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Biomedical subjects

A Moreno

Publications and source records attributed to A Moreno.

At least 505 records · Page 28Linked to original sources
PubMed1983

[Eruptive vellus cyst].

The vellus eruptive cyst is characterized by the development of multiple papules that are dermal cysts with vellus hair inside them. We present a case and a literature review.

Adolescent↗
PubMed1982

Dinucleosidetetraphosphatase from Ehrlich ascites tumour cells: inhibition by adenosine, guanosine and uridine 5'-tetraphosphates.

1. An enzyme has been partially purified from Ehrlich ascites tumour cells which specifically hydrolyses dinucleosidetetraphosphates, with Km values of around 2 microM. The products of the hydrolysis are the corresponding nucleoside tri- and monophosphates. Dinucleoside Tri- and diphosphates were not substrates of the reaction. 2. The enzyme requires Mg2+ or Mn2+, is maximally active at a pH value of approx. 7.5 and has a mol, wt of 19,800 as estimated by filtration on Sephadex G-75. Nucleoside mono-, di- and triphosphates were competitive inhibitors of the reaction with Ki values in the 0.1 mM range. 3. Particularly relevant is the inhibition of this enzyme by adenosine and guanosine 5'tetraphosphates. In the course of this investigation, the presence of uridine 5'-tetraphosphate was detected in a commercial preparation of UTP. Adenosine, guanosine and uridine 5'-tetraphosphates were very strong inhibitors of the reaction with Ki values in the nM range.

Acid Anhydride Hydrolases↗
PubMed1982

[Actinic granuloma. Presentation of 3 cases].

Three cases of actinic granuloma which presented anular lesions with central atrophy in the frontotemporal region are reviewed. Microscopy changes showed the center of the lesion devoid of elastic fibers, an inflammatory reaction at the edge of the lesion and normal elastic fibers in the surrounding area. We discuss the differential diagnosis with granuloma annulare and the possible etiological role of previous actinic damage.

Aged↗
PubMed1982

Pulmonary alveolar microlithiasis with an unusual radiological pattern.

We present a case of pulmonary alveolar microlithiasis with an unusual radiological pattern in an an otherwise asymptomatic young woman. It was characterized by a reticulonodular pattern predominantly in the lower lung fields with Kerley B lines. The diagnosis was made by transbronchial lung biopsy. We found an otherwise asymptomatic brother with the same radiological pattern.

Adult↗
PubMed1981

[Acute Q fever: study of 23 patients (author's transl)].

Twenty-three patients with Q fever who were diagnosed over a 3 year period are described. The majority came from the Madrid urban area and less than half had epidemiological antecedents. Nine patients presented with pulmonary infiltrations, 12 with suppressed fever and in 2 criteria for fever of unknown origin were met. The majority had clinical or analytic data of hepatic disease and liver biopsy practiced in 4 patients showed granulomas. Diagnosis was established through the increment of seric antibodies against antigens of phase II C. burnetii, detected by complement fixation test. Acute Q fever is not a rare disease in our environment and must be taken into account when a differential diagnosis is looked for in processes such as fever of short evolution, fever of unknown origin, pneumoniae and granulomatous hepatitis.

Adolescent↗
PubMed1981

Inheritance of Kartagener syndrome.

The surmised autosomal recessive inheritance of situs inversus of Kartagener syndrome is re-examined on the hypothesis that the homozygous state replaces lateralization of the viscera in normal ontogeny by an indifferent lateralization. The segregation ratio in the progeny of two carrier parents (if there were no ascertainment bias) would then be 1/8. The estimated segregation ratio under the assumption of complete (truncate) ascertainment is 0.124. The implications for genetic counseling are discussed.

Diseases in Twins↗
PubMed1981

Poly I:C accelerates ovum transport in the rabbit by a prostaglandin-mediated mechanism.

Administration of poly I:C (1 mg/kg i.v.) to rabbits 24 h after an ovulating injection of hCG caused accelerated ovum transport; only 30% of the ova were still found in the oviducts 24 h later compared with 79% of ova in control animals. This action of poly I:C was prevented by concomitant administration of indomethacin. Poly I:C (0.5 mg/kg i.v.) given to anaesthetized rabbits produced significantly increased levels of prostaglandins (PGs) E and F in uterine vein blood up to 2 h later. Production of PGs by lung, oviduct and myometrium was unaffected 2 h after poly I:C administration, but production of both PGE and PGF by endometrium was significantly elevated at the same time. Metabolism of PGs by cytosols of lung, oviduct and uterus was inhibited to various degrees at 2 h after poly I:C (1 mg/kg i.v.), but by 4 h after treatment this process was reduced to 70--80% of pretreatment values. It is concluded that poly I:C accelerates ovum transport through the oviduct by a PG-mediated mechanism, and that elevated levels of PGs in oviduct are due to inhibition of metabolism of PGs.

Animals↗
PubMed1980

Mathematical models of synaptic plasticity: I. Posttetanic potentiation.

A mathematical model of post-tetanic potentiation is proposed. The model uses differential equations and is based upon physiological postulates of the electrical, metabolic, and neuroendocrine activities that are related to synaptic connectivity. These activities may modify some important parameters in synaptic function. In the proposed model these parameters are restricted to the presynapse in view of the physiological evidence indicating that posttetanic potentiation is probably due to presynaptic mechanisms. The model takes into consideration the size of the transmitter pool available for release, the mobilization of transmitter from and to this pool, and the fraction of transmitter released. Based upon the above postulates, we have simulated different phases of the phenomenon of posttetanic potentiation, and we have presented the results of several preparations in which this event has been studied. This work represents a successful attempt to reproduce the dynamics of posttetanic potentiation based upon physiological results with a mathematical model.

Calcium↗
PubMed1980

Mathematical model of synaptic plasticity: II. Habituation.

A mathematical model of the phenomenon of habituation as a homosynaptic depression of the amount of transmitter release is proposed. The model is based on the physiological studies of habituation in invertebrates and in the spinal cord of vertebrates, where a single synapse has been isolated and some of the physiological mechanisms of this process have been elucidated. The model simulates the following properties of habituation: (1) reduced amount of transmitter release attributed to a repetitive stimulus through changes in the membrane permeability to Ca2+ ions; (2) spontaneous recovery by rest; (3) the amplitude and frequency dependence of habituation; (4) modulation of habituation: sensitization, through an increase in membrane Ca2+ permeability, and presynaptic inhibition, through a reduced depolarization of the physiological stimulus; (5) long-term habituation attributed to repetitive trials of habituation and spontaneous recovery.

Animals↗
PubMed1980

Mathematical model of synaptic plasticity: III. Heterosynaptic changes.

A mathematical model, using differential equations, of heterosynaptic plasticity is proposed. The model is based on physiological studies of invertebrates in which nonspecific conditioning, such as sensitization and heterosynaptic inhibition, starts to be elucidated and behavioral studies of classical and instrumental conditioning, which we postulate to have the same mechanisms as those found in nonspecific conditioning. The model permits us to simulate the following heterosynaptic changes: sensitization, heterosynaptic inhibition, classical and instrumental conditioning--including short- and long-term memory--extinction and recuperation--spontaneously and by stimulation.

Animals↗