in other types of neonatal seizures.

Autistic Disorder↗
PubMed1985

Effect of age, malnutrition and renutrition on free secretory component and IgA in secretions.

The development of free secretory component (FSC) was studied in the tears of normal infants, children and adults. The level of FSC in tears was higher in older adults than in children. Free secretory component was also measured in the tears of normal, moderately and severely malnourished Colombian children. Children suffering from kwashiorkor, combined protein-calorie malnutrition or marasmus were studied before and after renutrition. No change was detected in the concentration of FSC in tears of moderately malnourished (Grade I and II) children. There was a significant difference between normal and severely malnourished children which improved with renutrition. The levels of tear IgA were decreased in the moderately malnourished children. These results indicate that reduction in secretory IgA levels in moderate malnutrition may not be explained by a lack of available free secretory component in tears, but that severe malnutrition may impair the S-IgA system by significantly reducing the availability of free secretory component.

Adolescent↗
PubMed1984

Enzootic Brugia infection in a two-year-old Colombian girl.

Mature male and female filarial worms were present in a lymphatic vessel near a retro-auricular lymph node removed from a 2-year old Colombian girl. Although apparently mature microfilariae were present in the uterus of the female, none was detected in blood samples (Knott's) of peripheral blood taken during day or night. The identification of the worms as a species of Brugia is suggested by their location in a dilated lymphatic vessel, morphology of adults, and the distribution pattern of tail nuclei of the microfilariae. This case is similar to another Colombian case reported from the Departamento del Santander del Sur, and suggests that zoonotic filarial infections may not be uncommon in Colombia.

Brugia↗
PubMed1982

Effect of moderate malnutrition on immediate hypersensitivity and immunoglobulin E levels in asthmatic children.

Dermal reactions and IgE levels were compared in 51 asthmatic Colombian children identified on the basis of anthropometric measurements as nutritionally normal (25) or mildly (16) or moderately (10) undernourished. Twenty-five nonatopic children served as controls. Total serum IgE concentrations were significantly elevated in the asthmatic group as a whole. Moderately malnourished (grade II) asthmatic children had more than twice as much serum IgE as normal or mildly malnourished (grade I) asthmatic subjects and seven times more than nonatopic children. Intestinal parasitism did not appear to contribute to these differences in IgE levels. Serum levels of IgA and IgD were similarly elevated in grade II asthmatics. Concentrations of serum IgG, IgM, and C3 and C4 complement were unaffected by nutritional or allergic status. Eosinophilia in nasal mucus was significantly reduced in grade I and grade II malnourished asthmatic children. Among asthmatics, the most frequent dermal reactions were to mite antigens (96%), house dust (67%), and grass pollens (35%). Significant levels of specific IgE were detected by the RAST to two species of mites in nearly all atopic children. There was no apparent influence of nutritional status on the distribution of reactivity or specific IgE assay. The clinical significance of hyperimmunoglobulin E in atopic, moderately malnourished children remains to be elucidated.

Adolescent↗
PubMed1981

Effect of renutrition on humoral and cell-mediated immunity in severely malnourished children.

Forty-three Colombian children suffering from either kwashiorkor (21), combined protein-calorie malnutrition (11), or maramus (11) were hospitalized and provided a high protein, high calorie diet for 4 to 5 wk. Improvement in clinical and nutritional status was accompanied by significant increases in levels of serum immunoglobulins G and M and C3 complement and by significant decreases in serum immunoglobulin A concentrations, especially in infants with kwashiorkor. Skin test reactions to purified protein derivative and candidin improved during renutrition. Lymphocyte blastogenesis after stimulation in vitro with phytohemagglutinin and pokeweed mitogen increased rapidly during hospitalization. After 1 yr posttreatment, cell-mediated immune responses, both in vivo and in vitro, had diminished. These results indicate that some aspects of the immune response are affected to a different degree in kwashiorkor, maramus, and combined malnutrition. Short-term nutritional rehabilitation has a differential effect on the long-term restoration of various aspects of immunity.

Antibody Formation↗
PubMed1977

Pancreatic and salivary amylase activity in undernourished Colombian children.

Amylase activities were quantitated in secretions of marginally and severely malnourished Colombian children. In young children with a mean age of 21 months, the relative pancreatic and salivary amylase isozyme activities of urine were significantly changed in marginally malnourished children compared to normal children. There was a relative increase in salivary and decrease in pancreatic amylase activity in the undernourished children and total amylase activity was somewhat decreased. Amylase activity in saliva and tears was significantly lower in these malnourished children. Older children who were more severely malnourished had significantly lower amylase activity in their sera and tears. Thus marginal and severe malnutrition affects the production of amylase by the pancreas and salivary glands of young children distinctly. It significantly suppresses amylase activity in tears, saliva, and serum.

Aminopeptidases↗
PubMed1976

Etiology of respiratory tract infections in children in Cali, Colombia.

One hundred eighty children hospitalized for acute respiratory disease were studied in Cali, Colombia. In the majority of patients, pneumonia was the reason for hospitalization and remained the final diagnosis. Fifty-one cases of pneumonia of indeterminate etiology comprised the largest single diagnostic category, followed by 38 cases of pneumonia associated with measles, and 22 cases assocaited with serologic evidence of infection with other viral agents or Mycoplasma pneumoniae. Etiologic diagnosis could be assigned with a reasonable degree of confidence in 116 of the 180 patients (64%). The laboratory procedure found most likely to provide the etiologic diagnosis in this series was paired sera specimens for demonstration of rise in antibody titer against the common viral respiratory pathogens. Those most frequently implicated serologically as etiologic agents in the cases studied were, in order of decreasing frequency, measles, influenza, parainfluenza, and adenoviruses.

Adolescent↗