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Biomedical subjects

A Castañeda

Publications and source records attributed to A Castañeda.

15 recordsLinked to original sources
PubMed2005

Cystatin C as a marker of renal function in kidney transplant patients.

INTRODUCTION: Serum creatinine (sCr) is the most commonly used biochemical parameter for gauging kidney function, but, due to its limitations, it is not the ideal marker for glomerular filtration rate (GFR). Cystatin C (sCyC) appears to be an endogenous marker of GFR. AIM: To assess the use of sCyC as a marker of renal function in kidney transplant patients, we compared it with sCr and with creatinine clearance either in a 24-hour urine or calculated using the Cockroft-Gault formula. METHODS: Among 78 patients (62.8% men, 37.2% women) undergoing kidney transplantation (average age 44.87 +/- 13.37 years) we determined at 2, 5, 7, 15, and 30 days, and 6, 12 and 18 months after kidney transplantation: sCr (using the Jaffé colorimetric method), sCyC (immunonephelometry), creatinine clearance with a 24-hour urine, creatinine clearance using the Cockroft-Gault formula. RESULTS: During the first 30 days following transplantation, there was a progressive decline in sCr levels. sCyC increased up to the fifth day, coinciding with the highest doses of steroids, and then decreased. At 6, 12, and 18 months, there was a correlation between sCyC and sCr, creatinine clearance in a 24-hour urine or calculated with the Cockroft-Gault formula (R = 0.859; R = -0.713, and R = -0.684, respectively, P < .001.) CONCLUSIONS: sCyC is an endogenous marker of GFR. Its limitations relate to its being affected by the high doses of steroids in the first days following transplantation. In the 18-month posttransplant period, it correlated with creatinine clearance in a 24-hour urine or calculated by the Cockroft-Gault formula.

Adult↗
PubMed2001

Experimental infection of almond trees seedlings (Terminalia catappa) with an environmental isolate of Cryptococcus neoformans var. gattii, serotype C.

Recently, our laboratory reported the isolation of Cryptococcus neoformans var. gattii, serotype C for the first time from almond trees (Terminalia catappa) detritus. The aim of the present study was to establish the survival of C. neoformans in almond trees seedlings. Thirty seedlings were infected in the stems and samples were taken and processed at different times and by different techniques. No morphological alterations (macro or microscopic) were observed in the infected plants. However, C. neoformans was found to be viable for at least 100 days after infection. These data constitute our first approach towards the understanding of the yeast interactions with a host-plant.

Journal Article↗
PubMed2000

Effects of intestinal ischemia/reperfusion injury on gastric acid secretion.

BACKGROUND: The mechanism responsible for gastric colonization in critically injured ICU patients remains to be fully elucidated. Moreover, the effects of gut ischemia/reperfusion (I/R) injury on gastric function are unclear. It was our hypothesis that gut I/R injury would cause gastric dysfunction. MATERIALS AND METHODS: Rats were anesthetized and, via laparotomy, the superior mesenteric artery (SMA) was clamped at its aortic origin for 45 min followed by clamp removal. Rats were allowed to awaken and then killed after 6 h of reperfusion. Control rats underwent laparotomy with SMA isolation. Stomachs were removed, gastric fluid was aspirated, and the volume, pH, and protein, bicarbonate, and glucose contents were determined. Serum and antral mucosa were prepared for gastrin radioimmunoassay and the glandular mucosa was assessed for morphologic injury. RESULTS: SMA I/R injury caused significant accumulation of gastric luminal fluid that was alkaline and rich in protein, glucose, and bicarbonate content when compared with sham controls. SMA I/R injury also caused gastric surface epithelial cell injury and significantly increased serum and antral gastrin levels. In additional rats, gut I/R injury inhibited basal acid secretion and blunted the acid secretory response to pentagastrin. CONCLUSIONS: This study demonstrated for the first time that small intestinal I/R injury causes significant gastric dysfunction. The findings suggest that this type of injury, a frequent occurrence in critically injured ICU patients, may predispose patients to gastric colonization due to stasis and loss of the natural bactericidal effects of gastric acid.

Animals↗
PubMed2000

Mesigyna once-a-month combined injectable contraceptive: experience in Latin America.

A phase III clinical study was carried out among 534 fertile Latin American women to evaluate cycle control, side effects, and contraceptive efficacy of a once-a-month combined injectable, Mesigyna, consisting of 50 mg norethisterone enanthate and 5 mg estradiol valerate. The pregnancy rate at 1 year was 0 per 100 woman-years for a total experience of 4688 woman-months. The overall discontinuation rate at one year was 17.9%. Discontinuation rate for bleeding problems was 5.1%. The Colombian women had a significant increase (p <0.001) in bleeding problems compared to other countries. The discontinuation rate for amenorrhea was 1.1%. There were no significant differences between the groups regarding discontinuation for other medical or non-medical reasons. Mean weight gain after one year of use was 1.02 kg. Mesigyna is an appropiate once-a-month injectable contraceptive for Latin American women since it is highly effective and its perception of normal menstrual bleeding is of importance in the Latin American population.

Adolescent↗
PubMed1998

Vaginal bleeding patterns in users of Perlutal, a once-a-month injectable contraceptive consisting of 10 mg estradiol enanthate combined with 150 mg dihydroxyprogesterone acetophenide. A trial of 5462 woman-months.

Perlutal (other names: Topasel, Perlutan) is a once-a-month injectable contraceptive that contains 10 mg estradiol enanthate and 150 mg dihydroxyprogesterone acetophenide. A prospective trial was conducted in 216 women in Medellín, Colombia, over five years (5,462 woman-months) to establish the rates of the different vaginal bleeding patterns during the use of Perlutal, and to assess their relation with discontinuation of the Perlutal regimen. It was found that with the use of Perlutal, the duration of menstrual bleeding decreased from 3.9 to 2.7 days (p < 0.01), and that the incidence of dysmenorrhea decreased from 31% to 1.6% (p < 0.01). At one year of follow-up, the incidence of altered bleeding patterns was 5.1%. The discontinuation rate due to an altered bleeding pattern was 3.9%. It is concluded that the low incidence of altered bleeding patterns observed with the use of Perlutal leads to a low discontinuation rate among users.

Adolescent↗
PubMed1996

Trisomy 12 and p53 deletion in chronic lymphocytic leukemia detected by fluorescence in situ hybridization: association with morphology and resistance to conventional chemotherapy.

The incidence of trisomy 12 and p53 deletion was studied in a group of chronic B-lymphocytic leukemia (B-CLL) patients, using fluorescence in situ hybridization (FISH). Trisomy 12 was detected in eight of 50 patients (16%) and p53 deletion in six of 38 cases analyzed (15.8%). A statistically significant difference was observed between the incidence of trisomy 12 in patients with typical and atypical morphology (3.03% versus 41.18%). No correlation was found between this alteration and the rest of the clinical and biological parameters studied (adenopathies, hepatomegaly, splenomegaly, lymphocyte count, staging, CD11c expression, and resistance to chemotherapy). The p53 deletion was correlated with the presence of hepatomegaly and splenomegaly, advanced stage of disease, and resistance to conventional chemotherapy. The application of FISH to whole blood cell nuclei, without prior manipulation or culture, showed a higher percentage of cells with trisomy 12 than when the method was used following culture. We conclude that 1) FISH is a simple and sensitive technique for the detection of numerical and structural chromosome abnormalities; 2) Its application to uncultured samples obviates the alteration of results originated by the probable growth advantage of the normal or neoplastic cell population in vitro; 3) Trisomy 12 appears to define a B-CLL subgroup of atypical morphology; and 4) The p53 deletion is correlated with advanced stage of disease and resistance to treatment.

Aged↗
PubMedDate not supplied

[Infiltrating transitional carcinoma of the bladder (I). Comparison of 2 groups treated with preoperative radiotherapy (long-term protocol and short-term protocol) + radical cystectomy versus radical cystectomy only. Analysis of local recurrence and metastasis].

We analyze our experience in 175 patients with transitional bladder cancer for whom radical cystectomy was indicated. Patients were divided into three groups: one group was managed with radical cystectomy only and the other two with pre-operative radiotherapy: long-term approach and short-term approach. No significant differences have been observed when comparing current survival rate and disease-free intervals of all three groups. It can be deduced from our series that, by the scarce number of local recurrences observed, there is no other measure to be added to surgery directed to improve the tumour's local management. Most metastasis were diagnosed within 18 months after cystectomy. 58.4% patients presented bone dissemination. The risk of distant dissemination increases with the extent of vesical wall invasion, degree of anaplasia and presence of positive glands. The gland stage is not necessary for the metastasis to be present. Death's ratio with distant dissemination is significantly lower in the group managed Without pre-operative radiotherapy than in the others. Of the 11 patients where no tumour was observed in the cystectomy piece, 2 developed metastasis, indicating that this was already present before bladder extraction. Management of patients with infiltrating++ bladder cancer is complex, but no efforts should be spared to advise the most appropriate approach for each particular case. Chemotherapy plays an unquestionable role among the procedures we have to control, since most patients' deaths happen within two years after local-regional treatment of the primitive tumour and nearly all of them as a consequence of metastasis. Cytostatic agents are the only effective therapy for distant dissemination. We believe that every patient with a cancer extended to the perivesical fat or with dissemination to regional glands, whichever the stage, should be treated with chemotherapy after extirpation of the bladder, and starting as early as the patient's general status would allow it.

Actuarial Analysis↗
PubMedDate not supplied

[Prevalence of risk factors associated with hepatitis C in blood donors in the municipality of Durango, Mexico].

OBJECTIVE: To determine the prevalence of anti-viral hepatitis C antibodies (HCV-Ab+) in voluntary blood donors and to identify the main risk factors associated with it. MATERIAL AND METHODS: A case-control study was conducted over a 20-month period beginning in June 1993. A clinical history was obtained from all blood donors seen at the Centro Estatal de la Transfusión Sanguínea (State Blood Transfusion Center) and the Instituto Mexicano del Seguro Social in Durango, Mexico. HCV-Ab+ was determined in 5 915 serum assays using the second generation enzymatic immunoassay (UBI HCV EIA). RESULTS: The prevalence of HCV-Ab+ was 1.47 per 100 donors. The HCV-Ab+ prevalence was similar for urban and rural donors (1.54% and 1.34%) with no history of work migration. The main risk factors associated with HCV were a history of transfusions, (odds ratio -OR- 14.80, 95% confidence interval -CI-4.97-47.17) and sexual promiscuity or intercourse with prostitutes, (OR 6.53, 95% CI 2.61-16.54). CONCLUSIONS: The high prevalence of HCV-Ab+ may be explained by the lack of epidemiological surveillance of the population at risk. These data underscore the need for routine screening of HCV-Ab among voluntary blood donors and male or female prostitutes.

Adult↗