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S Rivas

Publications and source records attributed to S Rivas.

At least 37 records · Page 2Linked to original sources
PubMed2002

[Integra Artificial dermis in pediatric reconstructive surgery].

UNLABELLED: The recent release of artificial dermis for general use, has open wide a new field in pediatric reconstructive surgery. The aim of this paper is to analyze the results of Integra artificial dermis in our Plastic Surgery Department. MATERIALS AND METHODS: The records of the patients treated with Integra between february 1999 and january 2001 were analyzed, focusing on the indications, the complications and the final results. RESULTS: Fourteen Integra implantation procedures in 11 patients aged 16 months to 12 years (mean +/- SD: 80.9 +/- 48.5 months) were performed. Indications were: acute burns in 5 cases, burns sequelae in 5, and partial extirpation of a congenital giant nevus in the last one. Integra was used to replace between 2 and 30% of total body surface area. The percentage of "take" of skin grafts was 85%. The most frequent early complication was the development of infection under the Integra; it occurred in 2 cases and artificial dermis had to be partially removed. Hypertrophic scars developed in 2 patients; both had refused pressure garments. Cosmetic results in the remaining 9 patients are considered excellent. CONCLUSIONS: The use of artificial dermis has settled as a new procedure in plastic pediatric surgery. In spite of possible complications, the easy manipulation and the good results make Integra a perfect skin substitute in several cutaneous disorders.

Biocompatible Materials↗
PubMed2002

[Decrease in bacterial translocation in burned children treated with controlled nutritional support].

INTRODUCTION: Alteration in epithelial enteric cells are the main cause of bacteria translocation and local and systemic infections. Our aim is to evaluate these infections in burned children treated with enteral nutrition and compare the results with our previous observations. Material and methods. We designed a prospective study including 50 patients (0-14 years) with TBSA > 10% (total body surface area). Bacteriological cultures were performed at their admittance and weekly until the discharge. Nutritional necessities were evaluated using calorimetry. Nutritional support was supplied by nasoduodenal tube at continuous rates. RESULTS: Three (6%) patients with enteral nutrition (Group 1) showed positive blood cultures (two of them by enteric bacteriae). 14 patients (28%) showed local infections (five by enterococci). We performed a retrospective study in a homogenous group of 44 patients (Group 2), previously treated in our Department without controlling nutrition. We found five (11.3%) positive blood cultures (four by enteric bacteriae) and 22 (50%) local infections (eleven by enteric bacteriae). The improvement of systemic and local infection rates and the decrease in infections caused by enteric bacteriae were statistically significative (p < 0.05). CONCLUSIONS: A controlled nutritional support is a main cause of the improvement in infection rates and decrease in bacterial translocation in pediatric burned patients.

Adolescent↗
PubMed2001

No evidence for binding between resistance gene product Cf-9 of tomato and avirulence gene product AVR9 of Cladosporium fulvum.

The gene-for-gene model postulates that for every gene determining resistance in the host plant, there is a corresponding gene conditioning avirulence in the pathogen. On the basis of this relationship, products of resistance (R) genes and matching avirulence (Avr) genes are predicted to interact. Here, we report on binding studies between the R gene product Cf-9 of tomato and the Avr gene product AVR9 of the pathogenic fungus Cladosporium fulvum. Because a high-affinity binding site (HABS) for AVR9 is present in tomato lines, with or without the Cf-9 resistance gene, as well as in other solanaceous plants, the Cf-9 protein was produced in COS and insect cells in order to perform binding studies in the absence of the HABS. Binding studies with radio-labeled AVR9 were performed with Cf-9-producing COS and insect cells and with membrane preparations of such cells. Furthermore, the Cf-9 gene was introduced in tobacco, which is known to be able to produce a functional Cf-9 protein. Binding of AVR9 to Cf-9 protein produced in tobacco was studied employing surface plasmon resonance and surface-enhanced laser desorption and ionization. Specific binding between Cf-9 and AVR9 was not detected with any of the procedures. The implications of this observation are discussed.

Animals↗
PubMed2000

Synovectomy with rifampicine in haemophilic haemarthrosis.

The purpose of this paper was to assess the effectiveness of intra-articular injected rifampicine in haemophilic patients in order to achieve synovectomy by preventing repeated intra-articular bleeding. We have used this technique in haemophilic patients previously and reported our results on 13 cases [1]. Two hundred and fifty milligrams of rifampicine was injected into the elbow and ankle joints and 500 mg was injected into knee joints with 3-10 mL of lidocaine, depending on the joint size. The injections were repeated once a week for 7 weeks. Patients were only covered with antihaemophilic factor on the day of the injection at 30% above their coagulation level. We evaluated the results using two measures: subjective reports from the patient and objective assessment by the examiner. In the subjective reports the patient graded the results from their own perspective from 1 (poor) to 10 (excellent): 1-3, poor; 4-6, fair; 7-8, good; and 9-10, excellent. In the objective reports the grading was: excellent ('dry joint', full function, no haemarthrosis, no synovitis); good (clinical improvement, synovitis, reduction of haemarthroses, full function); fair synovitis (reduction of haemarthroses, no change in function); poor synovitis (persistent haemarthroses). This paper reports on the results of 38 patients with 39 joints with more that 3 years follow up, mean 1.8 years. There were 22 knees, nine elbows and eight ankles. Subjectively, there were excellent results in 21 joints (11 knees, six elbows and four ankles) good results in 15 joints (eight knees, three elbows and four ankles), fair results in two knees and a poor result in one knee. Objectively, results obtained were excellent in 20 joints (11 knees, six elbows and three ankles); good in 17 (nine knees, three elbows and five ankles); fair in one knee and poor in one knee.

Adolescent↗
PubMed2000

Functional, c-myc-tagged Cf-9 resistance gene products are plasma-membrane localized and glycosylated.

The Cf-9 resistance gene from tomato confers resistance to races of the fungal pathogen Cladosporium fulvum that express the corresponding avirulence gene, Avr9. Avr9 encodes a secreted peptide. To investigate Cf-9 function, we tagged the Cf-9 protein with a triple myc epitope at either the amino- or carboxy-terminus of the mature protein. Tobacco plants carrying these constructs activate a defence response to Avr9 peptide. The Cf-9 sequence predicts a protein of 94 kDa, with 22 glycosylation sites. Using c-myc antibodies, c-myc : Cf-9 protein was detected as a unique band with a molecular size of 160 kDa. The band shifted to approximately 105 kDa after glucosidase treatment, indicating that Cf-9 protein is highly glycosylated. Plasma membranes were isolated using two-phase partitioning, and c-myc : Cf-9 was enriched in these fractions, indicating that Cf-9 is a plasma membrane protein. This was confirmed by silver-enhanced immunogold labelling of tobacco protoplasts carrying the amino-terminal c-myc tag; a higher labelling density was observed on the surface of protoplasts derived from c-myc : Cf-9 tobacco compared to untransformed control. The presence of Cf-9 in the plasma membrane is consistent with its role in conferring recognition of the extracellular Avr9 peptide.

Alleles↗
PubMed1998

Congenital deficiency of the tibia: a report on 22 cases.

Congenital deficiency of the tibia (tibial hemimelia, aplasia, or dysplasia) is very rare, with an incidence of approximately 1 per 1 million live births. The disorder usually is accompanied by other congenital anomalies on the same limb or other parts of the body. A report is made of 22 limbs observed in 18 patients from 1970 to 1987 at San Juan de Dios Hospital in Caracas, Venezuela, with more than a 5-year follow-up. The report includes 11 girls and 7 boys, with observations of 11 left and 11 right tibiae. Familial antecedents were present in four patients: brother and sister and two brothers. According to the classification by Jones, Barnes, and Lloyd-Roberts, there were nine cases of type Ia, four of type Ib, three of type II, two of type III, and four of type IV. The foot of the affected limb was normal in only 12 cases. Treatment, always surgical, consisted of T/K amputation in 10 cases of types Ia and Ib, fibula pro tibia and B/K amputation in 1 case of type II, Syme amputations in 2 cases of type III, and astragalectomy and closure of diastasis in 4 cases of type IV deformity. Patients in five cases refused treatment. The sooner the amputation is performed, the easier and faster the rehabilitation and adaptation to the prosthesis. An early amputation is accepted by the child as a "congenital amputation."

Abnormalities, Multiple↗
PubMed1997

TrwD, a protein encoded by the IncW plasmid R388, displays an ATP hydrolase activity essential for bacterial conjugation.

A 1.7-kilobase pair segment from the conjugative transfer region of plasmid R388 DNA was cloned and sequenced. It contained trwD, a gene essential for plasmid R388 conjugation, for expression of the conjugative W-pilus and for sensitivity to phage PRD1. The deduced amino acid sequence of TrwD showed homology to the PulE/VirB11 superfamily of potential ATPases involved in various types of transport processes. A fusion of trwD with the glutathione S-transferase (GST) was constructed, and the resulting fusion protein was purified from overproducing bacteria. Factor Xa hydrolysis of GST-TrwD and further purification rendered TrwD protein with more than 95% purity. Antibodies raised against TrwD localized it both in the soluble fraction and in the outer membrane of Escherichia coli. TrwD is probably a peripheral outer membrane protein because it could be solubilized by increasing salt concentration to 0.5 M NaCl in the lysis buffer. Both purified GST-TrwD and TrwD could hydrolize ATP. ATPase activity increased 2-fold in the presence of detergent-phospholipid mixed micelles. To study the importance of the nucleotide-binding site, Walker box A (GXXGXGK(T/S)), present in TrwD, the conserved lysine residue was replaced by glutamine. The mutant protein, expressed and purified under the same conditions as the wild type, did not exhibit ATPase activity. TrwD(K203Q) was not able to complement the mutation in trwD of the R388 mutant plasmid, suggesting the essentiality of the ATPase activity of the protein in the conjugative process. Furthermore, the dominant character of this mutation suggested that GST-TrwD(K432Q) was still able to interact either with itself or with other component(s) of the conjugative machinery.

Adenosine Triphosphatases↗
PubMed1996

Radioactive synoviorthesis in hemophilic hemarthrosis: materials, techniques, and dangers.

Radioactive synoviorthesis with 198Au, 90Y, 186Re, and 31P would seem to be the treatment of choice for recurrent hemarthroses in hemophilia. The clinical results, obtained by different centers, show a definite diminution of hemarthroses in 88% of cases. The advantages of radioactive synoviorthesis compared with surgical synovectomy are: better results, the requirement of substantially reduced antihemophilic factor, the possibility of performing the procedure on multiple cases concurrently on an ambulatory basis, no interference with articular range of movement, and the low cost of the procedure. In cases of failure, the procedure can be repeated after 6 months, and on as many as 3 occasions. Studies performed on the chromosomal changes that could be attributed to the radioactive material show the disappearance of these alterations a few years after treatment. No physical changes have been found that could be attributed to cytogenic alteration (hematologic or other) in any reported patients.

Adolescent↗
PubMed1994

An intrinsic-tryptophan-fluorescence study of phage phi 29 connector/nucleic acid interactions.

The protein p10 of bacteriophage phi 29 assembled into connectors exhibit an intrinsic fluorescence with an emission peak centered at 335 nm, which suggests a hydrophobic environment of the three tryptohan residues that the protein contains. Upon incubation with linear DNA (but not with circular DNA), a decrease in the connector intrinsic fluorescence is measured which does not show any sequence specificity. The decrease in fluorescence is not observed when DNA is incubated with proteolyzed connectors, which lack the DNA-binding domain, suggesting that the fluorescence quenching is related to the binding of DNA to the phi 29 connectors. Acrylamide quenching studies reveal a higher accessibility of tryptophan residues to the quencher when the connector is bound to DNA. Protein denaturation by guanidine hydrochloride occurs at lower denaturant concentrations in the presence of linear DNA (but not circular DNA) than in its absence, suggesting a conformational change of phi 29 connector upon binding to linear DNA. This hypothesis is supported by the fact that the proteolyzed connectors, which do not bind DNA, are denatured at the same denaturant concentration, regardless of the presence of DNA. phi 29 connectors also bind RNA, but this interaction does not exert any effect on acrylamide quenching or guanidine hydrochloride denaturation. This result, together with that showing that proteolyzed connectors are able to interact with RNA, reinforces the idea that phi 29 connectors have two independent domains for interaction with DNA and RNA.

Bacillus Phages↗
PubMed1994

Reversal of extinction by scopolamine.

The aim of this experiment was to determine the effects of muscarinic blockade on extinction of passive avoidance conditioning. Rats were trained with a foot shock of 2.5, 3.0, or 6.0 mA and were tested for retention for 8 weeks (once weekly). Five minutes before the seventh test they were injected with 8 mg/kg scopolamine. The groups that had been trained with 2.5 and 3.0 mA showed extinction, which was reversed by the scopolamine; the overreinforced group (6.0 mA) did not show extinction and the scopolamine did not alter the conditioned response. The data support the hypothesis that extinction represents the learning of a new response sustained by a set of cholinergic neurons, different from that which mediated original passive avoidance learning.

Acetylcholine↗
PubMed1993

Congenital absence of the radius.

Between 1971 and 1987, we treated 26 patients with congenital absence of the radius which had produced a club hand; 37 hands were affected. Treatment before the age of 8 months was by gentle manipulation and serial plasters. If a functional position was not obtained, and in patients over 8 months, surgical reduction was carried out. A modified Riordan procedure was used until 1983, and thereafter a double Z-plasty. The best results were achieved in patients under 4 years of age.

Child, Preschool↗
PubMed1990

Achilles tendinitis in ballet dancers.

Overuse injuries of tendons are known to occur in persons whose activities submit the tendon to excessive stress. Classical ballet dancers performing en pointe, demie point, or plié exert forces that, although normal in magnitude, are increased in frequency, thus overusing the Achilles tendon. In the present study all cases of Achilles tendinopathy seen in a period of three years in three ballet companies were reviewed by a special orthopedic clinic. The cause, whether by abnormal tension or incorrect use, development, and progression to chronic tendinopathy, as well as measures to prevent it, were analyzed in 19 cases. The methods of treatment, including conservative treatment with rest and refraining from dancing, local treatment such as ice and adhesive strapping, antiinflammatory drugs, local injections, thermotherapy, and laser therapy, were compared, and the time of recovery and ability to resume dancing were evaluated. Two cases required surgical treatment to subside, and the patients had to retire from professional dancing. The roentgenographic diagnosis of stage and progression of the tendinopathy is emphasized as a valuable accessory sign. The similarity in lesions between Achilles and patellar tendon problems was observed and confirmed.

Achilles Tendon↗
PubMed1987

Jejunal malignant lymphoma in a patient with adult-onset hypo-gamma-globulinemia and nodular lymphoid hyperplasia of the small bowel.

A malignant lymphoma of the small bowel developed in a 55-yr-old woman who had intestinal malabsorption for 20 yr, late-onset hypo-gamma-globulinemia, and nodular lymphoid hyperplasia. The tumor arose in the first jejunal loop and appeared to be of B-immunoblastic type (diffuse large noncleaved cells). This case indicates that nodular lymphoid hyperplasia in the context of immunodeficiency may be a condition leading to lymphoid malignancy.

Agammaglobulinemia↗
PubMed1986

Prostaglandin E1 (PGE1) stimulates in vitro renin release in the hibernating ground squirrel.

Using a renal cortical slice preparation obtained from hibernating ground squirrels, this study investigated whether three major intrarenal prostaglandins (PG) and other agents added at a 10(-5) M dose can affect renin release (RR), and if their effect on RR is correlated with changes in tissue cyclic AMP content (tcAMPc). Resting in vitro levels for RR and tcAMPc during hibernation were found to be comparable to those observed in non-hibernating (NH) mammals. Addition of PGE1 significantly stimulated RR while PGE2 and PGF2-alpha were ineffective. None of the three PG's tested altered resting levels of tcAMPC. When added by itself or in conjunction with any of the three PG's, the phosphodiesterase inhibitor theophylline did not modify resting levels of RR and tcAMPc, but it prevented the previous stimulatory effect of PGE1 alone on RR. Addition of lipid-soluble dcAMP, either alone or in conjunction with any of the three PG's, resulted in an increase in tcAMPc in all instances, no change in resting RR regarding PGE2 and PGF2-alpha, and again the prevention of the stimulatory effect of PGE1 alone on RR. These data suggest that: the resting activity of the renin-angiotensin system (RAS) and the adenylate cyclase-cAMP system (AC-cAMP) of the hibernating ground squirrel is comparable to that of NH species; in contrast, the sensitivity of the RAS of the hibernator to PG stimulation is less than that exhibited by the RAS of NH species when comparable in vitro concentrations of three major PG's are used; PGE1 stimulation of RR in the hibernator is independent of changes in tcAMPc; changes in tcAMPc may be inversely related to those in RR in the hibernator; and the known stimulatory effect of PG's on the renal cortical AC-cAMP of NH species is not seen in the hibernating ground squirrel at comparable PG doses.

Adenylyl Cyclases↗
PubMed1985

Dietary sodium deficiency potentiates the effect of prostaglandin E2 on in vitro renin release in the rat.

Using a renal cortical slice system from sodium loaded (SL) or sodium deficient (SD) rats, this study investigated whether the effect of prostaglandin E2 (PGE2) on renin release (RR) is mediated by tissue cyclic AMP content (TcAMPc) changes, and if it can be modified by dietary sodium manipulation. At 10(-5) M, PGE2 significantly stimulated RR and TcAMPc in both SL and SD groups of slices. PGE2 doses of 10(-9) M and 10(-7) M were ineffective, although RR, but not TcAMPc, was significantly greater in the SD group in response to 10(-7) M PGE2 than RR in the SL group. Addition of the phosphodiesterase inhibitor theophylline (10(-4) M) together with the same three PGE2 doses maintained the stimulatory effect of 10(-5)M PGE2 alone on RR and TcAMPc in both groups of slices, and reversed the effect of 10(-7) M PGE2 alone on RR and TcAMPc in the SD group of slices only. Added by itself, theophylline was ineffective. These data indicate that: PGE2 can stimulate RR by a direct effect on the juxtaglomerular cells; the RR responses to PGE2 and theophylline administration are enhanced in the SD state; and the possibility of cAMP mediation of the effect of PGE2 on RR is discussed.

Animals↗