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Biomedical subjects

A Gonzalez

Publications and source records attributed to A Gonzalez.

At least 235 records · Page 13Linked to original sources
PubMed1988

Surgical treatment of borderline velopharyngeal insufficiency using homologous cartilage implantation with videonasopharyngoscopic monitoring.

Borderline cases of velopharyngeal insufficiency were treated with homologous cartilage implants. The selection of patients and technique for this procedure are described. Videonasopharyngoscopy was used to identify a specific location on the posterior pharyngeal wall for the implant. A small cube of homologous cartilage was implanted in the selected site in order to achieve adequate closure. The preliminary nasopharyngoscopic and speech evaluation results in 10 patients, who were followed every 3 months for at least 1 year, are reported. Hypernasality and audible nasal emission were eliminated. The displacement and reabsorption of the implants that occurred was minimal and did not affect velopharyngeal closure. Homologous cartilage, which is inexpensive and easy to obtain, appears to be a good option for implantation in the posterior pharyngeal wall in borderline cases of velopharyngeal insufficiency.

Cartilage↗
PubMed1988

The area acustico-vestibularis of Discoglossus pictus. I. Cytoarchitecture and ultrastructure features.

The cytoarchitecture of the area acustico-vestibularis (AAV) in Discoglossus pictus is studied by means of normal stained material. In addition, the main ultrastructural features of the cells in the AAV are described. Basically, three different components are found: the dorsal, ventral and medial cell columns. While the two former are made up by the dorsal and ventral nuclei respectively, the medial column is formed by a rostrally located cerebellar nucleus and a caudal nucleus, which extends up to the obex level. The ultrastructure of the neurons in the AAV reveals a typical cell organization similar to that of other cell types in the anuran brain. Resemblances with vestibular cells of other vertebrates, together with certain own peculiarities are discussed. The most common synapses in the AAV are also commented.

Animals↗
PubMed1988

The area acustico-vestibularis of Discoglossus pictus. II. The primary afferent projections.

In the present report the primary projections to the dorsal rhombencephalic alar plate (area acustico-vestibularis, AAV) of the adult anuran amphibian Discoglossus pictus have been studied by means of the anterograde transport of horseradish peroxidase (HRP). As in Alytes cisternasii, other member of the family Discoglossidae, no primary afferent fibers to the AAV were found from nerves other than the VIIIth cranial nerve. No remanent of the lateral line system in the adult stage is present. The projections of the dorsal root of nerve VIIIth distribute over the dorsal nucleus and rostrally reach the aspect of the cerebellum. Caudally projects to the large cells of the ventral nucleus and terminate caudally, in the dorsolateral neuropil, at levels coincident with the IX motor nucleus. The projection of the ventral root also reaches the cerebellum in its lateral aspect but also fibers to the nucleus cerebelli were observed. The extensive projection to the ventral nucleus is also continued caudally to the caudal nucleus and ends around the solitary tract. Main terminal fields were located in two neuropils, one subventricular and other in an intermediate position. In addition, from both nerve branches, fibers leave the AAV and reach the reticular formation. Particularly, fibers from the posterior branch enter the superior olivary nucleus. Retrograde labeled neurons in the vicinity of the VII motor nucleus are interpreted as efferent cells to the labyrinth.

Animals↗
PubMed1987

Some connections of the area octavolateralis of Pleurodeles waltlii. A study with horseradish peroxidase under in vitro conditions.

Horseradish peroxidase application in exsanguinated, pre-perfused newts, Pleurodeles waltlii, appeared to be very useful to study the connections of the area octavolateralis. Efferents from the octavolateral area course via bilateral lemnisci to the tectum and a presumptive torus semicircularis in the midbrain. Additional projections to the oculomotor nuclei, cerebellum, reticular formation, contralateral octavolateral area, and spinal cord were observed. The area octavolateralis receives inputs from the cerebellum and the contralateral octavolateral area. It is concluded that the octavolateral second order projections in Pleurodeles waltlii resemble in many respects those reported for other vertebrates that possess a complete octavolateralis system.

Afferent Pathways↗
PubMed1987

Distribution and morphology of abducens motoneurons innervating the lateral rectus and retractor bulbi muscles in the frog Rana ridibunda.

The distribution and morphology of the neurons innervating the lateral rectus and retractor bulbi muscles of the frog Rana ridibunda were studied by means of retrograde axonal transport of horseradish peroxidase (HRP). The neurons are located in the rhombencephalon in two distinct groups which lie dorsolateral and lateral to the fasciculus longitudinalis medialis and represent the main and accessory abducens nuclei, respectively. From HRP injections into the two muscles, it can be concluded that multipolar neurons located rostrally in the main abducens nucleus innervate the lateral rectus muscle. The retractor bulbi muscle receives its innervation from bipolar, fusiform neurons located in the caudal portion of the main abducens nucleus and throughout the rostrocaudal extent of the accessory abducens nucleus.

Abducens Nerve↗
PubMed1987

Perinatal anterior cerebral artery Doppler flow indexes: methods and preliminary results.

Using a standard 5 MHz continuous-wave Doppler system, we were able to record velocities from the anterior cerebral arteries of 20 infants both in utero (at 6 to 10 cm cervical dilatation) and after delivery. In utero tracings were of the same quality as neonatal tracings. Difficulties encountered in the course of the study included abnormal lie, small fontanelle, and excessive caput. Despite these problems our success rate in obtaining good tracings was 80%. Results showed that indexes of cerebral vascular resistance were increased during labor and decreased after birth. However, Doppler indexes of blood flow remained constant throughout the perinatal period. This preliminary report describes the methodology of this new technique. In addition our results demonstrate that in utero intracranial tracings are obtainable and may provide valuable information about cerebral hemodynamics during labor.

Asphyxia Neonatorum↗
PubMed1987

Nonpolarized secretion of truncated forms of the influenza hemagglutinin and the vesicular stomatitus virus G protein from MDCK cells.

The demonstration that the envelope glycoproteins G of vesicular stomatitus virus and hemagglutinin of influenza virus synthesized in polarized epithelial cells transfected with the corresponding genes are effectively segregated to the basolateral or apical plasma membrane domains, respectively, implies that the information determining this segregation resides within the structures of the proteins themselves. To localize the sorting information within these proteins, the polarity of secretion of truncated hemagglutinin and G glycoproteins secreted from confluent monolayers of MDCK cells transformed with vectors containing the corresponding truncated cDNAs was examined. It was found that, even though the transformed cells continued to secrete a major endogenous glycoprotein exclusively from the apical surface, the modified viral glycoproteins were secreted in a nonpolarized fashion from both sides of the monolayers. These observations suggest that important information for the sorting of the viral glycoprotein is contained within their membrane anchoring or cytoplasmic segments or that, if sorting signals are luminally located, these signals must be present in a conformation that is not attainable when the polypeptides are not attached to the membrane.

Animals↗
PubMed1987

The influenza hemagglutinin insertion signal is not cleaved and does not halt translocation when presented to the endoplasmic reticulum membrane as part of a translocating polypeptide.

The co-translational insertion of polypeptides into endoplasmic reticulum membranes may be initiated by cleavable amino-terminal insertion signals, as well as by permanent insertion signals located at the amino-terminus or in the interior of a polypeptide. To determine whether the location of an insertion signal within a polypeptide affects its function, possibly by affecting its capacity to achieve a loop disposition during its insertion into the membrane, we have investigated the functional properties of relocated insertion signals within chimeric polypeptides. An artificial gene encoding a polypeptide (THA-HA), consisting of the luminal domain of the influenza hemagglutinin preceded by its amino-terminal signal sequence and linked at its carboxy-terminus to an intact prehemagglutinin polypeptide, was constructed and expressed in in vitro translation systems containing microsomal membranes. As expected, the amino-terminal signal initiated co-translational insertion of the hybrid polypeptide into the membranes. The second, identical, interiorized signal, however, was not recognized by the signal peptidase and was translocated across the membrane. The failure of the interiorized signal to be cleaved may be attributed to the fact that it enters the membrane as part of a translocating polypeptide and therefore cannot achieve the loop configuration that is thought to be adopted by signals that initiate insertion. The finding that the interiorized signal did not halt translocation of downstream sequences, even though it contains a hydrophobic region and must enter the membrane in the same configuration as natural stop-transfer signals, indicates that the HA insertion signal lacks essential elements of halt transfer signals that makes the latter effective membrane-anchoring domains. When the amino-terminal insertion signal of the THA-HA chimera was deleted, the interior signal was incapable of mediating insertion, probably because of steric hindrance by the folded preceding portions of the chimera. Several chimeras were constructed in which the interiorized signal was preceded by polypeptide segments of various lengths. A signal preceded by a segment of 111 amino acids was also incapable of initiating insertion, but insertion took place normally when the segment preceding the signal was only 11-amino acids long.(ABSTRACT TRUNCATED AT 400 WORDS)

Cytochrome P-450 Enzyme System↗
PubMed1987

Isolation of group A swine rotaviruses displaying atypical electropherotypes.

Swine rotaviruses displaying distinctive electropherotypes were isolated from the feces of diarrheic piglets in two swine herds in the province of Buenos Aires, Argentina. In one case all samples isolated showed abnormal electropherotypes. All samples were classified as group A reactive when assayed by an enzyme-linked immunosorbent assay. Three samples from this herd were adapted to grow in tissue culture. The electrophoretic pattern of the genomic RNA as well as the group A reactivity of one of these viruses was retained after cloning in MA-104 cells. In the other pig unit were found samples displaying both classical and abnormal electropherotypes. These viruses were also positive in the enzyme-linked immunosorbent assay; however, since they could not be adapted to grow in tissue culture, this classification must be considered tentative. The abnormal electropherotype exhibited by these pig viruses strongly resembles those of human origin called super short.

Animals↗
PubMed1987

Endocrinology of the postpartum period in the Pelibuey ewe.

The postpartum (PP) period in the Pelibuey ewe was studied. Laparotomies were performed on 14 ewes in the first year at d 10, 20 and 30 PP, and at d 10 and 20 PP in the second year on 17 ewes. Progesterone concentrations were determined in serum taken daily, from 4 to 7 d after parturition until estrus. Temporal fluctuation of luteinizing hormone (LH) was determined in samples taken at 30-min intervals for 4 h weekly. The mean interval from lambing to first ovulation was longer (P less than .001) in 1980 (59 +/- 4.9 d) than 1979 (26 +/- 3.1 d), the mean interval from lambing to first estrus was also longer (P less than .001) in 1980 (91 +/- 5.6 d) than 1979 (51 +/- 5.5 d). Follicles were present on the ovaries of the majority of the ewes at d 10. The mean diameter of the largest follicles on each ovary was reduced (P less than .025) in ewes in 1980 (6 mm) compared with 1979 (7.7 mm). Corpora lutea (CL) occurred in 67 and 75% of the ewes by d 20 and 30, respectively in 1979; no CL were found by d 20 in 1980. Progesterone profiles suggested that the PP period was composed of a period of anestrus, and a period of cyclic ovarian activity with one, two or three ovulations without behavioral estrus. In some ewes, the first cycle was of shorter duration, and its CL secreted less progesterone (P less than .05) relative to CL of silent and regular estrous cycles. Luteinizing hormone peaks were recorded as early as 6 d PP. When progesterone concentrations were elevated to luteal phase levels, the frequency, but not magnitude, of LH peaks per 4-h bleeding period was reduced (P less than .05) relative to anestrus. It is concluded that there are periods of anestrus and of silent cycles, which precede the first postpartum estrus in Pelibuey ewes.

Animals↗
PubMed1987

A correlation and path coefficient analysis of components of calciuria in normal subjects and idiopathic stone formers.

The composition of 24 h urine samples collected by 50 normal controls and 76 stone formers (30 hypercalciurics, 13 hyperuricosurics and 33 patients without metabolic abnormalities) were studied. Statistically significant multiple regression equations were obtained between calciuria and the urinary excretions of sulfate, citrate, sodium and creatinine. The three former ions were selected as variables because they were assumed to affect the tubular fluid concentration of ionized calcium and interfere with the reabsorption of calcium. Urinary creatinine was included because it increased the statistical significance of the multiple regression equations; it is assumed to be a function of body size. The regression equations differed between both groups of subjects because stone formers excreted significantly more sulfate and less citrate than controls. The four factors considered (sulfate, citrate, sodium and creatinine) account for 28.3, 6.8, 7.3 and 26.4% of the total variation of calciuria of normal controls and 45.0, 2.6, 8.6 and 14.7%, respectively, for stone formers.

Adult↗