Geometry and quantum delocalization of interstitial oxygen in silicon

The problem of the geometry of interstitial oxygen in silicon is settled by proper consideration of the quantum delocalization of the oxygen atom around the bond-center position. The calculated infrared absorption spectrum accounts for the 517 and 1136 cm$^{-1}$ bands in their position, character, and isotope shifts. The asymmetric lineshape of the 517 cm$^{-1}$ peak is also well reproduced. A new, non-infrared-active, symmetric-stretching mode is found at 596 cm$^{-1}$. First-principles calculations are presented supporting the nontrivial quantum delocalization of the oxygen atom.Comment: uuencoded, compressed postscript file for the whole. 4 pages (figures included), accepted in PR

Resultados en la cirugía de revisión de la artroplastia de rodilla con aporte de aloinjerto óseo

Hemos realizado un estudio retrospectivo de 12 pacientes (13 rodillas) intervenidos entre 1975 y 2001 de revisión de prótesis de rodilla utilizando aloinjerto óseo, valorando el resultado funcional y clínico. La edad media fue de 62 años. La indicación primaria fue de gonartrosis primaria en 8 casos (9 rodillas), artrosis postraumática en 1 caso y 2 casos de artritis reumatoide. Los defectos óseos fueron clasificados utilizando la clasificación del Anderson Orthopedic Institute Research. Se utilizó aloinjerto de forma fragmentada en 11 casos y de forma estructural en 2. El seguimiento medio fue de 69 meses. En la valoración clínica se utilizó la escala de la Knee Society; la evaluación radiográfica evaluó la existencia de integración del injerto en el huésped. Los 2 casos de artritis reumatoide presentaron infección profunda protésica y que necesitaron de una artrodesis como solución definitiva. El resto de pacientes mostró unos resultados satisfactorios con buena integración del injerto al huésped. La utilización de aloinjerto fragmentado y estructural en la cirugía de revisión protésica de rodilla resuelve de manera satisfactoria la presencia del defecto óseo, aunque en enfermos con algú tipo de inmunopresión, el elevado riesgo de infección profunda en cirugía de revisión nos obliga a extremar las precauciones.We have carried out a retrospective study of 12 patients (13 knees) treated between 1975 and 2001 after failed total knee arthroplasty (TKA), by means of revision surgery using bone allograft. The mean age was of 62 years. The primary indication was degenerative osteoarthritis in 8 cases (9 knees), postraumatic osteoarthritis in 1 case and rheumatoid artritis in 2 cases. The bony defects were classified according to the Anderson's Orthopedic Institute classification. Fragmented allograft was used in 11 cases and structural allograft in 2. The mean follow-up time was of 69 months. Outcome was evaluated through functional and clinical result. For the clinical evaluation the scale of the Knee Society was used; the radiographic evaluation assessed the degree of integration of the graft. The 2 cases of rheumatoid artritis presented deep infection of the TKA that required an arthrodesis for definitive solution. The rest of patients showed satisfactory results with good integration of the bone graft. The use of fragmented and structural allograft in revision surgery of failed TKA solves in a satisfactory way the presence of bony defects, although in patients with some degree of inmunosupression the high risk of deep infection forces to extreme the cautions

Frequency of breast cancer with hereditary risk features in Spain: Analysis from GEICAM “El Álamo III” retrospective study

Purpose: To determine the frequency of breast cancer (BC) patients with hereditary risk features in a wide retrospective cohort of patients in Spain. Methods: a retrospective analysis was conducted from 10, 638 BC patients diagnosed between 1998 and 2001 in the GEICAM registry “El Álamo III”, dividing them into four groups according to modified ESMO and SEOM hereditary cancer risk criteria: Sporadic breast cancer group (R0); Individual risk group (IR); Familial risk group (FR); Individual and familial risk group (IFR) with both individual and familial risk criteria. Results: 7, 641 patients were evaluable. Of them, 2, 252 patients (29.5%) had at least one hereditary risk criteria, being subclassified in: FR 1.105 (14.5%), IR 970 (12.7%), IFR 177 (2.3%). There was a higher frequency of newly diagnosed metastatic patients in the IR group (5.1% vs 3.2%, p = 0.02). In contrast, in RO were lower proportion of big tumors (> T2) (43.8% vs 47.4%, p = 0.023), nodal involvement (43.4% vs 48.1%, p = 0.004) and lower histological grades (20.9% G3 for the R0 vs 29.8%) when compared to patients with any risk criteria. Conclusions: Almost three out of ten BC patients have at least one hereditary risk cancer feature that would warrant further genetic counseling. Patients with hereditary cancer risk seems to be diagnosed with worse prognosis factors

Phase II randomised trial of raltitrexed–oxaliplatin vs raltitrexed–irinotecan as first-line treatment in advanced colorectal cancer

The purpose of this phase II randomised trial was to determine which of two schemes, raltitrexed-irinotecan or raltitrexed-oxaliplatin, offered better activity and less toxicity in patients with advanced colorectal cancer (CRC). A total of 94 patients with previously untreated metastatic CRC were included and randomised to receive raltitrexed 3 mg m−2 followed by oxaliplatin 130 mg m−2 on day 1 (arm A), or CPT-11 350 mg m−2 followed by raltitrexed 3 mg m−2 (arm B). In both arms treatment was repeated every 3 weeks. Intent-to-treat (ITT) analysis showed an overall response rate of 46% (95% CI, 29.5–57.7%) for arm A, and 34% (95% CI, 19.8–48.4%) for arm B. Median time to progression was 8.2 months for arm A and 8.8 months for arm B. After a median follow-up of 14 months, 69% of patients included in arm A were still alive, compared to 59% of those included in arm B. Overall, 31 patients (65%) experienced some episode of toxicity in arm A and 32 patients (70%) in arm B, usually grade 1–2. The most common toxicity was hepatic, with 29 patients (60%) in arm A and 24 patients (62%) in arm B, and was grade 3–4 in four (8%) and four (9%) patients, respectively. In all, 14 patients (29%) from arm A and 24 patients (52%) from arm B had some grade of diarrhoea (P<0.03). Neurologic toxicity was observed in 31 patients (64%) in arm A, and was grade 3–4 in five patients (10%), while a cholinergic syndrome was detected in nine patients (19%) in arm B. There were no differences in haematologic toxicity. One toxic death (2%) occurred in arm A and three (6.5%) in arm B. In conclusion, both schemes have high efficacy as first-line treatment in metastatic CRC and their total toxicity levels are similar. Regimens with raltitrexed seem a reasonable alternative to fluoropyrimidines

Cirugía de la escoliosis: evolución y Resultados

Los autores, presentan una revisión de las tres series de escoliosis, intervenidas quirúrgicamente en el Servicio, en base a tres diferentes series de artrodcsis: artrodesis con barra distractora de lla:rrington, en segundo lugar con llarrington más el Dispositivo de Tracción Transversal (DTT) y por último con instrumentación Cotrcl-Dubousset (C-D). Se analizan los resultados obtenidos tras una revisión al año y a los cinco años del postopcratorio, el instrumental implantado y por último las complicaciones derivadas del mismo así como de la técnica quirúrgica.A revicw ofpatients with scoliosistreated by surgery is presented. Tbere are tbree groups of cases: Spinal fusion with Harrington Instrumentation, Harrington Instrumentation with D.T.T. (Dispositive of transversal Traction), and Cotrel-Duboussct Instrumentation. Tbey analyse the results obtained after one and five years offollow up after surgery, the instrum,cntation and the complications