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C Calderón

Publications and source records attributed to C Calderón.

At least 37 records · Page 2Linked to original sources
PubMed1994

Isolation of a nitric oxide inhibitor from mammary tumor cells and its characterization as phosphatidyl serine.

Macrophages from mice bearing large D1-DMBA-3 mammary tumors have a decreased capacity to kill tumor targets. This effect is due to an impaired ability to produce nitric oxide (NO) in response to lipopolysaccharide (LPS) stimulation. Here we report that the DA-3 tumor cell line, derived from the in vivo adenocarcinoma D1-DMBA-3, produces a factor that inhibits both NO production/release and cytotoxicity of LPS-activated peritoneal exudate macrophages (PEM). However, other complex macrophage functions such as phagocytosis, superoxide production, mitochondrial dehydrogenase activity, and synthesis of proteins were not reduced by this factor. The NO inhibitor has been found to be lipid in nature. Lipid extracts from DA-3 cell culture supernatants were purified by repeated silica gel column chromatography. The active molecule was unambiguously characterized as phosphatidyl serine (PS) by fast atom bombardment tandem mass spectrometry. Preliminary results indicate a lack of induced NO synthase (iNOS) activity in the lysates of LPS-activated PEM pretreated with PS. The ubiquity of PS in the inner leaflet of biological membranes and its NO inhibitory property, suggest that this phospholipid may be one of the long elusive molecules responsible for regulating physiological levels of NO in the host and hence preventing cellular dysfunction and/or tissue damage. Furthermore, the possible overexpression and shedding of PS by DA-3 tumor cells may represent a novel mechanism to impair macrophage cytotoxicity, a host function that contributes to the protection against developing neoplasms.

Animals↗
PubMed1994

[Focal hepatic lesions observed by echotomography with special reference to hydatidosis].

This article reports the results of 1080 ultrasonographic examinations of the liver in a clinic of the Ninth Region of Chile, using a SSD 620 Aloka equipment. In 61 examinations (5.6%) a focal liver lesion was found. Of these, 9 (14.7% of lesions) appeared as malignant (6 metastasis and 3 hepatomas) and 52 (85.3% of lesions) appeared as benign (10 inespecific calcifications of less than 10 mm, 6 vascular lesions, 12 simple cysts, 2 cases of polycystic liver and 9 cases fulfilled Gharbi's criteria for hepatic hydatidosis). The diagnosis in these 9 cases was confirmed by serology or surgery Thus, 14.7% of all focal lesions of the liver were due to hydatidosis. Considering that simple cysts are indistinguishable from hydatid cysts in early stages, hydatidosis could be misdiagnosed in this sample. It is concluded that serologic tests should be performed to all cystic hepatic ultrasonographic lesions, specially in zones with high infestations rates.

Echinococcosis, Hepatic↗
PubMed1993

Abundance of airborne Penicillium CFU in relation to urbanization in Mexico City.

Air was sampled simultaneously at three localities in Mexico City differing in urbanization index and air pollution level on 22 days during a period covering both dry and rainy seasons. An Andersen two-stage microbial sampler was used for 15 min at 28 liters min-1 to isolate culturable fungi on malt extract agar. After exposure, plates were incubated at 25 degrees C for 48 to 72 h before colonies were counted and identified to give concentrations of total fungal spores and of Penicillium spp., expressed as CFU per cubic meter of air. Total fungi numbered 91 to 602 CFU m-3 in Tlalpan Borough (southern area), 40 to 264 CFU m-3 in Cuauhtémoc Borough (downtown), and 26 to 495 CFU m-3 in Gustavo A. Madero Borough (northern area). Although Penicillium spp. were the second most frequently isolated fungal genus, concentrations were small, with a maximum of only 133 CFU m-3. Twice as many colonies were isolated in the southern area, with an urbanization index of 0.25 (arithmetic mean, 41 CFU m-3), as at other sampling stations with greater urbanization indices (arithmetic means, 19 and 20 CFU m-3). In the downtown area, with an urbanization index of 1.0, Penicillium spp. were more numerous than any other genus and formed 25% of the total fungal count compared with 14 and 17% in the other areas. Concentrations of airborne Penicillium spp. did not differ significantly between rainy and dry seasons.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Microbiology↗
PubMed1992

[Simultaneous digestive and cardiological studies in asymptomatic chagasic patients].

Prognosis in patients with Chagas disease is related to systemic involvement. 43 asymptomatic chagasic subjects, 28 males and 15 females aged 28 to 85 years, were subjected to electrocardiograms and upper and lower gastrointestinal radiological studies. 23 patients (53%) had evidence of involvement of at least one organ. Multiple involvement was demonstrated in 5 individuals (12%): one patient had megaesophagus, megacolon and abnormal EKG; 2 had megaesophagus and abnormal EKG; 1 had megaesophagus and dolicocolon and 1 had dolicocolon and abnormal EKG. Dilated esophagus was found in 6 patients (14%), dolico or megacolon in 13 (20%) and abnormal EKG, mostly bifascicular block in 10 (23%). Thus, isolated or multiple organ involvement is frequent in asymptomatic chagasic subjects. Routine screening of this population is advisable for early diagnosis and prevention of complications.

Adult↗
PubMed1992

[Esophageal achalasia of chagasic origin: report of a case diagnosed in the pre-symptomatic stage].

A 42 year old male that presented with functional gastrointestinal symptoms is presented. X ray examination showed an esophageal diameter of 3 cm, measured 6 cm above the gastroesophageal junction. This finding, according to previous experiences of the authors, is highly suggestive of Chagasic esophageal involvement. The patient resided in a highly endemic area for Chagas disease; hemagglutination, latex agglutination and ELISA serological tests for Chagas disease were positive. The manometric study of the esophagus confirmed the diagnosis showing an elevated lower esophageal sphincter pressure and hypomotility and poor amplitude contractions of the esophageal body. Barium enema and EKG were normal. Upper gastrointestinal endoscopy disclosed an erosive gastritis that could explain the patients' symptomatology. The antiquity of Chagas infection was estimated in 18 years. This case represents an example of early diagnosis of esophageal involvement in the course of Chagas disease.

Adult↗
PubMed1990

Prevalence and characteristics of smoking among adolescents.

The purpose of this study was to determine the prevalence of smoking and factors associated to the use of cigarettes in the adolescent population of the Francisco Oller High School in Cataño, Puerto Rico. A survey was administered to 106 randomly chosen students, regarding previous use of cigarette, age of first exposure, source of cigarettes, and smoking among peers. The average age was 16 years old. Fifty six percent (56%) of the participants denied ever using cigarettes, 34.5% admitted having used cigarettes and 9.5% admitted to be smokers. A higher prevalence of cigarette experimentation was reported among females (43% versus 26% in males). Smoking was reported among 16% of males vs 3% of females. A 44% admitted having used cigarettes before 14 years of age. A 42.5% of the adolescents reported obtaining their knowledge of tobacco effect from the communication media. This data is similar to published information on adolescents smoking in the United States.

Adolescent↗
PubMed1990

Exercise and physical activity of adolescents.

Multiple studies point toward the beneficial role of regular exercise in preventing cardiovascular disease. The purpose of this study is to determine the prevalence of physical activity and exercise among adolescents from the only high school in Cataño, Puerto Rico. An open-ended, multiple choice questionnaire was administered to 106 students who were randomly chosen. Questions included frequency of exercise, type of sports which they practiced and would like to practice. Results were statistically analyzed. The study revealed that 53% of the participants did not exercise regularly, exercising less than once a week. Those who did exercise were involved in a competitive team sport (35% of females: volleyball; 65.8% of males: basketball). Approximately 1/3 of the females and of the males replied they would like to practice noncompetitive sports which should be incorporated into their lifestyles through early intervention in the school, home and through the primary care physician.

Adolescent↗