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Biomedical subjects

T Castro

Publications and source records attributed to T Castro.

11 recordsLinked to original sources
PubMed2005

[Influence of climatic factors on the incidence of upper gastrointestinal bleeding].

OBJECTIVES: Several studies have suggested the existence of seasonal variation in the incidence of upper gastrointestinal bleeding (UGB). However, the role of climatic factors has not been elucidated. The aim of the present study was to investigate the role of these factors in the incidence of UGB secondary to esophageal varices (EV), gastric ulcer (GU), and duodenal ulcer (DU). MATERIAL AND METHODS: Based on the use of the Minimum Data Set and the International Classification of Diseases, cases of endoscopically-confirmed UGB secondary to EV, GU and DU were retrospectively included (1998-2001). The incidence of UGB was correlated with daily climatic factors (temperature, atmospheric pressure, humidity, direction and speed of wind) in Jerez de la Frontera (Spain) during the study period. RESULTS: A total of 499 patients were included (GU = 192, DU = 199, EV = 108). No significant differences were found in the monthly or seasonal incidence of UGB. Episodes of UGB were grouped according to the climatic conditions present on the day of admission. No significant relationship was found between UGB and any of the daily climatic factors studied. DISCUSSION: The results of our study do not support the existence of a seasonal pattern in the incidence of UGB secondary to GU, DU or EV and allow us to conclude that, in our geographical area, these factors are not involved in episodes of bleeding.

Adult↗
PubMed2002

[Clinico-epidemiologic study of urolithiasis in a Caribbean urban area].

Urolithiasis is a common clinical disorder. Its frequency has risen with the development of humanity and varies wirl the country, geographic area, etc. It poses health problems in most countries. The urolithiasis has some potential risk factors such as intrinsic and extrinsic epidemiological, metabolic, physic-chemistry of the urine, mechanics and urinary infection. Our objective in this epidemiological study in a general population was to know the frequency, the potential risk factors, the morbidity, and social and economical impact of the urolithiasis in our subtropical Caribbean country. The prevalence was 4.64% and the annual incidence was 0.1%. Both are with in the estimated range of urolithiasis frequency in the world. It mainly started between 20 and 29 years in both genders. The white (5.2%) and the male (6.36%) patients were the most affected. 40% of all patients had a family history of urolithiasis. It was highly associated with diabetes mellitus, ischaemic cardiopathy, urinary tract infection and arterial hypertension. Stone formation was related to the warmer season. High calcium, protein-purine, carbohydrates and oxalic acid intake together with low fluid intake were closely associated with this disorder. 85% of patients had suffered renal colic and 75% of them more than once. Stone recurrence affected 33.8% of patients and 54.5% of them had more than one recurrence. Procedures for stone removal were needed in 33.8% of subjects. 40% of all patients were admitted to hospital due to urolithiasis morbidity. Non-specific medical treatment had been taken by 49.2% of the patients and specific treatment by none. Urolithiasis in this population was the some as has been reported in others studies. It has shown high frequency, increasing incidence, the same risks factors, high morbidity, and high social and economical impact. The low cost treatment is only taken by half of the patients.

Adolescent↗
PubMed2001

Negative feedback on the effects of stem cell factor on hematopoiesis is partly mediated through neutral endopeptidase activity on substance P: a combined functional and proteomic study.

Hematopoietic regulation is a complex but dynamic process regulated by intercellular and intracellular interactions within the bone marrow (BM) microenvironment. Through neurokinin-1 (NK-1) and NK-2 receptors, peptides (eg, substance P [SP]) encoded by the preprotachykinin-I gene mediate distinct hematopoietic effects. Cytokines, associated with hematopoietic stimulation, and SP regulate the expression of each other in BM mesenchymal and immune cells. Neutral endopeptidase (NEP) uses SP as a substrate to produce SP(1-4), which inhibits the proliferation of matured myeloid progenitor. This study determines whether the degradation of SP to SP(1-4) by endogenous NEP in BM stroma could be a feedback on hematopoietic stimulation by stem cell factor (SCF). SP(1-4) induced the production of transforming growth factor (TGF)-beta and tumor necrosis factor-alpha in BM stroma. TGF-beta production accounted for part of the inhibitory effects by SP(1-4) on the proliferation of early (granulocyte-macrophage colony-forming units) and late (long-term culture-initiating cells) hematopoietic progenitors. Enzyme-linked immunosorbent assays and/or protein-chip arrays indicated a timeline change of SP to SP(1-4) in BM stroma stimulated with SCF, which correlated with increase in NEP messenger RNA. Since SP and its fragment, SP(1-4), interact with the same receptor to mediate opposing hematopoietic effects, 2 interactive studies were done to understand the dual responses of NK-1: (1) a 3-dimensional molecular model of NK-1 and SP and (2) screening of a random dodecapeptide library for SP(1-4) interacting sites. The effects of SP(1-4) on hematopoietic progenitors and the timeline change of SP to SP(1-4), together with the 3-dimensional model, provide a partial explanation for the feedback on the stimulatory effects of SCF and SP on hematopoiesis.

Binding Sites↗
PubMed1999

Cloning and expression of bovine neutrophil beta-defensins. Biosynthetic profile during neutrophilic maturation and localization of mature peptide to novel cytoplasmic dense granules.

beta-Defensins are microbicidal peptides implicated in host defense functions of phagocytic leukocytes and certain surface epithelial cells. Here we investigated the genetic structures and cellular expression of BNBD-4, -12, and -13, three prototypic bovine neutrophil beta-defensins. Characterization of the corresponding cDNAs indicated that BNBD-4 (41 residues) derives from a 63-amino acid prepropeptide and that BNBD-12 (38 residues) and BNBD-13 (42 residues) derive from a common 60-amino acid precursor (BNBD-12/13). The peptides were found to be encoded by two-exon genes that are closely related to bovine epithelial beta-defensin genes. BNBD-4 and BNBD-12/13 mRNAs were most abundant in bone marrow, but were expressed differentially in certain non-myeloid tissues. In situ hybridization and immunohistochemical studies demonstrated that BNBD-4 synthesis is completed early in myelopoiesis. BNBD-12 was localized exclusively to the novel dense granules, organelles that also contain precursors of cathelicidins, antimicrobial peptides that undergo proteolytic processing during phagocytosis. In contrast to cathelicidins, Western blot analyses revealed that mature beta-defensins are the predominant organellar form in myeloid cells. Stimulation of neutrophils with phorbol myristate acetate induced secretion of BNBD-12, indicating that it is co-secreted with pro-cathelicidins. The exocytosis of BNBD-12 by activated neutrophils reveals different mobilization pathways for myeloid alpha- and beta-defensins.

Amino Acid Sequence↗
PubMed1997

Response of chronic hepatitis C to interferon-alpha treatment and relationship with iron metabolism.

AIM: to prospectively analyze the influence of iron metabolism of the response to interferon-alpha therapy in chronic hepatitis C. METHODS: ninety-two patients with chronic hepatitis C treated with recombinant alpha-interferon were included. Basal serum levels of iron, ferritin and transferrin saturation were compared in responding and nonresponding patients. Additional epidemiologic, histologic and biochemical variables were studied as predictors of response to interferon-alpha therapy. RESULTS: we studied 57 men (62%) and 35 women (35%) with a mean age of 40 years. Biopsy specimens were classified as having chronic active hepatitis (63%), chronic persistent hepatitis (33.8%) or cirrhosis (3.2%). The basal serum levels of iron and ferritin were significantly higher in non responders (126 +/- 9.1 mu/dL and 222.7 +/- 31.9 eta g/dL respectively; p < 0.05) than in responders (101 +/- 5.7 micrograms/dL and 136 +/- 24.1 eta g/dL). Mean transferrin saturation was also higher in nonresponders (29.7% +/- 2.7% vs 26% +/- 2.02%) although this difference was not significant. Younger age, absence of cirrhosis and parenteral transmission were associated with an improved response to interferon therapy. No relationship was found between the presence of iron in the hepatic parenchyma and response to interferon treatment. CONCLUSIONS: elevated serum levels of iron, ferritin, or both may be associated with a worse response to interferon-alpha therapy.

Adult↗
PubMed1989

Incertal projections from the brainstem and cerebellum: a horseradish peroxidase study in the cat.

This study, carried out in the cat, shows the input to the zona incerta (ZI) from the brainstem and cerebellum by means of a retrograde horseradish peroxidase technique. The largest contingent of afferents to the ZI comes from the superior and inferior colliculus, griseum centrale, formatio reticularis mesencephali and nuclei tractus mesencephalici of the nerve trigemini, cuneatus, dentatus and interpositus. Other nuclei such as ruber, lemnisci lateralis dorsalis, raphe magnus, sensorius superior of the nerve trigemini, vestibularis lateralis, reticularis lateralis and reticularis gigantocellularis send moderate projections to the ZI. In addition, a substantial number of brainstem nuclei reach the ZI, but weakly. These anatomical pathways suggest that the ZI might play a role in nociceptive, sensorial, motor, auditive, visual, ingestive and sleep-waking mechanisms.

Afferent Pathways↗
PubMedDate not supplied

Rapid orotracheal intubation in the clenched-jaw patient: a modification of the lightwand technique.

Emergency airway management of the patient with a clenched jaw can present a special challenge to the anesthesiologist. We describe four cases in which the patients had a clenched jaw and nasotracheal intubation was either contraindicated or several attempts had failed. All patients were successfully orotracheally intubated by a modification of the lightwand technique.

Adolescent↗