[Subcutaneous nodules in a patient undergoing renal transplantation].
Explore the source record for details and available documents.
Female↗
Biomedical subjects
G Ruiz
Publications and source records attributed to G Ruiz.
Amphetamine-produced attenuation of latent inhibition is modulated by stimulus preexposure duration: implications for schizophrenia.
The relationship between amphetamine-produced dopamine overreactivity and attention to irrelevant stimuli is reflected in an attenuated latent inhibition (LI) effect. This occurs in both animal and human subjects. The present study examines the manner in which this effect in rats is modulated by the duration of stimulus preexposure. A factorial design was used with three levels of stimulus preexposure duration and either amphetamine or saline administration. In addition, there were corresponding groups that did not receive stimulus preexposure. It was found that although amphetamine did indeed abolish LI at short exposure intervals (30 sec), the LI effect was normal for long stimulus preexposure durations (150 sec). The data were discussed in terms of the affects of amphetamine on the processing of irrelevant stimuli and the relationship of such a dysfunctional attentional process to schizophrenia.
Animals↗
The presence of atrial natriuretic peptide (ANP) in spermatozoa of Bufo arenarum, and effects of GnRH.
Atrial natriuretic peptide (ANP)-like immunoreactivity has been demonstrated in the testes of adult Bufo arenarum. Reaction was limited to the head of mature spermatozoa attached to Sertoli cells, interstitial tissue, and seminiferous tubules walls. An immunohistochemical study of isolated spermatozoa showed the reaction to be limited to the basal area of spermatozoon head. After spermiation induced by GnRH, testicular spermatozoa were not immunoreactive. Neither isolated spermatozoa from homogenized testes nor isolated spermatozoa from urine immunostained. The demonstration of immunoreactive ANP in B. arenarum testes, its specific location in specific regions of spermatozoa, and the absence of immunostaining after GnRH treatment, suggest that the "cardiac" peptide may be involved in testicular function.
Animals↗
Plasma lipids and liver histochemistry of rats fed sea-lion or corn oil with or without cholesterol supplementation.
Sea-lion oil (SO) is used as a dietary supplement in the treatment of cardiovascular disease. The effects of SO on plasma lipid concentration and liver lipid histochemistry were compared with those of corn oil (CO). Male Sprague-Dawley rats were fed diets containing 15% (w/w) SO or CO with or without 1% cholesterol for 25 days. Compared with rats fed CO, SO-fed rats showed lower plasma cholesterol levels (P < 0.001), high-density lipoproteins (HDL) (P < 0.05), very-low-density lipoproteins (P < 0.05), triglycerides (P < 0.05) and total lipids (P < 0.05). Rats fed SO and cholesterol had lower plasma concentrations of cholesterol (P < 0.001) and HDL (P < 0.05) than those of animals fed CO. Alterations in liver cytology were observed in rats fed SO, including a differential accumulation of lipids in the canalicular regions of hepatocytes and a high density of lipid vesicles in hepatic lobule triads. The results indicated that, compared with CO, SO reduces plasma lipid levels and causes histochemical changes associated with an increased excretion of lipids from the liver.
Analysis of Variance↗
Seasonal changes of blood values in the Andean mouse Abrothrix andinus.
1. Biomonthly measurements of hematological indices were conducted in freshly captured Abrothrix andinus (Rodentia:Cricetidae) over a period of one year. 2. All blood values were in the same range for adult males and females, but juveniles showed lower red blood cell counts (RBC) and erythrocytes of larger size. 3. High RBC numbers, a slight but significant increase of blood hemoglobin concentration (Hb), and a significant decrease in mean cell volume (MCV) were found during the winter months. 4. Hematocrit values (Hct) and the mean cell Hb concentration (MCHC) were relatively constant throughout the year. 5. Plasticity of MCV and an inverse correlation between size and the number of RBC may provide an enlarged diffusion area during winter. This mechanism appears to be a useful seasonal adjustment, since the increase of Hct and the concurrent increase in blood viscosity are avoided.
Animals↗
Latent inhibition and recall/recognition of irrelevant stimuli as a function of pre-exposure duration in high and low psychotic-prone normal subjects.
Learning to ignore non-relevant stimuli (coloured geometric shapes) was evaluated in high and low psychotic-prone normal subjects in two experiments. In the first, subjects were tested in a latent inhibition paradigm in a 2 x 2 x 3 factorial design (high vs. low psychotic proneness, as measured by MMPI subscales; pre-exposure of the stimuli such that they were non-relevant before the test but relevant in the test vs. absence of such pre-exposure; three levels of pre-exposure duration: 3-, 6- and 15-min). Low psychotic-prone subjects showed the latent inhibition effect (poorer learning as a result of pre-exposure to the non-relevant stimuli as compared to no pre-exposure) at 6- and 15-min durations, but not at 3-min. High psychotic-prone subjects failed to show latent inhibition at 3- and 6-min durations, but did show the effect at 15-min. The second experiment employed a 2 x 3 design (high vs. low psychotic proneness; three levels of pre-exposure duration of the same stimuli used in Expt 1). High psychotic-prone normal subjects recalled and recognized more previously non-relevant stimuli than low psychotic-prone subjects, particularly after 6-min pre-exposure to those stimuli. The data of the two experiments suggest that the attenuation of latent inhibition in high psychotic-prone subjects as compared to low psychotic-prone subjects is a result of the increased attention to non-relevant information.
Adult↗
[Are congenital malformations increasing? Comparative study of 2 periods: 1971-1977 and 1982-1991, in the maternity of the Clinical Hospital of the University of Chile].
The aim of this work was to analyze the global incidence of congenital malformations at the Maternity of University of Chile Clinical Hospital in the periods between 1971 and 1977 and between 1982 and 1992. A significant and sustained increase in incidence was observed in the first period from 10.64 per 1000 born alive in 1971 to 33.79 in 1977. In the second period, the rates were stabilized at 60 to 70 per 1000 born alive. When comparing the incidence of 20 major or easily diagnosed malformations in the two periods, there was a significant increase in all during the second period. The possible causes of the increase in incidence are discussed, such as better diagnosis and registry, the use of ultrasound diagnosis and the incorporation of stillbirths to the registry during the second period.
Chile↗
[MN blood group and congenital malformations].
This work analyzes the mother-son segregation of MN blood group in malformed and normal newborns. MN blood group was measured in 90 malformed, 70 paired normal newborns and their respective mothers, at the Maternity of the University of Chile Clinical Hospital. The expected values for the different mother-child pairs were calculated according to the ITO matrix method, using maximally probable appraisers. Among malformed newborns, there was an excess of heterozygous sons when the mother was homozygous for the MN system. Among malformed males, there was an excess of MM-MN and MN-MM mother-son pairs. Among control newborns, no distortions were found. These results suggest that there is a strong association between MN heterozygosis, sex and congenital malformations.
Congenital Abnormalities↗
Effect of histamine on signal transduction in cultured human trabecular meshwork cells.
Stimulation of cultured human trabecular meshwork cells by histamine caused time and dose related increases in inositol phosphates and intracellular free calcium. The increase in inositol trisphosphate (IP3) was immediate and calcium independent while that of inositol monophosphate (IP1) was gradual and calcium dependent. The rise in intracellular calcium was also rapid and occurred as a result of mobilization from intracellular stores and influx from external medium. Histamine also caused time and concentration related de novo synthesis of inositol phospholipids. Mepyramine but not cimetidine inhibited the action of histamine. These results indicate that histamine, via H1 receptor, evokes an early hydrolysis of inositol phospholipids and increase in intracellular free calcium, signals which may be involved with the function of the trabecular meshwork cells.
Adult↗
Differentiation of endocrine myocardiocytes in the developing heart of the toad (Bufo arenarum Hensel).
The differentiation of endocrine myocardiocytes was investigated in the heart of developing toad Bufo arenarum Hensel, combining ultrastructural and immunocytochemical procedures. The distribution of immuno-reactive atrial natriuretic peptide (ANP) in the whole heart was appraised by light microscopy, applying biotin-streptavidin and immunofluorescence techniques. With the latter procedures ANP was first recognized at embryonic stage 22, in both atrium and ventricle. In the ensuing stages the ANP-reactivity became stronger in the atrium, while it became dimmer in the ventricle. At the end of the larval prometamorphic stage, atrial myocardiocytes acquired almost all the features of adult myoendocrine cells. At electron microscope level, small inclusions, about 110-120 nm in diameter, resembling secretory granules were found in myoendocrine cells beginning at embryonic stage 22. However, no immunogold labeling of ANP occurred until stage 25. The number of secretory granules diminished in the ventricles and increased in the atrium of the larval heart and at the end of the prometamorphic stage the atrial myoendocrine cells presented the ultrastructural characteristics of active secretory cells. The synthesis of ANP in larvae is enhanced at a critical period of development when the developing toad switches from an aquatic environment to terrestrial life. The cardiac hormones seem to play a key role in the regulation of the osmolarity of body fluids at this developmental stage.
Animals↗
[Epidemiologic study of factors associated with hypospadias].
From August 60 to December 90, 103 male newborns with hypospadias were diagnosed among 124 588 consecutive newborns examined (8.3 per 10,000). Mortality among them was 1.94%. The annual incidence rate increased significantly over the study period (p < 0.001. Hypospadias was an isolated finding in 92% of cases, and its was associated to other non genital malformation in 8.7%. Location of hypospadias was distal in 73% and proximal in 15.5%. There was no seasonal variation in the incidence rate. Weight of affected individuals did not differ from that of controls. Older age of parents among affected individuals was not statistically significant.
Abnormalities, Multiple↗
[Increase of incidence of Down syndrome and its possible relation with increased maternal age].
Among 47,458 consecutive births taking place between july 1977 and december 1989, we found 83 newborns with Down syndrome, for a 1.74/1000 live births incidence rate. This compares to a rate of 1.39 rate observed at the same maternity from 1971 to 1977 (NS). The mean age of all mothers was 25.9 years as compared to 31.87 for mothers of children with Down syndrome (p < 0.00001). The mean maternal age has increased from 24.34 in 1977 to 27.38 in 1988 (p < 0.0001), mostly due to a greater proportion of the 25 to 29 year-old group of mothers. These data support, although not conclusively, that the increased incidence of Down syndrome in our population is related to older maternal age.
Adolescent↗
[Incidence of malformations of the central nervous system: 1978-1988].
During the period Jan 1978 to Dec 1988, 41,867 deliveries took place at the University of Chile Hospital. Among them, 148 babies were found to have malformations of the central nervous system, an incidence of 3.6 per 1000 live births. A longitudinal study from 1969 to 1988 suggests a yearly increment of 0.1% in the incidence rate of these malformations. The comparison of some quantitative variables, such as gestational age, birthweight, number of previous abortions and some risk factors like maternal illness, bleeding, radiation exposure, drug ingestion during the first trimester of pregnancy and instructional level of both parents show significant differences between the malformed and the control newborns. No significant differences were found for maternal age, sex nor seasonal variation.
Abnormalities, Drug-Induced↗
Chronic phenytoin treatment decreases GABAA but not beta-adrenoceptors in the cerebellum of young rats.
The effects of chronic treatment with phenytoin (50 mg/kg p.o. daily, for the first 30 days after birth) on GABAA and beta-adrenoceptors in the rat cerebellum were investigated by using in vitro quantitative autoradiography and binding assays with membranes. A significant decrease in [3H]muscimol binding to GABAA sites and, to a lesser extent, [3H]flunitrazepam binding to benzodiazepine sites was observed in the granular and molecular layers of the cerebellar cortex at the end of the treatment. Scatchard analyses demonstrated that these effects were associated with a decreased Bmax for the respective binding sites in cerebellar membranes the (Kd was not changed). In contrast, [125I]cyanopindolol binding remained unaffected. These data provide further support for the involvement of GABAergic synapses in the anticonvulsant action of phenytoin.
Adrenergic beta-Antagonists↗
Interspecific variations of cerebral endothelial cholinesterases in rodents and carnivores.
The cholinesterase equipment of cerebral microvessels was studied in some rodents and carnivores using the Koelle-Friedenwald histochemical method with 3 artificial substrates and specific inhibitors for butyrylcholinesterase or acetylcholinesterase. Our observations reveal a great heterogeneity in cholinesterase types and their distribution in each of the different species studied. Only in the rat, butyrylcholinesterase appears to be a marker for the microvessels provided with a blood-brain barrier.
Acetylcholine↗
Altitudinal distribution and blood values in the toad, Bufo spinulosus Wiegmann.
1. Red blood cell (RBC) count, RBC size, hematocrit, cell and blood hemoglobin concentrations and plasma total solid concentration were measured in 16 lowland (from near sea level up to 2700 m) and 18 highland (3200 up to close to 4500 m) adult toads (Bufo spinulosus). 2. Lowland toads showed higher hematocrit values than highland toads, but their blood hemoglobin concentration and plasma solid concentration were not significantly different. 3. Highland toads had smaller RBC size, higher corpuscular hemoglobin concentration, a trend toward larger RBC count and a considerably smaller body size. These features may contribute to their successful life at high altitude.
Adaptation, Physiological↗
Sustained decreases in systemic blood pressure do not cause ocular hypotension.
The unilateral, topical administration of certain ocular hypotensive agents, notably clonidine, is reported to result in a bilateral decrease in intraocular pressure. It has been previously proposed that such bilateral ocular hypotensive responses may be centrally mediated. However, the possible influence of blood pressure changes on intraocular pressure has remained a complicating factor in determining mechanisms of action. In order to further clarify the potential relationship between systemic blood pressure changes and intraocular pressure, the effects of two systemic antihypertensive drugs were determined in the conscious rabbit. Topical, unilateral administration of either hydralazine or prizidilol did not lower the intraocular pressure of either eye. A bolus intravenous injection of either hydralazine or prizidilol caused substantial systemic hypotension that persisted for at least 3 h, but no decreases in intraocular pressure occurred. These studies indicate that sustained decreases in systemic blood pressure of approximately 15 mm Hg do not result in ocular hypotension.
Animals↗
[Incidence of congenital malformations in Chile from 1969 to 1986. Results of a Latin-American collaborative study].
At present, congenital malformations contribute more to infant mortality, given the significant decrease in overall infant mortality rate observed in Chile. A significant and steady increase in the prevalence of congenital malformations was demonstrated at the Clinical Hospital, University of Chile, from 1969 to 1986. Better epidemiologic surveillance is needed to accurately estimate the magnitude of this problem and give orientation for preventive measures.
Chile↗