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Biomedical subjects

C Figueroa

Publications and source records attributed to C Figueroa.

16 recordsLinked to original sources
PubMed1998

[Bone marrow transplantation for severe aplastic anemia].

Severe aplastic anemia is a hematological disease with a high mortality rate, for which bone marrow transplantation is the treatment of choice, specially in children and young adults. The number of transfusions undergone before the transplant is the most important factor to predict the possibility of graft failure. Twenty patients with severe aplastic anemia, most of them already multiple transfused, were transplanted utilizing cyclophosphamide combined with antilymphocyte globulin as a conditioning regiment. All the evaluable patients engrafted and there were no episodes of graft failure. Three patients died, and 17 (85%) are alive with hematopoietic recovery at a median of 27.7 months post-transplant. Bone marrow transplantation was an excellent therapeutic option in this series of patients with severe aplastic anemia and the conditioning regiment appeared to be sufficiently myeloablative and immunosuppressive to avoid early or late graft failure.

Adolescent↗
PubMed1997

Estrogen and luminal stimulation of rat uterine kallikrein.

To understand the regulation of rat uterine kallikrein, we evaluated its variations in animals that had been ovariectomized and supplemented with estradiol or progesterone, in pseudopregnant animals intraluminally oil-stimulated or unstimulated, and in unilaterally pregnant animals. The content of kallikrein, determined by an RIA highly specific for rK1 (true tissue kallikrein), rose in ovariectomized rats with estradiol supplementation (0.28 +/- 0.03 to 0.44 +/- 0.05 ng/mg) and decreased with progesterone (0.13 +/- 0.02 ng/mg; n = 15; p < 0.001). Kallikrein content rose from Day 1 of pseudopregnancy (PP1) to a maximum on PP7 (0.18 +/- 0.01 to 0.39 +/- 0.04 ng/mg protein; n = 36; p < 0.001). On PP7 with unilateral oil intraluminal stimulation, the decidualized horn had higher kallikrein content than did the contralateral (0.98 +/- 0.09 vs. 0.35 +/- 0.05 ng/mg protein; n = 7; p < 0.001). Immunocytochemistry revealed that mainly rK1 is localized in the luminal and glandular epithelium, and it increased in the stimulated horn. In the unilaterally pregnant rat on Day 7, the fertile horn had a higher kallikrein content than its contralateral control (0.71 +/- 0.07 vs. 0.37 +/- 0.03 ng/mg protein, p < 0.001; n = 8), as well as a higher kininogenase activity (239 +/- 34.3 vs. 83.5 +/- 7.9 ng bradykinin(BK)/h per horn, p < 0.003; and 945 +/- 90 vs. 585 +/- 40 ng BK/h per gram tissue, p < 0.002; n = 6). These results indicate that estrogen stimulates, whereas progesterone inhibits, kallikrein production, and that hormonal regulation is overridden by intraluminal stimulation, thus associating the enzyme with decidualization.

Animals↗
PubMed1997

Accuracy of invasive and noninvasive tests to diagnose Helicobacter pylori infection after antibiotic treatment.

OBJECTIVES: To compare the diagnostic accuracy of the most widely available tests for diagnosis of Helicobacter pylori infection after antibiotic treatment. METHODS: A total of 59 H. pylori-positive, duodenal ulcer patients (mean age, 40.7 +/- 11.7 yr; 40 male and 19 female) were treated for 2 wk with either amoxicillin-metronidazole (n = 36) or omeprazole-amoxicillin-tinidazole (n = 23), and after 4 wk, were tested for H. pylori infection by [14C]urea breath test (UBT), serum IgG antibody level, and multiple antral biopsies for rapid urease testing, histology, Warthin-Starry stain, and polymerase chain reaction to detect H. pylori DNA. Infection status was established by a concordance of test results. RESULTS: H. pylori was eradicated in 47 patients (80%). UBT and rapid urease testing had the best sensitivity and specificity, although not statistically different to Warthin-Starry stain and polymerase chain reaction. Serology and histology had little diagnostic value in this setting due to high proportion of false-positive results. CONCLUSIONS: Noninvasive UBT is as accurate in predicting H. pylori status after antibiotic treatment as rapid urease testing and Warthin-Starry stain. Especially for duodenal ulcer patients, UBT could be considered the gold standard to confirm eradication of H. pylori.

Adolescent↗
PubMed1996

Moderate expansion of a normally biallelic trinucleotide repeat in spinocerebellar ataxia type 2.

The gene for spinocerebellar ataxia type 2 (SCA2) has been mapped to 12q24.1. A 1.1-megabase contig in the candidate region was assembled in P1 artificial chromosome and bacterial artificial chromosome clones. Using this contig, we identified a CAG trinucleotide repeat with CAA interruptions that was expanded in patients with SCA2. In contrast to other unstable trinucleotide repeats, this CAG repeat was not highly polymorphic in normal individuals. In SCA2 patients, the repeat was perfect and expanded to 36-52 repeats. The most common disease allele contained (CAG)37, one of the shortest expansions seen in a CAG expansion syndrome. The repeat occurs in the 5'-coding region of SCA2 which is a member of a novel gene family.

Amino Acid Sequence↗
PubMed1995

Identification of immunoreactive tissue kallikrein in human ductal breast carcinomas.

Various proteases have been shown to be present in malignant breast tissue. Although the question of the involvement of tissue kallikrein, a serine protease, in the pathophysiology of tumours has been raised, the presence of this enzyme in human breast carcinoma has so far not been examined. In the present study, both neoplastic and normal human breast are scanned by immunocytochemistry for the presence and cellular localization of tissue kallikrein. In the healthy breast, tissue kallikrein was observed as a deposit of immunoreactive material that localized in the apical portion of duct cells. In the malignant breast tumours surveyed, the enzyme was observed only in ductal carcinomas, whereas lobular carcinomas were devoid of immunostaining. In ductal carcinomas, the immunoreactivity for tissue kallikrein appeared to be associated with gradations of malignancy, being absent in dedifferentiated tumours. The presence of tissue kallikrein in malignant breast tumours poses the question of the role of this enzyme in malignant breast tissue. The enzyme may participate within the tissue either in proteolytic processes (it has been shown to activate procollagenase) or by enhancing vascularity or mitogenicity by the generation of kinins.

Breast Neoplasms↗
PubMed1995

Enhanced biliary excretion of canalicular membrane enzymes in estrogen-induced and obstructive cholestasis, and effects of different bile acids in the isolated perfused rat liver.

BACKGROUNDS/AIMS: Canalicular membrane enzymes are normally released into bile by partially known processes. This study was undertaken to investigate whether hepatocellular cholestatis induced in rats by ethynylestradiol or obstructive cholestasis produced by complete biliary obstruction for 24 h is associated with an increased release of alkaline phosphatase and gamma-glutamyl transpeptidase into bile, and to clarify how this process is affected by different bile acids. METHODS: The studies were performed in the isolated perfused liver during infusion of sodium taurocholate, taurochenodeoxycholate and tauroursodeoxycholate at increasing rates. RESULTS: Maximum sodium taurocholate, taurochenodeoxycholate and tauroursodeoxycholate secretory rates were decreased in both cholestatic groups (complete biliary obstruction > ethynylestradiol) compared with controls. Maximum biliary outputs of alkaline phosphatase and gamma-glutamyl transpeptidase were significantly increased in the ethynylestradiol group during infusion of sodium taurocholate and taurochenodeoxycholate, but not of tauroursodeoxycholate, and were increased in the complete biliary obstruction group during the infusion of sodium taurocholate and tauroursodeoxycholate but not of taurochenodeoxycholate. The biliary outputs of alkaline phosphatase and gamma-glutamyl transpeptidase showed a significant and direct linear relationship with sodium taurocholate and taurochenodeoxycholate secretory rates in both cholestatic groups. However, only in the complete biliary obstruction group did alkaline phosphatase and gamma-glutamyl transpeptidase excretion show a significant correlation with tauroursodeoxycholate secretory rates. The slope of the line, which indicated the mU of enzyme activity secreted per nmol of sodium taurocholate or taurochenodeoxycholate, was greater for gamma-glutamyl transpeptidase and alkaline phosphatase in both cholestatic groups (ethynylestradiol > complete biliary obstruction) than in the control group. Alkaline phosphatase activity in purified isolated canalicular and sinusoidal membranes was significantly increased in both cholestatic groups (complete biliary obstruction > ethynylestradiol), while gamma-glutamyl transpeptidase activity was unchanged compared with controls. CONCLUSION: The marked increase in sodium taurocholate and taurochenodeoxycholate-mediated release of alkaline phosphatase and gamma-glutamyl transpeptidase into bile in cholestatic rats suggests an increased lability of these intrinsic membrane proteins to the detergent effects of secreted bile acids. It remains to be elucidated whether this phenomenon, which was particularly intense in ethynylestradiol induced cholestasis, is important in the pathogenesis and perpetuation of bile secretory failure. In contrast, tauroursodeoxycholate administration did not result in enhanced biliary excretion of these membrane enzymes, in either the control group or the ethynylestradiol group, supporting the concept that this bile salt lacks the membrane toxicity of common bile acids.

Alkaline Phosphatase↗
PubMed1994

Characterization of human peroxisomal membrane proteins.

The peroxisomal membrane appears to play a crucial role in transporting proteins into the organelle. Some human genetic disorders involving peroxisome biogenesis, such as Zellweger syndrome, may be caused by genetic defects of the import machinery located in the peroxisomal membrane. In order to characterize the proteins of the human peroxisomal membrane, we isolated peroxisomes from human liver. We obtained their membranes using various procedures and analyzed their proteins by SDS-polyacrylamide gel electrophoresis and silver staining. We compared the protein composition of peroxisomal membranes with membranes derived from mitochondria and microsomes. The main peroxisomal membrane proteins (PMPs) have apparent molecular masses of 147, 112, 95, 87, 81, 79, 74, 69(70), 53-52 (double band), 47, 45, 43, 37, 31, 28, 22, and 17 kDa. The following PMPs of 147, 112, 79, 69(70), 53-52 (double band), 47, 43, 31, 28, 22, and 17 kDa fit the criteria for integral membrane proteins. We then produced rabbit polyclonal and mouse monoclonal antibodies that recognized some human PMPs. One of these antibodies detected mainly PMP43. We used this antiserum to evaluate the presence and subcellular distribution of the PMP43 in fibroblasts derived from patients affected by Zellweger syndrome. These results represent new information about the protein composition of the human peroxisomal membrane and provide biological tools for further characterization of the human PMPs and their genes in normal and pathological conditions.

Animals↗
PubMed1987

Identification of kallikrein in cultures of adult renal cells.

Cortical tubular cultures enriched with distal segments were prepared from the kidney of adult Fisher 344 rats bearing thyroid tumors. After two years of cultivation (20 passages) cell monolayers contained immunocytochemically detectable cytokeratin and kallikrein material in their cytoplasm. Furthermore cell pellets showed a true renal type of kininogenase activity corresponding to active kallikrein which ranged from 22.3 to 1.5, and total Kallikrein from 29.9 to 2.8 pg kinins/min per mg of protein.

Animals↗