PubMed Health⌕ Search

Biomedical subjects

S Zúñiga

Publications and source records attributed to S Zúñiga.

17 recordsLinked to original sources
PubMed2005

Coronavirus reverse genetics and development of vectors for gene expression.

Knowledge of coronavirus replication, transcription, and virus-host interaction has been recently improved by engineering of coronavirus infectious cDNAs. With the transmissible gastroenteritis virus (TGEV) genome the efficient (>40 microg per 106 cells) and stable (>20 passages) expression of the foreign genes has been shown. Knowledge of the transcription mechanism in coronaviruses has been significantly increased, making possible the fine regulation of foreign gene expression. A new family of vectors based on single coronavirus genomes, in which essential genes have been deleted, has emerged including replication-competent, propagation-deficient vectors. Vector biosafety is being increased by relocating the RNA packaging signal to the position previously occupied by deleted essential genes, to prevent the rescue of fully competent viruses that might arise from recombination events with wild-type field coronaviruses. The large cloning capacity of coronaviruses (>5 kb) and the possibility of engineering the tissue and species tropism to target expression to different organs and animal species, including humans, has increased the potential of coronaviruses as vectors for vaccine development and, possibly, gene therapy.

Animals↗
PubMed2005

Retinoic acid increases tissue and plasma contents of nerve growth factor and prevents neuropathy in diabetic mice.

BACKGROUND: Decreased production of nerve growth factor (NGF) may contribute to diabetic neuropathy; however, exogenous administration of NGF induces only a modest benefit. Retinoic acid (RA) promotes the endogenous expression of nerve growth factor and its receptor. We studied the effects of RA on diabetic neuropathy in mice with streptozotocin-induced diabetes. MATERIAL AND METHODS: One hundred and twenty National Institutes of Health (NIH) albino mice randomly separated into three groups (A, n = 30; B, n = 30; C, n = 60). Diabetes mellitus was induced with streptozotocin in groups A and B. Animals from group A received a subcutaneous injection of 25 microl of mineral oil daily for 90 days, while those from group B received a subcutaneous injection of 20 mg kg(-1) of all trans RA. Animals from group C were taken as controls. At the end of the experiment, blood glucose and NGF levels (both in serum and sciatic nerve) were measured. Two behavioural tests were conducted in a blind fashion to detect abnormalities of thermal and nociceptive thresholds. RESULTS: Contents of NGF in healthy untreated mice were 1490 +/- 190 pg mg(-1) in nerve and 113 +/- 67 pg mg(-1) in serum; in diabetic untreated mice the values were 697 +/- 219 pg mL(-1) in nerve and 55 +/- 41 pg mL(-1) in serum; and in diabetic mice treated with RA the values were 2432 +/- 80 pg mL(-1) in nerve and 235 +/- 133 pg mg(-1) in serum (P < 0.002). Ultrastructural evidence of nerve regeneration and sensitivity tests improved in diabetic mice treated with RA as compared with nontreated diabetic mice. CONCLUSION: Our findings indicate that administration of RA increases serum and nerve contents of NGF in diabetic mice and suggest a potential therapeutic role for retinoic acid in diabetic patients.

Animals↗
PubMed2001

[Pediatric lung resection. A case series and evaluation of postoperative lung function].

The most common causes of pulmonary lobectomy in children are congenital lung malformations (CLM) and bronchiectasias. Our aim was to present the causes and clinical course and lung function of lobectomized patients. Between 1990 and July 1999 27 lobectomies were performed on patients whose ages ranged from newborn to 14 years. Lobectomies were performed to correct CLM in 124 cases and for acquired pulmonary disease (APD) in 13. Among CLM cases, half (n = 7) had cystic adenomatoid malformation. Among the APD patients, 10 had bronchiectasias, with etiological confirmation in 6 cases (3 secondary to serious adenovirus infection). Mean hospital stay was 4.6 days among those who experienced no postoperative complications. Symptoms resolved after surgery for most symptomatic patients. Lung function tests could be carried out with 8 patients over 6 years old whose operations had taken place 7 to 78 months earlier (x = 35 months) and whose age at the time of surgery was a mean 7 years 6 months (range 60 to 144 months). Spirometry showed normal forced vital capacity for 7 of 8 patients (87 to 143% of theoretical value). Arterial oxygen saturation measured during and after a 6-minute walking test was normal for 7 of 8 patients. Chest films showed reduced lung volume on the affected side in 5 of 8 patients. In summary, lobectomy is a procedure with few complications. It requires a short hospital stay and has good postoperative prognosis. Function and x-ray studies show adequate lung growth and development, with normal lung function in those who could be so examined because they were old enough to cooperate.

Adolescent↗
PubMed2000

[Medical-surgical experience of intestinal intussusception. Experience of a university institution].

BACKGROUND: Management of intestinal intussusception in children has evolved from exclusively surgical treatments to nonoperative reduction under fluoroscopic monitoring. AIM: To report a 10 year experience in a University Hospital in the management of intestinal intussusception. PATIENTS AND METHODS: Seventy two patients, aged 2 to 72 months of age, with an uncomplicated intussusception, that were treated by barium or air enema, were studied. RESULTS: The success rate was 73% with barium reductions, and 100% with air reductions. In 17 patients (24%), enema reduction was unsuccessful and were subjected to a surgical reduction. CONCLUSIONS: Nonsurgical reduction is safe and effective as the initial treatment of uncomplicated intussusception in children.

Air↗
PubMed2000

[Vegetal foreign body in the airway: an unusual cause of hemoptysis in childhood. Clinical case].

Hemoptysis is an infrequent symptom in childhood and potentially life threatening. The most common causes in this age group are bronchiectasis secondary to cystic fibrosis, cardiovascular and pulmonary congenital anomalies and a miscellaneous group of causes including retained intrabronchial aspirated foreign bodies. We report a previously healthy 5-year-old girl with recurrent pneumonias associated with episodes of hemoptysis. She was admitted in our institution to investigate the persistence of hemoptysis. Based on clinical history, aspiration of a vegetal foreign body was postulated as the etiology and it was confirmed in the pathological examination after surgical exploration, with pulmonary lobe resection. The importance of a good history taking in pediatric hemoptysis is emphasized.

Bronchi↗
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

Deletion of 24 open reading frames from chromosome XI from Saccharomyces cerevisiae and phenotypic analysis of the deletants.

As a part of the EUROFAN program, 24 open reading frames from Saccharomyces cerevisiae (YKR010c to YKR013w, YKR015c to YKR025w, YKR081c to YKR083c, YKR087c to YKR091w and YKR096w) were disrupted in two genetic backgrounds, FY1679 and W303. Systematic deletions and phenotypic analysis were performed following a hierarchical strategy, the so-called 'mass murder'. Of the 24 genes thus deleted, four are essential, whereas the deletion of 17 did not reveal any significant difference between the parental and mutant strains. Deletions of the remaining three show some growth phenotype; ykr024c mutants grow slowly under any conditions, ykr019c mutants grow slower in a rich medium and ykr082w mutants are temperature sensitive, being unable to germinate at 30 degrees C and above.

Base Sequence↗
PubMed1999

Disruption of six Saccharomyces cerevisiae novel genes and phenotypic analysis of the deletants.

As a part of the EUROFAN programme, six open reading frames from Saccharomyces cerevisiae (YNL083w, YNL086w, YNL087w, YNL097c, YDL100c and YOR086c) were disrupted in two genetic backgrounds, FY1679 and W303. Individual deletions in diploid strains and tetrad analysis of heterozygous deletants revealed that none of them is essential. Basic phenotypic analysis did not reveal any significant difference between the parental and mutant strains. Although YNL087w and YOR086c are 55% identical, the double disruptant also behaves the same as the parental cells. Ydl100p seems to be involved in metal detoxification, the phenotype of the null mutants being enhanced when the assays are performed at 37 degrees C.

Cloning, Molecular↗
PubMed1999

Simple intratesticular cysts in children: preoperative sonographic diagnosis and histological correlation.

BACKGROUND: Simple intratesticular cysts are rare in children and have been considered the most uncommon cause of scrotal cystic masses in this age group. The exact etiology of these lesions is still unclear. High-resolution ultrasonography has been proved to be a reliable and accurate imaging modality in the evaluation of scrotal abnormalities in children. PATIENTS AND METHODS: We report the sonographic findings in five boys aged from 4 to 10 months who presented with a scrotal mass and had a simple intratesticular cyst. Ultrasonography showed that all of them displayed a characteristic appearance and provided the necessary information to perform conservative surgery, with testicular preservation in four infants. In one infant, the cyst involved most of the testis, and an orchiectomy was performed. RESULTS: Pathological examination revealed a single smooth-walled cystic structure, with clear and serous fluid, lined with flattened epithelial cells in all of the infants. CONCLUSION: Our findings appear to support the hypothesis that these cysts could correspond to mesothelial inclusions. Sonographically, differential diagnosis should include mainly epidermoid cysts of the testis, which are mostly cystic but characteristically contain some echoes within them, in contrast to simple cysts and cysts of the tunica albuginea, which lie outside the testicular parenchyma.

Cysts↗
PubMed1997

[Hydrostatic reduction of intestinal intussusception in children. Experience in 43 cases].

BACKGROUND: Intestinal intussusception, a medical emergency, is more commonly idiopathic and ileocolic and occurs with higher frequency in children aged 6 months to 2 years. Barium enema confirms the diagnosis and allows its hydrostatic reduction, that is the treatment of choice of this condition. AIM: To report our experience with hydrostatic reduction of intestinal intussusception in children. PATIENTS AND METHODS: Hydrostatic reduction was attempted in 43 children with intestinal intussusception: 20 male, aged 2 to 48 months, that consulted at the Clinical Hospital of the Catholic University in Santiago. RESULTS: Hydrostatic reduction was successful in 33 children (77%) that were discharged from the hospital 24 to 96 hours after the procedure. A partial reduction was achieved in 10 patients (23%) who required surgery and were discharged from the hospital 5 to 8 days after the procedure. CONCLUSIONS: Our results are similar to those reported abroad and allow the recommendation of hydrostatic reduction as the treatment of choice for intestinal intussusception.

Barium Sulfate↗
PubMed1994

[Ultrasonography: the diagnostic method of choice in hypertrophic pyloric stenosis. Experience with 67 patients].

Hypertrophic pyloric stenosis (HPS) is a common medical emergency in newborns and lactating infants. Ultrasonography (US) is the diagnostic imaging procedure of choice in most centers, leaving the radiological study with barium for those cases in which US is negative and clinical symptoms persist or when other causes of vomiting must be discarded. We report our experience in 67 children (58 male) with suspected HPS. The US findings were consistent with HPS in 45 patients, and the diagnosis was surgically confirmed in all. In the remaining 22 patients with negative US findings, symptoms improved during follow up, with medical treatment. In one patient US was negative for HPS but showed an antral web, that was surgically confirmed. Since there were no false positive or negative results, the specificity and sensitivity of US for HPS diagnosis was 100%. We strongly recommend the use of US in patients with suspected HPS.

Female↗
PubMed1987

Rhabdomyosarcoma arising in a congenital giant nevus associated with neurocutaneous melanosis in a neonate.

The case of a newborn with a pedunculated embryonal rhabdomyosarcoma arising from a pigmented giant congenital nevus located on the posterior part of the neck and upper trunk is presented. The nevus was associated with melanosis of the leptomeninges and central nervous system. The pedunculated tumor was removed and the infant was given subsequent chemotherapy. In spite of well-tolerated chemotherapy, he died on the 30th day of life due to a staphylococcal pneumonia.

Central Nervous System Diseases↗
PubMedDate not supplied

[Ultrasonographic diagnosis of hypertrophic pyloric stenosis].

Hypertrophic pyloric stenosis (HPS) is one of the most common causes of abdominal surgery during the first weeks of life. The primary cause of the muscular hypertrophy is unknown and the pathogenesis is obscure. Clinically, vomiting is always present and sometimes there is a palpable pyloric mass (olive). Upper gastrointestinal tract study with barium has been the most usual method for the diagnosis. Since the first report of the use of ultrasound (US) in the diagnosis of HPS in 1977, this technique has been widely used and accepted, being by now, the diagnostic imaging examination of choice for infants in whom this abnormality is suspected. This is our experience with the use of US in 27 infants with clinically suspected HPS. In 17 cases there was US evidence of HPS and in 10 patients results were negative. We did not have false positive neither false negative results. We strongly recommend this diagnostic method for all infants under clinical suspicion of HPS.

Female↗