Biomedical subjects

H Navarro

Publications and source records attributed to H Navarro.

At least 19 recordsLinked to original sources

PubMed2006

Endoscopic release of limb constriction rings in utero.

Amniotic band syndrome is a sporadic condition that may result in constriction bands, amputation and multiple craniofacial, visceral and body wall defects. It occurs in 1/1,200 to 1/15,000 live births. Most cases present with multiple congenital anomalies that are incompatible with life. A small group of fetuses shows isolated limb constrictions that may cause severe limb dysfunction or limb amputation if left untreated. Successful in utero surgical lyses of constriction rings have been reported. We report a case of constriction amniotic bands involving both legs and compromising blood flow to the distal extremity. The constriction ring was successfully released by a minimally invasive endoscopic surgical technique avoiding severe limb dysfunction or foot amputation.

Amniotic Band Syndrome↗

PubMed2001

Early risk factors for sepsis in patients with severe blunt trauma.

We studied 43 patients with blunt trauma (injury severity score, > or =25), age >14 years and length of the intensive care unit (ICU) stay >48 h in order to estimate the frequency of sepsis and to identify early risk factors related to its development. Clinical data were collected during the first 24 h and several inflammatory mediators were determined from serum samples of the first 2 days after injury.Twenty-one patients (48.8%) met sepsis criteria during their ICU stay, 9 (20.9%) fulfilled only criteria for sepsis; 6 (13.9%) fulfilled criteria for severe sepsis and another 6 (13.9%) criteria for septic shock. An APACHE II score > or =14, the presence of hypovolemic shock, the need for three or more units of blood to be transfused and the administration of a total volume of fluids > or =10 l were all factors associated significantly with the development of sepsis. In the multivariant analysis, the need for a total volume of fluids > or =10 l was the only independent risk factor (adjusted odds ratio=10.49, 95% CI, 2.34-47.02; P=0.002). No significant differences were documented in relation to the behaviour of the serum markers.

Adult↗

PubMed2001

[C reactive protein as marker of infection among patients with severe closed trauma].

BACKGROUND: Injury and infection are characterized by the activation of the acute phase proteins response. C-reactive protein (CRP), an acute phase protein, has been mentioned as an useful indicator of infection and sepsis in critically ill patients. OBJECTIVE: To study the evolution of serum CRP in patients with severe blunt trauma and to ascertain its ability as a biological marker of infection during the first seven days after injury. METHODS: We prospectively studied 54 patients with blunt trauma (injury severity score>=16) age>14 years and length of the Intensive Care Unit (ICU) estay>= 7 days, over a 4-month period. Culture-proven infections were collected and serum CRP was determinated every day, during the first week after ICU admission. RESULTS: Twenty-eight patients (51.8%) developed an infection during the first week, and the median day of diagnosis of infection was day 6. Pneumonia was the most common infection (50%) and Gram-negative bacilli (63.3%) were the most common microorganisms recovered. Serum CRP levels were significantly higher in the infected patients group after day 4, showing a median value higher than 170 mg/l. Based on the receiver operating characteristic (ROC) curve analysis, a cutoff value of 109.5 mg/l for CRP gives a sensitivity of 78.6% and a specifity of 73.1% in predicting the presence of infection. CONCLUSIONS: The course of serum CRP levels is different in the group of patients with severe blunt trauma and infection, compared with the non-infected group during the first week after injury and it could be an useful supplementary marker for infection after postinjury day 4. A value of 110 mg/l or higher for CRP should suggest an underlying infectious complication.

Acute-Phase Reaction↗

PubMed2001

[Identification of mutation in the gene cystic fibrosis transmembrane regulator (CFTR) in Chilean patients with cystic fibrosis].

BACKGROUND: Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the CFTR gene, that codes for a chloride channel located in the apical surface of epithelial cells. The main role of this protein is the regulation of chloride transport, and secondarily, of sodium and water to the extracellular space. More than 900 gene mutations have been described, and their relative frequency in different populations depends on their ethnic origin. AIM: To report the findings of Chilean patients with cystic fibrosis, in whom the presence of 20 common mutations was analyzed. PATIENTS AND METHODS: Fifty seven patients with established diagnosis or suspicion of CF were studied. The simultaneous identification of 20 mutations and the normal delta F508 allele was done using polymerase chain reactions with a commercial assay. RESULTS: Eight mutations were found. Fifty patients fulfilled diagnostic criteria proposed by the Consensus Panel of the CF Foundation and 66% of alleles were identified in this group. delta F508 mutation was found in 45%. We did not identify mutations in any of the remaining 7 patients. CONCLUSIONS: Our results suggest that the majority of undetected mutations are associated with atypical phenotypes or that some patients in this series could have other diseases. We recommend to include mutation analysis in the evaluation of Chilean patients with CF. It is useful to establish prognosis and genetic counselling.

Adolescent↗

PubMed2001

[Pleural effusion and complicated empyema in children. Evolution and prognostic factors].

BACKGROUND: Complicated pleural empyema has a torpid and longer clinical evolution, requiring in some patients surgical management. The predictive factors for surgical treatment are not well known. AIM: To search for clinical, laboratory or radiological predictors for the requirement of surgical treatment in pediatric patients with empyema. PATIENTS AND METHODS: A retrospective review of the charts of 108 patients hospitalized for pneumonia plus pleural effusion at the Pediatric Service of the Catholic University Hospital between January 1985 and July 2000. RESULTS: Eighty one patients had complete radiological evaluation and pleural fluid biochemical analysis. Forty nine (60%) fulfilled the criteria for empyema and 32 (40%) for an exudate. Thirteen patients with empyema required surgery and 36 were treated medically. The mean age was 3 years (range 9 months-6 years) for the surgically treated and 4 years (range 12 months-14 years) for the non-surgical group. The male/female ratio was 5:1 in the surgical group and 1:1 for the non-surgical group. Pleural fluid cultures were positive in 21 of 79 patients. Streptococcus pneumonia was the most frequently isolated agent. No significant differences were found between groups for the average days of fever prior to the diagnosis or total days of fever, days of hospital stay, pleural fluid pH (6.8 and 7.0 respectively) and glucose (21 and 31 mg/dl respectively). No differences were either observed for pleural fluid risk factors (pH < 7 and glucose < 20 mgdl), the presence of extensive pleural effusions, pleural loculations or bands on pleural ultrasonography and positive Gram stain or cultures in the pleural fluid. Surgical patients required oxygen for more days than medical patients (7.7 and 5.1 days; p = 0.037). CONCLUSIONS: This study failed to find predictive clinical, radiological or pleural fluid parameters, for the requirement of surgical treatment of empyema.

Adolescent↗

PubMed2000

New bioactive aromatic compounds from Vismia guianensis.

Five benzophenones, vismiaguianones A-E, and two benzocoumarins, vismiaguianins A and B were isolated from the CHCl3 extract of the roots of Vismia guianensis by bioassay-directed fractionation using the DNA strand-scission assay and KB cell line. Of the isolates obtained, vismiaguianone B exhibited DNA strand-scission activity, whereas vismiaguianones D and E and vismiaguianin A were found to be significantly cytotoxic.

Antineoplastic Agents, Phytogenic↗

PubMed2000

[Clinical experience in home care of children with tracheostomy].

BACKGROUND: Home care of tracheostomized children is considered a safe and low-cost alternative. AIM: To report the experience with tracheostomized children at the Pediatric Respiratory Unit of the Catholic University Hospital. PATIENTS AND METHODS: The records of 16 children (9 male) with tracheostomy (TQ) in home care between 1992 and 1998 were reviewed. RESULTS: The average age at the moment of TQ was 9 months (range 1-30 months) and the postoperative hospital management period was 5 months (range 1-11 months). The average age at discharge was 13 months (range 3 to 30 months). Surgical indication were upper airway obstruction (congenital or acquired subglottic stenosis in three, upper airway malformations in one, vocal cord palsy in one and tracheobronchomalacia in one) and chronic assisted ventilation (severe tracheobronchomalacia in four, pulmonary hypoplasia in two, myopathy in one, central nervous injury in one and bronchopulmonary dysplasia in one). Overall rate complications were 2 per 100 tracheostomy months during home care and 8 per 100 tracheostomy months during hospital care. No tracheostomy-related deaths were observed. A parenteral education program to teach about tracheostomy management and cardiopulmonary resuscitation was carried out. CONCLUSIONS: Tracheostomized children can be safely managed at home.

Child Health Services↗

PubMed1999

Cytotoxic constituents from the roots of Tovomita brevistaminea.

Two known xanthones, trapezifolixanthone and manglexanthone were isolated as cytotoxic constituents from the CHCl3 extract of the roots of Tovomita brevistaminea by bioassay-guided fractionation using the KB cell line. In addition, a new compound, tovophenone C, and two known compounds, tovophenones A and B which are benzophenones, were found to be inactive constituents in this investigation. The structure of the new isolate was determined by detailed analysis of spectroscopic parameters including its 1D and 2D NMR spectroscopy data.

Antineoplastic Agents, Phytogenic↗

PubMed1999

New biphenyl compounds with DNA strand-scission activity from Clusia paralicola.

Three new biphenyl derivatives, clusiparalicolines A (1), B (2), and C (3), were isolated from the roots of Clusia paralicola by bioassay-directed fractionation using the DNA strand-scission and the KB human cancer cell line cytotoxicity assays. Compounds 1 and 2 were found to be active in the DNA strand-scission assay, whereas all three compounds exhibited modest cytotoxicity against the KB cell line. The structures of 1-3 were elucidated by spectroscopic methods including 1D and 2D NMR techniques.

Antineoplastic Agents, Phytogenic↗

PubMed1999

[Primary ciliary dyskinesia. Experience in 6 patients].

BACKGROUND: Primary ciliary dyskinesia is characterized by a congenital alteration of the ciliary ultrastructure and function. As a consequence, their respiratory tract sweeping action is lost and recurrent respiratory infections ensue. AIM: To analyze a clinical series of patients with primary ciliary dyskinesia, their clinical and laboratory features. PATIENTS AND METHODS: A retrospective review of patients with primary ciliary dyskinesia seen a University Hospital, between 1994 and 1998. Bronchial biopsies were obtained with 3.6 mm diameter Olympus fibrobronchoscope, using a cayman type forceps. Ultrastructural alterations of respiratory tract ciliated cells were recorded. RESULTS: Six patients (four male) aged 9 months to 13 years old were reviewed. Three patients had situs inversus. All had repeated bouts of obstructive bronchitis and pneumonia, five had sinusitis, four atelectasis, three recurrent otitis and three had bronchiectasis. Cystic fibrosis and immunological alterations were ruled out in five children. Ultrastructural analysis revealed absence of dynein arms in three cases, absence of the internal dynein arm in one, additional peripheral microtubules and absence of dynein arms in one case. CONCLUSIONS: Primary ciliary dyskinesia must be considered in the differential diagnosis of recurrent respiratory infections. Ultrastructural analysis of ciliary structure can be done in bronchial biopsies obtained through bronchoscopy.

Adolescent↗

PubMed1998

Molecular features associated with polyamine modulation of NMDA receptors.

The effect of 1,3-diamines on basal and spermine-stimulated [3H]MK-801 binding was investigated. Systematic variations in the molecular parameters revealed that, in general, lipophilic 1,3-diamines inhibited and hydrophilic 1,3-diamines enhanced [3H]MK-801 binding in the nominal absence of glutamate and glycine. Furthermore, 1,3-diamines which were highly monoprotonated at physiologic pH were more effective in modulating basal binding (at 100 microM 1,3-diamine) than analogues which were mostly diprotonated or unprotonated. Finally, the internuclear distance between the amino nitrogens and the extent of modulation of basal [3H]MK-801 binding were correlated. Similar, but more modest, effects were seen for spermine-enhanced [3H]MK-801 binding. These results are consistent with the existence of two polyamine binding sites associated with the NMDA receptor complex. One of the sites appears to preferentially recognize lipophilic substances while the other favors hydrophilic materials. Both sites appear to recognize polyamines with at least one charged (protonated) amino group and one uncharged amino group. The distance between amino groups is a determining factor as well.

Animals↗

PubMed1998

New compounds with DNA strand-scission activity from the combined leaf and stem of Uvaria hamiltonii.

Two flavanones, hamiltones A (1) and B (2), an aurone, hamiltrone (3), a chalcone, hamilcone (4), and a tetrahydroxanthene, hamilxanthene (5), were isolated from Uvaria hamiltonii extracts guided initially by fractionation based on DNA strand-scission and/or 9KB cytotoxicity assays. Compounds 2-5 have not been reported previously, while 1 is new as a natural product. Structural assignments were made based on extensive spectroscopic measurements. Compounds 1-3 were inactive in the 9KB cytotoxicity assay, with compounds 4 and 5 having weak activity. In the DNA strand-scission assay, 3 was the most active compound found in the DNA strand-scission assay, being 10 times more potent than 1 or 2. Compound 4 was only weakly active, and 5 was inactive.

Antineoplastic Agents, Phytogenic↗

PubMed1998

Effect of L-aspartate on the ventilatory response to hypoxia in sedated newborn piglets.

L-aspartate (L-ASP) acts as an excitatory amino acid neurotransmitter at the synapses of brain stem respiratory neurons. In order to determine the effect of L-ASP on the neonatal ventilatory response to hypoxia, 9 control piglets [age 4.3 +/- (SD) 0.9 days, weight 1.9 +/- 0.5 kg] and 9 L-ASP-treated animals [age 5.0 +/- (SD) 1.4 days, weight 2.1 +/- 0.7 kg] were studied. Minute ventilation, oxygen consumption, arterial blood pressure, and blood gases were measured in sedated piglets while spontaneously breathing room air and during 1, 5, and 10 min of hypoxia (O2 concentration in inspired gas 0.10). Measurements were obtained before and 60 min after the administration of L-ASP (580 mg/kg i.v. over 1 h) or 5% dextrose solution. In the control animals, the ventilatory response to hypoxia was similar before and after dextrose infusion. In contrast, a significant and sustained increase in ventilation was observed at 1, 5, and 10 min of hypoxia after the administration of L-ASP. Changes in oxygen consumption, heart rate, arterial blood pressure, pH, and arterial O2 tension with hypoxia were similar before and after the L-ASP infusion, while the arterial CO2 tension decreased significantly during hypoxia after the administration of L-ASP. These data suggest that the excitatory amino acid L-ASP is an important mediator of the hypoxic hyperventilation in the neonate. We speculate that the administration of exogenous L-ASP modifies the balance of central nervous system neurotransmitters during hypoxia, resulting in predominance of excitatory neurotransmission.

Anesthesia↗

PubMed1996

Study of the action of intramuscularly administered erythromycin on the L-threonine transport and the digestive enzymatic activity in rabbit jejunum.

Erythromycin has been shown to inhibit the intestinal transport of L-threonine and D-galactose in strips of mucosal jejunum when it was directly added to the incubation medium. Nevertheless, the effect of erythromycin administered therapeutically by intramuscular injection on both the intestinal absorption of nutrients and the intestinal digestive activity, remains unknown. The results obtained show that, firstly, the intestinal absorption of L-threonine is inhibited in animals treated with erythromycin. The kinetic study shows that the effect seems to be mainly due to an alteration of the affinity apparent constant (Kt) of the Na(+)-dependent system of transport located in the mucosal border. However, the Na(+)-dependent L-threonine transport in BBMV was not altered by the treatment with erythromycin. The (Na(+)-K+) ATPase activity in BLMV from treated jejunum was 40% of the activity in control BLMV. Secondly, the treatment with erythromycin did not modify the digestive enzymatic activity of sucrase and aminopeptidase N.

Aminopeptidases↗

PubMed1996

Effects of chloral hydrate on the cardiorespiratory response to hypoxia in newborn piglets.

To assess the effects of chloral hydrate (CH) on the cardiorespiratory response to hypoxia in the neonate, 17 newborn piglets were chronically instrumented 48-72 h before study and randomly assigned to a CH group (100 mg/kg, i.p.) or saline group. The animals were intubated and studied under quiet sleep which was determined by behavioral states, and continuous electro-oculographic and electroencephalographic monitoring. Minute ventilation (VE), tidal volume, respiratory rate, arterial blood gases (ABG), oxygen consumption (VO2), arterial blood pressure (ABP) and heart rate (HR) were measured before and after CH or saline administration during room air and after 10 min of hypoxia (fraction of inspired oxygen concentration = 0.10). Cardiorespiratory response to hypoxia was similar before and after saline infusion. Basal VE and the ventilatory response to hypoxia were similar before and after CH administration. In contrast, the basal ABP decreased significantly (p < 0.05) after CH administration, but the ABP response to hypoxia was similar before and after CH. A significant increase in both basal HR and HR with hypoxia was observed after CH administration. In addition, VO2 and ABG were not modified by CH treatment during normoxia and hypoxia. These data demonstrate that a sedative dose of CH does not significantly modify the ventilatory response to hypoxia in newborn piglets. However, CH produced some changes in the cardiovascular system which should be considered when using it in infants with hemodynamic derangements.

Animals↗

PubMed1995

Effect of motilin on the L-leucine transport in rabbit jejunum.

Motilin is a gastrointestinal peptide that stimulates the gastrointestinal motility in several species. The aim of the present work has been to determine the effect of motilin on the L-leucine absorption in rabbit jejunum. The results show that motilin inhibits the L-leucine Na(+)-dependent system of transport located in the mucosal border mainly by diminishing the apparent Vmax. Motilin did not directly affect the Na(+)-dependent system of transport, but it seems to act across the protein kinase C (PKC). These results suggest that motilin may act as a regulatory hormone of the intestinal absorption of nutrients.

Animals↗

PubMed1994

[Flocculation of NPH insulin].

In the past decade, human insulins have been substituting animal insulins, offering the advantage of its lesser antigenic capacity. One of the most clinically important problems with human NPH insulins is its tendency to flocculate. We present four diabetic patients who, after using flocculated human NPH insulin, encountered a deterioration in the metabolic control of their diabetes, and in two of them, there were bouts of diabetic Ketoacidosis "without any other apparent causal factors". Among those causes favoring flocculation are movement during transport, high temperatures, and probably leaving the vial open for an excessively long period of time, as with the extraction of multiple doses. Physicians, educators, diabetics, and their relatives should be informed of this phenomenon. Diabetics, especially those who carry insulin with them, should carefully inspect their vials before each injection to detect signs of flocculation.

Adult↗

PubMed1993

Nicarbazin stimulates intestinal transport of L-leucine in rabbit.

Nicarbazin is an anticoccidial drug used mainly in birds, but also in rabbits. Besides the anticoccidial activity, nicarbazin has shown several other effects such as inhibition of growth and feed efficiency in poultries, and stimulation of sugar intestinal absorption in rabbits. The present work has been performed in order to check whether nicarbazin also affects L-leucine intestinal absorption. The results obtained show that nicarbazin decreases L-leucine accumulation in the jejunal tissue, and increases mucosal to serosal transepithelial fluxes of this amino acid in a dose-dependent way, without modifying its diffusion across the intestinal epithelium. The drug stimulates the amino acid uptake in brush-border and basolateral membrane vesicles, thus suggesting that nicarbazin increases the absorption of L-leucine mediated by carriers.

Animals↗