Oncotype DX Predictive Nomogram for Recurrence Score Output: The Novel System ADAPTED01 Based on Quantitative Immunochemistry Analysis.

PURPOSE: Oncotype DX (ODX) predicts breast cancer recurrence risk, guiding the choice of adjuvant treatment. In many countries, access to the test is not always available. We used correlation between phenotypical tumor characteristics, quantitative classical immunohistochemistry (IHC), and recurrence score (RS) assessed by ODX to develop a decision supporting system for clinical use. PATIENTS AND METHODS: Breast cancer patients who underwent ODX testing between 2014 and 2018 were retrospectively included in the study. The data selected for analysis were age, menopausal status, and pathologic and IHC features. IHC was performed with standardized quantitative methods. The data set was split into two subsets: 70% for the training set and 30% for the internal validation set. Statistically significant features were included in logistic models to predict RS ≤ 25 or ≤ 20. Another set was used for external validation to test reproducibility of prediction models. RESULTS: The internal set included 407 patients. Mean (range) age was 53.7 (31-80) years, and 222 patients (54.55%) were > 50 years old. ODX results showed 67 patients (16.6%) had RS between 0 and 10, 272 patients between 11 and 25 (66.8%), and 68 patients > 26 (16.6%). Logistic regression analysis showed that RS score (for threshold ≤ 25) was significantly associated with estrogen receptor (P = .004), progesterone receptor (P < .0001), and Ki-67 (P < .0001). Generalized linear regression resulted in a model that had an area under the receiver operating characteristic curve (AUC) of 92.2 (sensitivity 84.2%, specificity 80.1%) and that was well calibrated. The external validation set (183 patients) analysis confirmed the model performance, with an AUC of 82.3 and a positive predictive value of 91%. A nomogram was generated for further prospective evaluation to predict RS ≤ 25. CONCLUSION: RS was related to quantitative IHC in patients with RS ≤ 25, with a good performance of the statistical model in both internal and external validation. A nomogram for enhancing clinical approach in a cost-effective manner was developed. Prospective studies must test this application in clinical practice.

Autotrophic and Heterotrophic Growth Conditions Modify Biomolecole Production in the Microalga Galdieria sulphuraria (Cyanidiophyceae, Rhodophyta).

Algae have multiple similarities with fungi, with both belonging to the Thallophyte, a polyphyletic group of non-mobile organisms grouped together on the basis of similar characteristics, but not sharing a common ancestor. The main difference between algae and fungi is noted in their metabolism. In fact, although algae have chlorophyll-bearing thalloids and are autotrophic organisms, fungi lack chlorophyll and are heterotrophic, not able to synthesize their own nutrients. However, our studies have shown that the extremophilic microalga Galderia sulphuraria (GS) can also grow very well in heterotrophic conditions like fungi. This study was carried out using several approaches such as scanning electron microscope (SEM), gas chromatography/mass spectrometry (GC/MS), and infrared spectrophotometry (ATR-FTIR). Results showed that the GS, strain ACUF 064, cultured in autotrophic (AGS) and heterotrophic (HGS) conditions, produced different biomolecules. In particular, when grown in HGS, the algae (i) was 30% larger, with an increase in carbon mass that was 20% greater than AGS; (ii) produced higher quantities of stearic acid, oleic acid, monounsaturated fatty acids (MUFAs), and ergosterol; (iii) produced lower quantities of fatty acid methyl esters (FAMEs) such as methyl palmytate, and methyl linoleate, saturated fatty acids (SFAs), and poyliunsaturated fatty acids (PUFAs). ATR-FTIR and principal component analysis (PCA) statistical analysis confirmed that the macromolecular content of HGS was significantly different from AGS. The ability to produce different macromolecules by changing the trophic conditions may represent an interesting strategy to induce microalgae to produce different biomolecules that can find applications in several fields such as food, feed, nutraceutical, or energy production.

The prognostic role of FDG PET/CT before combined radio-chemotherapy in anal cancer patients.

OBJECTIVE: We assessed the prognostic value of several FDG PET/CT parameters, measured within the primary tumor and the involved lymph nodes, before definitive radio-chemotherapy (RCT) in anal cancer patients. METHODS: Anal cancer patients with positive baseline FDG PET/CT who underwent definitive RCT from May 2011 to February 2018 were retrospectively assessed. Primary tumour (T)-SUVmax, T-SUVpeak, T-SUVmean, T-MTV, T-TLG, whole-body (WB) MTV, and WB-TLG were measured. Kaplan-Meier curves, Cox-regression analysis, and logistic regression machine-learning technique were used to test for associations between clinical data, metabolic parameters, and outcomes as overall survival (OS), disease-specific survival (DSS), metastatic-free survival (MFS), disease-free survival (DFS), local relapse-free survival (LRFS), and colostomy-free survival (CFS). RESULTS: Fifty-nine patients were included in the study. Median follow-up was 28 months. Higher pre-treatment WB-MTV, T-TLG, and WB-TLG were associated with worse OS (p = 0.025, 0.021, and 0.02, respectively). PET parameters resulted also statistically significant for DSS, DFS, and CFS (p = 0.032, 0.043, 9 × 10-4 for WB-TLG). Cox analysis showed that PET parameters are significant predictors of OS, DSS, DFS, CFS, and LRFS. On multivariate analysis, age, stage, T-SUVpeak, WB-MTV, and T-TLG resulted significantly related to OS. A further stratification for patients with advanced stage (cT3-4 any N or any cT, N + ) showed that MTV and TLG, measured within the primary tumor and the involved nodes, are significantly higher in patients with a worse prognosis. In this subgroup, cut-off values of T- and WB-TLG as well as T- and WB-MTV showed a statistically significant correlation with clinical outcomes. CONCLUSIONS: Pre-treatment metabolic parameters measured within the primary tumor and the involved nodes may represent additional new biomarkers for estimating prognosis in anal cancer patients, especially in advanced stage patients.

Self-assessed neurological disturbances after surgical removal of impacted lower third molar: a pragmatic prospective study on 423 surgical extractions in 247 consecutive patients.

OBJECTIVES: The aim of this study was to assess the combined role of current radiographic risk indicators and patient age in predicting lower lip sensitivity disturbances after surgical removal of impacted lower third molars. The question was which combinations indicate low or high risk. MATERIALS AND METHODS: A prospective study was implemented involving 247 consecutive outpatients who underwent 423 surgical extractions. The predictor variables were patient age and risk indicators observed on panoramic radiographs. The outcome variable was the incidence of self-assessed lip sensitivity alterations. The extractions were subdivided into four groups according to the predictors. RESULTS: Two hundred forty-five teeth were extracted in patients younger than 25 years and 178 in patients 25 years old or older; radiographic risk indicators were associated with 226 out of 423 teeth (53.43%). No permanent neurological damage was observed. Transient lip sensitivity alterations were observed in five cases (1.18%; 95% confidence interval = 0.4 to 2.7%), all in the older group with radiographic risk indicators. CONCLUSIONS: The data indicate a low overall incidence of transient lip sensitivity impairment that occurred only in the presence of radiographic risk indicators in patients aged ≥ 25 years. CLINICAL RELEVANCE: Informed consent should include the possibility of inferior alveolar nerve injury in mature patients with radiographic risk indicators. Prophylactic removal of impacted teeth with radiographic signs of risk may be indicated when the patient is not yet aged 25 years.

Degradation of some representative polycyclic aromatic hydrocarbons by the water-soluble protein extracts from Zea mays L. cv PR32-B10.

The ability of the water-soluble protein extracts from Zea mais L. cv. PR32-B10 to degrade some representative polycyclic aromatic hydrocarbons (PAHs), has been evaluated. Surface sterilized seeds of corn (Zea mais L. Pioneer cv. PR32-B10) were hydroponically cultivated in a growth chamber under no-stressful conditions. The water-soluble protein extracts isolated from maize tissues showed peroxidase, polyphenol oxidase and catalase activities. Incubation of the extracts with naphthalene, fluorene, phenanthrene and pyrene, led to formation of oxidized and/or degradation products. GC-MS and TLC monitoring of the processes showed that naphthalene, phenanthrene, fluorene and pyrene underwent 100%, 78%, 92% and 65% oxidative degradation, respectively, after 120 min. The chemical structure of the degradation products were determined by (1)H NMR and ESI-MS spectrometry.

Control of Prosthetic Hands via the Peripheral Nervous System.

This paper intends to provide a critical review of the literature on the technological issues on control and sensorization of hand prostheses interfacing with the Peripheral Nervous System (i.e., PNS), and their experimental validation on amputees. The study opens with an in-depth analysis of control solutions and sensorization features of research and commercially available prosthetic hands. Pros and cons of adopted technologies, signal processing techniques and motion control solutions are investigated. Special emphasis is then dedicated to the recent studies on the restoration of tactile perception in amputees through neural interfaces. The paper finally proposes a number of suggestions for designing the prosthetic system able to re-establish a bidirectional communication with the PNS and foster the prosthesis natural control.

Peritoneal Dialysis as a First versus Second Option after Previous Haemodialysis: A Very Long-Term Assessment.

UNLABELLED: For renal replacement therapy, overall survival is more important than the choice of currently available individual therapy. Objectives. To compare patients and technique survival on peritoneal dialysis as first treatment (PDF) versus after previous haemodialysis (HDPD) and other indicators of follow-up. Methods. We prospectively studied 110 incident patients, during the period from August 4, 1993, to June 30, 2012, for patients and technique survival (Kaplan-Meier) (log rank P < 0.05). Results. Groups: (A) PDF: 37 patients, 24 females, age: 52.2 ± 14.9 years old, time at risk: 2123 patient-months (p/m), mean: 57 ± 42 months; (B) HDPD: 73 patients, 42 females, age: 52.45 ± 14.7 years old, time in haemodialysis: 3569.2 (p/m), range: 3-216 months, mean: 49 ± 45 months, time at risk in PD: 3700 (p/m), mean: 51 ± 49 months. Patients' survival: (A) PDF: 100%, 76.6%, 65.6%, and 19.7%; (B) HDPD: 95.4%, 65.6%, 43%, and 43% at 12, 60, 120, and 144 months, respectively, P = 0.34. TECHNIQUE: (A) PDF: 100%, 90%, 59.8%, and 24%; (B) HDPD: 94%, 75%, 32%, and 32% at 12, 60, 120, and 144 months, respectively, P = 0.40. Conclusions. Comparable patient and technique survival were observed. Peritoneal dialysis enables a greater extension of renal replacement therapy for patients with serious difficulties continuing with haemodialysis.

A technique for fabricating a definitive immediate implant-supported prosthesis for the edentulous mandible.

A technique for fabricating a definitive immediate fixed implant-supported prosthesis to rehabilitate the edentulous mandible is described. Temporary abutments were used first as impression copings, later modified to achieve parallelism, and finally incorporated in the definitive framework. The metal framework was fabricated with holes for the abutments and connected to the abutments with composite resin cement intraorally to obtain passive fit. This technique reduced the number of steps, thereby decreasing insertion time of the definitive prosthesis to 2 days.

Continuous ambulatory peritoneal dialysis versus automated peritoneal dialysis and peritonitis in the short and very long term at risk.

Peritonitis (P) is the most important infectious complication in peritoneal dialysis (PD), but disagreement remains about the impact of PD modality on the frequency of P episodes. We compared indices linked to P between patients on continuous ambulatory PD (CAPD) and those on automated PD (APD) in the short and very long term. The study included 9 prevalent and 72 incident patients on CAPD (twin-bag system) and 37 incident patients on APD from 4 August 1995 to 31 March 2011. Data were collected prospectively from our database. The cumulative P rate (CPR) by weighted Student t-test (p < 0.05) expressed as the probabilities of remaining free of a first P episode and remaining free of all P episodes were compared by the Kaplan-Meier method (log rank p < 0.05). The proportion of patients with P (PPP) per group (chi2 p < 0.05) and the relative risk (RR) of P were also calculated. The CAPD patients included 51 women and 30 men [mean age.: 50.2 +/- 14.21 years (range: 15-82 years); duration of treatment: 3579 patient-months (mean: 44.2 +/- 34.2 patient-months); P episodes: 111] had a CPR of 0.38 episodes (1 episode in 31.35 patient-months) and a P rate per year (PRY) in the range 0.08-0.89 episodes. The APD patients [23 women and 14 men; mean age: 53.62 +/- 13.61 years (range: 26-78 years); duration of treatment: 1718 patient-months (mean: 46.4-38.3 patient-months); P episodes: 46] had a CPR of 0.32 episodes (1 episode in 373 patient--months) and a PRY in the range 0-1.12 episodes. At 1, 3, 5, and 10 years respectively, a first P episode occurred in 73%, 36%, 23%, and 8% of CAPD and 72%, 59%, 35%, and 23% ofAPD patients (log-rank p = 0. 056; CPR: p = 0.01; PPP: chi2 p = 0.39), for a RR of 0.83 linked to CAPD compared with APD. A lower P frequency and a trend of less time to first P was observed for APD compared with CAPD. The CAPD patients did not show a higher risk of developing P than did the APD patients. For comparisons between the modalities, CPR is a reliable index in the very long term at risk. Depending on the size of the population and the time at risk, the PRYobtained on short follow-up could result in a misinterpretation of the performance of each treatment modality.

The importance of the Patient's training in chronic peritoneal dialysis and peritonitis.

In a chronic disease, traineeship in the methodology to be used to treat oneself is a key part of success from the beginning and during long-term treatment. In chronic peritoneal dialysis (PD), peritonitis emphasizes, in a certain way, the result of the apprenticeship. We set out to evaluate the relationship between the number of PD training lessons and the frequency of peritonitis. According to the number of lessons, we established three groups: A, up to 8 lessons; B, 9-13 lessons; and C, 14 or more lessons. We evaluated peritonitis rates and micro-organisms, and for the three groups, we compared (Kaplan-Meier method) peritonitis-free survival (PFS) at 1 year of treatment, with significance set at (log rank) p < 0.05. The study enrolled 90 patients (mean age: 51.5 +/- 15.33 years; 37 men). Respectively, groups A, B, and C included 27, 46, and 17 patients with an at-risk duration of 1535, 2879, and 665 patient-months (mean: 56.9 +/- 44, 62.6 +/- 47, and 39.1 +/- 37.8 patient--months), of whom 35%, 37%, and 24% experienced no peritonitis, for peritonitis rates of 0.31, 0.37, and 0.47, with coagulase-negative Staphylococcus (CNS) peritonitis rates of 0.125, 0.12, and 0.235, and PFS rates of 76.9%, 80.4%, and 70.6%. The PFS was not significantly different between the groups (p > 0.05). During 1 year of treatment, all three groups experienced a satisfactory PFS. More frequent retraining should be considered in patients who needed more training lessons at the start of PD.

Radiographic interpretation agreement in implant dentistry.

PURPOSE: The aim of this survey is to assess the different radiographic interpretations of simulated dental implant cases among a group of specialists in oral surgery. MATERIAL AND METHODS: A total of 76 active members of the Italian Society of Oral Surgery and Implantology were recruited for the study. The participants in the study were requested to assign scores to radiographic images of 12 simulated cases of dental implants: a baseline and follow-up image for cases with different bone loss (0, 1 or 5 mm), implant length (8 or 12 mm) and years of follow-up (1 or 5 years). RESULTS: In total, 63 active members agreed to participate in the survey. The inter-rater agreement was 0.86 (CI 95% 0.74; 0.95). In cases where the bone loss was absent (0 mm) no difference was detected at 1 or 5 years of follow-up. In contrast, when bone loss was present (1 or 5 mm) the longer follow-up (5 years) revealed the highest score. The lowest score was attributed to 5 mm of bone loss and 1 year of follow-up. Moreover, a significant difference between the short (8 mm) and the long (12 mm) implant was observed (score difference 0.45; CI 95% 0.28; 0.63). CONCLUSIONS: This investigation suggests that subjective evaluation of radiographs on simulated implants by skilled clinicians is rather uniform, and bone loss, follow-up and implant length are factors considered in the perception of implant success.

Peritonitis en diálisis peritoneal: análisis comparativo de los índices de seguimiento en dos períodos consecutivos en un hospital universitario: [revisión] / Peritonitis in peritoneal dialysis: comparative analysis of the follow-up indexes in two consecutive periods in a university hospital: [review]

La peritonitis (P) ha sido la complicación más importante de la diálisis peritoneal crónica (DPC) y la causa más frecuente de exclusión del programa. En este trabajo se evaluaron los índices de seguimiento de las P en DPC en 2 períodos consecutivos de 10 años en un hospital universitario, tras los avances de la técnica dialítica y la aplicación de un programa de educación médica continua y de los pacientes.

Peritonitis en diálisis peritoneal: análisis comparativo de los índices de seguimiento en dos períodos consecutivos en un hospital universitario: [revisión] / Peritonitis in peritoneal dialysis: comparative analysis of the follow-up indexes in two consecutive periods in a university hospital: [review]

La peritonitis (P) ha sido la complicación más importante de la diálisis peritoneal crónica (DPC) y la causa más frecuente de exclusión del programa. En este trabajo se evaluaron los índices de seguimiento de las P en DPC en 2 períodos consecutivos de 10 años en un hospital universitario, tras los avances de la técnica dialítica y la aplicación de un programa de educación médica continua y de los pacientes.(AU)

Body surface area, adequacy, and technique failure in chronic peritoneal dialysis.

Large body surface area (BSA) could be a pitfall in long-term peritoneal dialysis. We analyzed the viability of the peritoneum in terms of adequacy and technique survival in patients of varying BSA. We grouped our PD patients into three categories (BSA < or = 1.59 m2, BSA 1.60 - 1.79 m2, and BSA > or = 1.80 m2) and used the Student t-test to compare the mean weekly Kt/V urea between the groups (significance set at p < 0.05). We also measured and used Kaplan-Meier analysis to compare technique survival overall and in anuric patients from the onset of PD to the endpoints of transfer to hemodialysis or death linked to dialysis technique (log-rank test, p < 0.05). Group A consisted of 24 patients [2 men, 22 women; age: 41.9 +/- 12 years; BSA: 1.49 +/- 0.07 m2; total treatment duration: 1703.4 patient-months (mean: 71 +/- 50.6 months); diabetic: 8.33%; anuric: 62%; weekly Kt/V urea: 2.36 +/- 0.45; technique survival: 100%, 89%, 89%, 53%, and 53% at 1, 3, 5, 8, and 15 years]. Group B consisted of 35 patients [12 men, 23 women; age: 57.19 +/- 18 years; BSA: 1.69 +/- 0.05 m2; total treatment duration: 1870 patient-months (mean: 53.4 +/- 462 months); diabetic: 17.14%; anuric: 37.14%; weekly Kt/V urea: 2.28 +/- 0.41; technique survival: 97%, 93%, 87%, 78%, and 19% at 1, 3, 5, 8, and 14 years]. Group C consisted of 34 patients [24 men, 10 women; age: 56.2 +/- 13 years; BSA: 1.90 +/- 0.09 m2; total treatment duration: 1557.5 patient-months (mean: 45.8 +/- 34.4 months); diabetic: 20.6%; anuric: 41%; weekly Kt/V urea: 1.98 +/- 0.38; technique survival: 97%, 79%, 67.6%, 56%, and 28% at 1, 3, 5, 8, and 12 years]. Using the log-rank test, comparisons of technique survival overall and in anuric patients showed for A vs. B, p = 0.49 and p = 0.58 respectively; for A vs. C, p = 0.45 and p = 0.06; for B vs. C, p = 0.56 and p = 0.10. No significant differences in weekly Kt/V urea were observed between the groups (all p > 0.05). Peritoneal dialysis is viable for patients with a high BSA. There is a tendency toward worse technique survival in anuric patients with a high BSA.

Peritoneum: a noble membrane in long-term dialysis treatment.

The durability of the peritoneum as a dialysis membrane is as yet an unanswered question. Peritonitis episodes have an important effect in long-term treatment. To evaluate survival of the peritoneum for dialysis, we analyzed peritoneal failure related to technique dropout because of peritonitis, inadequate dialysis, and ultrafiltration disorders. We retrospectively analyzed data for 89 peritoneal dialysis patients who had been treated for at least 3 months [52 women, 37 men; mean age: 50.91 +/- 13.72 years (range: 22 - 81 years)] from August 4, 1993, to July 1, 2008. The Kaplan-Meier method was used to measure peritoneum survival, with only a definitive switch to hemodialysis or death from peritonitis, ultrafiltration failure, or inadequate dialysis as endpoints. Total treatment time was 5008 patient-months (mean: 55 +/- 44 patient-months), and the historical annual rate of peritonitis was 0.37 per year at risk (1 episode in 32.52 patient-months). Of the 89 patients, 19 dropped treatment because of peritonitis and 1 because of ultrafiltration failure. Peritoneum survival was 98.8%, 93.7%, 87.6%, 66.9%, 46.4%, and 33.8% at 1, 3, 5, 8, 10, and 14 years. In the 15 years of our program, peritoneum failure represented less than 1.5% of drop-out causes annually. The peritoneum is a reliable membrane to reach dialysis targets in long-term therapy.

Evaluation of cortical bone by peripheral quantitative computed tomography in continuous ambulatory peritoneal dialysis patients.

Several studies have suggested an increased prevalence of osteopenia in dialysis. Peripheral quantitative computed tomography (pQCT) is a new technique that allows the noninvasive evaluation of trabecular and cortical bone separately. The aim of the study was: (1) to evaluate cortical bone by pQCT in continuous ambulatory peritoneal dialysis (CAPD) patients and compare the data with that obtained in healthy controls; and (2) to correlate cortical bone parameters with bone mineral density (BMD) of the lumbar spine and femoral neck and total bone mineral content (TBMC). Cortical bone parameters were obtained in 22 CAPD patients and 27 healthy individuals at the distal radius using a Stratec XCT 960 pQCT machine. In the dialysis patients, we also determined BMD and TBMC by bone densitometry. Dialysis patients, compared with controls, showed a significant reduction in volumetric cortical BMD (VcBMD) (p = 0.04) and cortical thickness (cThk) (p < 0.0001) with a significant increase in radial total cross-sectional area (TA) (p = 0.006), endosteal circumference (p < 0.0001), and buckling ratio (p < 0.0001). In CAPD patients, total time on dialysis correlated negatively with radial total BMD (p < 0.01) and VcBMD (p < 0.01). Age correlated positively with TA (p < 0.01), endosteal (p < 0.01), and periosteal circumferences (p < 0.01). Serum intact parathyroid hormone (PTH) levels correlated positively with endosteal (p = 0.04) and periosteal perimeter (p = 0.01). Total alkaline phosphatase correlated negatively with VcBMD (p < 0.01), and positively with endosteal perimeter (p = 0.02). Total bone mineral content correlated significantly with radial cortical content (p < 0.001), cross-sectional cortical area (cA; p < 0.001), and cThk (p < 0.01) but not with total radial BMD, VcBMD, or buckling ratio. No correlations were found between radial cortical parameters and BMD measured at the lumbar spine or femoral neck. We conclude that dialysis patients show cortical osteopenia with marked cortical thinning partially mediated by PTH action on bone. Total bone mineral content correlated with various radial cortical parameters (content, area, and thickness) but not with others. No correlations were found between cortical bone parameters measured at the peripheral skeleton with areal bone density measured at the axial skeleton. These findings suggest that pQCT may be a new tool in the assessment of bone fragility in dialysis patients.

On the thermal stability of the two dimeric forms of ribonuclease A.

The thermal stability of the two dimers of RNase A with N- or C-terminal swapped ends is investigated by means of dissociation kinetics, differential scanning calorimetry, and circular dichroism measurements. The data indicate that the dimer characterized by the swapping of the N-terminal alpha-helices is less prone to monomerize when compared to the dimer characterized by the swapping of the C-terminal beta-strands. This finding is correlated to the structural features of the so-called open interface of the dimeric forms.

Monitoring food quality by microfluidic electrophoresis, gas chromatography, and mass spectrometry techniques: effects of aquaculture on the sea bass (Dicentrarchus labrax).

Monitoring food quality is a critical task for analytical chemistry and an important way to preserve human health. Fish is a valuable source of highly digestible proteins and contains large amounts of polyunsaturated fatty acids and fat-soluble vitamins. Since the world's wild fish stocks are limited, farmed fish is nowadays proposed as an alternative to consumers. It is now emerging that the fish muscle protein content is assuming great importance from an aquaculture perspective. Many data have been collected on the physiology and biochemistry of fish muscle, but few proteomic studies are available on farmed fish. Application of proteomics to aquaculture may play a key role in the development of new farming strategies. In this paper, a proteomic approach based on SDS-PAGE separation of proteins, in situ protein hydrolysis, de novo sequencing of peptides by MALDI and ESI MS(2), protein identification, and relative quantitation of protein by denaturing capillary electrophoresis was coupled with the determination of fatty acids and metal ions content by GM-MS and ICPMS in farmed and wild sea bass filet. Our results show that aquaculture could induce significant chemical and biochemical differences in fish muscle that may have an impact on food quality.