Search PubMed⌕ Search

Biomedical subjects

E Molina

Publications and source records attributed to E Molina.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Analysis of food stimulation of gastrin release in dogs by a panel of inhibitors.

The release of gastrin into the serum of five conscious gastric fistula dogs after a meat meal was monitored for 2 hours. Neither the rate of increase in serum gastrin nor the 2 hour cumulative integrated gastrin response was changed by administration of small doses of somatostatin tetradecapeptide (0.5 microgram/kg.hr IV for 2 hr), 16-16 dimethyl prostaglandin E2 (0.25 microgram/kg.hr IV for 2 hr or 1 microgram/kg intragastrically), or bethanechol (20 micrograms/kg.hr IV for 2 hr). Acidification of the food in the antrum to pH 1.2 to 1.4 eliminated serum gastrin release in response to food. In control studies, serum gastrin levels were not altered by IV administration of saline for 2 hr with no food or when a plate of food was held just out of the dogs' reach (teasing). Food-stimulated gastrin release was contrasted with that stimulated by bombesin under identical laboratory conditions [17]. In each case, antral acidification, somatostatin, prostaglandin E2 and bethanechol affected bombesin-stimulated gastrin release differently from that stimulated by food. We conclude that food and bombesin release gastrin by different pathways.

Animals↗
PubMedDate not supplied

Functional comparison between nuvenzepine and pirenzepine on different guinea pig isolated smooth muscle preparations.

The antimuscarinic agents nuvenzepine and pirenzepine were tested on four guinea pig isolated smooth muscle preparations in order to better investigate the existence of differences in the functional activities of such antagonists, as suggested by previous reports. The effects of both compounds were compared to those of atropine. Nuvenzepine showed a four-fold higher affinity than pirenzepine in competitively antagonizing acetylcholine-induced contractions on isolated ileal musculature (pA2 = 7.08 +/- 0.15) and on longitudinal ileum dispersed cells (pA2 = 7.11 +/- 0.19). By contrast, unlike pirenzepine which was ineffective, nuvenzepine inhibited histamine-induced ileal motor activity in a dualistic manner, behaving as an irreversible competitive H1 antagonist (pA2 = 5.02 +/- 0.11). Nuvenzepine was almost equipotent to pirenzepine in competitively preventing bethanechol-induced gall-bladder contractions (pA2 = 7.23 +/- 0.16) and it displayed a four-fold higher potency than pirenzepine in blocking vagal-stimulated tracheal constrictions (pIC50 = 6.77 +/- 0.06). Both compounds were definitely less potent than atropine. On the whole, these findings indicate that, on the selected preparations, nuvenzepine substantially shares the antimuscarinic properties of pirenzepine but it is also endowed with a (weak) H1-blocking action. Furthermore, based on some observations, the presence in gallbladder smooth muscle of muscarinic receptors distinguishable from those of ileum could be speculated.

Animals↗
PubMedDate not supplied

3D connectivity indices in QSPR/QSAR studies.

Topographic (3D) molecular connectivity indices based on molecular graphs weighted with quantum chemical parameters are used in QSPR and QSAR studies. These descriptors were compared to 2D connectivity indices (vertex and edge ones) and to quantum chemical descriptors in modeling partition coefficient (log P) and antibacterial activity of 2-furylethylene derivatives. In describing log P the 3D connectivity indices produced a significant improvement (more than 29%) in the predictive capacity of the model compared to those derived with topological and quantum chemical descriptors. The best linear discriminant model for classifying antibacterial activity of these compounds was also obtained with the use of 3D connectivity indices. The global percent of good classification obtained with 3D and 2D connectivity as well as quantum chemical descriptors were 94.1, 91.2, and 88.2, respectively. In general, all these models predict correctly the antibacterial activity of a set of nine new 2-furylethylene derivatives. The best result is obtained with 3D connectivity indices that classified correctly 100% of these compounds versus 88.9% obtained with 2D connectivity or quantum chemical descriptors.

Journal Article↗
PubMedDate not supplied

Can 3D structural parameters be predicted from 2D (topological) molecular descriptors?

The dihedral angle between both phenyl rings determined by photoelectron spectroscopy in a series of seven alkylbiphenyl is described by the local spectral moments of the bond matrix. This series is extended to 78 alkylbiphenyl compounds by estimating the dihedral angle from molecular mechanics force field calculations. The linear correlation obtained between this angle and the local spectral moments shown a correlation coefficient of 0.9838. This result proves that 2D (topological) descriptors can account for 3D structural parameters. A new substituent constant is calculated as the contribution of groups to the studied rotational angle by using the information encoded into the local spectral moments. This substituent constant is not linearly related to the Taft's steric constants E(S) as they have a correlation coefficient of only 0.75. These steric constants are able to account only for 71% of the variance in the studied 3D parameter. The implications for QSPR/QSAR studies of the demonstration that 2D (topological) descriptors can describe 3D structural parameters are also analyzed.

Journal Article↗
PubMedDate not supplied

[Comparison between the communities of parasitic nematoda of sheep and goats bred in arid zones of Venezuela].

Under the studied conditions, the structure and composition of community of parasitic nematodes observed in both sheeps and goats, is similar (rS = 0.90 P less than or equal to 0.05 and CSS = 93.33%), the Shannon-Weaver index of diversity was 1.23 +/- 0.15 bits and 1.15 +/- 0.24 bits for sheeps and goats, respectively. The equitability index resulted in 0.49 +/- 0.06 for sheep-nematodes and 0.44 +/- 0.09 for goats-nematodes. However, no significant difference was observed when the means of these indexes, were compared. Not withstanding, a greater homogenity was observed in the ovine parasitic nematodes.

Animals↗
PubMedDate not supplied

[Microecological characterization of parasitic nematoda present in goats of arid zones of Venezuela].

Goats from the Venezuelan northern arid zones were found infested by the following nematodes: Haemonchus contortus, Trichostrongylus axei, T. colubriformis, Cooperia curticei, Oesophagostomum columbianum, Skrjabinema ovis y Trichuris globulosa. The Shannon-Weaver index of diversity values oscillated between 0.045 and 1.73 bits (means = 1.16 +/- 0.24 bits). The maximum value of montly diversity ranged from 1 to 2.80 bits (means = 2.49 +/- 0.28 bits) and the equitability ranged from 0.045 to 0.67 (means = 0.44 +/- 0.09). Parasitic associations were found among 1) T. axei, T. colubriformis and H. contortus, 2) T. colubriformis, H. contortus and O. columbianum and 3) T. colubriformis, S. ovis and T. globulosa. The above results suggest that in months when the diversity index is close to the maximum value and the equitability index is near unity, wide spectrum antihelmintic treatment should be used for poly-parasitized animals.

Animals↗
PubMedDate not supplied

Determination of fat, protein, and total solids in ovine milk by near-infrared spectroscopy.

Analysis by near-infrared spectroscopy (NIRS) was investigated as a means of predicting quality parameters of ovine milk. Calibration equations were developed with samples of ovine milk obtained from a flock of Manchega and Lacaune dairy ewes at different stages of lactation for a wide variation in milk composition. Prediction equations for milk protein, fat, and total solids content were developed by use of reflection or transflection methods to measure absorbance values. Accuracies of measurements were compared. R2 (squared multiple correlation coefficient) values were satisfactory in most cases. The highest R2 value for milk protein content (0.92) was obtained in transflectance mode with unhomogenized milk. The highest R2 values for fat (0.99) and total solids (0.98-0.96) content were obtained in both a transflectance mode without sample conditioning and in a transflectance mode with milk homogenized at 40 degrees C. To validate the calibration, an independent set of 40 milk samples was used. The best r2 (simple correlation coefficient) values for protein, fat, and total solids were 0.92, 0.97, and 0.92, respectively. The study showed that NIRS is a potentially useful technique for evaluating the composition of unhomogenized ovine milk.

Animals↗
PubMedDate not supplied

Hemodynamically significant suture line obstruction immediately after heart transplantation.

Mechanical complications after heart transplantation are uncommon. We describe a case of hemodynamically significant suture line obstruction that was recognized immediately after heart transplantation using transesophageal echocardiography. Transesophageal echocardiography has proved to be a powerful tool in recognizing mechanical complications in the early posttransplant period.

Adult↗
PubMedDate not supplied

[Determination of serum Fe in prostatic pathology].

We have determined serum Fe concentrations in 75 patients whose post-surgical anatomo-pathological diagnostic was: 25 cases with prostate benign hyperplasia, 25 cases where besides hyperplasia there was also an associated chronic prostatitis and 25 cases of moderately differentiated prostatic adenocarcinoma stage D according to the Jewett classification. No patient had received prior medication nor had associated metabolic pathology. Serum Fe concentration was significantly decreased in the cases with prostatic adenocarcinoma. The methodology used for these determinations is presented, discussing the possible pathogenic hypothesis explaining this finding together with the clinical consequences.

Adenocarcinoma↗
PubMedDate not supplied

[Duodenal amebiasis].

Entamoeba histolytica was found in duodenal content obtained through fiberoptic gastroduodenoscopy in 13 patients. Clinical, radiological and endoscopic findings are analized. The possibility of an amoebic duodenitis is proposed.

Adult↗
PubMedDate not supplied

[Sudden deafness in patients undergoing cardiac surgery with extracorporeal circulation].

Between January 1974 and December 1986, 5,975 patients underwent open heart surgery at National Institute of Cardiology "Ignacio Chávez". We reviewed all open heart cases carried out at this Center. Eleven patients (1.8/1000) presented unilateral sudden hearing loss following cardiopulmonary bypass surgery. Pure tone audiograms, speech reception threshold, discrimination testing, tympanometry and stapedius reflex testing were carried out. We then studied the relationship between the auditory deficit and the type of surgical procedure, length of time on the pump, preexisting ear disease, coexistence of diabetes, use of ototoxic drugs and occurrence of hemodynamic complications. There are 3 possible causes for hearing loss in cardiopulmonary bypass: 1) Microembolism from the cardiopulmonary bypass pump to the arteries that supply only the cochlea. 2) Decreasing cerebral flow, or 3) Microhemorrhage of the internal ear. Ototoxic drugs are used frequently, but the hallmark of these drugs is bilateral toxicity, and all the cases under discussion have been unilateral. Unilateral sudden deafness after open heart surgery constitutes another complication, fortunately rare and benign in most cases. Further studies should be undertaken to clarify the pathophysiology of this entity.

Adult↗