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1.
Ann Oncol ; 2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38777726

RESUMEN

BACKGROUND: POLE and POLD1 proofreading deficiency (POLE/D1pd) define a rare subtype of ultramutated metastatic colorectal cancer (mCRC; over 100 mut/Mb). Disease-specific data about the activity and efficacy of immune checkpoint inhibitors (ICIs) in POLE/D1pd mCRC are lacking and it is unknown whether outcomes may be different from mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) mCRCs treated with ICIs. PATIENTS AND METHODS: In this global study, we collected 27 patients with mCRC harboring POLE/D1 mutations leading to proofreading deficiency and treated with anti-programmed cell death-ligand 1 alone +/- anti-cytotoxic T-lymphocyte antigen-4 agents. We collected clinicopathological and genomic characteristics, response, and survival outcomes after ICIs of POLE/D1pd mCRC and compared them with a cohort of 610 dMMR/MSI-H mCRC patients treated with ICIs. Further genomic analyses were carried out in an independent cohort of 7241 CRCs to define POLE and POLD1pd molecular profiles and mutational signatures. RESULTS: POLE/D1pd was associated with younger age, male sex, fewer RAS/BRAF driver mutations, and predominance of right-sided colon cancers. Patients with POLE/D1pd mCRC showed a significantly higher overall response rate (ORR) compared to dMMR/MSI-H mCRC (89% versus 54%; P = 0.01). After a median follow-up of 24.9 months (interquartile range: 11.3-43.0 months), patients with POLE/D1pd showed a significantly superior progression-free survival (PFS) compared to dMMR/MSI-H mCRC [hazard ratio (HR) = 0.24, 95% confidence interval (CI) 0.08-0.74, P = 0.01] and superior overall survival (OS) (HR = 0.38, 95% CI 0.12-1.18, P = 0.09). In multivariable analyses including the type of DNA repair defect, POLE/D1pd was associated with significantly improved PFS (HR = 0.17, 95% CI 0.04-0.69, P = 0.013) and OS (HR = 0.24, 95% CI 0.06-0.98, P = 0.047). Molecular profiling showed that POLE/D1pd tumors have higher tumor mutational burden (TMB). Responses were observed in both subtypes and were associated with the intensity of POLE/D1pd signature. CONCLUSIONS: Patients with POLE/D1pd mCRC showed more favorable outcomes compared to dMMR/MSI-H mCRC to treatment with ICIs in terms of tumor response and survival.

2.
Urol Oncol ; 41(12): 486.e15-486.e23, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37821306

RESUMEN

BACKGROUND: Advanced bladder squamous cell carcinoma (aBSCC) is an uncommon form of urinary bladder malignancy when compared with the much higher urothelial carcinoma incidence. We studied the genomic alteration (GA) landscape in a series of aBSCC based on the association with human papilloma virus (HPV) to determine if differences in GA would be observed between the positive and negative groups. METHODS: Using a hybrid capture-based FDA-approved CGP assay, a series of 171 aBSCC were sequenced to evaluate all classes of GA. Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on up to 114 loci. Programmed cell death ligand -1 (PD-L1) expression was determined by IHC (Dako 22C3) with negative expression when PD-L1 was 0, lower expression of positivity set at 1 to 49%, and higher expression set at ≥50% expression. RESULTS: Overall, 11 (6.4%) of the aBSCC were found to harbor HPV sequences (10 HPV16 and 1 HPV 11). HPV+ status was identified slightly more often in women (NS) and in younger patients (P = 0.04); 2 female patients with aBSCC had a prior history of SCC including 1 anal SCC and 1 vaginal SCC. HPV+ aBSCC had fewer GA/tumor (P < 0.0001), more inactivating mutations in RB1 (P = 0.032), and fewer inactivating GA in CDKN2A (P < 0.0001), CDKN2B (P = 0.05), TERT promoter (P = 0.0004) and TP53 (P < 0.0001). GA in genes associated with urothelial carcinoma including FGFR2 and FGFR3 were similar in both HPV+ and HPV- aBSCC groups. MTAP loss (homozygous deletion) which has emerged as a biomarker for PRMT5 inhibitor-based clinical trials was not identified in any of the 11 HPV+ aBSCC cases, which was significantly lower than the 28% positive frequency of MTAP loss in the HPV- aBSCC group (P < 0.0001). MTOR and PIK3CA pathway GA were not significantly different in the 2 groups. Putative biomarkers associated with immunotherapy (IO) response, including MSI and TMB status, were also similar in the 2 groups. PD-L1 expression data was available for a subset of both HPV+ and HPV- cases and showed high frequencies of positive staining which was not different in the 2 groups. CONCLUSIONS: HPV+ aBSCC tends to occur more often in younger patients. As reported in other HPV-associated squamous cell carcinomas, HPV+ aBSCC demonstrates significantly reduced frequencies of inactivating mutations in cell cycle regulatory genes with similar GA in MTOR and PIK3CA pathways. The implication of HPV in the pathogenesis of bladder cancer remains unknown but warrants further exploration and clinical validation.


Asunto(s)
Carcinoma de Células Escamosas , Carcinoma de Células Transicionales , Infecciones por Papillomavirus , Neoplasias de la Vejiga Urinaria , Humanos , Femenino , Neoplasias de la Vejiga Urinaria/genética , Neoplasias de la Vejiga Urinaria/complicaciones , Vejiga Urinaria/patología , Carcinoma de Células Transicionales/genética , Carcinoma de Células Transicionales/complicaciones , Infecciones por Papillomavirus/complicaciones , Infecciones por Papillomavirus/genética , Infecciones por Papillomavirus/epidemiología , Antígeno B7-H1/genética , Homocigoto , Eliminación de Secuencia , Carcinoma de Células Escamosas/patología , Genómica , Biomarcadores de Tumor/genética , Fosfatidilinositol 3-Quinasa Clase I/genética , Serina-Treonina Quinasas TOR/genética , Mutación , Proteína-Arginina N-Metiltransferasas/genética
3.
Clin Microbiol Infect ; 24(1): 82.e1-82.e4, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28506784

RESUMEN

OBJECTIVES: This study aims to assess the association between patient contact and intestinal carriage of multidrug-resistant organisms (MDRO) by sampling healthcare personnel (HCP) and staff without patient contact. METHODS: For this observational study, we recruited 400 HCP who worked in our 200-bed research hospital and 400 individuals without patient contact between November 2013 and February 2015. Participants submitted two self-collected perirectal swabs and a questionnaire. Swabs were processed for multidrug-resistant Gram-negative bacteria and vancomycin-resistant enterococci (VRE). Questionnaires explored occupational and personal risk factors for MDRO carriage. RESULTS: Among 800 participants, 94.4% (755/800) submitted at least one swab, and 91.4% (731/800) also submitted questionnaires. Extended spectrum ß-lactamase-producing organisms were recovered from 3.4% (26/755) of participants, and only one carbapenemase-producing organism was recovered. No VRE were detected. The potential exposure of 68.9% (250/363) of HCP who reported caring for MDRO-colonized patients did not result in a rate of MDRO carriage among HCP (4.0%; 15/379) significantly higher than that of staff without patient contact (3.2%; 12/376; p 0.55). CONCLUSIONS: This is the largest US study of HCP intestinal MDRO carriage. The low colonization rate is probably reflective of local community background rates, suggesting that HCP intestinal colonization plays a minor role in nosocomial spread of MDROs in a non-outbreak setting. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01952158.


Asunto(s)
Infecciones Bacterianas/transmisión , Enterobacteriaceae Resistentes a los Carbapenémicos/aislamiento & purificación , Portador Sano/microbiología , Personal de Salud , Intestinos/microbiología , Enterococos Resistentes a la Vancomicina/aislamiento & purificación , Adulto , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Bacterianas/microbiología , Proteínas Bacterianas/análisis , Infección Hospitalaria/microbiología , Farmacorresistencia Bacteriana Múltiple , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Encuestas y Cuestionarios , beta-Lactamasas/análisis
4.
Clin Pharmacol Ther ; 100(1): 63-6, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-26850569

RESUMEN

Hospital systems increasingly utilize pharmacogenomic testing to inform clinical prescribing. Successful implementation efforts have been modeled at many academic centers. In contrast, this report provides insights into the formation of a pharmacogenomics consultation service at a safety-net hospital, which predominantly serves low-income, uninsured, and vulnerable populations. The report describes the INdiana GENomics Implementation: an Opportunity for the UnderServed (INGENIOUS) trial and addresses concerns of adjudication, credentialing, and funding.


Asunto(s)
Farmacogenética/organización & administración , Proveedores de Redes de Seguridad/organización & administración , Poblaciones Vulnerables , Centros Médicos Académicos/organización & administración , Humanos , Pacientes no Asegurados , Pobreza
5.
Clin Pharmacol Ther ; 98(1): 19-24, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25801146

RESUMEN

Tacrolimus is the mainstay immunosuppressant drug used after solid organ and hematopoietic stem cell transplantation. Individuals who express CYP3A5 (extensive and intermediate metabolizers) generally have decreased dose-adjusted trough concentrations of tacrolimus as compared with those who are CYP3A5 nonexpressers (poor metabolizers), possibly delaying achievement of target blood concentrations. We summarize evidence from the published literature supporting this association and provide dosing recommendations for tacrolimus based on CYP3A5 genotype when known (updates at www.pharmgkb.org).


Asunto(s)
Citocromo P-450 CYP3A/genética , Inmunosupresores/administración & dosificación , Tacrolimus/administración & dosificación , Pruebas Genéticas , Genotipo , Trasplante de Células Madre Hematopoyéticas , Humanos , Trasplante de Órganos
6.
J Cell Physiol ; 230(5): 989-1002, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25503065

RESUMEN

In this review we summarize the current understanding of a novel integrative function of Fibroblast Growth Factor Receptor-1 (FGFR1) and its partner CREB Binding Protein (CBP) acting as a nuclear regulatory complex. Nuclear FGFR1 and CBP interact with and regulate numerous genes on various chromosomes. FGFR1 dynamic oscillatory interactions with chromatin and with specific genes, underwrites gene regulation mediated by diverse developmental signals. Integrative Nuclear FGFR1 Signaling (INFS) effects the differentiation of stem cells and neural progenitor cells via the gene-controlling Feed-Forward-And-Gate mechanism. Nuclear accumulation of FGFR1 occurs in numerous cell types and disruption of INFS may play an important role in developmental disorders such as schizophrenia, and in metastatic diseases such as cancer. Enhancement of INFS may be used to coordinate the gene regulation needed to activate cell differentiation for regenerative purposes or to provide interruption of cancer stem cell proliferation.


Asunto(s)
Proteína de Unión a CREB/metabolismo , Núcleo Celular/metabolismo , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/metabolismo , Transducción de Señal , Animales , Humanos , Neoplasias/metabolismo , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/química , Células Madre/citología , Células Madre/metabolismo
7.
Clin Pharmacol Ther ; 96(3): 307-9, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24807457

RESUMEN

Pharmacogenomics (PGx) technology is advancing rapidly; however, clinical adoption is lagging. The Indiana Institute of Personalized Medicine (IIPM) places a strong focus on translating PGx research into clinical practice. We describe what have been found to be the key requirements that must be delivered in order to ensure a successful and enduring PGx implementation within a large health-care system.


Asunto(s)
Atención a la Salud/organización & administración , Farmacogenética/organización & administración , Medicina de Precisión , Conducta Cooperativa , Difusión de Innovaciones , Humanos , Comunicación Interdisciplinaria , Objetivos Organizacionales , Desarrollo de Programa , Investigación Biomédica Traslacional
8.
J Biotechnol ; 112(1-2): 139-49, 2004 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-15288949

RESUMEN

Self-assembled monolayer films based on iodobenzoyloxy-functionalized resorc[4]arenes were prepared on gold substrates to serve as model systems for future time-resolved studies of molecular recognition, a mechanism of outstanding importance in bioorganic systems. The film properties were tested using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and imaging ellipsometry. An apparatus for time-resolved electron spectroscopy utilizing femtosecond soft X-ray pulses is capable of detecting iodine core-level photolines and the photoinduced dissociation after ultraviolet illumination. The developed technique holds promise for tracking the temporal evolution of chemical shifts of atomic markers as local probes for the dynamics of the guest-host interaction.


Asunto(s)
Benzoatos/química , Biopolímeros/análisis , Biopolímeros/química , Membranas Artificiales , Energía Filtrada en la Transmisión por Microscopía Electrónica/métodos , Sondas Moleculares/química , Mapeo de Interacción de Proteínas/métodos , Difracción de Rayos X/métodos , Cinética , Energía Filtrada en la Transmisión por Microscopía Electrónica/instrumentación , Mapeo de Interacción de Proteínas/instrumentación , Factores de Tiempo , Difracción de Rayos X/instrumentación
9.
J Cataract Refract Surg ; 27(4): 560-4, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11311624

RESUMEN

PURPOSE: To evaluate the effect of brimonidine tartrate ophthalmic solution 0.2% (Alphagan) on pupil size in normal eyes. Three luminance conditions were used to assess the potential use of brimonidine in postoperative refractive patients who experience nighttime vision problems related to large pupil size. SETTING: McDonald Eye Associates, Fayetteville, Arkansas, USA. METHODS: Pupil size was measured in 16 eyes of 16 participants with the Colvard pupillometer under 3 luminance conditions. One drop of brimonidine 0.2% was administered to each patient. Pupil size was then measured using the same technique 30 minutes and 4 and 6 hours after drop administration. RESULTS: Under scotopic conditions, 100% of the pupils showed significant miosis at 30 minutes (P <.05). The effect continued in all eyes for 4 hours. At 6 hours, a miotic effect was still present in 81.3%. However, under photopic luminance, there was no significant effect on pupil size in all 16 eyes (P >.05). The pupil size in 5 eyes (31.2%) was not affected at 30 minutes or 4 or 6 hours. At 6 hours, 15 eyes (93.8%) had returned to their preinstillation size. CONCLUSION: Brimonidine tartrate 0.2% had a significant effect in decreasing pupil size under scotopic conditions. The results indicate that the drug can decrease night-vision difficulties such as halos, star bursts, glare, and monocular diplopia in postoperative refractive patients.


Asunto(s)
Agonistas alfa-Adrenérgicos/administración & dosificación , Iluminación , Pupila/efectos de los fármacos , Quinoxalinas/administración & dosificación , Adulto , Tartrato de Brimonidina , Femenino , Humanos , Masculino , Persona de Mediana Edad , Miosis/inducido químicamente , Soluciones Oftálmicas , Reflejo Pupilar , Trastornos de la Visión/prevención & control
11.
J Histochem Cytochem ; 46(7): 855-61, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9632745

RESUMEN

We investigated carbonic anhydrase IV (CA IV) in rat and human heart with immunohistochemical methods by both light and electron microscopy. In cryosections that were incubated with anti-CA IV/FITC, the capillaries showed a strong reaction for CA IV. In paraffin and semithin sections treated with anti-CA IV/ABC (avidin-biotin-peroxidase complex) blood vessels, capillaries, and sarcolemma (SL) were positively stained. By staining ultrathin sections with anti-CA IV/immunogold, CA IV could also be demonstrated at the latter two locations, including the specialized sarcolemmal structures intercalated discs, and T-tubules. In addition, by this method CA IV was seen to be associated with the sarcoplasmic reticulum (SR). The absence of immunostaining in SR and/or SL with some techniques probably indicates a problem of accessibility of the antigenic sites. In line with the immunohistochemical results, CA IV mRNA expression was visualized in both endothelial and muscle cells by in situ hybridization histochemistry.


Asunto(s)
Anhidrasas Carbónicas/análisis , Miocardio/química , Animales , Endotelio Vascular/química , Endotelio Vascular/ultraestructura , Técnica del Anticuerpo Fluorescente Directa , Humanos , Inmunohistoquímica , Hibridación in Situ , Músculo Esquelético/química , Miocardio/ultraestructura , ARN Mensajero/análisis , Ratas , Sarcolema/química , Sarcolema/ultraestructura , Retículo Sarcoplasmático/química , Retículo Sarcoplasmático/ultraestructura
12.
Am J Sports Med ; 26(1): 103-8, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9474410

RESUMEN

In each of 30 skeletally mature sheep, the posterior cruciate ligament was replaced in one knee by a free patellar tendon autograft using the central third of the ipsilateral patellar tendon. The healing autograft was compared with the contralateral posterior cruciate ligament and the patellar tendons and posterior cruciate ligaments of nonoperated animals. The content of glycosaminoglycans, chondroitin sulfate disaccharides, and dermatan sulfate disaccharides was assessed biochemically at six periods during the 2 years after surgery. The total glycosaminoglycans and chondroitin sulfate disaccharides in the native posterior cruciate ligament was threefold that in the native patellar tendon. In contrast, the amount of dermatan sulfate disaccharides was similar in both the native tendon and native ligament. In the autograft, glycosaminoglycans and chondroitin sulfate disaccharides increased significantly to about 144% and 172%, respectively, of the contralateral posterior cruciate ligament at Week 104. The dermatan sulfate disaccharides in the autograft also showed a significant increase up to Week 26, followed by a remarkable but not significant decrease until the end of the study. In the contralateral posterior cruciate ligament, the dermatan sulfate disaccharides increased significantly between Weeks 52 and 104. Thus, the amount of dermatan sulfate disaccharides was similar in both the autograft and the contralateral posterior cruciate ligament after 2 years. This study suggests that the patellar tendon autograft did not completely assume the biochemical properties of the posterior cruciate ligament.


Asunto(s)
Ligamento Cruzado Posterior/cirugía , Tendones/trasplante , Cicatrización de Heridas , Animales , Sulfatos de Condroitina/análisis , Dermatán Sulfato/análisis , Modelos Animales de Enfermedad , Glicosaminoglicanos/análisis , Miembro Posterior , Ovinos , Trasplante Autólogo
15.
J Nurse Midwifery ; 42(4): 364-6, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9277067

RESUMEN

The health care industry is a massive system that is changing so rapidly that it is reinventing itself. With these changes, added demands have been placed on the knowledge base and practice of nurse-midwifery with emphasis on primary care, administration, and research as well as traditionally accepted nurse-midwifery practice. The American College of Nurse-Midwives (ACNM) has a history of being alert to consumer demands, sociopolitical forces, and the health care industry itself as stimuli for change after full dialogue with the membership and appropriate study. Because the ACNM Division of Accreditation will be requiring a baccalaureate degree upon entrance or completion of each midwifery education program by June 1999, dialogue should begin now about the benefits of requiring a masters degree as the entry-level credential.


Asunto(s)
Certificación/normas , Educación de Postgrado en Enfermería , Enfermeras Obstetrices/educación , Humanos , Estados Unidos
16.
Peptides ; 18(10): 1531-7, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9437713

RESUMEN

Mechanical activity was recorded in circular and longitudinal smooth muscle preparations isolated from extensive regions of the porcine gastrointestinal tract in response to the FMRFamide-like neuropeptides F8Famide and A18Famide. In all preparations, the peptides were about equipotent in producing phasic contractions or enhancing spontaneous activity. The most prominent responses were observed in jejunal longitudinal strips which were on the average 91% (+/- 4% SEM, n = 15; 10(-6) M) of the histamine (10(-5) M) responses. The peptide-induced phasic activity was completely abolished by nifedipine but was unaffected by tetrodotoxin, atropine, phentolamine, yohimbine, phenoxybenzamine, propranolol, methysergide, cimetidine, indomethacin, levallorphane or naloxone. Both peptides enhanced acetylcholine-induced contractions. However, bovine ileum and guinea-pig taenia coli was not affected by these peptides. The results indicate that F8F- and A18F-amide contract porcine gastrointestinal smooth muscle by acting directly via non-opioid receptors on L-type calcium channels. In addition an increase of the sensitivity to cholinergic stimulation occurs.


Asunto(s)
FMRFamida/farmacología , Motilidad Gastrointestinal/efectos de los fármacos , Neuropéptidos/farmacología , Oligopéptidos/farmacología , Animales , Canales de Calcio/metabolismo , Canales de Calcio Tipo L , Encefalina Leucina/farmacología , Encefalina Metionina/farmacología , FMRFamida/análogos & derivados , Histamina/farmacología , Técnicas In Vitro , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Neuropéptidos/química , Nifedipino/farmacología , Nitroprusiato/farmacología , Porcinos
17.
Histochem Cell Biol ; 106(4): 405-11, 1996 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8911968

RESUMEN

Carbonic anhydrase IV (CA IV) was examined by light microscopy and electron microscopy in rat soleus muscle. Semithin sections of aldehyde-fixed Epon-embedded muscle were stained with rabbit anti-rat lung CA IV and the avidin-biotin-peroxidase complex. With this technique, capillaries and sarcolemma showed positive CA IV staining. For electron microscopy, rat soleus specimens were aldehyde-fixed, with or without subsequent osmication, and embedded in Epon. Ultrathin sections were immunostained with anti-rat lung CA IV/immunogold. Omitting osmium allowed ample antigen-antibody reactions but could not prevent the release of glycosylphosphatidylinositol-anchored CA IV from the membranes, which led to apparent background staining. Postosmication significantly reduced tissue antigenicity but kept the antigen bound to the membranes and thus allowed a very precise localization of CA IV. By electron microscopy, membrane-bound CA IV is found to be associated with capillary endothelium, sarcolemma, and sarcoplasmic reticulum (SR). Conceivably, the presence of SR staining in ultrathin sections and its absence in semithin sections reflect a problem of accessibility of the antigenic sites.


Asunto(s)
Anhidrasas Carbónicas/análisis , Músculo Esquelético/química , Sarcolema/química , Retículo Sarcoplasmático/química , Animales , Capilares/química , Capilares/ultraestructura , Citoplasma/química , Citoplasma/ultraestructura , Endotelio/química , Endotelio/ultraestructura , Inmunohistoquímica , Microscopía Electrónica , Músculo Esquelético/ultraestructura , Ratas , Sarcolema/ultraestructura , Retículo Sarcoplasmático/ultraestructura , Conservación de Tejido/métodos
18.
Unfallchirurg ; 99(3): 183-90, 1996 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-8685723

RESUMEN

The treatment of injuries to the posterior cruciate ligament (PCL) remains controversial. Various problems have prevented PCL reconstruction from consistently producing the knee stability desired. Biological graft tissue undergoes a remarkable healing process comprising different phases. The strength of autogenous graft material decreases soon after the operation. During this early healing phase synthetic augmentation could protect the graft tissue from overloading or overstretching, supporting the tissue restoration process. In order to evaluate the morphological effects of the ligament augmentation device (LAD) on a free patellar tendon autograft in PCL reconstruction a comparative study in sheep was conducted. In 24 mature sheep the PCL was replaced with either a patellar tendon autograft alone or a patellar tendon autograft augmented by the LAD. The LAD was fixed at both ends. The animals were not immobilized after the operation. Tibial fixation was released 8 weeks after the operation. The autografts of both groups were histologically evaluated after 2, 6, 16, 26, 52 and 104 weeks. In addition to necrotic and degenerative alterations a pronounced inflammatory reaction could be seen in the LAD-augmented autografts soon after the operation. Compared with the non-augmented autograft, tissue formation and remodeling was delayed in the augmented group. After 1 and 2 years, the morphology of the autograft tissue was similar in the augmented and the non-augmented group and was different from that of a normal PCL. The LAD was surrounded by a chronic inflammatory reaction, and collagen fiber ingrowth into the LAD was not observed. Transmission electron microscopy showed that small-diameter collagen fibrils were predominant in the graft tissue of both groups. Thus, better remodeling of the autograft tissue in the presence of the LAD was not demonstrable in this particular study. The value of synthetic augmentation of biological grafts of PCL reconstruction seems to be questionable at present.


Asunto(s)
Traumatismos de la Rodilla/cirugía , Polipropilenos , Ligamento Cruzado Posterior/lesiones , Prótesis e Implantes , Transferencia Tendinosa , Animales , Femenino , Reacción a Cuerpo Extraño/patología , Traumatismos de la Rodilla/patología , Ligamento Cruzado Posterior/patología , Ligamento Cruzado Posterior/cirugía , Ovinos , Cicatrización de Heridas/fisiología
19.
Arch Orthop Trauma Surg ; 115(3-4): 176-81, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8861586

RESUMEN

The treatment of posterior cruciate ligament (PCL) injuries remains controversial. Due to various problems, PCL reconstruction has not consistently produced the knee stability desired. Biological graft tissue undergoes a remarkable healing process comprising different phases. The strength of autogenous graft material decreases soon after operation. During this early healing phase synthetic augmentation could protect the graft tissue from overloading or overstretching, supporting the tissue revitalization and remodeling process. In order to evaluate the morphological effects of the ligament augmentation device (LAD) on a free patellar tendon autograft in PCL reconstruction, a comparative study in sheep was conducted. In 24 mature sheep, the PCL was replaced with either a patellar tendon autograft alone or a patellar tendon autograft augmented by the LAD. The LAD was fixed at both ends. After the operation the animals were not immobilized. Tibial fixation was released 8 weeks postoperation. The autografts of both groups were histologically evaluated after 2, 6, 16, 26, 52, and 104 weeks. In addition to necrotic and degenerative alterations, a remarkable inflammatory reaction could be seen in the LAD-augmented autografts early postoperation. Compared with the nonaugmented autografts, tissue formation and remodeling were delayed in the augmented group. After 1 and 2 years, the morphology of the autograft tissue was similar in both the augmented and nonaugmented group and differed from that of a normal PCL. The LAD was surrounded by a chronic inflammatory reaction, and collagen fiber ingrowth into the LAD was not observed. Using transmission electron microscopy, small diameter collagen fibrils were predominant in the graft tissue of both groups. Thus, a better remodeling of the autograft tissue in the presence of the LAD could not be demonstrated in this particular study. The value of synthetic augmentation of biological grafts in PCL reconstruction seems to be questionable at present.


Asunto(s)
Reacción a Cuerpo Extraño/etiología , Ligamento Rotuliano/trasplante , Ligamento Cruzado Posterior/cirugía , Prótesis e Implantes , Animales , Microscopía Electrónica , Ligamento Rotuliano/citología , Ovinos
20.
J Anat ; 187 ( Pt 1): 161-7, 1995 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7591977

RESUMEN

The alterations in collagen fibril diameter distribution, mean fibril diameter and the area occupied by collagen after posterior cruciate ligament reconstruction using a patellar tendon autograft were estimated 2, 6, 16, 26, 52 and 104 wk postoperatively. Patellar tendons and posterior cruciate ligaments from unoperated animals were used as control tissues. Collagen fibrils were divided into histograms according to their diameter in order to analyse distribution maxima. There was a significant decrease in mean fibril diameter of the grafts in comparison with the control tissues. At 104 wk it was only about 51% of that for control posterior cruciate ligaments. The total area occupied by collagen was significantly reduced at 6 wk postoperatively and was about 57% in comparison with normal posterior cruciate ligaments. A considerable increase of small diameter collagen fibrils together with a loss of large fibrils was responsible for these results. There was no evidence of reestablishment of large diameter fibrils, which are normally found in tendon and ligaments, up to 2 y after transplantation. The total area covered by collagen was still reduced at this stage although the number of fibrils had increased.


Asunto(s)
Colágeno/ultraestructura , Articulación de la Rodilla/cirugía , Ligamento Cruzado Posterior/cirugía , Transferencia Tendinosa , Tendones , Animales , Fenómenos Biomecánicos , Articulación de la Rodilla/ultraestructura , Ligamento Cruzado Posterior/ultraestructura , Periodo Posoperatorio
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