Study of micromotion in modular acetabular components during gait and subluxation: a finite element investigation

Polyethylene wear after total hip arthroplasty may occur as a result of normal gait and as a result of subluxation and relocation with impact. Relocation of a subluxed hip may impart a moment to the cup creating sliding as well as compression at the cup liner interface. The purpose of the current study is to quantify, by a validated finite element model, the forces generated in a hip arthroplasty as a result of subluxation relocation and compare them to the forces generated during normal gait. The micromotion between the liner and acetabular shell was quantified by computing the sliding track and the deformation at several points of the interface. A finite element analysis of polyethylene liner stress and liner/cup micromotion in total hip arthroplasty was performed under two dynamic profiles. The first profile was a gait loading profile simulating the force vectors developed in the hip arthroplasty during normal gait. The second profile is generated during subluxation and subsequent relocation of the femoral head. The forces generated by subluxation relocation of a total hip arthroplasty can exceed those forces generated during normal gait. The induced micromotion at the cup polyethylene interface as a result of subluxation can exceed micromotion as a result of the normal gait cycle. This may play a significant role in the generation of backsided wear. Minimizing joint subluxation by restoring balance to the hip joint after arthroplasty should be explored as a strategy to minimize backsided wear.

Rescue of a living donor with liver transplantation

Postoperative liver failure is a rare complication after living donor liver resection. This is a case report of a 22-year-old healthy donor who was rescued with liver transplantation 11 days after right hemihepatectomy. Nine months later the patient is alive, and has fully recovered from his multiple organ failure. According to a review of the literature, there are four additional living liver donors, who received a liver transplant. Our own patient is the only survivor, so far. This case demonstrates that even in supposedly healthy living donors postoperative complications cannot be completely prevented. Although liver failure is rare in these patients, timely transplantation may need to be considered as the only life-saving treatment.

A pilot experience launching a national dose protocol for vascular and interventional radiology

The design of a national dose protocol for interventional radiology has been one of the tasks during the European SENTINEL Coordination Action. The present paper describes the pilot experience carried out in cooperation with the Spanish Society on Vascular and Interventional Radiology (SERVEI). A prospective sample of procedures was initially agreed. A common quality control of the X-ray systems was carried out, including calibration of the air kerma area product (KAP) meters. Occupational doses of the radiologists involved in the survey were also included in the survey. A total of 10 Spanish hospitals with interventional X-ray units were involved. Six hundred and sixty-four patient dose data were collected from 397 diagnostic and 267 therapeutic procedures. Occupational doses were evaluated in a sample of 635 values. The obtained KAP median/mean values (Gy.cm2) for the gathered procedures were: biliary drainage (30.6/68.9), fistulography (4.5/9.8), lower limb arteriography (52.2/60.7), hepatic chemoembolisation (175.8/218.3), iliac stent (45.9/73.2) and renal arteriography (39.1/59.8). Occupational doses (mean monthly values, in mSv) were 1.9 (over apron); 0.3 (under apron) and 4.5 (on hands). With this National experience, a protocol was agreed among the SENTINEL partners to conduct future similar surveys in other European countries.

Experimental set-up and sensory glove interface for microsurgery

One of the most fundamental prerequisites for successful microsurgery is thoughtful and adequate training. A combination of knowledge, technical skill, and decision making directly influences the surgical outcome. This study aims to analyse microsurgical hand coordinations quantitatively and to study the utility of a sensory glove interface in identifying the hand coordination patterns during microsurgery. A sensory glove interface used to measure the angular flexion—extension movements of the major interphalangeal joints of the hand, the grasp pressure, and the relative hand movements has been developed. Experiments of two suturing techniques were conducted with five experienced microsurgeons, and microsurgery practice was examined. The custom sensory glove interface required both signal conditioning and amplification which was directly interfaced with a custom-designed LABView software code. The sensory glove interface was calibrated using regression techniques and the set-up was validated using the Bland—Altman correlation technique.

The hand coordination patterns were analysed using principal-component analysis. Pareto plots showing the contribution of the principal components were analysed. The contributions of the first two sensory data components have also been compared with hand coordination studies. The temporal variations provided new insights into the underlying synergetic mechanisms and in particular the relation between different suture techniques on grasp pressure.

Novel molecular profiles of endometrial cancer-new light through old windows

Endometrial carcinoma (EC) is the most common gynecological malignancy in the western world. A widely accepted dualistic model, which has been established on a morphological basis, differentiates EC into two broad categories: Type I oestrogen-dependent adenocarcinoma with an endometrioid morphology and Type II non-oestrogen-dependent EC with a serous papillary or clear cell morphology. Molecular genetic evidence indicates that endometrial carcinoma, as described in other malignancies, likely develops as the result of a stepwise accumulation of alterations in cellular regulatory pathways, such as oncogene activation and tumor suppressor gene inactivation, which lead to dysfunctional cell growth. These molecular alterations appear to be specific in Type I and Type II cancers. In type I endometrioid endometrial cancer, PTEN gene silencing in conjunction with defects in DNA mismatch repair genes, as evidenced by the microsatellite instability phenotype, or mutations in the K-ras and/or beta-catenin genes, are recognized major alterations, which define the progression of the normal endometrium to hyperplasia, to endometrial intraepithelial neoplasia, and then on to carcinoma. In contrast, Type II cancers show mutations of TP53 and Her-2/neu and seem to arise from a background of atrophic endometrium. Nevertheless, despite the great effort made to establish a molecularly-based histological classification, the following issues must still be clarified: what triggers the tumor cells to invade the myometrium and what causes vascular or lymphatic dissemination, finally culminating in metastasis? RUNX1, a transcription factor, was recently identified as one of the most highly over-expressed genes in a microarray study of invasive endometrial carcinoma. Another candidate gene, which may be associated with an initial switch to myometrial infiltration, is the transcription factor ETV5/ERM. These studies, as well as those conducted for other genes possibly involved in the mitotic checkpoint as a major mechanism of carcinogenesis in non-endometrioid endometrial cancer, could help in understanding the differences in the biology and the clinical outcome among histological types.

Molecular heterogeneity in chronic lymphocytic leukemia is dependent on BCR signaling: clinical correlation

Chronic lymphocytic leukemia (CLL), the most frequent form of adult leukemia in Western countries, is characterized by a highly variable clinical course. Expression profiling of a series of 160 CLL patients allowed interrogating the genes presumably playing a role in pathogenesis, relating the expression of functionally relevant signatures with the time to treatment. First, we identified genes relevant to the biology and prognosis of CLL to build a CLL disease-specific oligonucleotide microarray. Second, we hybridized a training series on the CLL-specific chip, generating a biology-based predictive model. Finally, this model was validated in a new CLL series. Clinical variability in CLL is related with the expression of two gene clusters, associated with B-cell receptor (BCR) signaling and mitogen-activated protein kinase (MAPK) activation, including nuclear factor-kappaB1 (NF-kappaB1). The expression of these clusters identifies three risk-score groups with treatment-free survival probabilities at 5 years of 83, 50 and 17%. This molecular predictor can be applied to early clinical stages of CLL. This signature is related to immunoglobulin variable region somatic hypermutation and surrogate markers. There is a molecular heterogeneity in CLL, dependent on the expression of genes defining BCR and MAPK/NF-kappaB clusters, which can be used to predict time to treatment in early clinical stages.

Role of MTHFR (677, 1298) haplotype in the risk of developing secondary leukemia after treatment of breast cancer and hematological malignancies

Therapy-related myelodysplasia and acute myeloid leukemia (t-MDS/AML) is a malignancy occurring after exposure to chemotherapy and/or radiotherapy. Polymorphisms involved in chemotherapy/radiotherapy response genes could be related to an increased risk of developing this neoplasia. We have studied 11 polymorphisms in genes of drug detoxification pathways (NQO1, glutathione S-transferase pi) and DNA repair xeroderma pigmentosum, complementation group (3) (XPC(3), X-ray repair cross complementing protein (1)), Nijmegen breakage syndrome (1), excision repair cross-complementing rodent repair deficiency, complementation group (5) and X-ray repair cross complementing protein (3) and in the methylene tetrahydrofolate reductase gene (MTHFR(2), 677C>T, 1298A>C), involved in DNA synthesis. The analyzed groups were a t-MDS/AML patients group (n=81) and a matched control group (n=64) treated similarly, and they did not develop t-MDS/AML. We found no significant differences when the groups were compared globally. However, when analysis was carried out according to the primary neoplasia involved, a significant association was observed between the MTHFR haplotype (single nucleotide polymorphisms 677 and 1298) and the risk of developing t-MDS/AML in the breast cancer patients group (P=0.016) and cyclophosphamide-treated hematological disease group (P=0.005). Risk haplotype was different for each case, corresponding to the 677T1298A haplotype after breast cancer treatment and the 677C1298C haplotype after hematological malignancy treatment. We postulate that such differences are related to variations in chemotherapy schemes between hematological and breast cancers and their differential interaction with the MTHFR route.

Characterization of a reference material for BCR-ABL (M-BCR) mRNA quantitation by real-time amplification assays: towards new standards for gene expression measurements

Monitoring of BCR-ABL transcripts has become established practice in the management of chronic myeloid leukemia. However, nucleic acid amplification techniques are prone to variations which limit the reliability of real-time quantitative PCR (RQ-PCR) for clinical decision making, highlighting the need for standardization of assays and reporting of minimal residual disease (MRD) data. We evaluated a lyophilized preparation of a leukemic cell line (K562) as a potential quality control reagent. This was found to be relatively stable, yielding comparable respective levels of ABL, GUS and BCR-ABL transcripts as determined by RQ-PCR before and after accelerated degradation experiments as well as following 5 years storage at -20 degrees C. Vials of freeze-dried cells were sent at ambient temperature to 22 laboratories on four continents, with RQ-PCR analyses detecting BCR-ABL transcripts at levels comparable to those observed in primary patient samples. Our results suggest that freeze-dried cells can be used as quality control reagents with a range of analytical instrumentations and could enable the development of urgently needed international standards simulating clinically relevant levels of MRD.

Low cost, biocompatible elastic and conformable electronic technologies using MID in stretchable polymer

For user comfort reasons, electronic circuits for implantation in the human body or for use as smart clothes should ideally be soft, stretchable and elastic. In this contribution the results of an MID (Molded Interconnect Device) technology will be presented, showing the feasibility of functional stretchable electronic circuits. In the developed technology rigid or flexible standard components are interconnected by meander shaped metallic wires and embedded by molding in a stretchable substrate polymer. Several technologies have been developed to this purpose, which combine low cost and good reliability under mechanical strain. In this way reliable stretchability of the circuits above 100% has been demonstrated. Enhanced reliability has been reached using an additional conductive polymer layer.

Molecular characterization of two isoforms of defensin from hemocytes of the oyster Crassostrea gigas

Antimicrobial peptides (AMPs) are important components of the host innate immune response against microbial invasion. We previously characterized the first AMP from an oyster, a defensin, that was shown to be continuously expressed in the mantle of Crassostrea gigas. In this study, we report the cDNA cloning of two new isoforms of the defensin AMP family (Cg-defh1 and Cg-defh2) from the hemocytes of the oyster. The deduced amino acid sequences reveal two peptides of 73 amino acid residues with a mature portion consisting of 43 amino acid residues. Cg-Defh1 and Cg-Defh2 share 86% amino acid identity and belong to the "arthropod-molluscs defensin family". qRT-PCR analyses indicate that Cg-defh2 is continuously expressed in the hemocytes of C. gigas. In addition, after a bacterial challenge, the level of Cg-defh2 transcripts decreases dramatically in the circulating hemocyte population and this decrease can be correlated with an increase of Cg-defh2 transcripts in the gill and the mantle tissue, suggesting a possible migration of the hemocytes expressing Cg-defh2 towards the tissues implicated in the first defense barrier of the oyster. These results would suggest an important role of Cg-Defh2 in the oyster response to a microbial challenge.

The treatment of primary and metastatic renal cell carcinoma (RCC) with image-guided stereotactic body radiation therapy (SBRT)

PURPOSE

Brain metastases from renal cell carcinoma (RCC) have been successfully treated with stereotactic radiosurgery (SRS). Metastases to extra-cranial sites may be treated with similar success using stereotactic body radiation therapy (SBRT), where image-guidance allows for the delivery of precise high-dose radiation in a few fractions. This paper reports the authors' initial experience with image-guided SBRT in treating primary and metastatic RCC.

MATERIALS AND METHODS

The image-guided Brainlab Novalis stereotactic system was used. Fourteen patients with 23 extra-cranial metastatic RCC lesions (orbits, head and neck, lung, mediastinum, sternum, clavicle, scapula, humerus, rib, spine and abdominal wall) and two patients with biopsy-proven primary RCC (not surgical candidates) were treated with SBRT (24-40 Gy in 3-6 fractions over 1-2 weeks). All patients were immobilised in body cast or head and neck mask. Image-guidance was used for all fractions. PET/CT images were fused with simulation CT images to assist in target delineation and dose determination. SMART (simultaneous modulated accelerated radiation therapy) boost approach was adopted. 4D-CT was utilised to assess tumour/organ motion and assist in determining planning target volume margins.

RESULTS

Median follow-up was nine months. Thirteen patients (93%) who received SBRT to extra-cranial metastases achieved symptomatic relief. Two patients had local progression, yielding a local control rate of 87%. In the two patients with primary RCC, tumour size remained unchanged but their pain improved, and their renal function was unchanged post SBRT. There were no significant treatment-related side effects.

CONCLUSION

Image-guided SBRT provides excellent symptom palliation and local control without any significant toxicity. SBRT may represent a novel, non-invasive, nephron-sparing option for the treatment of primary RCC as well as extra-cranial metastatic RCC.

Hyperhomocysteinemia is a risk factor of recurrent coronary event in young patients irrespective to the MTHFR C677T polymorphism

Despite the well-known pro-coagulant effect of hyperhomocysteinemia, data is limited regarding the result on recurrent coronary event (RCE) in young people. One hundred and forty patients <55 years old with a first acute coronary syndrome (ACS) were prospectively followed for a mean (+/-S.D.) follow-up of 49+/-14 months in order to investigate the relationship between homocysteine levels (tHcy) at admission and the incidence of RCE. The tHcy values were divided into quartiles to examine their relationship with end points. Furthermore, we determined the effect of C677T methylene tetrahydrofolate reductase (MTHFR) polymorphism, as well as other risk factors for developing a RCE. The median plasma homocysteine concentration was 9.6 mumol/L (interquartile range, 3.7). In the screening of MTHFR C677T polymorphism in patients with ACS, the T allele frequency was 0.4 and the genotype frequency distributions were in Hardy-Weinberg equilibrium. At time of final evaluation, 49 (35%) of the 140 valuable patients had developed a RCE. Increasing numbers of RCE were observed for increasing quartiles of tHcy according to Kaplan-Meier survival (Log-rank test=0.0092). The MTHFR C677T polymorphism was not associated with an increased incidence of RCE. In multivariate analysis, the variables independently associated with a higher risk of RCE were age older than 45 years [HR=2.7; (95% CI, 1.3-6.1); p=0.030], body mass index more than 25 [HR=2.6; (95% CI, 1.1-5.9); p=0.034] and tHcy levels into quartile 4 (tHcy>12.37 mumol/L) [HR=2.5; (95% CI, 1.1-4.7); p=0.04]. Elevated plasma homocysteine level at admission is an independent risk factor for RCE after the first episode of ACS in young patients irrespective of the status of MTHFR C677T.

Intestinal transplantation for short bowel syndrome secondary to gastroschisis

BACKGROUND/PURPOSE

Gastroschisis is the most frequent cause of pediatric intestinal transplantation. This study reviews our experience of intestinal transplantation secondary to gastroschisis to elucidate those factors affecting the outcome of children with short bowel syndrome.

METHODS

A retrospective review was performed for children who underwent intestinal transplantation for gastroschisis at the University of Miami between June 2003 and August 1994.

RESULTS

Thirty-two transplants were performed in 28 children with gastroschisis during the study period. Associated intestinal anomalies were present in 22 infants (atresia [n = 14], volvulus [n = 3], and/or ischemia [n = 16]). Spontaneous prenatal closure of gastroschisis, a rare anomaly associated with bowel atresia and ischemia because of a very small abdominal defect, was seen in 9 patients. Most of the patients had a complicated course and required multiple abdominal surgeries before transplant. Fifteen (53.6%) patients are currently alive at a median follow-up of 23.5 months. Short-term survival rate has significantly improved in recent years.

CONCLUSIONS

Patients with complex gastroschisis and intestinal anomalies have a significant risk for progression to short bowel syndrome. Intestinal transplantation can be a lifesaving option and provides a satisfactory outcome for children with short bowel syndrome secondary to gastroschisis.

[Surgical treatment of duodenal stenosis in Crohn's disease]

Crohn's disease may involve any part of the alimentary tract, including the stomach and duodenum. We report herein the case of a 22 year-old male in whom Crohn disease was diagnosed due to weight loss in relation with a stenosis of the first and second parts of the duodenum. A gastrojejunostomy was performed with a good subsequent result. The initial management of a Crohn's disease with involvement of the duodenum is medical. When there is an indication for surgery, a gastroenterostomy is preferred, albeit with a high incidence of outlet obstruction and marginal ulceration.

A phase II trial of epirubicin (E), estramustine phosphate (EP), and celecoxib (C) as second line treatment of patients (pts) with hormone resistant prostate cancer (HRPC)

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Background: Celecoxib, epirubicin, and estramustine phosphate affect prostate cancer cells through different mechanisms. All three could be synergistic. We studied the effects of this combination on PSA, response, toxicity and survival in pts with HRPC. Methods: Pts after progression from first line taxane-based chemotherapy with rising PSA and radiographic progression were eligible. Treatment was E30 mg/m2 iv on day 1 and 8 of each 4 week cycle; EP 280 mg po bid daily × 3 days every wk × 2 followed by 2 wks rest; C 400 mg po bid daily for 28 days. All pts were assessed for response every 2 cycles. Dose modifications for hematologic and hepatorenal toxicity were made. RECIST criteria and PSA decline>50% were used to define response. Results: Sixteen pts enrolled, and 13 are evaluable for toxicity and response. Two withdrew before treatment and one for toxicity. The Median (M) age was 71.5 yrs (59–87), ECOG PS 1 (0–1), Gleason score 7 (4–9), LDH 172 (131–244), Hgb 11.1 (8.8–11.9), PSA 75 (6–814). Pts received M 4 cycles (2–10). Nine (69%) pts had soft tissue and 12 (92%) pts had bone metastases. For radiographic response, 11 pts were evaluable; 6 had stable disease and 2 had complete response by CT. Two pts had response by bone scan. Nine (69%) pts had PSA response. The M survival was 441 days (10–995). There were 5 SAE - DVT, diarrhea, bowel obstruction, cord compression and myocardial infarction. There was good renal and cardiac tolerance. Conclusions: This combination was safe and showed good and durable response as a second line regimen.

[Table: see text]