Measurements of Electrodermal Activity, Tissue Oxygen Saturation, and Visual Analog Scale for Different Cuff Pressures

The quantification of comfort in binding parts, essential human-machine interfaces (HMI) for the functioning of rehabilitation robots, is necessary to reduce physical strain on the user despite great achievements in their structure and control. This study aims to investigate the physiological impacts of binding parts by measuring electrodermal activity (EDA) and tissue oxygen saturation (StO2). In Experiment 1, EDA was measured from 13 healthy subjects under three different pressure conditions (10, 20, and 30 kPa) for 1 min using a pneumatic cuff on the right thigh. In Experiment 2, EDA and StO2 were measured from 10 healthy subjects for 5 min. To analyze the correlation between EDA parameters and the decrease in StO2, a survey using the visual analog scale (VAS) was conducted to assess the level of discomfort at each pressure. The EDA signal was decomposed into phasic and tonic components, and the EDA parameters were extracted from these two components. RM ANOVA and a post hoc paired t-test were used to determine significant differences in parameters as the pressure increased. The results showed that EDA parameters and the decrease in StO2 significantly increased with the pressure increase. Among the extracted parameters, the decrease in StO2 and the mean SCL proved to be effective indicators. Such analysis outcomes would be highly beneficial for studies focusing on the comfort assessment of the binding parts of rehabilitation robots.

Augmented reality in bone tumour resection: An experimental study

OBJECTIVES

We evaluated the accuracy of augmented reality (AR)-based navigation assistance through simulation of bone tumours in a pig femur model.

METHODS

We developed an AR-based navigation system for bone tumour resection, which could be used on a tablet PC. To simulate a bone tumour in the pig femur, a cortical window was made in the diaphysis and bone cement was inserted. A total of 133 pig femurs were used and tumour resection was simulated with AR-assisted resection (164 resection in 82 femurs, half by an orthropaedic oncology expert and half by an orthopaedic resident) and resection with the conventional method (82 resection in 41 femurs). In the conventional group, resection was performed after measuring the distance from the edge of the condyle to the expected resection margin with a ruler as per routine clinical practice.

RESULTS

The mean error of 164 resections in 82 femurs in the AR group was 1.71 mm (0 to 6). The mean error of 82 resections in 41 femurs in the conventional resection group was 2.64 mm (0 to 11) (p < 0.05, one-way analysis of variance). The probabilities of a surgeon obtaining a 10 mm surgical margin with a 3 mm tolerance were 90.2% in AR-assisted resections, and 70.7% in conventional resections.

CONCLUSION

We demonstrated that the accuracy of tumour resection was satisfactory with the help of the AR navigation system, with the tumour shown as a virtual template. In addition, this concept made the navigation system simple and available without additional cost or time.Cite this article: H. S. Cho, Y. K. Park, S. Gupta, C. Yoon, I. Han, H-S. Kim, H. Choi, J. Hong. Augmented reality in bone tumour resection: An experimental study. Bone Joint Res 2017;6:137-143.

Peach skin powder inhibits oxidation in cooked turkey meat

The objective of this study was to measure the antioxidant activity of peach skin and test the antioxidant effect of peach skin powder on cooked ground turkey meat during 12 d of refrigerated storage. Antioxidant activity of 3 cultivars of peaches grown in South Carolina was first evaluated by 3 antioxidant assays. The peach variety O'Henry showed the greatest antioxidant effect and therefore was used for further study. Two levels of peach skin powder (0.5%, 1%) and 0.01% butylated hydroxylanisole (BHA) were applied to ground turkey meat. Oxidation of cooked turkey meat was measured by detection of hexanal using gas chromatography-mass spectrometry. Results indicated that all levels of peach skin powder used in this study had an antioxidant effect on ground turkey with a greater effect at the higher concentration. O'Henry peach skin powder was as effective as BHA in preventing oxidation at the levels tested.

RHEB: a potential regulator of chondrocyte phenotype for cartilage tissue regeneration

As articular cartilage has a limited ability to self-repair, successful cartilage regeneration requires clinical-grade chondrocytes with innate characteristics. However, cartilage regeneration via chondrocyte transplantation is challenging, because chondrocytes lose their innate characteristics during in vitro expansion. Here, we investigated the mechanistic underpinning of the gene Ras homologue enriched in brain (RHEB) in the control of senescence and dedifferentiation through the modulation of oxidative stress in chondrocytes, a hallmark of osteoarthritis. Serial expansion of human chondrocytes led to senescence, dedifferentiation and oxidative stress. RHEB maintained the innate characteristics of chondrocytes by regulating senescence, dedifferentiation and oxidative stress, leading to the upregulation of COL2 expression via SOX9 and the downregulation of p27 expression via MCL1. RHEB also decreased the expression of COL10. RHEB knockdown mimics decreased the expression of SOX9, COL2 and MCL1, while abrogating the suppressive function of RHEB on p27 and COL10 in chondrocytes. RHEB-overexpressing chondrocytes successfully formed cartilage tissue in vitro as well as in vivo, with increased expression of GAG matrix and chondrogenic markers. RHEB induces a distinct gene expression signature that maintained the innate chondrogenic properties over a long period. Therefore, RHEB expression represents a potentially useful mechanism in terms of cartilage tissue regeneration from chondrocytes, by which chondrocyte phenotypic and molecular characteristics can be retained through the modulation of senescence, dedifferentiation and oxidative stress. Copyright © 2016 John Wiley & Sons, Ltd.

AIMP1 downregulation restores chondrogenic characteristics of dedifferentiated/degenerated chondrocytes by enhancing TGF-β signal

Dedifferentiation and degeneration of chondrocytes critically influences the efficiency of cartilage repair. One of the causes is the defect of transforming growth factor (TGF)-β signaling that promotes chondrogenic differentiation and degeneration. In the present study, we found that aminoacyl-tRNA synthetase-interacting multifunctional protein 1 (AIMP1) negatively regulates TGF-β signaling via interactions with Smad2 and Smad3 in immunoprecipitation assay and luciferase assay. In addition, we observed that the AIMP1 expression level was significantly increased in osteoarthritis (OA) patient-derived degenerated chondrocytes compared with healthy control. So, we hypothesized that downregulation of AIMP1 using small-interfering RNA (siRNA) technology in dedifferentiated (collected at passage #6) and degenerated (obtained from OA-affected areas) chondrocytes could lead to recover TGF-β signaling in both chondrocytes. Indeed, AIMP1 downregulation restored TGF-β signaling by promoting phosphorylation of Smad2 and Smad3, which shows redifferentiated characteristics in both dedifferentiated and degenerated chondrocytes. Additionally, implantation analyses using in vivo mouse model clearly showed that AIMP1 downregulation resulted in the increased chondrogenic potential as well as the enhanced cartilage tissue formation in both dedifferentiated and degenerated chondrocytes. Histological analyses clarified that AIMP1 downregulation increased expression levels of collagen type II (Col II) and aggrecan, but not Col I expression. Taken together, these data indicate that AIMP1 downregulation using siRNA is a novel tool to restore TGF-β signaling and thereby increases the chondrogenic potential of dedifferentiated/degenerated chondrocytes, which could be further developed as a therapeutic siRNA to treat OA.

Regulation of senescence associated signaling mechanisms in chondrocytes for cartilage tissue regeneration

Adult articular chondrocytes undergo slow senescence and dedifferentiation during in vitro expansion, restricting successful cartilage regeneration. A complete understanding of the molecular signaling pathways involved in the senescence and dedifferentiation of chondrocytes is essential in order to better characterize chondrocytes for cartilage tissue engineering applications. During expansion, cell fate is determined by the change in expression of various genes in response to aspects of the microenvironment, including oxidative stress, mechanical stress, and unsuitable culture conditions. Rapid senescence or dedifferentiation not only results in the loss of the chondrocytic phenotype but also enhances production of inflammatory mediators and matrix-degrading enzymes. This review focuses on the two groups of genes that play direct and indirect roles in the induction of senescence and dedifferentiation. Numerous degenerative signaling pathways associated with these genes have been reported. Upregulation of the genes interleukin 1 beta (IL-1β), p53, p16, p21, and p38 mitogen-activated protein kinase (MAPK) is responsible for the direct induction of senescence, whereas downregulation of the genes transforming growth factor-beta (TGF-β), bone morphogenetic protein-2 (BMP-2), SRY (sex determining region Y)-box 9 (SOX9), and insulin-like growth factor-1 (IGF-1), indirectly induces senescence. In senescent and dedifferentiated chondrocytes, it was found that TGF-β, BMP-2, SOX9, and IGF-1 are downregulated, while the levels of IL-1β, p53, p16, p21, and p38 MAPK are upregulated followed by inhibition of the normal molecular functioning of the chondrocytes. This review helps to elucidate the underlying mechanism in degenerative cartilage disease, which may help to improve cartilage tissue regeneration techniques.

Malva verticillata seed extracts upregulate the Wnt pathway in human dermal papilla cells

OBJECTIVE

Mesenchymal-epithelial interactions are important in controlling hair growth and the hair cycle. The β-catenin pathway of dermal papilla cells (DPCs) plays a pivotal role in morphogenesis and normal regeneration of hair follicles. Deletion of β-catenin in the dermal papilla reduces proliferation of the hair follicle progenitor cells that generate the hair shaft and induces an early onset of the catagen phase. In this study, a modulator of the Wnt/β-catenin activity was studied in oriental herb extracts on cultured human DPCs.

METHODS

The effect of Malva verticillata (M. verticillata) seeds on human DPCs was investigated by a Wnt/β-catenin reporter activity assay system (β-catenin-TCF/LEF reporter gene) and cell proliferation analysis. The synthesis of the factors related to hair growth and cycling was measured at both the mRNA and the protein level by semi-quantitative PCR and Western blot analysis, respectively.

RESULTS

An extract from M. verticillata seeds increased Wnt reporter activity in a concentration-dependent manner and also led to increased β-catenin levels in cultured human DPCs. Myristoleic acid, identified as an effective compound of M. verticillata seeds, stimulated the proliferation of DPCs in a dose-dependent manner and increased transcription levels of the downstream targets: IGF-1, KGF, VEGF and HGF. Myristoleic acid also enhanced the phosphorylation of MAPKs (Akt and p38).

CONCLUSION

Overall, the data suggest that this extract of M. verticillata seeds could be a good candidate for treating hair loss by modulating the Wnt/β-catenin pathway in DPCs.

Osteoarthritis of the hip in fibrous dysplasia of the proximal femur

Deformity of the proximal femur in fibrous dysplasia leads to deviation of the mechanical axis of the hip, which may lead to the development of secondary osteoarthritis (OA). This study investigated the prevalence and predisposing factors for the development of OA in patients with fibrous dysplasia of the proximal femur. We reviewed the records of 209 patients from our institutional database with fibrous dysplasia of the proximal femur, investigating possible predisposing factors including patient demographics, the extent of the coxa vara deformity, the presence of peri-articular disease, and the overall burden of skeletal disease. Of the 209 patients, 24 (12%) had radiological evidence of OA in the ipsilateral hip. The prevalence was significantly higher in patients with polyostotic fibrous dysplasia compared with those with monostotic disease (p < 0.001). In a subgroup analysis of patients with polyostotic disease, the extent of deformity (quantified using the neck–shaft angle), and the presence of peri-articular disease (whether in the head of the femur or the acetabulum) were significant predictors of osteoarthritis (neck–shaft angle likelihood ratio (LR) = 0.847 per 1° increase, p = 0.004; presence of lesion in the head of the femur LR = 9.947, p = 0.027; presence of lesion in the acetabulum LR = 11.231, p = 0.014).

Our data suggest that patients with polyostotic fibrous dysplasia have a high risk of developing secondary OA of the hips. This risk is higher in patients with peri-articular disease, and those with a more severe deformity of proximal femur.

Cite this article: Bone Joint J 2015;97-B:1007–11.

The MRI appearances of cancellous allograft bone chips after the excision of bone tumours

Cancellous allograft bone chips are commonly used in the reconstruction of defects in bone after removal of benign tumours. We investigated the MRI features of grafted bone chips and their change over time, and compared them with those with recurrent tumour. We retrospectively reviewed 66 post-operative MRIs from 34 patients who had undergone curettage and grafting with cancellous bone chips to fill the defect after excision of a tumour. All grafts showed consistent features at least six months after grafting: homogeneous intermediate or low signal intensities with or without scattered hyperintense foci (speckled hyperintensities) on T1 images; high signal intensities with scattered hypointense foci (speckled hypointensities) on T2 images, and peripheral rim enhancement with or without central heterogeneous enhancements on enhanced images. Incorporation of the graft occurred from the periphery to the centre, and was completed within three years. Recurrent lesions consistently showed the same signal intensities as those of pre-operative MRIs of the primary lesions. There were four misdiagnoses, three of which were chondroid tumours. We identified typical MRI features and clarified the incorporation process of grafted cancellous allograft bone chips. The most important characteristics of recurrent tumours were that they showed the same signal intensities as the primary tumours. It might sometimes be difficult to differentiate grafted cancellous allograft bone chips from a recurrent chondroid tumour.

Monostotic fibrous dysplasia of the proximal femur

Monostotic fibrous dysplasia of the proximal femur has a variable clinical course, despite its reported limited tendency to progress.

We investigated the natural history and predisposing factors for progression of dysplasia in a group of 76 patients with a mean follow-up of 8.5 years (2.0 to 15.2). Of these, 31 (41%) presented with an asymptomatic incidental lesion while 45 (59%) presented with pain or a pathological fracture. A group of 23 patients (30%) underwent early operative treatment for pain (19: 25%) or pathological fracture (4: 5%).

Of the 53 patients who were initially treated non-operatively, 45 (85%) remained asymptomatic but eight (15%) needed surgery because of pain or fracture. The progression-free survival of the observation group was 81% (sd 6.4%) at five-years follow-up. An initial presentation of pain (p < 0.001), a limp (p < 0.001), radiological evidence of microfracture (p = 0.001) and younger age (< 17 years) (p = 0.016) were significant predisposing factors for disease progression.

The risk of experiencing pain or pathological fracture is considerable in monostotic fibrous dysplasia of the proximal femur. Patients presenting with pain, a limp or radiological evidence of microfracture have a high chance of needing surgical treatment.

Cite this article: Bone Joint J 2014;96-B:673–6.

Clinicopathological characteristics and prognostic factors of T1 (≤5 cm) soft tissue sarcoma -- a comparative study with T2 (>5 cm) soft tissue sarcoma

BACKGROUND

T1 (≤5 cm) soft tissue sarcoma (STS) may represent a distinct subgroup with different biological characteristics resulting in favorable outcomes, when compared with T2 (>5 cm) STS. However, only few studies focusing on T1 STS have been reported.

METHODS

A retrospective review was conducted on 373 patients (163 with T1 STS [T1 group] and 210 with T2 STS [T2 group]) who underwent surgical removal of STS. Clinicopathologic characteristics and prognostic factors for local recurrence and disease-specific survival (DSS) of T1 STS was investigated and compared with those of T2 STS.

RESULTS

T1 group was younger (p = 0.004), had fewer metastases at initial presentation (p < 0.001), more previous unplanned excisions (p < 0.001), more synovial sarcomas (p = 0.024), fewer liposarcomas (p < 0.001), lower histological grade (p = 0.013), and fewer deep-seated tumors (p < 0.001) than T2 group. For local recurrence, older age (p = 0.008), previous unplanned excision (p = 0.012), and malignant peripheral nerve sheath tumor subtype (p = 0.014) independently predicted poor prognosis in the T2 group whereas only anatomical site of lower extremity (p = 0.046) was a favorable prognostic factor in the T1 group. For DSS, higher histologic grade (p = 0.037) and larger tumor size (p = 0.020) predicted poor prognosis in T2 group whereas only older age (p = 0.005) was prognostic in the T1 group.

CONCLUSIONS

Clinicopathological characteristics and prognostic factors of T1 STS differed from those of T2 STS. Established prognostic factors for STS were of limited value for T1 STS. These findings suggest the necessity of a different assessment strategy for T1 STS.

Antioxidant activity of carnosine extracted from various poultry tissues

The aim of the present research was 1) to extract carnosine from different low economic value poultry tissues and 2) to measure their antioxidant activities using different analytical methods. Low economic value poultry tissues such as the head, liver, lungs, tail, gizzard, brain, and heart were used in this study. Results have indicated that carnosine was present in all the tissue samples investigated. The liver had the highest (102.29 mg/g) and brain the lowest carnosine content (0.95 mg/g; P ≤ 0.05). Except for the brain, all tissue ultrafiltrates and reconstituted dry powders showed TBA reactive species inhibition ranging from 20.87 to 39.57% and 5.66 -14.47%, respectively. Free radical scavenging activity of ultrafiltrate from all tissues samples ranged from 25.11 to 79.38%, whereas this activity was higher (29.76 to 84.05%) in the reconstituted dry powder of all tissue samples. Conclusions include that extraction of bioactive dipeptide carnosine can be exploited from low economic value poultry tissues to increase the economy of the poultry industry.

The outcomes of navigation-assisted bone tumour surgery: minimum three-year follow-up

We evaluated the oncological and functional outcome of 18 patients, whose malignant bone tumours were excised with the assistance of navigation, and who were followed up for more than three years. There were 11 men and seven women, with a mean age of 31.8 years (10 to 57). There were ten operations on the pelvic ring and eight joint-preserving limb salvage procedures. The resection margins were free of tumour in all specimens. The tumours, which were stage IIB in all patients, included osteosarcoma, high-grade chondrosarcoma, Ewing's sarcoma, malignant fibrous histiocytoma of bone, and adamantinoma. The overall three-year survival rate of the 18 patients was 88.9% (95% confidence interval (CI) 75.4 to 100). The three-year survival rate of the patients with pelvic malignancy was 80.0% (95% CI 55.3 to 100), and of the patients with metaphyseal malignancy was 100%. The event-free survival was 66.7% (95% CI 44.9 to 88.5). Local recurrence occurred in two patients, both of whom had a pelvic malignancy. The mean Musculoskeletal Tumor Society functional score was 26.9 points at a mean follow-up of 48.2 months (22 to 79). We suggest that navigation can be helpful during surgery for musculoskeletal tumours; it can maximise the accuracy of resection and minimise the unnecessary sacrifice of normal tissue by providing precise intra-operative three-dimensional radiological information.

Effect of stress on carnosine levels in brain, breast, and thigh of broilers

The objective of the present study was to compare carnosine levels in tissues of broilers under stress conditions with those of broilers under nonstress conditions. Blood heterophil:lymphocyte ratio and corticosterone levels were measured as indicators of the level of stress. Corticosterone levels of stressed broilers (24,358.67 pg/mL) were 10-fold higher (P = 0.002) than those of nonstressed broilers (2,275.46 pg/mL). However, no difference (P = 0.29) was found in heterophil:lymphocyte ratio of nonstressed (0.29) and stressed (0.31) birds. Carnosine content in breast of stressed birds (17.39 mg/g) was 10 times higher (P = 0.005) than that of nonstressed birds (1.85 mg/g). Carnosine content in thigh of stressed birds (21.25 mg/g) was approximately 2-fold higher (P = 0.001) than that of nonstressed birds (11.10 mg/g). Carnosine content in brain of stressed birds did not differ (P = 0.82) from that of nonstressed birds. Based on the present study, muscle carnosine recovery levels increase during short-term stress, whereas levels in the brain are not affected.

Angular dependence of L₃-subshell X-ray emission following photoionisation

L₃-subshell alignment of Th and U ionized by 59.5 keV photons has been investigated by evaluating the angular dependence of L{i}(i=l, α, η, β and γ) X-ray lines. The angular dependence measurements were performed by measuring the fluorescence cross section, σ{Li}(i=1, η, α, β and γ) and σ{Ll}/σ{Lγ}, σ{Lη}/σ{Lγ }, σ{Lα}/σ{Lγ } and σ{Lβ}/σ{Lγ} ratios at different angles. It was observed from the measurements that L{i}(i=l and α) X rays for the L₃-subshell depended on the emission angle and had an anisotropic spatial distribution. On the other hand, there was no dependence of emission angle and any significant anisotropy for other L X rays. The both Ll and Lα X-rays originate from the filling of vacancies in states L₃-subshell with J =3/2. The results of measurements indicate that the L₃-subshell vacancy states with J = 3/2 are aligned, whereas L{1}, and L{2}vacancy states with J =1/2 are non-aligned. Integral cross-sections for the L{i}(i=l, η, α, β and γ) X-rays and L subshell fluorescence yields ω{i} (i= 1, 2 and 3) were also determined and results were compared with theoretically calculated values and results of others and fairly good correspondence was observed.

A study on the mean free path and half value layer at various alloys for different photon energies

The mean free path (mfp) and half value layer (x_1 / 2) values of binary and ternary alloys consist of 3d transition metals have been have been calculated at photon energies 22.1, 25.0, 59.5 and 88.0 keV. The experimental linear attenuation coefficients (μ) for present photon energies have been used to obtain the values of mfp and (x_1 / 2) . The experimental mfp and (x_1 / 2) results have compared with the theoretically calculated results based on attenuation coefficients obtained from WinXCom program. A good correspondence has been observed among the present results and the theoretical results.

Studies on effective atomic numbers, electron densities and mass attenuation coefficients in Au alloys

The total mass attenuation coefficients (mu/rho) for pure Au and Au99Be1, Au88Ge12, Au95Zn5 alloys were measured at 59.5 and 88.0 keV photon energies. The samples were irradiated with 241Am and 109Cd radioactive point source using transmission arrangement. The gamma- rays were counted by a Si(Li) detector with resolution of 160 eV at 5.9 keV. Total atomic and electronic cross-sections (sigmat and sigmae), effective atomic and electron densities (Zeff and Nel) were determined using the obtained mass attenuation coefficients for investigated Au alloys. The theoretical mass attenuation coefficients of each alloy were estimated using mixture rule.

Survival of patients with skeletal metastases from hepatocellular carcinoma after surgical management

Skeletal metastases from hepatocellular carcinoma are highly destructive vascular lesions which severely reduce the quality of life. Pre-existing liver cirrhosis presents unique challenges during the surgical management of such lesions. We carried out a retrospective study of 42 patients who had been managed surgically for skeletal metastases from hepatocellular carcinoma affecting the appendicular skeleton between January 2000 and December 2006. There were 38 men and four women with a mean age of 60.2 years (46 to 77). Surgery for a pathological fracture was undertaken in 30 patients and because of a high risk of fracture in 12. An intralesional surgical margin was achieved in 36 and a wide margin in six. Factors influencing survival were determined by univariate and multivariate analyses. The survival rates at one, two and three years after surgery were 42.2%, 25.8% and 19.8%, respectively. The median survival time was ten months (95% confidence interval 6.29 to 13.71). The number of skeletal metastases and the Child-Pugh grade were identified as independent prognostic factors by Cox regression analysis. The method of management of the hepatocellular carcinoma, its status in the liver, the surgical margin for skeletal metastases, the presence of a pathological fracture and adjuvant radiotherapy were not found to be significantly related to the survival of the patient, which was affected by hepatic function, as represented by the Child-Pugh grade.

Association between radiological findings and symptoms at the patellofemoral joint in advanced knee osteoarthritis

We investigated the association between the radiological findings and the symptoms arising from the patellofemoral joint in advanced osteoarthritis (OA) of the knee. Four radiological features, joint space narrowing, osteophyte formation, translation of the patella and focal attrition were assessed in 151 consecutive osteoarthritic knees in 107 patients undergoing total knee replacement. The symptoms which were assessed included anterior knee pain which was scored, the ability to rise from a chair and climb stairs, and quadriceps weakness.

Among the radiological features, only patellar translation and obliteration of the joint space had a statistically significant association with anterior knee pain (odds ratio (OR) 4.85; 95% confidence interval (CI) 1.83 to 12.88 and OR 11.23; 95% CI 2.44 to 51.62) respectively. Patellar translation had a statistically significant association with difficulty in rising from a chair (OR 9.06; 95% CI 1.75 to 45.11). Other radiological features, including osteophytes, joint space narrowing, and focal attrition had no significant association.

Our study indicates that the radiological findings of patellar translation and significant loss of cartilage are predictive of patellofemoral symptoms and functional limitation in advanced OA of the knee.

Residence time and food contact time effects on transfer of Salmonella Typhimurium from tile, wood and carpet: testing the five-second rule

AIMS

Three experiments were conducted to determine the survival and transfer of Salmonella Typhimurium from wood, tile or carpet to bologna (sausage) and bread.

METHODS AND RESULTS

Experiment 1. After 28 days, 1.5 to 2.5 log(10) CFU cm(-2) remained on tile from and the more concentrated media facilitated the survival of S. Typhimurium compared with the more dilute solutions. Experiments 2 and 3. The bacterial transfer rate to food decreased as the bacterial residence time on the surface increased from 2, 4, 8 to 24 h with transfers of 6.5, 4.8, 4.6 and 3.9 log CFU ml(-1) in the rinse solutions, respectively. Over 99% of bacterial cells were transferred from the tile to the bologna after 5 s of bologna exposure to tile. Transfer from carpet to bologna was very low (<0.5%) when compared with the transfer from wood and tile (5-68%).

CONCLUSIONS

(i) Salmonella Typhimurium can survive for up to 4 weeks on dry surfaces in high-enough populations to be transferred to foods and (ii) S. Typhimurium can be transferred to the foods tested almost immediately on contact.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrated the ability of bacteria to survive and cross-contaminate other foods even after long periods of time on dry surfaces, thus reinforcing the importance of sanitation on food contact to minimize the risk of foodborne illness.

Measurement of K X-ray fluorescence cross-sections, fluorescence yields and intensity ratios for some elements in the atomic range 22⩽Z⩽68

The Kalpha, Kbeta, and total K X-rays fluorescence cross-sections, as well as the average fluorescence yields for 24 elements with 22 <or= Z <or= 68 have been measured at an excitation energy 59.54 keV gamma-rays from an Am-241 filtered point source. Furthermore, the I(Kalpha)/I(Kbeta) intensity ratios for these elements have been investigated. The K X-rays emitted by samples have been counted by a Si(Li) detector. Experimental values of the K X-ray fluorescence cross-sections, fluorescence yields, and the I(Kalpha)/I(Kbeta) intensity ratios have been compared with theoretical values. In most cases, there is an agreement between the experimental and theoretical values within the standard uncertainties.

Quality of fresh chicken breasts using a combination of modified atmosphere packaging and chlorine dioxide sachets

The objective of this research was to observe the effect of chlorine dioxide (ClO2) combined with modified atmosphere packaging on the quality of fresh chicken breasts under refrigerated storage for 15 days. Each chicken breast was inoculated with a 4-log CFU/ml culture of Salmonella Typhimurium (nalidixic acid-resistant strain) and placed into a barrier foam tray. Fast- or slow-release ClO2 sachets were placed next to the chicken in each package. A control set of packages that did not contain a ClO2 sachet was also included in the study. Packages were flushed with either 100% N2 or 75% N2-25% CO2 and stored at 3 degrees C. Microbial analysis, CIE L.a.b. color, and sensory (appearance and aroma) were performed every 3 days for 15 days. Total plate counts for chicken increased steadily after 6 to 9 days of storage regardless of package atmosphere or ClO2 treatment. However, those treated with ClO2 sachets had 1 to 1.5 log CFU per chicken breast lower total plate counts compared with those without ClO2 sachets. After 15 days, samples treated with ClO2 (fast- and slow-release sachets) had significantly lower Salmonella Typhimurium (nalidixic acid-resistant strain) populations (approximately 1 log) compared with chicken that did not contain ClO2 sachets. The ClO2 adversely affected the color of the chicken in areas close to the sachet. No off-odor was detected by the sensory panelists.

Correlation of the condition of the patellar articular cartilage and patellofemoral symptoms and function in osteoarthritic patients undergoing total knee arthroplasty

We sought to determine the degree of correlation between the condition of the patellar articular cartilage and patellofemoral symptoms and function in osteoarthritic patients undergoing total knee arthroplasty. The depth of the osteoarthritic lesion, as graded by the Outerbridge classification and its size and location were assessed to determine the condition of the patellar cartilage in 80 consecutive osteoarthritic knees undergoing total knee arthroplasty. The association between the condition of the cartilage and patellofemoral symptoms and function was investigated by correlation analysis. The depth and size of the lesion had a significant but weak correlation with anterior knee pain (r = -0.300 and -0.289; p = 0.007 and 0.009, respectively), whereas location had no significant association (p > 0.05). None had a significant association with patellofemoral functional parameters (chair-rising, stair-climbing, and quadriceps power) (p > 0.05). Our study indicates that patellofemoral symptoms and function are not completely determined by the condition of the cartilage. Caution should be taken when the symptoms and functional limitations are attributed to a lesion in the patellofemoral joint in making a decision regarding patellar resurfacing in total knee arthroplasty.

Characterization of humic substances isolated from Han River water and change in the structural and chemical characteristics by ozonation

This study investigated the characteristics of extracted humic substances, which are ubiquitous in river waters and affect the treatment of water. Humic substances were extracted from the Han River water and analyzed using the samples obtained before/after ozonation with various analytical items. Ozonation was conducted in a batch-type reactor, and ozone was dosed from 0 to 2.0 mg O3 mg(-1) humic substances. The humic fraction was 56.0% of total organic carbon in the Han River and the ratio of fulvic to humic acids was approximately 3.46, including aromatic ring structures and/or various functional groups. Humic substances could not completely be oxidized to CO2, H2O, etc., but partly oxidized to low molecular weight matter, thus low removal efficiencies in terms of dissolved organic carbon (31% at 1.0 mg O3 mg(-1) humic substances) were observed. For UV absorbance at the wavelength 254 nm, ozone dose at 1.0 mg O3 mg(-1) humic substances showed more than 80% removal efficiencies. The molar ratios of H/C and O/C of the humic substances structure relatively increased by ozonation, indicating the degradation of aromatic groups in the humic substances molecule. The Fourier transform infrared spectra and proton nuclear magnetic resonance spectra of humic substances showed the increase in carboxylic acids and the decrease in aromatic protons through ozonation, respectively. As specific reaction sites in the humic substances including aromatic ring structures were reduced through ozone oxidation, contents of carboxylic acids, ketones and quinones in the humic substances molecule increased.

Enhanced transfollicular delivery of adriamycin with a liposome and iontophoresis

To find a better way to deliver drugs into hair follicles, we tried two approaches: single topical application using various liposomes; and iontophoresis combined with topical application of ionic liposome. After delivery of adriamycin (ADR) to wax-depilated rat skin, the transport of the drug was examined under fluorescence microscopy. Most liposomal ADR showed more effective transdermal and transfollicular penetration than free ADR. Among tested liposomes, the non-ionic GDL liposome (GDL/CH/POE-10 = glycerol dilaulate/cholesterol/polyoxyethylene-10) was the most selective to hair follicles against skin, while the cationic liposome (GDL/CH/POE-10/DOTAP, dioleoyl trimethylammonium propane) containing monocationic DOTAP was less selective; however, it was better at improving the delivery amount and penetration of ADR into the follicles and skin. The DMPC/DMPG (7/3) formulation of anionic PC liposome (DMPC/DMPG = dimyristoyl-phosphocholine/-phospoglycerol) showed results similar to the cationic liposome. The DMPC/DMPG (3/7) formulation yielded poor results, however, probably because of its increased viscosity and anionic property. Although ADR delivery was enhanced by liposomal formulations, topical applications had some limitations in delivery capacity and speed. To accelerate delivery, iontophoresis was combined with the cationic liposome at positive 0.2-0.4 mA/cm(2) for 20-30 min. The resulting delivery of ADR through follicular routes was excellent. This combination method diffused ADR 3.0-fold more efficiently, rapidly and deeply than single topical application of cationic liposomal ADR. This system also achieved a 3.5-fold higher diffusive follicular delivery than a free ADR/iontophoresis combination. Furthermore, it was demonstrated that the tetracationic lipid DOSPER and hydrophile spermine could serve as a cationic additive instead of the monocationic DOTAP in the liposome. These results suggest that the combinative system of the topically applied cationic liposome followed by iontophoresis has a significant synergistic effect on the transfollicular delivery of ADR.

Ozonation of Han River humic substances

This study investigated the characteristics of extracted humic substances (HS) which are ubiquitous in river waters and affect the treatment of the water. HS were extracted from the Han River and the samples obtained were analyzed before/after oxidation with the following analytical methods: DOC, THMFP, UV-abs, chemical composition, molecular weight distribution, IR. Ozonation experiments were conducted in batch-type reactors. Ozone dose was 1 mg/L and contact time was varied from 0 to 20 minutes. The fraction of hydrophobic matter was 56.0% of total organic carbon in the Han River and the ratio of humic/fulvic acids was 22.4/77.6, showing high fractions of aromatic and/or double carbon bond functional groups and high fractions of saturated aliphatic carbons. Oxygen fraction of Han HS was relatively high compared with other humic substances (Suwannee River humic and fulvic acids), which are consistent with the results of IR spectra. The IR spectra showed the increase in aliphatic groups by ozonation of the Han HS. Humic substances could not completely be oxidized to CO2, H2O etc., but were partly oxidized to low molecular weight matter (aliphatics, aldehydes, carboxylics, polysaccharides etc.), so low removal efficiencies in terms of DOC (31-35% with 5 minute contact) were observed. For UV254, 5 minute or shorter contact showed more than 80% removal efficiencies.

C-terminal heparin-binding domain of fibronectin regulates integrin-mediated cell spreading but not the activation of mitogen-activated protein kinase

Fibronectin (FN) stimulates multiple signalling events including mitogen-activated protein kinase (MAPK) activation. During cell spreading, both the cell-binding domain and the C-terminal heparin-binding domain (HepII) of FN co-operatively regulate cytoskeleton organization. However, in comparison with the large number of studies on the functions of cell-binding domain, there is little information about the role of HepII. We therefore investigated the effect of HepII on integrin-mediated cell spreading and adhesion on FN and MAPK activation. In contrast with cells on FN substrates, rat embryo fibroblasts on FN120, which lacks HepII, were less spread, had weaker adhesion to FN and failed to form focal adhesions and actin stress fibres. Phosphotyrosine was present in the focal contacts of rat embryo fibroblasts on FN within 30 min but was absent from cells on FN120. Overall, tyrosine phosphorylation was much less in cell lysates from cells on FN120, with decreased phosphorylation of focal adhesion kinase ('pp125FAK') on tyrosine-397, implying additional regulation of tyrosine phosphorylation by HepII. Nevertheless, adhesion-mediated MAPK activity was similar in cells on FN and on FN120. Furthermore, cells spread on FN and on FN120 substrates showed similar MAPK activation in response to treatment with epidermal growth factor and with platelet-derived growth factor. Consistently, overexpression of syndecan-4, which binds to HepII, enhanced cell spreading and adhesion on FN but did not affect integrin-mediated MAPK activation. We therefore conclude that both HepII and syndecan-4 regulate integrin-mediated cell spreading but not MAPK activation.

Ex vivo fluorescence microscopy provides simple and accurate assessment of neutrophil-endothelial adhesion in the rat lung

Neutrophil adhesion to the pulmonary endothelium is prerequisite to neutrophil transmigration and activation, both of which may lead to lung injury. A simple method to evaluate neutrophil adherence in the lung would be useful for developing new strategies for neutrophil-mediated lung injury. The purpose was to establish a simple method to evaluate neutrophil adhesion in the lung using ex vivo fluorescence microscopy. Rats were anesthetized, and the right jugular veins were catheterized. Neutrophils were isolated from another set of rats and labeled with 5,(6)-carboxyfluorescein diacetate. Animals were killed 120 s after a 1 x 10(6) labeled neutrophil injection. The pulmonary labeled neutrophil number was counted under a fluorescence microscope. In the first experiment, rats were given 0, 20, 200, or 2000 microg/kg lipopolysaccharide (LPS) i.p. At 4 h after challenge, the pulmonary labeled neutrophil number was determined. Kinetic studies were also performed at 0, 1, 4, and 8 h after 200 microg/kg LPS. Finally, anti-ICAM-1 Ab was injected i.v. before LPS 200 microg/kg, and the labeled neutrophil number in the lung was determined at 4 h. The number of pulmonary labeled neutrophils was higher after LPS 200 or 2000 microg/kg than after the other doses. The pulmonary labeled neutrophil number was increased at 4 h compared with the other time points. ICAM-1 blocking normalized the pulmonary labeled neutrophil number in the LPS group. In conclusion, our method seems to reflect ICAM-1-mediated neutrophil adherence to the endothelium in the present setting. This simple technique may be useful for evaluating neutrophil adhesion.

Solution structure of the dimeric cytoplasmic domain of syndecan-4

The syndecans, transmembrane proteoglycans which are involved in the organization of cytoskeleton and/or actin microfilaments, have important roles as cell surface receptors during cell-cell and/or cell-matrix interactions. Since previous studies indicate that the function of the syndecan-4 cytoplasmic domain is dependent on its oligomeric status, the conformation of the syndecan-4 cytoplasmic domain itself is important in the understanding of its biological roles. Gel filtration results show that the syndecan-4 cytoplasmic domain (4L) itself forms a dimer stabilized by ionic interactions between peptides at physiological pH. Commensurately, the NMR structures demonstrate that syndecan-4L is a compact intertwined dimer with a symmetric clamp shape in the central variable V region with a root-mean-square deviation between backbone atom coordinates of 0.95 A for residues Leu(186)-Ala(195). The molecular surface of the 4L dimer is highly positively charged. In addition, no intersubunit NOEs in membrane proximal amino acid resides (C1 region) have been observed, demonstrating that the C1 region is mostly unstructured in the syndecan-4L dimer. Interestingly, two parallel strands of 4L form a cavity in the center of the dimeric twist similar to our previously reported 4V structure. The overall topology of the central variable region within the 4L structure is very similar to that of 4V complexed with the phosphatidylinositol 4,5-bisphosphate; however, the intersubunit interaction mode is affected by the presence of C1 and C2 regions. Therefore, we propose that although the 4V region in the full cytoplasmic domain has a tendency for strong peptide--peptide interaction, it may not be enough to overcome the repulsion of the C1 regions of syndecan-4L.

Rat embryo fibroblasts require both the cell-binding and the heparin-binding domains of fibronectin for survival

Fibronectin (FN) is known to transduce signal(s) to rescue cells from detachment-induced apoptosis (anoikis) through an integrin-mediated survival pathway. However, the functions of individual FN domains have not been studied in detail. In the present study we investigated whether the interaction of the cell-binding domain of FN with integrin is sufficient to rescue rat embryo fibroblasts (REFs) from detachment-induced apoptosis. REFs attached and spread normally after plating on substrates coated with either intact FN or a FN fragment, FN120, that contains the cell-binding domain but lacks the C-terminal heparin-binding domain, HepII. REFs on FN maintained a well-spread fibroblastic shape and even proliferated in serum-free medium at 20 h after plating. In contrast, previously well-spread REFs on FN120 started losing fibroblastic shape with time and detached from FN120-coated plates after approx. 8 h. Nuclear condensation indicated apototic cell death. This was due to the decreased activity/stability of focal adhesion kinase (pp125FAK) in the absence of HepII domain. A peptide in the HepII domain [peptide V, WQPPRARI (single-letter amino acid codes)], which has previously been implicated in cytoskeletal organization, rescued apoptotic changes. Consistently, pp125FAK phosphorylation was increased, and both cleavage of pp125FAK and activation of caspase 3 on FN120 were partly blocked by peptide V. Thus the interaction of the cell-binding domain with integrin has a major role in cell survival but is itself not sufficient for cell survival. One or more additional survival signals come from the HepII domain to regulate pp125FAK activity/stability.

Effects of pH and dissolved oxygen on the reduction of hexavalent chromium by dissolved ferrous iron in poorly buffered aqueous systems

The effects of pH and dissolved oxygen (DO) on the reduction of Cr(VI) by dissolved Fe(II) were investigated for aqueous solutions having relatively low buffering capacities. All solutions were maintained at a constant ionic strength (generally 0.05 M) and temperature (23 +/- 2 degrees C). For the majority of the experiments conducted, initial concentrations of Fe(II) and Cr(VI) were 50 and 20 microM, respectively, representing a deficient amount of Fe(II) (i.e. nonstoichiometric conditions). Experiments conducted in the absence and presence of DO were performed in an anaerobic chamber and in vessels open to the atmosphere, respectively. Specific initial pH values were obtained by adjusting the pH of Cr(VI) and Fe(II) stock solutions prior to their mixing or by spiking Cr(VI)-Fe(II) systems with strong base to rapidly increase the pH in situ. Consistent with previous reports, Cr(VI) reduction rates for our systems increased with increasing pH (pH ranges of 3.5-6 and 3.5-7.2 for oxic and anoxic experiments, respectively). Because of our poorly buffered experimental systems, pH values decreased over the course of the reactions which, in turn, caused decreases in the reduction rates with time. Spiking some experimental systems with NaOH to rapidly raise the pH resulted in faster rates of Cr(VI) reduction than when the pH was adjusted prior to mixing the stock solutions together; this observation is likely due to the presence of microenvironments in the reactors for which local, short-term pH values greatly exceed the equilibrium value (i.e. mixing is slower than the reduction reaction in these high pH microenvironments). The molar ratios of Fe(II) oxidized to Cr(VI) reduced were close to the expected stoichiometric value of 3 for the majority of our experimental systems, which shows that DO will not cause a serious interference in most applications using Fe(II) to reduce Cr(VI).

EBNA-LP associates with cellular proteins including DNA-PK and HA95

EBNA-LP-associated proteins were identified by sequencing proteins that immunoprecipitated with Flag epitope-tagged EBNA-LP (FLP) from lymphoblasts in which FLP was stably expressed. The association of EBNA-LP with Hsp70 (72/73) was confirmed, and sequences of DNA-PK catalytic subunit (DNA-PKcs), HA95, Hsp27, prolyl 4-hydroxylase alpha-1 subunit, alpha-tubulin, and beta-tubulin were identified. The fraction of total cellular HA95 that associated with FLP was very high, while progressively lower fractions of the total DNA-PKcs, Hsp70, Hsp 27, alpha-tubulin, and beta-tubulin specifically associated with EBNA-LP as determined by immunoblotting with antibodies to these proteins. EBNA-LP bound to two domains in the DNA-PKcs C terminus and DNA-PKcs associated with the EBNA-LP repeat domain. DNA-PKcs that was bound to EBNA-LP phosphorylated p53 or EBNA-LP in vitro, and the phosphorylation of EBNA-LP was inhibited by Wortmannin, a specific in vitro inhibitor of DNA-PKcs.

Dietary restriction impairs neutrophil exudation by reducing CD11b/CD18 expression and chemokine production

HYPOTHESIS

Patients with malnutrition are susceptible to infection. Polymorphonuclear neutrophils (PMNs) are the major effector of the nonspecific immune response in host resistance to infection. Dietary restriction may impair PMN-mediated immunity in the peritoneal cavity by reducing PMN exudation, adhesion molecule expression on PMNs, and chemokine production.

DESIGN

Randomized study of murine glycogen-induced peritonitis with dietary restriction.

SETTING

University research laboratory.

MATERIALS

Male C57BL/6J mice.

INTERVENTIONS

Mice (N = 204) were assigned to ad libitum, moderate, and severe diet-restricted groups receiving mouse chow ad libitum (132 g/kg, 66 g/kg, and 33 g/kg daily for 7 days, respectively). After dietary restriction with or without 1 day of refeeding, mice were administered glycogen intraperitoneally to induce cell exudation.

MAIN OUTCOME MEASURES

CD11b, CD18, and CD62L expressions on circulating PMNs, phagocytosis, and reactive oxygen intermediate production by exudative PMNs were measured after glycogen installation. The levels of PMN-specific chemokine, macrophage inflammatory protein 2 (MIP-2), in peritoneal lavage fluid were also measured. These parameters were measured after glycogen installation in the refeeding experiment.

RESULTS

Seven days of dietary restriction decreased CD11b/CD18 expression on circulating PMNs, MIP-2 levels in peritoneal lavage fluid, and subsequent PMN exudation into the peritoneal cavity early in peritonitis. Both CD11b and CD18 expression on circulating PMNs and MIP-2 levels correlated significantly with numbers of exudative PMNs. Seven days of dietary restriction also impaired phagocytosis, while up-regulating reactive oxygen intermediate production by exudative PMNs. Only 1 day of ad libitum refeeding normalized CD11b/CD18 expression with PMN exudation into the peritoneal cavity.

CONCLUSIONS

Short-term dietary restriction impairs PMN exudation into local inflammatory sites in murine peritonitis by reducing CD11b/CD18 expression and MIP-2 production. Even brief nutritional replenishment in diet-restricted patients may improve host defense via restoring these PMN functions and chemokine production at local inflammatory sites.

Cytokine-modulated inhibition of neutrophil apoptosis at local site augments exudative neutrophil functions and reflects inflammatory response after surgery

BACKGROUND

The fate of exudative polymorphonuclear neutrophils (PMNs) at the local site after surgery is not well understood. We evaluated the fate and functions of exudative PMNs at the local site in patients who were undergoing major surgery. We also investigated the relation between PMN apoptosis and cytokine levels at the local site during the postoperative period.

METHODS

Exudative PMNs were isolated from 11 patients during the postoperative period. Apoptosis, reactive oxygen intermediates (ROI) production, CD16, and tumor necrosis factor receptor expression of the PMNs were determined by flow cytometry. Cytokine levels in the drainage fluid were measured.

RESULTS

Exudative PMN apoptosis was markedly inhibited on postoperative day 1 and then increased in a time-dependent manner. IL-6 and granulocyte macrophage colony-stimulating factor were significant factors to inhibit exudative PMN apoptosis; tumor necrosis factor-alpha and IL-10 were the factors to increase apoptosis. ROI production and CD16 expression of exudative PMNs were augmented when PMN apoptosis was inhibited in the early postoperative period.

CONCLUSIONS

Exudative PMN apoptosis was inhibited after surgery; PMN function was augmented after surgery. Cytokines at the local site may modulate exudative PMN apoptosis. Exudative PMN apoptosis reflected the inflammatory response after surgery. Understanding the mechanisms of PMN apoptosis and its pathophysiologic significance at local inflammatory sites in vivo may help in the design of more rational treatments.

DiSSiMiL: Diverse Small Size Mini-Libraries applied to simple and rapid epitope mapping of a monoclonal antibody

Methods for screening protein-protein interactions are useful in protein science and for the generation of drug leads. We set out to develop a simplified assay to rapidly test protein-protein interactions, with a library of 400 pentapeptides comprising the 20 natural amino acids at two variable positions followed by three glycines (NH2-X1X2GGG). The library was used to identify the epitope of monoclonal antibody (mAb) 10D11 directed against the HOXD4 protein. Three pentapeptide 'hits' were selected (VYGGG, PWGGG and WKGGG) from direct binding assays screening for pentapeptide-mAb interactions; and from assays using pentapeptides in solution to competitively block HOXD4-mAb interactions. Alignment of the three 'hit' pentapeptides to the HOXD4 sequence predicts the mAb 10D11 epitope as NH2-VYPWMK. Synthesis of NH2-VYPWMK hexapeptide confirmed this prediction; and an alanine scan of HOXD4 ablated binding by mAb 10D11 when amino acids in the putative epitope were mutated. We propose that these simplified but diverse libraries can be used for rapid epitope mapping of some mAbs, and for generating lead small peptide analogs that interfere with receptor-ligand or other protein-protein interactions, or with enzymatic activity.

Intercellular delivery of a herpes simplex virus VP22 fusion protein from cells infected with lentiviral vectors

Effective gene therapy depends on the efficient transfer of therapeutic genes and their protein products to target cells. Lentiviral vectors appear promising for virus-mediated gene delivery and long-term expression in nondividing cells. The herpes simplex virus type 1 tegument protein VP22 has recently been shown to mediate intercellular transport of proteins, raising the possibility that it may be helpful in a setting where the global delivery of therapeutic proteins is desired. To investigate the effectiveness of lentiviral vectors to deliver genes encoding proteins fused to VP22, and to test whether the system is sufficiently potent to allow protein delivery from transduced cells in vitro and in vivo, fusion constructs of VP22 and the enhanced green fluorescent protein (EGFP) were prepared and delivered into target cells by using HIV-1-based lentiviral vectors. To follow the spread of VP22-EGFP to other cells, transduced COS-7 cells were coplated with a number of different cell types, including brain choroid plexus cells, human endothelial cells, H9 cells, and HeLa cells. We found that VP22-EGFP fusion proteins were transported from transduced cells to recipient cells and that such fusion proteins accumulated in the nucleus and in the cytoplasm of such cells. To determine the ability to deliver fusion proteins in vivo, we injected transduced H9 cells as well as the viral vector directly into the brain of mice. We present evidence that VP22-EGFP fusion proteins were transported effectively from lentivirus transduced cells in vivo. We also show that the VP22-EGFP fusion protein encoded by the lentivirus is transported between cells. Our data indicate that such fusion proteins are present in the nucleus and in the cytoplasm of neighboring cells. Therefore, lentiviral vectors may provide a potent biological system for delivering genes encoding therapeutic proteins fused to VP22.

Neutron radiation enhances cisplatin cytotoxicity independently of apoptosis in human head and neck carcinoma cells

Recent advances in combined modality treatment of locally advanced head and neck cancer have improved local and regional disease control and survival with better functional outcome. However, the local and regional failure rate after radiation therapy is still high for tumors that respond poorly to cisplatin-based neoadjuvant chemotherapy. This clinical observation suggests a common biological mechanism for resistance to cisplatin and photon irradiation. In this report, we investigated the molecular basis underlying cisplatin resistance in head and neck squamous carcinoma (HNSCC) cells and asked if fast neutron radiation enhances cisplatin cytotoxicity in cisplatin-resistant cells. We found that cisplatin sensitivity correlates with caspase induction, a cysteine proteinase family known to initiate the apoptotic cell death pathway, suggesting that apoptosis may be a critical determinant for cisplatin cytotoxicity. Neutron radiation effectively enhanced cisplatin cytotoxicity in HNSCCs including cisplatin-resistant cells, whereas photon radiation had little effect on cisplatin cytotoxicity. Interestingly, neutron-enhanced cisplatin cytotoxicity was associated neither with apoptosis nor with cell cycle regulation, as determined by caspase activity assay, annexin V staining, and flow cytometric analysis. Taken together, the present study provides a molecular insight into cisplatin resistance and may also provide a basis for more effective multimodality protocols involving neutron radiation for patients with locally advanced head and neck cancer.