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Biomedical subjects

A Palma

Publications and source records attributed to A Palma.

At least 73 records · Page 4Linked to original sources
PubMed1989

[Tensiometric study of muscular strips of guinea pig gallbladder].

The tensiometric properties of smooth muscle strips from 10 male guinea pig gallbladders were evaluated following acetylcholine (ACH), cholecystokinin octapeptide (CCK-OP), cerulein (CRL) and histamine (HIS) administration. All agonists induced dose-dependent tonic contractions with the maximum effect caused by the octapeptide. CRL showed a 9-folds higher relative potency when compared to CCK-OP. ED50s of agonists were: ACH 1.36 +/- 0.28 SEM microM (n = 14; range 0.20-3.60); HIST, 5.7 +/- 1.9 microM (n = 12; range 1-23); CRL 0.72 +/- 0.15 nM (n = 8; range 0.35-1.07); CCK-OP, 6.77 +/- 1.80 nM (n = 12; range 0.44-20.32); For the same strips, max tension (g), was: 1.97 (SEM 0.12) for ACH; 1.5 (0.18) for HIST; 1.81 (0.18) for CRL; 2.44 (0.14) for CCK-OP. Pretreatment of the strips with atropine (1 microM) completely abolished ACh-induced contractions, without affecting either CCK-OP or CRL responses. The model represents a valid "in vitro" study of different molecules whose action might stimulate, enhance or inhibit the physiological hormonal and non-hormonal effect of the agonists at the level of animal and human gallbladder smooth muscle.

Acetylcholine↗
PubMed1988

Intermolecular potential for thermal H2O-He collisions.

Theoretical potentials for rotational excitation of H2O by He were constructed via several methods, all of which start with a large basis set SCF interaction. The semiempirical Hartree-Fock with damped dispersion (HFD) model adds a damped long-range attraction with parameters adjusted to fit experimental total differential cross sections. Purely ab initio potentials add correlation energies obtained via perturbation theory (MP2 and MP4) or a variational method (ICF1). Scattering calculations were performed on all surfaces to compare with available beam scattering and pressure broadening data and to assess sensitivity of state-to-state rates to uncertainties in the potential. From comparison with the limited experimental data, the ICF1 surface appears to be marginally better than the MP4 surface. Thermal rates calculated from this surface should be accurate to better than 50%, at least for the larger, more important rates.

Chemical Phenomena↗
PubMed1988

Lateral percutaneous spinothalamic tractotomy.

The main elements of the percutaneous spinothalamic tractotomy technique by the lateral approach are presented and the results obtained in 163 consecutive patients are communicated. We emphasize the importance of its early use in cases of intractable pain avoiding drug addiction. The simplicity of the method permits a less strict selection of the patients compared with the classic open cordotomy.

Adolescent↗
PubMed1988

Collisional excitation of interstellar water.

Rates for rotational excitation of water molecules in collisions with He atoms have been obtained from a new, accurate theoretical interaction potential. Rates among the lowest 40 ortho levels are given for kinetic temperatures to 1400 K and among the lowest 29 para levels for kinetic temperatures to 800 K.

Energy Transfer↗
PubMed1986

Association of a spin-labeled local anesthetic with the allosterically coupled noncompetitive inhibitor site on the acetylcholine receptor.

Radioligand binding and ESR were used to study the association of a spin-labeled local anesthetic, 2-[N,N-dimethyl-N-(2,2,6,6-tetramethylpiperidinooxyl)] ethyl-4-hexyloxybenzoate iodide (C6SLMel), with acetylcholine receptor-enriched membranes from Torpedo californica. In the presence of carbamylcholine, we found that C6SLMel competitively inhibits [3H]phencyclidine binding with high affinity (KD = 8.7 X 10(-7) M for C6SLMel), whereas in the presence of alpha-toxin or in the absence of agonist, C6SLMel binds with lower affinity (KD = 2 X 10(-5) M). At concentrations lower than 1 X 10(-5) M, C6SLMel does not bind to the agonist site but enhances [3H]acetylcholine binding. These findings show that C6SLMel binds to the allosterically coupled noncompetitive inhibitor site which is regulated by agonist binding. In addition, C6SLMel preferentially associates with the desensitized receptor state known to exhibit high affinities for agonists and local anesthetics. ESR measurements of C6SLMel bound to receptor membranes in the absence of agonist show moderately immobilized spectra. Addition of carbamylcholine results in the appearance of a strongly immobilized component. Prior exposure to alpha-toxin blocks the carbamylcholine-induced, strongly immobilized component in the ESR spectrum. Furthermore, in the presence of carbamylcholine, back-titration of bound C6SLMel with phencyclidine decreases the highly immobilized component at concentrations consistent with the KD for phencyclidine. These findings indicate that C6SLMel detects conformational changes between the resting and desensitized acetylcholine receptor states that occur at the noncompetitive inhibitor binding site. The strongly mobilized component is not affected by ferricyanide addition, suggesting that the binding site is in a region not readily accessible to anion collision from the aqueous phase.

Acetylcholine↗
PubMed1985

Gammasubdurography in the diagnosis of chronic subdural bilateral and communicating effusion in infants.

The results obtained by means of Gammasubdurography (G.S.G.) in 37 infants having chronic subdural bilateral effusions, are presented. The use of this procedure, which consists of unilateral injection of Radioiodinated Human Sero Albumin (RIHSA-I 131), into the subdural effusion, is suggested for the determination of a communication between the two cavities. At the same time it is possible to get valuable information about their exact localization and extension. Once the communication is diagnosed, the treatment proposed is internal or external unilateral drainage. The method is safe and is performed in a short time which permits its use in the screening of these patients, especially in conjunction with Gammaencephalography (G.E.G.) and Computer Tomography (CT), patients to it. The test (G.S.G.) has been used by us since 1979. All our cases are included in this series. All of them had been diagnosed by subdural puncture, transillumination, G.E.G. and or CT Scan, as having bilateral subdural collections. All the patients received a saturated iodine solution, 24 hours in advance and for 10 days, as a thyroid blocking agent, which was administered in the usual oral dosage. The radiopharmaceutical administration was performed through a unilateral subdural puncture in a dose of 50 to 80 microcurie of RIHSA-I 131 with a high specific activity. Immediately after this, sequential analog images were obtained with the patient supine and in anterior and lateral head projections. This was accomplished by using a PICKER DYNA 4 Gammacamera equipped with a medium energy parallel hole collimator. The interval between the images was determined during the test in agreement with the findings.

Cerebrospinal Fluid Shunts↗
PubMed1984

[Ultrastructural observations on the presence of stereocilia in myoblasts of Scyllium stellare].

Many Authors described primary 9+0 cilia in different tissue of different animal species. In relation to the study on the ultrastructural architecture of the embryonic heart of a elasmobranch "Scyllium stellare", we saw some primary 9+0 cilia in very undifferentiated heart tissue. The hearts dissected from the Scyllium stellare embryo at 6 months of gestation, were processed for the observations at the transmission electron microscope. The cilia are found in deep invagination of the plasma membrane, near the Golgi complex and in the perinuclear region. Various functions have been postulated for the primary 9+0 cilia.

Animals↗
PubMed1981

Progressive systemic sclerosis and nephrotic syndrome. An unusual association resulting in postpartum acute renal failure.

A 27-year-old, full-term pregnant woman with progressive systemic sclerosis (PSS) came to the hospital with marked proteinuria and edema. Two days later, she gave birth to a normal baby. After delivery and during the next 48 hours, renal failure developed. A renal biopsy specimen disclosed findings characteristic of PSS, and immunofluorescence studies displayed nonspecific deposits of fibrinogen and complement. The patient's general condition deteriorated, with development of pericarditis and pulmonary failure; after several peritoneal dialysis treatments, a peritoneal infection developed, and the patient died of Gram-negative sepsis. The association of PSS and nephrotic syndrome is unusual.

Acute Kidney Injury↗
PubMed1980

Subacute spongiform encephalopathy (Creutzfeldt-Jakob disease) associated with normal-pressure hydrocephalus Anatomoclinical report of one case.

The occurrence of two different dementing diseases, Creutzfeldt-Jakob disease and normal-pressure hydrocephalus in a single patient is described. The inefficacy of a shunt procedure in this particular case, and the need of a brain biopsy in patients with normal-pressure hydrocephalus before undergoing cerebrospinal fluid shunting are stressed. A purely coincidental occurrence, or a possible aetiopathogenic relationship between both diseases are postulated.

Adult↗