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Biomedical subjects

M Castillo

Publications and source records attributed to M Castillo.

At least 235 records · Page 13Linked to original sources
PubMed1987

Effect of clofibrate on brain mevalonate-5-pyrophosphate decarboxylase.

The effect of clofibrate on the activity of the three mevalonate-activating enzymes has been studied for the first time in brain by reactions carried out using [2-14C] mevalonic acid as substrate and 105,000 g supernatants from 14-day-old chick brain. Mevalonate-5-pyrophosphate decarboxylase was clearly inhibited, while mevalonate kinase and mevalonate-5-phosphate kinase were not significantly affected. The effect of clofibrate on decarboxylase activity was progressive with increasing concentrations (1.25-5.00 mM) of the inhibitor. A transient inhibition and a subsequent activation as a function of clofibrate concentration seemed to occur for mevalonate kinase. Direct measurements of decarboxylase activity utilizing [2-14C] pyrophosphomevalonate as the specific substrate of this enzyme corroborated these results. Kinetic studies showed that clofibrate competes with the substrate ATP.

Animals↗
PubMed1987

Spontaneous rupture of the membranes, functional dystocia, oxytocin treatment, and the route of delivery.

The details of clinical management were examined in 96 nulliparous patients with functional dystocia who had spontaneous rupture of the membranes before admission and were treated with oxytocin in the first stage of labor. It was our hypothesis that if the allegedly "high" rate of cesarean sections was the result of mediocre or flawed practices, these should be most evident in patients delivered abdominally. A group of 59 patients delivered vaginally were compared with 37 patients delivered by cesarean section. The means of many variables were not statistically different. The cesarean section group was characterized by smaller stature, a lesser cervical dilatation rate both before and after oxytocin administration, a larger maximum oxytocin dose, a longer period of oxytocin administration, more frequent cessation of oxytocin administration or dose reduction because of hypercontractility or an abnormal fetal heart rate or both, and a higher incidence of intra-amniotic infection. We conclude that the decision to perform cesarean section in nulliparous women with functional dystocia arises from disabilities of the patient and not from differences in the application of our management principles, services, or treatments.

Cesarean Section↗
PubMed1987

[Biological significance of the endogenous secretion of insulin in response to breakfast in diabetic children].

In 20 insulin dependent diabetics and in eight age-matched healthy children, we have measured basally HbA1 and the plasma lipid profile; and both basally and after a standard breakfast of 400 cal, blood glucose, C-peptide (CPR), immunoreactive glucagon (IRG), growth hormone and nonesterified fatty acids (NEFA). No difference was found in the lipid profile of diabetic and non diabetic children. In diabetics basal blood glucose was significantly correlated to both basal C-peptide (r = 0.5332, p less than 0.05) and to the ratio C-peptide/glucagon (r = 0.8563, p less than 0.01). The C-peptide response to the breakfast was accompanied of a significant increase in IRG and NEFA in diabetics, while in non-diabetics there was no change in IRG and a significant decrease in NEFA levels. Diabetic children with basal C-peptide levels higher than 0.6 ng/ml had lower blood glucose levels (187 +/- 43 vs 315 +/- 20 mg/dl, p less than 0.02), but no difference in blood glucose or any other parameter was observed as a function of the increase in CPR after breakfast. From these results we conclude that the evaluation of residual B-cell function in diabetic children by measuring the C-peptide response to a provocative stimulus is not more informative than the single basal measurement of C-peptide and does not have an additional biological significance, at least in hyperglycaemic insulin dependent diabetic children.

Blood Glucose↗
PubMed1986

Influence of inorganic phosphate on glucose-induced insulin release in vitro.

The effect of various extracellular phosphate concentrations on glucose induced insulin secretion has been investigated in two experimental systems the isolated perfused rat pancreas and the isolated rat pancreatic islets incubated in vitro. In both systems, total insulin secretion in response to 16.7 mmol/l glucose increased as extracellular phosphate concentration increased from 0 to 3.6 mmol/l. In perfusion experiments insulin secretion was significantly reduced at 4.8 mmol/l phosphate. In incubation experiments insulin secretion was inhibited only at 9.6 mmol/l phosphate concentration. When IBMX 1 mmol/l was used in incubation experiments glucose induced insulin secretion increased as extracellular phosphate increased from 0 to 3.6 mmol/l, but was also inhibited at 4.8 mmol/l.

1-Methyl-3-isobutylxanthine↗
PubMed1986

Amniotomy and oxytocin treatment of functional dystocia and route of delivery.

The details of clinical management were examined in 101 nulliparous patients with functional dystocia who underwent amniotomy and were treated with oxytocin in the first stage of labor. It was our hypothesis that if the alleged "high" rate of cesarean sections was the result of mediocre or flawed practices, these should be most evident in patients delivered abdominally. A group of 68 patients delivered vaginally are compared with 33 patients delivered by cesarean section. The means of many variables were statistically similar. The cesarean group was characterized by less cervical dilatation at admission, greater birth weights, larger maximum doses of oxytocin, and longer durations of oxytocin therapy. We conclude from our analysis that the decision to perform cesarean section in nulliparous women with functional dystocia arises from disabilities of the patient and not from differences in the application of our management principles, services, or treatments.

Adult↗
PubMed1986

Review of computed tomography findings in thrombosis of the major abdominal venous pathways.

Computed tomography is commonly the first diagnostic modality to detect venous thrombosis. The relatively constant location and anatomic relations of the major abdominal veins allow for their proper recognition and differentiation from other tubular structures. Whether the occlusion is secondary to blood clot or tumor extension, the vessels demonstrate a characteristic appearance. The presence of adjacent tumor mass is the single most important factor to differentiate the two types of thrombi. Invaluable aid is provided by computed tomography in the management of this clinical situation. Uncommonly, the diagnosis remains unclear and venography must be done. Selected examples of major abdominal venous thrombosis are presented.

Abdomen↗
PubMed1986

Pathogenic and free-living protozoa cultured from the nasopharyngeal and oral regions of dental patients: II.

Protozoa of the nose, mouth, and pharynx of 30 randomly chosen male caries patients at an odontological clinic of the National Autonomous University of Mexico, in Mexico City, were surveyed by culture from swabs. Culture tubes from swabs were observed every other day for 5 weeks. Pathogens found included Entamoeba histolytica, Naegleria fowleri, Acanthamoeba castellanii, A. culbertsoni, A. polyphaga, and Giardia lamblia. Such isolations of pathogens suggest that patients may be healthy carriers of cysts and trophic forms of protozoa responsible for several human diseases. Amoebae responsible for primary amoebic meningoencephalitis were well represented in the samples. Small pathogenic free-living amoebae have not been isolated before from healthy males in Mexico. Many species of free-living cyst-forming protozoa and some commensals without cysts were also cultured from swabs.

Adult↗
PubMed1986

Oxytocin and prolactin responses associated with nipple stimulation contraction stress tests.

Levels of oxytocin in plasma of pregnant women in the third trimester undergoing nipple stimulation-contraction stress tests were found, by parametric (paired t test) statistical analysis to be elevated. No differences in the plasma increases in oxytocin levels were found between those patients undergoing successful and those undergoing unsuccessful nipple stimulation-contraction stress tests. No significant differences in plasma levels of prolactin were associated with nipple stimulation in these patients.

Breast↗
PubMed1986

Effect of amniotic fluid bacteria on the course of labor in nulliparous women at term.

Patients with intraamniotic infection have an increased rate of cesarean delivery. To determine whether bacterial colonization of amniotic fluid affects uterine activity or delivery outcome, serial amniotic fluid samples were collected from 41 nulliparous patients in active labor with ruptured membranes for longer than 12 hours. To define positive changes, these samples were divided arbitrarily by colony count change using an increase of less than 10(2) colony-forming units per milliliter; greater than or equal to 10(2) but less than 10(4) colony forming units per milliliter; or greater than or equal to 10(4) colony forming units per milliliter. Nineteen, seven, and 15 sample sets fulfilled these criteria, respectively. Comparing serial samples with these changes in colony count revealed no significant difference in ten labor and delivery variables. Based on virulence of the isolates identified, samples were then divided into high (N = 19) or low (N = 16) virulence in both samples. Compared with sample sets with persistently low-virulence organisms, sample sets with persistently high-virulence isolates had a lower cervical dilatation rate (0.49 +/- 0.39 versus 0.98 +/- 0.58 cm/hour, P = .04), despite an increased maximum oxytocin dose (10.0 +/- 8.0 versus 5.4 +/- 5.2 mU/minute, P = .03). Controlling for birth weight, labor length, and epidural, magnesium sulfate, and oxytocin use, it was found that patients with high-virulence bacteria also had a higher cesarean section rate (57.9 versus 25.0%, P = .05). These results support a causal relationship between high-virulence bacteria in the amniotic fluid and poor cervical dilatation response to oxytocin in patients at risk for the development of intrapartum infection.

Amniotic Fluid↗
PubMed1985

Amniotomy and the use of oxytocin in labor in nulliparous women.

A group of 242 nulliparous women in spontaneous, term, first-stage, true labor, with cephalic presentations and intact membranes, underwent amniotomy in the first stage. Sixty-nine of 242 (29%) received oxytocin prior to complete dilatation. The group that received oxytocin was characterized by fewer women less than 20 years of age, more patients with an additional diagnosis such as preeclampsia, longer labors, and slower mean rates of dilatation before and after amniotomy. There was no correlation between the last dilatation rate before and the first after amniotomy. The only significant predictors of oxytocin use were cervical dilatation at amniotomy and the first rate of dilatation afterward. Of patients with dilatation at a rate of greater than or equal to 1 cm/hr from admission to amniotomy, 16% received oxytocin; if less than 1 cm/hr, 39%. Two different rate standards were used to differentiate "unsatisfactory" from "satisfactory" labor: (1) less than 1 or greater than or equal to 1 cm/hr and (2) no change or some change in dilatation. Neither of these standards, when applied to the first examination after amniotomy, predicts patients who will receive oxytocin with any reasonable degree of efficiency. Examination of cervical dilatation after amniotomy in patients who did not receive oxytocin demonstrated failure of the cervix to dilate in approximately 20% of each of three sequential examinations. Contrariwise, no dilatation for 2 hours was uncommon. Amniotomy appears to enhance the dilatation rate in patients with well-dilated cervices that are already dilating at a satisfactory rate and slows dilatation in some patients, particularly those with cervices that are less dilated. These results suggest that amniotomy should be performed for specific indications only.

Adult↗
PubMed1985

Oxytocin augmentation of dysfunctional labor. V. An alternative oxytocin regimen.

A regimen is described in which the time from the start of a large dose of oxytocin to a myometrial response was used for selection of a maintenance dose. The method is based on our experience that continuous intravenous doses of oxytocin in the therapeutic range for the augmentation of labor require about 40 minutes of intravenous infusion to achieve a steady-state plasma concentration of oxytocin. The method effectively identified the proper maintenance dose on the first attempt in 43 of 59 patients (73%) and on the second in 58 of 59. The doses selected effected cervical dilatation in 55 of 59 cases (93%). Comparison of the timed dose method with an arithmetic progression regimen revealed the former method to select the minimum effective dose more rapidly, but that method had no advantage in shortening the time from the start of oxytocin to complete cervical dilatation. Examination of the plasma concentration of oxytocin by radioimmunoassay demonstrates that the maintenance dose selected by the duration of the interval from the start of infusion to a myometrial response sustains the plasma oxytocin concentration obtained by the initial dose. These data lend additional evidence that any particular dose of oxytocin in the therapeutic range requires approximately 40 minutes to achieve a steady-state plasma concentration.

Cervix Uteri↗
PubMed1985

Computed tomography of diaphragmatic lipoma.

Five cases of lipomas of the diaphragm are reviewed, and findings on computed tomography and conventional radiography are compared. Due to the high specificity of computed tomography in identifying fat-containing structures, the diagnosis of lipoma was established with certainty. In repeated chest roentgenograms during an average follow-up of 14 months, there was no change in the appearance of the masses in the patients' diaphragms.

Aged↗