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Biomedical subjects

L Contreras

Publications and source records attributed to L Contreras.

13 recordsLinked to original sources
PubMed1992

Restoration of malonyl-CoA sensitivity of soluble rat liver mitochondria carnitine palmitoyltransferase by reconstitution with a partially purified malonyl-CoA binding protein.

Solubilization of rat liver mitochondria in 5% Triton X-100 followed by chromatography on a hydroxylapatite column resulted in the identification of malonyl-CoA binding protein(s) distinct from a major carnitine palmitoyltransferase activity peak. Further purification of the malonyl-CoA binding protein(s) on an acyl-CoA affinity column followed by sodium dodecyl sulfate gel electrophoresis indicated proteins with Mr mass of 90 and 45-33 kDa. A purified liver malonyl-CoA binding fraction, which was devoid of carnitine palmitoyltransferase, and a soluble malonyl-CoA-insensitive carnitine palmitoyltransferase were reconstituted by dialysis in a liposome system. The enzyme activity in the reconstituted system was decreased by 50% in the presence of 100 microM malonyl-CoA. Rat liver mitochondria carnitine palmitoyltransferase may be composed of an easily dissociable catalytic unit and a malonyl-CoA sensitivity conferring regulatory component.

Animals↗
PubMed1991

Patterns of electromyographic activity in subjects with different skeletal facial types.

Integrated electromyographic activity of masseter and anterior temporal muscles was recorded using bipolar surface electrodes in 33 young adults. Subjects were skeletally classified according to ANB angle reading corrected both for maxillary position and rotation of the jaw. Postural activity for both muscles was higher in Class III subjects than in Class I and Class II, whereas in Class I and II subjects activity was similar. During swallowing, masseter muscle activity in Class III subjects was higher than Classes I and II, whereas anterior temporal muscle activity was not different between Classes III and I. During maximal voluntary clenching, activity was not different among classes. High correlations between electromyographic activity and corrected ANB angle as well as with overjet were observed. Skeletal classification used in the present study may have clinical relevance regarding treatment and prognosis, as well as in the assessment of the relationship between muscular activity and craniofacial characteristics.

Adolescent↗
PubMed1991

[Epidemiology of fractures in Chile].

Bone fractures represented 3.3% of diagnosis among 1,003,267 patients discharged from National Health System Hospitals in Chile during 1985. Among 73,534 certified deaths, 1.2% followed fractures. Significantly higher rates were observed in males; after age 75, fractures were more common in females. Rates per 100,000 for different fractures were: radio-cubital 45.4, shine and fibula 41, ankle 28.1, humerus 25.3, and hip 23.5. Among males the figures were shine and fibula 66.2, radius and cubitus 64.9, face 37.5 and ankle 37.1. Among females, hip 28.2, radius and cubitus 26.3, ankle 19.3 and humerus 16.5. Hip fracture is clearly related to age, the incidence raising from below 60 per 100,000 under age 60 to 617 in females and 330 in males above that age. Other fractures that increase with age include radius and cubitus, shine and fibula, ankle, humerus and femur.

Adolescent↗
PubMed1991

[Neurologic involvement in Reiter's disease. Report of 2 cases].

Neurologic involvements is a rare complication of Reiter syndrome. It may precede other manifestations and constitutes a cause of death. We report 2 cases. The first, an 18 year-old male developed arthritis, fever, balanitis and sacroileitis 2 months after non gonococcal urethritis. He received phenylbutazone and local steroids without improvement. Logic dysphagia, diplopia with bilateral paralysis of the IV and VI cranial nerves and generalized absent reflexes developed gradually 2 weeks after admission. Methylprednisolone pulses failed to improve the patient's condition and plasmapheresis was associated to near complete remission after 6 exchanges. The other patient, a 31 year old male started out with alternating lower extremity paresis. One month later, urethritis, conjunctivitis, arthritis and sacroileitis appeared. The electromyogram was characteristic of axon sensorimotor polyneuropathy. Administration of naproxen was associated to complete improvement within 2 weeks. Neither patient had shown evidence of recurrence after a 5 year follow up period.

Adolescent↗
PubMed1990

Characterization of a low molecular weight protein of the ATP synthetase complex from beef heart and rat liver mitochondria with a high affinity monoclonal antibody.

A monoclonal antibody raised against beef heart mitochondria elicited a strong reaction on Western Blot with a 16 kD protein in preparations of beef heart mitochondria, ammonia particles, oligomycin sensitive ATPase and Complex V, in addition to showing a lesser affinity for the partially purified 30 kD ADP/ATP carrier. The antibody also reacted with a 17 kD protein in rat liver mitochondria and an enriched membrane vesicle fraction. The N-terminal sequence of the first twenty amino acids of both the beef heart and rat liver proteins contained significant homology. Comparison with results in the literature indicate that the proteins represent the delta subunit of the ATP synthetase complex. Further evidence suggests that the epitope for the antibody may reside at the C-terminal 30-40 amino acid residues of both proteins.

Amino Acid Sequence↗
PubMed1989

Photoaffinity labeling of hamster brown adipose tissue mitochondria by an [125I] coenzyme A derivative: differential interaction with the uncoupling protein and ADP/ATP carrier.

We have recently synthesized an azido [125I] CoA photolabel, N-(3-iodo-4-azidophenyl propionamide) cysteinyl-5-(2'thiopyridyl cysteine) CoA that specifically labeled the ADP/ATP carrier in beef heart mitochondria. In this study brown adipose tissue mitochondria were photolabeled with the azido [125I] ACT-CoA derivative with or without inhibitors. SDS gel electrophoresis and autoradiography of the separated proteins revealed exclusive photolabeling of two polypeptides corresponding to the ADP/ATP carrier and uncoupling protein. In the presence of carboxyatracytloside only the 32 kD UCP was labeled by [125I] ACT-CoA, whereas preincubation with GDP resulted in exclusive photolabeling of the 30 kD ADP/ATP carrier. Palmitoyl CoA but not palmitic acid inhibited photolabeling of both polypeptides.

Acyl Coenzyme A↗
PubMed1986

Reliable serology of Taenia solium cysticercosis with antigens from cyst vesicular fluid: ELISA and hemagglutination tests.

New levels of reproducibility and sensitivity have been achieved in the detection of anticysticercus antibodies in human sera by using cysticercus vesicular fluid as the source of antigens for both ELISA and hemagglutination assays. Reproducibility both between tests on a serum and between similar sera was significantly improved over typical results using antigens from whole parasite extracts. Sera collected from uninfected individuals in endemic areas gave somewhat elevated values over those collected in nonendemic areas. This necessitated the use of a higher threshold in endemic areas to avoid false positives. With the threshold appropriate for a nonendemic area, both ELISA and hemagglutination were sensitive enough to detect infection in 95% of cases. With the threshold value for sera from an endemic area, these sensitivities were reduced to 80%-90%. A prominent 103-Kd protein of vesicular fluid, not related to antigen B, elicited the strongest antibody response in neurocystercotic patients.

Antibodies↗
PubMed1975

Oxygen transport of hemoglobin in high-altitude animals (Camelidae).

To clarify the mechanisms by which high-altitude Camelidae can adapt to hypoxia, the study of some blood characteristics were carried out in apacas and llamas. The results show that there is a peculiar dissociation curve of hemoglobin in alpacas which permits great affinity of hemoglobin for oxygen at lung level and the release of oxygen at the tissue level with a facility similar to that in man. Fetal hemoglobin was found high in adult alpacas (55 percent). Electrophoretic studies of hemoglobin showed that this pigment has two components, both of which have a very low mobility. Lactic dehydrogenase was found six times higher than in humans. RBC glucose-6-phosphate dehydrogenase was two times higher than in man living at the same altitude. Myoglobin was found to be higher than in man living at altitude. Alpacas have erythrocytes in which the amount of 2,3-DPG is approximately the same as in man. RBC are more resistent to hypotonic solutions than humans. The amount of lactic dehydrogenase, myoglobin, and glucose-6-phosphate dehydrogenase dimishes when alpacas are bought down to sea level.

Adaptation, Physiological↗
PubMedDate not supplied

[Tracheoesophageal fistula secondary to ingestion of a button battery].

An eleven month old girl was admitted to a county hospital because of persistent low grade fever, cough, vomitus and food and oral fluids rejection. A small radiopaque, button sized, round object was seen impacted in the upper esophageal third on X ray examination and later extracted by endoscopy, corresponding to an electric cell, from a father's handwatch, which had been ingested by the baby without knowledge of parents about 30 h before. After 12 h fasting, oral feedings were resumed being apparently well tolerated, but in the following day fever and respiratory distress reappeared, together with drooling, cianosis, abdominal distention and pale skin. Patient was transferred to a regional hospital where extensive bilateral pneumonia and anemia were documented. Gastric drainage via nasogastric tube, antibiotic treatment, blood transfusion and oxygen therapy were given from admission, but she died within a few hours. At necropsy a 3 per 2.5 cm diameter orifice of sharp borders was seen in the upper third of the esophagus, communicating to tracheal lumen through its upper six cartilages. Extensive, severe, bilateral pneumonia was confirmed. When this kind of electric cells become impacted into the esophagus, wall necrosis may occur within 4 h and perforation within 8 to 12 h and can be prevented by immediate endoscopic extraction. Otherwise fistulae should be suspected and patients managed accordingly. Emergency room medical staff must always be aware of this potentially lethal condition and its proper management. Infants should not be permitted to play with such apparently innocent objects as battery operated handwatches.

Electric Power Supplies↗