[Evaluation of symptomatology in uncinariasis].
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Child↗
Biomedical subjects
C Gonzalez
Publications and source records attributed to C Gonzalez.
In vivo validation of tissue segmentation based on a 3D feature map using both a hamster brain tumor model and stereotactically guided biopsy of brain tumors in man.
The purpose of this study was to validate our MR tissue segmentation technique using a hamster brain tumor model and malignant brain tumors in man. We used a multispectral tissue segmentation analysis. Three sets of MRI data were included: proton density, T2-weighted fast spin echo, and T1-weighted spin echo, as inputs. Three image preprocessing steps included correcting image nonuniformity, application of an anisotropic diffusion type filter, and data point selection by a qualified observer. We used the k-Nearest Neighbor segmentation algorithm, which does not require prior knowledge of the sample distribution. This choice allowed us to optimize the different tissue clusters present in three-dimensional (3D) feature space. In vivo validation of the technique was performed in hamsters harboring tumors induced with JC virus-transformed HJC-15 cells, as compared to three control animals. Human brain tumors obtained by stereotactically guided biopsy in six patients were also included in the study. Finally, brain tumors were removed from two patients who underwent conventional craniotomy using segmentation-derived images as a guide. In the hamsters, 10 tissues were correctly identified by segmentation and were confirmed histologically (P < .02). In the patients, there was also a strong correlation between our segmentation results and the tissue obtained by stereotactic biopsy (P < .01). In one of the two patients who underwent open craniotomy, segmentation images were useful in revealing tumor spread into vital areas of the brain (motor area). In conclusion, the results of segmentation correlate well with the tissues in vivo and thus warrant further clinical utilization and evaluation.
Adult↗
Effects of starvation on pituitary and plasma growth hormone in rats.
The present experiments were undertaken to study the effect of complete food removal on body weight, pituitary growth hormone (GH), plasma GH and glucose concentration in male and female Wistar rats. Plasma and pituitary GH levels were measured by means of a specific radioimmunoassay. Plasma glucose concentration decrease during the initial 60 h fasting in males and 72 h in females, and remained fairly constant thereafter in both groups. Pituitary GH content was unchanged in males and females by 36 h and 60 h, respectively, after the onset of starvation. Thereafter, pituitary GH decreased progressively with increase of the starvation period. In spite of the changes in pituitary GH, plasma GH concentration in fasted male and female rats was similar to or higher than in controls. In fact, during an initial period, up to 72 h in males and 96 h in females, plasma GH levels in fasting rats were similar to control values. With longer starvation periods, plasma GH concentration rose above control values. After 24 h of refeeding 102 h fasted rats, plasma GH concentrations were comparable to control levels. In addition, after an initial loss of 10 g after 24 h fasting, body weight of both male and female animals decreased, and by the end of the starvation period it was about 50% of control weight. From these results it seems that complete food removal has a direct effect on pituitary GH. Furthermore, the fact that changes in plasma GH concentrations were evidentiated just before the period when plasma glucose was maintained at constant levels in fasted rats of both sexes supports the hypothesis that growth hormone plays a physiological role in the regulation of glucose homeostasis during starvation.
Animals↗
MGI 114: augmentation of antitumor activity when combined with topotecan.
PURPOSE: 6-Hydroxymethylacylfulvene (HMAF; MGI 114; Irofulven) is a semisynthetic analogue of the mushroom toxin illudin S that has been shown to be a potent cytotoxic agent with an improved therapeutic index compared with its parent compound. The studies were conducted to evaluate the antitumor activity of MGI 114 as a single agent and in combination with topotecan against pediatric solid tumor cell lines and xenograft models. MATERIALS AND METHODS: In vitro studies were designed to determine the cytotoxic potential of MGI 114 using the MTT assay and 13 pediatric tumor cell lines. In addition, combination in vitro studies were performed with MGI 114 and topotecan to generate isoeffect plots. Single agent and combination in vivo studies were also performed using MGI 114 against rhabdomyosarcoma and neuroblastoma xenograft models. RESULTS: After a 1-hour exposure to MGI 114, the mean IC50 (+/-standard error of mean) for medulloblastoma, neuroblastoma, Ewing sarcoma/primitive neuroectodermal tumor, and rhabdomyosarcoma cell lines were 1.58+/-0.51, 1.60+/-0.82, 1.18+/-0.08, and 3.99+/-1.69 microg/mL, respectively. When tumor cells were exposed concurrently to MGI 114 and topotecan, evidence of synergy was observed in 10 of 12 (83%) cell lines. Single agent and combination in vivo studies with MGI 114 showed that this agent had substantial, and at times curative, antitumor activity against rhabdomyosarcoma and neuroblastoma xenograft tumors. CONCLUSIONS: These data suggest that MGI 114 has significant efficacy as a single agent in preclinical studies against pediatric tumors. In addition, based on previous reports and the results presented here, combining MGI 114 with topotecan appears to be an attractive approach to the treatment of pediatric malignancies. After completion of the pediatric phase I studies of MGI 114, consideration should be given to phase II single agent and phase I combination studies with a topoisomerase I inhibitor such as topotecan or irinotecan.
Animals↗
Nicotinic versus muscarinic binding sites in cat and rabbit carotid bodies.
It has been suggested that acetylcholine (ACh) might play an important role in carotid body chemoreception. However, a unified explanation of the actions of ACh in this organ has been lacking, due in part to the opposite pharmacological effects of this agent on carotid sinus nerve discharge in different animal species, most notably the cat, where ACh is excitatory, versus the rabbit, where it is inhibitory. In the present study, we utilized receptor binding techniques to compare the nicotinic and muscarinic receptor populations in the carotid bodies of these two species. Our results with the nicotinic ligand 125I-alpha-bungarotoxin and the muscarinic ligand 3H-quinuclidinyl benzilate suggest that nicotinic receptors predominate in the cat by a ratio of 2:1, while in the rabbit, a 12:1 ratio favors muscarinic receptors. Our data suggest that the relative numbers of muscarinic and nicotinic receptors in the carotid bodies of these two species determine the excitatory or inhibitory actions of exogenously administered ACh in this chemoreceptor organ.
Acetylcholine↗
Oxygen sensing in the carotid body.
In the present article we review in a concise manner the literature on the mechanisms of O2 chemoreception in the carotid body of adult mammals. In the first section we describe the basic structure of the carotid body, and define this organ as a secondary sensory receptor. In the second section is presented the most relevant literature on the O2 metabolism in the carotid body to define the parameters of O2 chemoreception, including hypoxic thresholds and P50 of the hypoxic responses. The final section is devoted to the mechanisms of detection of the hypoxic stimulus. We provide the data in favor and against each of the current three models on O2 chemoreception: the membrane model, the metabolic hypothesis with its different versions and the NAD(P)H oxidase model.
Adenosine Triphosphate↗
Synchronous airway lesions in infancy.
Stridor in the young infant is evaluated by careful laryngoscopy. When a lesion of the larynx is diagnosed, the necessity and risk of bronchoscopy are challenged. To assess the need for careful examination of both the upper and lower respiratory tract, a 2-year retrospective study was performed at the Children's Hospital of Pittsburgh. Of 103 infants who underwent diagnostic laryngoscopy and bronchoscopy for airway obstruction, stridor, or both, 18 (17.5%) had two or more synchronous airway lesions detected. Laryngoscopy alone, without further workup of the entire respiratory tract (ie, bronchoscopy, radiographic studies) may fail to detect concurrent disorders in infants with airway obstruction.
Airway Obstruction↗
Looking for "indicants" in the differential diagnosis of jaundice.
The differential diagnosis between intra- and extrahepatic causes of jaundice was studied. At the "20 Noviembre" ISSSTE Hospital in Mexico City, between January 1977 and May 1984, data were collected in 1,263 jaundiced patients. To the clinical data for 1,000 of these 1,263 patients and a new set of 105 jaundiced patients, the COMIC study group algorithm was applied. The differential diagnosis between medical and surgical causes of jaundice was correct in 90% of the cases. In 85% the algorithm could also differentiate between acute and chronic disease, or between benign and malignant causes of jaundice. The COMIC algorithm was then modified and applied to the same 1,000 cases examined previously, with 96% accuracy in distinguishing medical and surgical causes of jaundice and 94% accuracy in discriminating between acute and chronic, or benign and malignant, disease. In a new set of 105 cases of jaundiced patients the modified COMIC algorithm made the correct diagnosis between intra- and extrahepatic causes for 98% of the patients, and for 93% it was also capable of distinguishing benign from malignant and acute from chronic causes of jaundice.
Adult↗
Physicians' diagnoses compared with algorithmic differentiation of causes of jaundice.
Clinical data were collected in 194 cases of jaundiced patients treated at the "Adolfo Lopez Mateos" ISSSTE Hospital in Mexico City from July 1985 to July 1986. A copy of the clinical history of each patient was given to each of four physicians--one recently graduated from medical school, another in his first year of gastroenterology, and two others who were experienced gastroenterologists. The same clinical data were processed by a computer set up to use a modified Danish COMIC algorithm. All physicians and the computer technician were blinded to the "gold standard" pathologic diagnoses, with which their diagnoses were compared. Accuracy rates of the physicians in distinguishing intrahepatic (medical) from extrahepatic (surgical) jaundice were 78%, 86%, 86%, and 91%, and the accuracy of computer-assisted diagnoses was 96%. Chi-squared analysis of the diagnoses of three of the physicians and those of the computer showed significant differences (p between 0.1 and 0.01). For the diagnoses of the remaining physician, however, no significant difference was found after chi-squared continuity correction.
Adult↗
[Usefulness of total dry blood samples on filter paper in the detection of antitoxoplasma antibodies].
Direct Agglutination (DA) techniques, both, using dry blood samples in filter paper and serum samples, were compared with the ELISA test in order to detect antibodies against Toxoplasma gondii. The results show the validity of the dry blood samples in filter paper for detecting antitoxoplasma antibodies with a DA test. Our results would confirm their usefulness in field epidemiological surveys.
Agglutination Tests↗
Reinnervation of the nerve of the inferior oblique after iatrogenic denervation.
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Adolescent↗
Use of the Pierse procedure to treat congenital upbeat nystagmus with a chin-up head position.
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Chin↗
Denervation of the inferior oblique: current status and long-term results.
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Child↗
Chicken anemia virus and fowl adenoviruses: association to induce the inclusion body hepatitis/ hydropericardium syndrome.
The effects of a simultaneous and/or a subsequent coinfection with chicken anemia virus (CAV) isolate 10343 and fowl adenovirus (FAV) isolate 341 in specific-pathogen-free light chickens were evaluated. The simultaneous coinfection was conducted by the intramuscular route, whereas the subsequent coinfection trial considered FAVs administered orally. In trial 1, 20-day-old chickens simultaneously coinfected with CAV (10343) and FAV (341) intramuscularly (i.m.) showed 55% mortality and characteristic signs and lesions of inclusion body hepatitis/hydropericardium (IBH/HPS). In contrast, birds singly infected with FAV i.m. showed 10% mortality due to IBH/HPS. Trial 2 showed that birds receiving FAV 341 orally at day 7 post-CAV intramuscular infection (group A) developed a mild form of IBH/HPS with presence of inclusion bodies (INIBs) in 60% of the group and virus-neutralizing antibodies against FAV 341. Group B (FAV orally 14 days after CAV) showed significant decreased weight gain, nonspecific microscopic lesions in the liver, spleen, bursa, and thymus, and an antibody response against FAV 341. However, no INIBs could be detected in the hepatocytes of these chickens. Group C (FAV orally 35 days after CAV) showed nonspecific histopathologic changes in the liver and no antibody response to FAV. The oral single infection with FAV isolate 341 induced neither mortality nor macroscopic lesions of IBH/HPS in the birds. The present results corroborate previous reports on pathogenicity of Chilean FAV isolates, which suggest that synergism with other viruses or prior immunosuppression is necessary to produce IBH/HPS in chickens. These results also suggest that the susceptibility of chickens to FAV oral infection resulting in IBH/HPS varies throughout the course of CAV infection.
Adenoviridae Infections↗
Introducing Cynthia Gonzalez.
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Career Choice↗
Vertical induction of the inclusion body hepatitis/hydropericardium syndrome with fowl adenovirus and chicken anemia virus.
The hypothesis that fowl adenovirus (FAV) and chicken anemia virus (CAV), transmitted vertically and simultaneously, induce the inclusion body hepatitis (IBH)/hydropericardium (HP) syndrome in progeny chickens was tested. Thus, 35-wk-old light brown layer breeders, showing absence of antibodies against FAV and variable titers against CAV, were intramuscularly singly infected with the FAV serotype 4 isolate 341 or dually infected with CAV (isolate 10343) and FAV. All hens (groups A [FAV alone], B [FAV + CAV], and C [noninfected]) were clinically healthy throughout the experimental period. Both infectious viruses FAV and CAV were isolated from progenies obtained as early as 5 days after infection of their breeders. Hematocrit, serum proteins, and aspartate-aminotransferase values showed a few statistical differences between the progeny groups. Most of these differences were detected in the progeny chickens of group B. However, almost all values met reference values for the species. The pathologic findings showed that progeny chickens obtained from both singly and dually infected breeders developed macroscopic and histopathologic changes of IBH/HP. The pathologic findings shown by progeny chickens of group A (FAV) were not expected because neither synergism nor prior immunodepression by CAV was concurrent. Chickens of group B (CAV + FAV) also developed IBH/HP. Although not many differences in the evaluated parameters between groups A and B were statistically significant, most pathologic findings of group B indicated a more severe manifestation of the disease. However, because FAV alone did reproduce the syndrome, the results shown by group B would not allow a definitive confirmation of the hypothesis that the association of FAV and CAV is necessary for the successful induction of the IBH/HP syndrome in chickens when transmitted vertically.
Adenoviridae Infections↗
[Idiopatic nephrotic syndrome. Histopathological and clinical studies on 12 clinical cases].
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Biopsy↗
[Expressed emotion: past, present, future].
Expressed Emotion (EE) proved to be the best single predictor of relapse in schizophrenia in 1972. Since then, studies on EE were oriented in three directions: Replication of the original study in different countries, improvement of the methodology and clinical applications. The analysis of different key studies shows that EE is a powerful predictor factor, although it is influenced by other variables such as culture.
Emotions↗