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Biomedical subjects

J Flores

Publications and source records attributed to J Flores.

230 records · Page 13Linked to original sources
PubMed1969

Peptide formation mediated by hydrogen cyanide tetramer: a possible prebiotic process.

Chemical evolution on the primitive earth must have involved condensation of alpha-amino acids to peptides. Under aqueous conditions consistent with current conceptions of primordial waters, heating glycerine with the hydrogen cyanide tetramer, diaminomaleonitrile, yields dipeptide. If nitrogen was cycled through primordial waters as cyanide, peptide synthesis by stepwise tetramer-mediated condensation of alpha-amino acids would have been a plausible process.

Dipeptides↗
PubMedDate not supplied

Vaccination against hepatitis A in children aged 12 to 24 months [corrected].

BACKGROUND: Current hepatitis A vaccines are either licensed for children >2 years of age, as in the U.S. or Chile, or >1 year of age, as in Europe and other parts of the world. Recent recommendations for immunization against hepatitis A have included routine vaccination of children in areas or regions of higher endemicity. However, data on hepatitis A vaccination in toddlers aged between 1 and 2 years are scarce. METHODS: This open clinical study investigated the reactogenicity and immunogenicity of two doses (0, 6-month schedule) of an inactivated hepatitis A vaccine (Havrix pediatric, Glaxco SmithKline Biologicals, Rixensart, Belgium) in 120 seronegative children aged 12-24 months. RESULTS: Pain at the injection site and irritability were the most frequently reported local and general symptoms, respectively. No serious adverse events related to the study vaccine were reported. One month after the first dose, all but one subject had antibodies against hepatitis A with a GMT of 159 mIU/mL. After the booster dose, all had antibodies with a GMT of 2,939 mIU/mL. CONCLUSIONS: Our data show that the inactivated hepatitis A vaccine was well tolerated by these toddlers and that the vaccine elicits a good immune response.

Child, Preschool↗
PubMedDate not supplied

Prospects for development of a rotavirus vaccine against rotavirus diarrhea in infants and young children.

Major advances have been made in elucidating the etiologic agents of severe infantile diarrhea, and it is clear that rotaviruses are the single most important etiologic agents. Progress in the development of rotavirus vaccine candidates has also moved swiftly with the "Jennerian" approach, in which a related live, attenuated rotavirus strain from a nonhuman host is used as the immunizing antigen. If this strategy is not effective against all rotavirus serotypes, reassortant rotaviruses hold great promise for the development of a multivalent vaccine. Field trials with the "Jennerian" approach vaccines are under way, and phase 1 trials with the reassortants have been initiated.

Animals↗
PubMedDate not supplied

[Respiratory form of onset of motor neuron disease].

OBJECTIVE: To present a case of respiratory failure as the form of onset of amyotrophic lateral sclerosis, to review the main clinical findings, data of the investigations done which suggest the presence of this disorder and describe its therapeutic management. CLINICAL CASE: A 68 year old man presented with a subacute illness characterized by a sleep disorder with sleep fragmentation, snoring of increasing intensity, without clear pauses of apnea, progressive diurnal hypersomnia accompanied by progressive dyspnea followed by respiratory failure with respiratory acidosis and difficulty in manipulating things with his hands. Diagnostic investigations showed a restrictive pattern without pulmonary fibrosis, due to paralysis of the diaphragm, and the presence of electromyographic signs compatible with motorneuron disease. The patient was treated with riluzole 100 mg/day and non-invasive mechanical ventilation and maintained an acceptable quality of life. CONCLUSIONS: Motorneuron disease may start with acute or progressive respiratory failure without a clear etiological cause and may appear to be similar to obstructive sleep apnea syndrome. The treatment of choice for this respiratory problem is non-invasive mechanical ventilation. Absence of symptoms of bulbar involvement is essential for a favourable prognosis.

Acute Disease↗
PubMedDate not supplied

[Dose-effect of the administration of ferrous fumarate in aged persons with iron deficiency].

BACKGROUND: Anemia is the most prevalent hematological problem in elderly persons, affecting 14% of the males and 6% of the females of the population over 60 years of age in Mexico City. OBJECTIVE: To determine the effect produced by the prolonged administration of ferrous fumarate in elderly persons with iron deficiency. METHOD: In a population of 178 subjects, aged between 65 to 100 years, iron deficiency was diagnosed in 51 (28.6%), who had serum iron concentrations below 80 micrograms/dL for men and 60 micrograms/dL for women, but only 21 patients (11.8%), accepted to participated in the study. The response to a 6 months oral administration of ferrous fumarate were studied with a daily oral dose of 5 mg/kg of elemental iron. The patients were classified in 3 groups according to the abnormal parameters of iron metabolism (group 1 = 10.9% anemia, group 2 = 28.0% and group 3 = 63.0% anemia). RESULTS: The efficacy of treatment was evaluated by quantification of the changes occurred in serum iron concentrations, hemoglobin, ferritin and transferrin saturation index, at 0, 30, 90 and 180 days of treatment. This study showed that the treatment of oral ferrous fumarate in elderly patients with iron deficiency, produces a quantifiable improvement in measures of iron parameters within 6 months. CONCLUSIONS: The results of this study suggest the usefulness of prolonged treatment with ferrous fumarate in elderly patients with iron deficiency, to avoid therapeutic failure as a consequence of non-compliance as is common in elderly patients.

Age Factors↗
PubMedDate not supplied

Effect of synchronous and asynchronous pulsatile flow during left, right, and biventricular bypass.

Ventricular assist devices augment aortic or pulmonary flow while the patient's heart recovers from surgery or infarction. Most are used in the asynchronous full-to-empty mode, but they also may be used in a synchronous counter-pulsation mode. This study examines which assist mode optimally reduces myocardial oxygen consumption (MVO2). Eighteen pigs were instrumented with pulmonary artery, carotid artery, and coronary sinus catheters for determination of MVO2. Pierce-Donachy Ventricular Assist Devices (VAD) were used in left, right, or biventricular assist mode. Fifteen minute periods each of control, synchronous, and asynchronous bypass were randomly instituted. The mid-left anterior descending coronary artery was then ligated, and the sequence repeated. At the end of each period, MVO2 was determined. In comparison with controls, MVO2 was statistically significant in the BIVAD asynchronous mode only. Synchronized counterpulsation did not decrease MVO2. When ventricular assist devices are used to aid in cardiac recovery postoperatively or postmyocardial infarction, biventricular assist should be used.

Animals↗
PubMedDate not supplied

Diet therapy in severe clinical expression of debrancher deficiency.

An eleven year old boy was referred because of sudden loss of consciousness, muscular weakness, poor general health, severe hypoglycemia with seizures and hepatomegaly. Response to oral glucose and galactose increased blood lactic acid and glucose at different times. Fasting values of blood lactic was normal, but glucose was found at 33 mg/dl. Similar test made up two hours after feeding revealed hyperlactatemia (35-50 mg/dL) and hyperglycemia (129 mg/dL). Glucagon did not result in a rise of glucose at fasting or feeding. Hepatic glycogen content was found 15 gm/100 mg of tissue. The enzyme activities revealed a deficiency of the liver debranching enzyme while leukocytes had normal enzyme activity. Hepatic biopsy showed liver fibrosis. The present case had the clinical characteristics of severe form of glycogen storage disease. A low carbohydrate and high protein diet was indicated in order to increase the gluconeogenic precursors. Although debranching enzyme deficiency is almost always benign a high carbohydrate diet induced a more severe expression of the disease.

Child↗
PubMedDate not supplied

[Gastric emptying of different liquid test meals measured by ultrasonography].

The rate of gastric emptying of different liquid solutions was measured in 80 voluntary normal young male subjects (mean age 19.9 +/- 1.6 years) by direct real-time ultrasonic imaging. Multiple US scans were repeated at regular intervals (15-30 minutes) until complete gastric emptying was established, after ingestion of 500 cc of 8 different liquid test meals: isotonic saline, 50% glucose, 5% glucose, 40 g of proteins, 20 g of protein, 40 g of fat, 20 g of fat and mixed (carbohydrates, proteins and fat). Eight groups of ten subjects were studied, each one with a different test meal. Three types of gastric emptying were identified: slow (177 +/- 12 minutes) in subjects receiving 50% glucose, 40 and 20 grs of proteins and mixed test meals; intermediate (83 +/- 9 minutes) with 5% glucose, 40 and 20 g of fat; rapid (40 +/- 6 minutes) with isotonic saline. The mixed diet had the slowest emptying time (210 +/- 6 min). Our results are in accordance with published data regarding gastric motor physiology and demonstrates the usefulness of ultrasound in the study of gastric emptying of fluids.

Adolescent↗
PubMedDate not supplied

[Ultrasonographic changes in the gallbladder wall in non-gallbladder diseases].

Alterations of the gallbladder wall is a well known sonographic sign of acute cholecystitis. But thickening of the gallbladder wall is also found in patients without intrinsic gallbladder disease. We present our experience on this regard in patients with cirrhosis, acute viral hepatitis, infectious mononucleosis, halothane hepatitis, fulminant hepatic failure, malaria due to plasmodium falciparum, heart failure, severe malnutrition due to gastric obstruction, septicemia, pyogenic hepatic abscess, amoebic hepatic abscess and in a 14 years old patient with fracture of the skull-acute anemia-shock. Most of these diseases affected the liver directly or indirectly. Knowledge of these alterations of the gallbladder wall in these circumstances are important in order to avoid a the erroneous diagnosis of acute cholecystitis.

Acute Disease↗