Biomedical subjects

C Barrios

Publications and source records attributed to C Barrios.

At least 19 recordsLinked to original sources

PubMed2006

Hepatitis C recurrence after liver transplantation: Viral and histologic response to full-dose PEG-interferon and ribavirin.

Hepatitis C recurrence after liver transplantation (LT) is universal, and frequently leads to cirrhosis and death. The aim of our study was to assess the efficacy and safety of 48-weeks of full-dose peg-interferon-alpha-2a (n = 4) or alpha-2b (n = 51) plus ribavirin (>11 mg/kg/day) in a multicentric cohort of 55 patients > or =12 months after LT. All subjects had histologically proven HCV recurrence, excluding severe cholestatic recurrence. Mean age was 54.3 +/- 9.7, 77% male, 90.9% genotype 1, 32.7% cirrhotics. All but 5 patients received monotherapy with tacrolimus (54.5%), cyclosporine (30.7%) or mycophenolate mofetil (5.5%). The rates of end-of-treatment response and sustained virological response (SVR) were 66.7% and 43.6%, respectively. Low baseline HCV-RNA (p = 0.005) and a length from LT to therapy between 2-4 years (p = 0.011) were predictors of SVR. The lack of achieving a viral load decrease > or =1-log10 at week 4 and/or 2-log10 at week 12 was 100% predictive of failure. The most frequent side effects were neutropenia (76,4%), anemia (60%) and infectious complications (30.9%). Toxicity led to peg-interferon withdrawal in 16 (29%) subjects. In 15 patients with post-treatment biopsy, the histological activity index was significantly improved (p = 0.006), whereas fibrosis did not change (p = 0.14). Three patients died (cholangitis, hepatic artery thrombosis and lung cancer). In conclusion, HCV therapy after LT was very effective, although it led to a significant rate of toxicity.

Adolescent↗

PubMed2006

Hepatitis C virus recurrence after liver transplantation: influence of immunosuppressive regimens on viral load and liver histology.

Cyclosporine has recently been reported to produce in vitro suppression of hepatitis C virus replication driven by blockade of cyclophilins, an effect not shown for tacrolimus. However, the clinical consequence of this in vitro finding have not been well studied in vivo. We compared viral load and fibrosis in transplanted patients receiving monotherapy with tacrolimus or cyclosporine. Patients with recurrent hepatitis C after transplantation were selected from two tertiary centers with the following inclusion criteria: monotherapy with tacrolimus or cyclosporine for more than 12 months before viral load measurement, no antiviral treatment, corticosteroids stopped within 12 months after transplantation. HIV, hepatitis B, and active infection by cytomegalovirus were excluded. Patient characteristics, viral load, and fibrosis were compared by univariate analysis between the cyclosporine and tacrolimus groups. Significant variables, viral load, and fibrosis were included in a multivariate model. Sixty-six patients were included, 46 on tacrolimus and 20 on cyclosporine. Fifty-six were male, and the mean age was 55.3 +/- 10.1 years. Fibrosis (Ishak score) was 3.9 +/- 1.9 in the cyclosporine group and 2.7 +/- 1.9 in the tacrolimus group (P = .019). Viral load (log(10)IU/mL) was 5.8 +/- 0.5 and 5.9 +/- 0.5, respectively (P = .7) and time since liver transplantation was 95.3 +/- 47.7 and 41.1 +/- 16.8 months (P = .0001). In the multivariate model, viral load (P = .65) and fibrosis (P = .24) were not significantly different and only time since transplantation remained significant (P = .0001). In conclusion, viral load was not different in patients with tacrolimus as compared with cyclosporine, and the lower fibrosis observed in the cyclosporine group lacked significance when considered together with time since liver transplantation.

Aged↗

PubMed2005

Study on the efficacy and safety of adefovir dipivoxil treatment in post-liver transplant patients with hepatitis B virus infection and lamivudine-resistant hepatitis B virus.

Hepatitis B virus (HBV) recurrence and de novo HBV infection are frequent events in liver transplantation recipients. Treatment with lamivudine is initially efficient in both infections but the incidence of lamivudine-resistant HBV emergence increases over time. Adefovir appears to be promising in post-liver transplantation patients with recurrent HBV infection and lamivudine-resistant HBV. This study analyzed adefovir treatment in 42 post-liver transplantation patients who developed recurrent HBV or de novo HBV infection with lamivudine-resistant HBV (54.8% HCV-coinfected). Patients received 10 mg of oral adefovir once daily for a mean period of time of 21.5 months (range from 12 to 31 months). In 62.9% of patients, ALT levels decreased significantly. Serum HBV-DNA was undetectable in 64% of the cases. Twenty percent of patients lost HBeAg marker and 13.3% of them developed anti-HBe. In 9.5% of recipients, HBsAg became negative. There was no significant change in serum creatinine levels. In only one patient was worsening of the renal function detected, making dose adjustment necessary. No other side effects were reported. Our results confirm the efficacy and safety of adefovir treatment in post-liver transplantation patients with lamivudine-resistant HBV, neither were adefovir-resistant mutations identified in patients after 21 months of therapy, nor were there adverse events, especially renal toxicity.

Adenine↗

PubMed2001

Rapid cycling bipolar disorder.

Rapid cycling bipolar disorder (RCBD) is defined in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) as a type of manic-depressive illness in which the patient experiences four or more episodes of mania and/or major depression per year. It was first reported as a consequence of the reduced effectiveness of lithium carbonate in the treatment and prophylaxis of this form of bipolar disorder (BD) in contrast to those with less frequent cycling. Among the anticonvulsants, there have been reports with different degrees of controlled data concerning carbamazepine, valproate, lamotrigine, topiramate, gabapentin and primidone. There is a paucity of double-blind studies, but what is available supports the use of lamotrigine. There is open data supporting the use of carbamazepine, valproate and topiramate. Regarding other classes, nimodipine may have specific utility in ultradian- (ultra-ultra-) or ultra-RCBD and there is double-blind data regarding the specific utility of olanzapine in RCBD. Low thyroid function may be a factor in development of RCBD; therapies aimed at elevating thyroid levels, even beyond the usual range, have frequently produced benefits in open trials. More research is needed into the possible therapeutic benefits of verapamil, bupropion, choline, light therapy and electroconvulsive therapy (ECT).

Anticonvulsants↗

PubMed2000

Epidemiologic aspects of pediatric multiple trauma in a Spanish urban population.

BACKGROUND/PURPOSE: Trauma is still the most frequent cause of mortality and disability in childhood and adolescence. An epidemiologic prospective study on children under 16 years of age with multiple trauma (MT) was conducted in a large Spanish urban university hospital over a 6-year period. METHODS: Of 1,937 children admitted at the pediatric trauma unit for musculoskeletal injuries from March 1988 until March 1994, 56 patients including 37 boys and 19 girls had MT. MT was considered when at least 2 long bones were fractured or there was a fracture of 1 long bone combined with an injury of 4 other major anatomic regions (face and neck, thorax, abdomen, or neural system). The severity of injuries was evaluated according to the modified injury severity score (MISS). RESULTS: Injury to pedestrians was the most frequent cause of MT (54%). The overall mortality rate of the series, including those children dying during transport to the hospital was 11.5%. The average MISS for the whole group was 15 (range, 5 to 59). Head trauma was the most frequent associated injury (52%), two thirds of which were considered minor injuries (Glasgow Coma Scale >15). Seventy-seven fractures were registered, 10% of which were open fractures. External fixation was the most common surgical technique among operated fractures. The average hospitalization period was 16 (median, 13; range, 1 to 150) days. Children with a MISS above 18 points showed a significant longer hospitalization period (mean, 31 +/- 45 days) as compared with those with MISS below 18 points (mean, 10 +/- 7 days; P < .05). There was a strong correlation between the MISS and both the period of hospitalization at the pediatric intensive care unit and the total length of hospital stay. CONCLUSIONS: Pedestrian accidents caused by motor vehicles in children playing at the street contributed most significantly to MT in the urban pediatric population. Special care for prevention must be taken in the age group of 6 to 10 years. Head injury was the main cause of death in children with multiple trauma. MISS was found to be a good predictor of survival and duration of hospital stay in pediatric MT.

Adolescent↗

PubMed1999

[High-frequency oscillatory ventilation as salvage strategy in the newborn infant. Spanish multicenter study. I].

OBJECTIVE: The aim of this study was to evaluate the results of high frequency ventilation (HFV) used as a rescue strategy in newborn infants with severe lung disease who either failed conventional mechanical ventilation (CMV) or had an air block. PATIENTS AND METHODS: From April 1995 to June 1998, 241 infants with severe lung disease and managed according to a common protocol of HFV used as a rescue strategy were prospectively evaluated in the nine participating level III Spanish Neonatal Intensive Care Units. The most frequent diagnoses were respiratory distress syndrome (119), meconium aspiration (24), pneumonia (19) and congenital diaphragm hernia (18). RESULTS: Mean +/- SD gestational age and birth weight were 32.0 +/- 5.5 weeks and 1,187 +/- 1,071 g, respectively. All babies were previously manages with CMV for a mean of 59 hours. HFV was started at a mean postnatal age of 82 hrs, with a mean oxygenation index (OI) of 28.3 +/- 15.3 and an a/A DO2 of 0.10 +/- 0.08. Initial mean HFV settings were: mean airway pressure 12.8 +/- 3.4 mbar, frequency 8.3 +/- 1.4 Hz, amplitude 53 +/- 20 percent, tidal volume 2.2 +/- 0.7 ml/kg and FiO2 0.88 +/- 0.2. At two hours of HFV there was a significant increase in the mean PaO2 (from 48 to 80 mmHg), with a concomitant decrease in FiO2 (from 0.88 to 0.79), PaCO2 (from 60 to 46 mmHg) and OI (from 28 to 18). Mean a/A DO2 increased from 0.10 to 0.19; these changes remained similar thereafter. HFV was suspended after a mean of 95 hrs because of improvement in 70%, death in 19% and failure to improve the clinical condition in the remaining 19%. Intrahospital death rate was 32%. The following complications were observed: pneumothorax (10%), interstitial emphysema (4%), intraventricular hemorrhage grades III and IV (14.5%) and bronchopulmonary dysplasia (35%). CONCLUSIONS: HFV is an effective rescue strategy that improves pulmonary gas exchange within two hours of its initiation.

Female↗

PubMed1998

Influence of maternal antibodies on vaccine responses: inhibition of antibody but not T cell responses allows successful early prime-boost strategies in mice.

The transfer of maternal antibodies to the offspring and their inhibitory effects on active infant immunization is an important factor hampering the use of certain vaccines, such as measles or respiratory syncytial virus vaccine, in early infancy. The resulting delay in protection by conventional or novel vaccines may have significant public health consequences. To define immunization approaches which may circumvent this phenomenon, experiments were set up to further elucidate its immunological bases. The influence of maternal antibodies on antibody and T cell responses to measles hemagglutinin (MV-HA) were analyzed following MV-HA immunization of pups born to immune or control BALB/c mothers using four different antigen delivery systems: live or inactivated conventional measles vaccine, a live recombinant canarypox vector and a DNA vaccine. High levels (> 5 log10) of maternal anti-HA antibodies totally inhibited antibody responses to each of the vaccine constructs, whereas normal antibody responses were elicited in presence of lower titers of maternal antibodies. However, even high titers of maternal antibodies affected neither the induction of vaccine-specific Th1/Th2 responses, as assessed by proliferation and levels of IFN-gamma and IL-5 production, nor CTL responses in infant mice. On the basis of these unaltered T cell responses, very early priming and boosting (at 1 and 3 weeks of age, respectively) with live measles vaccine allowed to circumvent maternal antibody inhibition of antibody responses in pups of immune mothers. This was confirmed in another immunization model (tetanus toxoid). It suggests that effective vaccine responses may be obtained earlier in presence of maternal antibodies through the use of appropriate immunization strategies using conventional or novel vaccines for early priming.

Animals↗

PubMed1998

Selective impairment of endothelium-mediated vasodilation in liver transplant recipients with cyclosporin A-induced hypertension.

Arterial hypertension is commonly observed in orthotopic liver transplantation (OLT) recipients receiving cyclosporin A (CsA), but the precise pathogenetic mechanisms remain partially unknown. The aim of this study was to investigate endothelium-dependent and -independent dilation and adrenergic constriction of resistance vessels of OLT recipients treated with CsA. Vascular reactivity was examined in 22 OLT patients, 10 with and 12 without arterial hypertension, and in 10 control subjects by assessing the forearm blood flow response to the brachial artery infusion of increasing concentrations of methacholine chloride, sodium nitroprusside, and phenylephrine. In 10 OLT patients, the response to methacholine was also examined after acetylsalicylate. The ratio of serum nitrite and nitrate to serum creatinine was lower (P < .05) in OLT patients with hypertension than in nonhypertensive patients and controls. Basal forearm flow was similar in the three groups. Methacholine vasodilation was impaired in the hypertensive patients as shown by a lower maximum forearm vasodilator response and a shift in the dose response curve to methacholine to the right compared with the nonhypertensive OLT patients and the controls. The response to methacholine was not modified after salicylate. Forearm flow response to nitroprusside was similar in the three groups. No differences between the patients and the controls were found in the maximum forearm flow contraction in response to phenylephrine. An impairment in endothelium-dependent vasodilation could mediate arterial hypertension in OLT patients immunosuppressed with CsA.

Adult↗

PubMed1998

Liver transplantation in hepatitis C. A Spanish multi-centre experience.

OBJECTIVE: The purpose of this retrospective survey was to determine the prevalence and outcome of hepatitis C virus (HCV) infection in cirrhotic patients undergoing liver transplantation (OLT) in Spain in 1992. METHODS: Post-OLT HCV infection was defined by anti-HCV (second-generation ELISA) and/or PCR. Patients were divided into groups A (HCV-positive pre-OLT: n = 124, 46%) and B (HCV-negative pre-OLT: n = 145, 54%). RESULTS: HCV infection was more prevalent in patients originally diagnosed as having non-A non-B cirrhosis (97%) and cryptogenic cirrhosis (79%) than in patients with cholestatic or metabolic diseases. Group A patients were older (53.3+/-7.9 versus 47.6+/-9.7; P< 0.05) and had a higher prevalence of hepatocellular carcinoma (22% versus 4%, P< 0.05). Post-OLT HCV infection was 99% in group A versus 4% in group B (P< 0.05). Histological hepatitis developed in 39% (66% in group A versus 14% in group B, P< 0.05) with similar follow-up. Chronic rejection occurred in 6% (3% in group A versus 8.5% in group B, P= 0.07). Retransplantation rate (overall 8%) and two-year patient survival did not differ between groups (79% versus 72%). Graft survival was higher in group A (74% versus 65% at 2 years, P= 0.04). CONCLUSIONS: HCV-cirrhosis represented the most frequent indication for OLT in Spain in 1992. While HCV recurrence was universal, de novo acquisition was rare. HCV accounted for most post-OLT hepatitis (87%), but was not associated with chronic rejection, nor with a higher retransplantation rate. Patient survival was not different in HCV patients compared to a control group after a follow-up of 2-3 years. Therefore, at present, HCV-cirrhosis is an acceptable indication for OLT.

Adolescent↗

PubMed1998

Progressive opening-wedge osteotomy for severe tibia vara in adults.

Five patients with tibia vara were treated with progressive opening-wedge osteotomy. The maximum varus deviation of the mechanical axis of the tibia varied from 20 degrees to 12 degrees. The minimum postoperative follow-up was 26 months. Complete correction of the deformity was achieved without any major complications. Progressive opening-wedge osteotomy offers several advantages over conventional osteotomy in adults. First, fibular osteotomy is unnecessary. Second, knee mobility is only slightly restricted immediately following surgery. Third, it is possible to adjust correction postoperatively, and finally, progressive opening-wedge osteotomy does not induce shortening of the lower limb. The most significant disadvantage is the need for prolonged external fixation. This technique should be reserved for patients with severe deformities (minimum of 15 degrees varus) and mild or moderate osteoarthrosis.

Aged↗

PubMed1997

Effectiveness of periodontal treatments on cyclosporine-induced gingival overgrowth in transplant patients.

OBJECTIVE: Evaluation of the effectiveness of periodontal treatments on cyclosporine-induced gingival overgrowth. DESIGN: Longitudinal study between months 6 and 12 after transplant, in 80 cyclosporine-treated heart, liver and kidney transplant patients. SETTING: Madrid Puerta de Hierro Hospital. SUBJECTS AND METHODS: The 37 patients who had developed overgrowth in the sixth month were randomly split into three study groups. The remaining 43 were split into two additional groups. INTERVENTIONS: The first group underwent professional cleaning; the second underwent, additionally, scaling and root planing, and the third group received no treatment. The fourth and the fifth groups received no treatment and professional cleaning, respectively. MAIN OUTCOME MEASURES: O'Leary plaque index, Lenox and Kopczyk gingival index, and average gingival overgrowth. RESULTS: A significant (P = 0.008) increase in overgrowth was found in the third group that did not undergo treatment. Significantly (P = 0.002) less was found in the first and second groups. Highly significant (P = 0.001) reductions in the plaque and gingivitis indices were also found in these two groups. The fifth group showed a highly significant (P = 0.0001) decrease in the plaque and gingivitis indices. CONCLUSIONS: Professional cleaning is effective in reducing both gingivitis and cyclosporine-induced gingival overgrowth; the combination with scaling and root planing reinforces its effectiveness.

Adult↗

PubMed1997

DNA immunization circumvents deficient induction of T helper type 1 and cytotoxic T lymphocyte responses in neonates and during early life.

The relative deficiency of T helper type 1 (Th1) and cytotoxic T lymphocyte (CTL) responses in early life is associated with an increased susceptibility to infections by intracellular microorganisms. This is likely to reflect a preferential polarization of immature CD4 T cells toward a Th2 rather than a Th1 pattern upon immunization with conventional vaccines. In this report, it is shown that a single immunization within the first week of life with DNA plasmids encoding viral (measles virus hemagglutinin, Sendai virus nucleoprotein) or bacterial (C fragment of tetanus toxin) vaccine antigens can induce adult-like Th1 or mixed Th1/Th2 responses indicated by production of IgG2a vaccine-specific antibodies and preferential secretion of interferon-gamma (IFN-gamma) compared with interleukin (IL)-5 by antigen-specific T cells, as well as significant CTL responses. However, in spite of this potent Th1-driving capacity, subsequent DNA immunization was not capable of reverting the Th2-biased responses induced after early priming with a recombinant measles canarypox vector. Thus, DNA vaccination represents a novel strategy capable of inducing Th1 or mixed Th1/Th2 and CTL responses in neonates and early life, providing it is performed prior to exposure to Th2-driving conventional vaccine antigens.

Animals↗

PubMed1997

Intracapsular hip pressure after femoral neck fracture.

A consecutive series of 34 patients with femoral neck fractures was included in a prospective study aimed at evaluating preoperative variations in intracapsular pressure after changes in hip position, hip traction, and aspiration of hemarthrosis and their influence on the development of femoral head necrosis. Patients were observed for 7 years after surgery. Before aspiration, the mean intracapsular pressure in the antalgic physiologic position was 44.4 mm Hg. There were no differences between displaced and undisplaced fractures. The pressure was a maximum (mean value, 124.8 mm Hg) with the hip in extension and inward rotation, this pressure being greater than the blood systolic pressure in most cases. Hip traction of 3 kg in the antalgic physiologic position was found to be highly effective in preventing any bone flow tamponade effect in displaced and undisplaced femoral neck fractures: the mean intracapsular pressure decreased to 28.5 mm Hg. Aspiration of the hemarthrosis induced a significant decrease in intracapsular pressure only in cases with impaired vascularity of the femoral head as measured by scintigraphy using 99mTc labeled methyldiphosphonate. Aspiration of the hemarthrosis therefore is indicated only in the above cases, although it is less effective than hip traction in the antalgic position. There was no significant correlation between intracapsular pressure and the scintigraphy ratio. Avascular necrosis of the femoral head was detected in six cases. Among these, five patients had an intracapsular pressure below their diastolic blood pressure. This could indicate that vascular damage related to the fracture could be an important cause of bone necrosis despite that blood supply can be decreased by a tamponade effect.

Adolescent↗

PubMed1996

Neonatal and early life immune responses to various forms of vaccine antigens qualitatively differ from adult responses: predominance of a Th2-biased pattern which persists after adult boosting.

Induction of neonatal immune responses to vaccine antigens is believed to be of limited efficacy because of immune immaturity and particular susceptibility to tolerogenic signals during this period of life. To characterize particular features of neonatal immune responses to vaccine antigens, we assessed the capacity of BALB/c mice at different stages of immunological maturation to respond to a selection of vaccine antigens and presentation systems. Significant B and T cell responses to vaccine antigens (tetanus and measles virus peptides, tetanus toxoid, live viral attenuated measles virus, canarypox recombinant measles vector or bacillus Calmette-Guérin) were obtained as early as the first week of life. However, these neonatal responses differed qualitatively from adult responses by a decreased IgG2a/IgG1 ratio of vaccine-specific antibodies, the secretion of significantly higher interleukin-5 and lower interferon-gamma levels by vaccine-specific T cells and an impaired induction of cytotoxic T cell precursors. This pattern of biased Th2 versus Th1 responses induced upon early exposure to vaccines was not reversed by decreasing the doses of vaccine antigens. It did not disappear with aging and was still reflected in adult responses to booster immunization with the corresponding antigen. Thus, neonatal immunization can induce significant vaccine specific responses with a predominance of a Th2 pattern which can persist in boosted adult mice.

Aging↗

PubMed1996

Partial correction of the TH2/TH1 imbalance in neonatal murine responses to vaccine antigens through selective adjuvant effects.

We have recently shown that neonatal responses to a pannel of vaccine antigens and presentation systems differed qualitatively from adult responses by a bias towards a TH2 pattern. Here we report that a selected adjuvant comprising block copolymers in a water-in-oil emulsion can induce balanced TH1/TH2 responses in BALB/c mice primed at 1 week of age with an immunodominant tetanus peptide vaccine. However, using this specific TH1-driving adjuvant only at time of boosting was not sufficient to fully circumvent the persisting influence of TH2-biased neonatal responses. Unexpectedly also, a significant local toxicity was observed in newborn and young mice, whereas only mild reactions occurred in adults. Thus, although the induction of strong TH1 responses in the neonatal period can be achieved using specific adjuvants, through modulation of the immunological environment present at time of priming, whether such immunization strategies would be safe in the neonatal period remains to be demonstrated. These observations should be taken into consideration in the development of novel vaccines that will have to be already effective early in life.

Adjuvants, Immunologic↗

PubMed1996

Randomized trial of fluconazole versus nystatin for the prophylaxis of Candida infection following liver transplantation.

A prospective, randomized, multicenter study addressed the safety and efficacy of fluconazole therapy in 143 liver transplant patients. Seventy-six patients received daily oral fluconazole (100 mg), and 67 received nystatin (4 X 10(6) U) during the first 28 days after transplantation. Candida colonization occurred in 25% and 53% of patients in the fluconazole and nystatin groups, respectively (P = .04), and 13% and 34% of patients in the respective groups had Candida infections (P = .022). Of these patients, 10.5% in the fluconazole group and 25.3% in the nystatin group had superficial candidal infections (P = .024). Invasive candidiasis developed in 2 patients in the fluconazole group (2.6%) and 6 in the nystatin group (9.0%) (P = .12). There was no increased hepatotoxicity, cyclosporine interaction, or emergence of clinically relevant resistant Candida strains attributable to fluconazole. Thus, oral fluconazole (100 mg) is safe and reduces Candida colonization and infection after liver transplantation.

Adult↗

PubMed1996

Gender differences in sexual practices and sexually transmitted infections among adults in Lima, Peru.

OBJECTIVES: This study examined the prevalences of antibodies to Treponema pallidum, Chlamydia trachomatis, and herpes simplex virus type 2 in a sample of Peruvian adults. METHODS: Among adults seeking health certification in Lima, Peru, 600 were randomly selected to undergo interviews and serologic testing. RESULTS: Men's reported mean lifetime number of partners (10.6) far exceeded women's (1.1), yet antibody to sexually transmitted infection pathogens among sexually experienced participants was 2.8 times more prevalent among women than among men. Among men, female sex workers accounted for 37% of recent partners, and only sex with female sex workers while using condoms less than half of the time was independently associated with antibody (odds ratio = 3.6, 95% confidence interval = 1.5, 8.8). among women, number of partners was associated with any sexually transmitted infection antibody, while intercourse before 18 years of age was associated with C trachomatis antibody. At every level of perceived risk, sexually transmitted infection antibody was more frequent among women. CONCLUSIONS: Men having unprotected sex with female sex workers had the greatest risk of acquiring infections and (by inference) of transmitting them to women.

Adult↗

PubMed1995

Absence of mutation at the GAP-related domain of the neurofibromatosis type 1 gene in sporadic neurofibrosarcomas and other bone and soft tissue sarcomas.

The NF1 gene encodes neurofibromin, a GTPase-activating protein containing a GAP-related domain (NF1-GRD) that is capable of downregulating ras by stimulating ras intrinsic GTPase activity. We tested 44 sarcomas, nine of which corresponded to sporadic neurofibrosarcomas, for mutations at the NF1-GRD by the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique, finding no mutation in every sample tested. We suggest that inactivation of the NF1-GRD by gene mutation seems not to be an important event in the tumorigenesis of sarcomas.

Bone Neoplasms↗