[Primary mucinous gland lesions of fallopian tube: a clinicopathological analysis of fourteen cases].

Objective: To investigate the clinical and pathological characteristics of primary mucinous gland lesions of the fallopian tubes. Methods: The clinical data, pathomorphological characteristics and immunophenotype of 14 cases of primary mucinous gland lesions of the fallopian tube diagnosed at Obstetrics and Gynecology Hospital of Fudan University from 2015 to 2023 were analyzed retrospectively. In addition, a comprehensive review of relevant literature was conducted. Results: The age of 14 patients ranged from 53 to 83 years, with an average of 65 years. Among them, 13 cases exhibited unilateral involvement while one case showed bilateral presentation. Nine cases were mucinous metaplasia of the fallopian tube, four cases were invasive mucinous adenocarcinoma and one case was mucinous carcinoma in situ. Morphologically, mucinous metaplasia of the fallopian tube was focal, with or without inflammation. The cells of mucinous adenocarcinoma or mucinous carcinoma in situ exhibited characteristics indicative of gastrointestinal differentiation. Immunohistochemical analysis revealed diffuse positive expression of CK7, and negative expression of SATB2. CDX2 demonstrated positive staining in two cases. One case exhibited diffuse and strongly positive mutant expression of p53, whereas the remaining cases displayed wild-type expression. MUC6 showed diffuse or focally positive staining in mucinous gland lesions characterized by gastric differentiation. Some cases of mucinous adenocarcinoma of fallopian tube were subject to AB-PAS staining, resulting in red to purple cytoplasmic staining. Conclusions: Primary mucinous lesions of the fallopian tube are exceedingly uncommon. All cases of mucinous adenocarcinoma of fallopian tubes in this study exhibit the morphology and immunohistochemical characteristics of gastrointestinal differentiation. Mucinous metaplasia of the fallopian tube is a benign lesion of incidental finding, which is closely related to inflammation or gastric differentiation. Mucinous lesions of cervix, ovary and digestive tract are excluded in all patients, confirming the independent existence of mucinous lesions within fallopian tubes.

[Pseudocarcinomatous hyperplasia of the fallopian tube: a clinicopathological analysis of sixteen cases].

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of pseudocarcinomatous hyperplasia of the fallopian tubes. Methods: Sixteen cases of pseudocarcinomatous hyperplasia of the fallopian tubes diagnosed at Obstetrics and Gynecology Hospital of Fudan University from January 2011 to January 2024 were collected.The pathological sections were reviewed, the clinical and pathological data were consulted, and immunohistochemical examination was conducted along with follow-up. Results: The patients were aged from 19 to 57 years, with an average age of 41 and a median age of 38. Among the 16 cases, 4 were located in the right fallopian tubes, 6 in the left fallopian tubes, while the remaining cases presented bilaterally. The general manifestations were tubal edema, crispness and purulent secretion in the lumen. Morphologically, the fallopian tube mucosa exhibited a significant infiltration of neutrophils, lymphocytes and plasma cells. The epithelial cells of the fallopian tube displayed evident proliferation, stratification and disorganized arrangement leading to formation of small glandular cavity with back-to-back, fissure-like and sieve-like structures. Immunohistochemical analysis revealed positivity for CK7 and WT1, along with wild-type p53 expression, Ki-67 index ranged from 5% to 20%. During the follow-up period ranging from 1 to 156 months, all the patients remained free of disease. Conclusions: Pseudocarcinomatous hyperplasia of the fallopian tube is a rare non-neoplastic lesion, which can lead to epithelial hyperplasia and atypical hyperplasia. The most important significance of recognizing this lesion lies in avoiding misdiagnosis of fallopian tube cancer during intraoperative and postoperative pathological examination. This ensures that clinicians can administer correct clinical interventions.

[Clinicopathological analysis of primary gastric (gastrointestinal)-type mucoglandular lesion of endometrium].

Objective: To investigate the clinical and pathological features of primary gastric (gastrointestinal)-type mucoglandular lesions of the endometrium. Methods: Eight cases of primary gastric (gastrointestinal)-type mucoglandular lesions of endometrium diagnosed between 2014 to 2022 were retrieved from pathology archives of the Obstetrics and Gynecology Hospital Affiliated to Fudan University, Shanghai, China. The clinical history, pathological sections and follow-ups were analyzed. Results: The eight patients ranged in age from 35 to 67 years, with an average age of 55.5 years. Seven patients were examined for high-risk human papillary virus (HPV) before operation. Only one of them was positive for high-risk HPV52. No cervical mucinous lesions were found in any of the patients. Two cases were invasive gastric (gastrointestinal)-type adenocarcinoma, 2 cases were benign gastric (gastrointestinal)-type mucinous metaplasia, and the other 4 cases were atypical gastric (gastrointestinal)-type mucinous gland hyperplasia. Microscopically, tumor cells showed mucous epithelium with gastrointestinal differentiation. Immunophenotyping showed that MUC6 was diffusely or focally positive in 5 cases, CK20 and CDX2 were positive in 3 cases. And p16 was negative or focally positive in 5 cases and strongly positive in 1 case. ER was expressed in both benign and atypical lesions, and weakly positive or negative in the invasive adenocarcinoma. p53 showed mutant expression in one case and wild-type expression in the rest. HPV in situ hybridization was negative. Conclusions: Primary gastric (gastrointestinal)-type mucoglandular lesions of the endometrium show various forms of gastrointestinal differentiation, which are high-risk HPV independent. Morphology combined with immunohistochemistry is helpful for the diagnosis, which can only be made on exclusion of cervical gastrointestinal glandular lesion, gastrointestinal metastatic carcinoma and the mucinous subtype of endometrioid carcinoma.

Whole solid tumour volume histogram analysis of the apparent diffusion coefficient for differentiating high-grade from low-grade serous ovarian carcinoma: correlation with Ki-67 proliferation status.

AIM: To investigate whether apparent diffusion coefficient (ADC) histogram parameters based on whole solid tumour volume could differentiate high-grade (HGSOC) from low-grade serous ovarian carcinoma (LGSOC) and to correlate those parameters with the Ki-67 proliferation index. MATERIALS AND METHODS: One hundred and seven patients with HGSOCs and 19 patients with LGSOCs confirmed at surgery and histology who underwent conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) were analysed retrospectively. ADC histogram parameters (including the mean, standard deviation [SD], 10th, 25th, 50th, 75th, and 90th percentiles, kurtosis, and skewness) were obtained using the whole solid tumour volume region of interest (ROI). The Mann-Whitney U test, Pearson's chi-square test, Fisher's exact test, kappa test, Spearman's correlation, and receiver operating characteristic (ROC) curves were used for statistical analyses. RESULTS: For ADC histogram parameters, the mean (p<0.001), SD (p=0.003), and all percentiles (10th, 25th, 50th, 75th, and 90th percentile; all p<0.001) were significantly lower in HGSOC than in LGSOC, and the area under the ROC curve (AUC) was 0.717-0.807. Skewness was significantly higher in HGSOC than in LGSOC (p<0.001, AUC = 0.773); however, kurtosis was not significantly different between HGSOC and LGSOC (p=0.140). The 25th and 75th percentiles, SD and 10th percentile, and 75th percentile showed the highest sensitivity of 91.6%, specificity of 79.0%, and accuracy of 88.1%, respectively. All histogram parameters (except for kurtosis) were poorly correlated with the Ki-67 index (|r| = 0.191-0.274, p<0.05). CONCLUSION: ADC histogram parameters based on whole solid tumour volume can be helpful for differentiating between HGSOC and LGSOC.

[Ovarian clear cell borderline tumour: a clinicopathologic analysis].

Objective: To investigate the clinical and pathological characteristics and prognosis of ovarian clear cell borderline tumor. Methods: A total of 12 cases of ovarian clear cell borderline tumors recorded were collected from May 2011 to December 2017 at Obstetrics and Gynecology Hospital, Fudan University.Clinical histories were retrieved and pathological slides were reviewed. Results: The age of the patients ranged from 35 to 65 years with a mean age of 52 years. Seven cases were associated with cystic endometriosis of the ovary. All tumors consisted of irregular and crowded glands or cysts embedded in a fibromatous stroma. The cysts and glands were lined by mild to moderate atypical cells.CK7 and HNF-1ß were expressed in all cases, and Naspin A was expressed in 11 cases. ARID1A expression was absent in 5 cases and p53 showed wild-type expression. None of the cases developed recurrence during follow-up ranging from 7 to 79 months. Conclusions: Ovarian clear cell borderline tumor may be associated with endometriosis and tumor suppressor gene ARIDA. The tumor has a good prognosis without recurrence and progression to carcinoma.

[Synchronous mucinous metaplasia and neoplasia of the female genital tract].

Objective: To describe the clinicopathological features of synchronous mucinous metaplasia and neoplasia of the female genital tract (SMMN-FGT). Methods: The sample consisted of 7 cases of SMMN-FGT recorded from November 2014 to September 2017 at Obstetrics and Gynecology Hospital, Fudan University.PAP method was used in immunohistochemistry.Clinical histories were retrieved and pathological slides were reviewed. Results: The patients were 37 to 70 years old(mean 54 years old). All patients showed endometrial mucinous lesions associated with cervical lesions. Three cases were an admixture of minimal deviation adenocarcinoma(MDA) and gastrictype adenocarcinoma(GAS). Three cases were an admixture of lobular endocervical glandular hyperplasia (LEGH), atypical LEGH and focal gastrictype adenocarcinoma in situ, one of which had early invasive gastrictype adenocarcinoma.Endometrium showed a structure of LEGH in one patient with focal simple gastric mucinous metaplasia in her cervix. Gastric mucinous differentiation was found in unilateral fallopian tube in 6 patients. Ovarian mucinous lesions were found in 3 patients. p16 was negative staining in 6 cases and positive in 1 case. CK7 was diffusely positive in all lesions. CK20 and CDX2 were negative or only focally positive.The expression of MUC6 was strongly positive staining or focal staining. p53 in GAS and GAS in situ had mutant expression, but wild expression in MDA region. Patients were followed up for 2 to 34 months and no recurrence was found. Conclusions: SMMN-FGT is a series of rare mucinous lesions involving multiple areas of the female genital tract, including benign or malignant lesions with gastric differentiation. It is not related to infection with high-risk human papilloma virus. When cervical gastrictype lesions are found, SMMN-FGT should be considered and should be differentiated from metastatic mucinous adenocarcinoma.

[The 458th case: fever, cytopenia, abdominal pain, and multiple intestinal ulcerations with perforation].

Trisomy 8 in myelodysplastic syndrome (MDS) plays an important role in concurrent intestinal Behçet's disease (BD) pathogenesis. Here, we reported a case of intestinal BD combined with MDS involving trisomy 8. A 48-year-old woman who has had a 20-year history of recurrent oral ulcer, perineal ulcer and iris, was diagnosed as MDS with trisomy 8 four years ago. She developed high fever and acute abdominal pain. Multiple ulcerative perforations in ileum and colon were found by endoscopy, meeting the criteria for intestinal BD. The patient was successfully treated with immunomodulatory drugs.

PTEN hypermethylation profiles of Chinese Kazakh patients with esophageal squamous cell carcinoma.

Aberrant DNA methylation of promoter region CpG islands may serve as an alternative mechanism to genetic defects in the inactivation of tumor suppressor genes (TSGs) in human malignancies. The aim of this study was to examine the promoter methylation status of the PTEN TSG and its association with esophageal squamous cell carcinoma (ESCC) carcinogenesis in a Chinese Kazakh population, which is known to have a relatively high ESCC incidence and mortality. The methylation status of the PTEN promoter region was determined in patients with ESCC (n = 95) and healthy individuals (n = 65) using highly sensitive Sequenom Epityper assays. The methylation level of the PTEN gene was significantly higher in patients with ESCC than in healthy controls. The median methylation level was 10.0% (interquartile range [IQR]: 7.0-11.0%) in patients with ESCC and 6.0% in controls (IQR: 4.0-9.0%; P = 0.001). PTEN methylation levels were higher in male patients with ESCC than in male controls, whereas a trend toward significance was observed between female patients with ESCC and female controls (P = 0.005 and P = 0.086, respectively). The PTEN methylation level was associated with histopathological grade and lymph node metastasis in patients with ESCC (P = 0.002 and P = 0.009, respectively). To our knowledge, this is the first report to show the presence of PTEN promoter CpG hypermethylation in ESCC and its association with tumor metastasis.

QAM accommodated double-side band fast OFDM based on IDCT.

In this paper, we theoretically and experimentally prove that sub-carriers in double-side band fast orthogonal frequency division multiplexing (DSB-FOFDM) are orthogonal over a symbol interval independent of the signal phase and amplitude. Therefore, the commonly utilized DSB-FOFDM is quadrature amplitude modulation (QAM) accommodated; while previously DSB-FOFDM was usually modulated by amplitude shift keying (ASK) or binary phase shift keying (BPSK). In our proof-of-concept experiments, bit error ratio (BER) performance of 10 Gb/s quadrature phase shift keying (QPSK) modulated DSB-FOFDM was equivalent to that of 10 Gb/s QPSK modulated OFDM after 500 km standard single mode fiber (SSMF) transmission. 10 Gb/s QPSK modulated DSB-FOFDM largely outperformed the commonly utilized 4-ASK modulated DSB-FOFDM in BER performance. Additionally, BER performance of 10 Gb/s 16-QAM modulated DSB-FOFDM was equivalent to that of 10 Gb/s 16-QAM modulated OFDM after 500 km SSMF transmission.

[Analysis of prognostic factors of extranodal NK/T-cell lymphoma treated with pegaspargase/L-asparaginase: a multicenter retrospective study].

Objective: To explore the prognostic factors of extracellular NK/T cell lymphoma (ENKTL) treated with pegaspargase/L-asparaginase. Methods: The clinical data of 656 ENKTL patients diagnosed at 11 medical centers in the Huaihai Lymphoma Working Group from March 2014 to April 2021 were retrospectively analyzed. The patients were randomly divided into two groups: a training set (460 cases) and a validation set (196 cases) at 7∶3, and the prognostic factors of the patients were analyzed. A prognostic scoring system was established, and the predictive performance of different models was compared. Results: Patients' median age was 46 (34, 57) years, with 456 males (69.5% ) and 561 nasal involvement (85.5% ). 203 patients (30.9% ) received a chemotherapy regimen based on L-asparaginase combined with anthracyclines, and the 5-year overall survival rate of patients treated with P-GEMOX regimen (pegaspargase+gemcitabine+oxaliplatin) was better than those treated with SMILE regimen (methotrexate+dexamethasone+cyclophosphamide+L-asparaginase+etoposide) (85.9% vs 63.8% ; P=0.004). The results of multivariate analysis showed that gender, CA stage, the Eastern Cooperative Oncology Group performance status (ECOG PS) score, HGB, and EB virus DNA were independent influencing factors for the prognosis of ENKTL patients (P<0.05). In this study, the predictive performance of the prognostic factors is superior to the international prognostic index, Korean prognostic index, and prognostic index of natural killer lymphoma. Conclusion: Gender, CA stage, ECOG PS score, HGB, and EB virus DNA are prognostic factors for ENKTL patients treated with pegaspargase/L-asparaginase.

[Clinical prognostic analysis of 124 adult patients with hemophagocytic lymphohistiocytosis: a multicenter retrospective study of the Huaihai Lymphoma Working Group].

Objective: Factors influencing the prognosis of hemophagocytic lymphohistiocytosis (HLH) in adults were analyzed based on multicentric data. Methods: Clinical data of 124 adult patients with HLH diagnosed in eight medical centers in the Huaihai Lymphoma Working Group from March 2014 to July 2020 were collected. The optimal truncation value of continuous variables was obtained based on the Maxstat algorithm, X-Tile software, and restricted cubic spline. Cox proportional risk regression model was used to construct the adult HLH risk prediction model, and the visualization of the model was realized through the histogram. The bootstrap resampling method was used to verify the model, C-index and calibration curve was used to verify the histogram, and the prediction accuracy was checked. Kaplan-Meier analysis was used to calculate the survival rate and draw the survival curve. Furthermore, the differences between groups were tested by log-rank. Results: The median age of the 124 patients was 55 (18-84) years, including 61 (49.19%) males. The most common etiology was infection. Serum ferritin increased in 110 cases (88.71%) , hepatosplenomegaly in 57 cases (45.97%) . Of the 124 patients, 77 (62.10%) died, and the median survival time of the patients was 7.07 months. Univariate results showed that the prognosis of adult HLH was influenced by sex, age, fibrinogen, serum creatinine, alanine aminotransferase, and albumin (P<0.05) . The results of multivariate analysis showed that gender, platelet, albumin, alanine aminotransferase, and treatment regimens were independent influencing factors for prognosis. Based on the above five risk factors, the prediction model of the histogram was established, and the C-index of the model was 0.739. Finally, the calibration chart showed good consistency between the observed and predicted values of HLH. Conclusion: The prognosis of the adult hemophagocytic syndrome is influenced by many factors. Gender, platelet, albumin, alanine aminotransferase, and treatment regimens are independent risk factors. Therefore, the established histogram provides a visual tool for clinicians to evaluate the prognosis of adult HLH.

Successful Treatment of Cytogenetically Normal Acute Myeloid Leukemia With Ten-Eleven Translocation 2-Isocitrate Dehydrogenase 2 and Additional Sex Comb-like 1-Nucleophosmin Co-mutations by HLA Haploidentical Stem Cell Transplantation: A Case Report and Literature Review.

The presence of recurrent gene mutations is increasingly important in acute myeloid leukemia (AML) and sheds new insights into the understanding of leukemogenesis, prognostic evaluation, and clinical therapeutic efficacy. Until now, ten-eleven translocation 2 (TET2) and isocitrate dehydrogenase 2 (IDH2) mutations were reported to be mutually exclusive in AML patients. Similarly, nucleophosmin (NPM1) and additional sex comb-like 1 (ASXL1) mutations were rarely coexisted in AML. A 47-year-old man diagnosed with high-risk AML presented simultaneous mutations of TET2-IDH2 and NPM1-ASXL1 revealed by next-generation sequencing. After successful treatment with chemotherapy followed by HLA haploidentical transplantation, he achieved a clinical complete remission without evidence of overt graft-versus-host disease. This case highlights that HLA haploidentical transplantation might be a safe and feasible therapy for AML patients who are characterized by TET2-IDH2 and NPM1-ASXL1 co-mutations.

Isolation and phylogenetic analysis of porcine deltacoronavirus from pigs with diarrhoea in Hebei province, China.

Porcine deltacoronavirus (PDCoV) is a recently identified coronavirus in the genus Deltacoronavirus that can cause enteric disease with clinical signs including diarrhoea, vomiting, dehydration and mortality in neonatal piglets. Although evidence of the prevalence of PDCoV in China is accumulating, little published information about Chinese PDCoV isolates is available. In this study, we investigated the presence of PDCoV in 49 faecal/intestinal samples from piglets with diarrhoea on different farms in Hebei province. Five samples (10.2%) were positive for PDCoV, but no coinfection of PDCoV with other enteropathogens was observed. A PDCoV strain named HB-BD was successfully isolated from the intestinal contents of a diarrhoeic piglet and serially propagated in swine testicular (ST) cells for >40 passages. The complete genome of the HB-BD strain was sequenced and analysed. Genomic analysis showed that the HB-BD strain had a closer relationship with Chinese strains than those from other countries and was grouped within the Chinese PDCoV cluster. The results of this study will be valuable for further research of PDCoV genetic evolution and development of effective diagnostic reagents, assays and potential vaccines against newly emerged PDCoV strains.

Suppressed CCL2 expression inhibits the proliferation of leukemia cells via the cell cycle protein Cyclin D1: preliminary in vitro data.

OBJECTIVE: Chemokine (C-C motif) ligand 2 (CCL2) is a member of the CC subfamily, which displays chemotactic activity for monocytes and basophils. This molecule plays a very important role in many solid tumors and shows changes in the bone marrow microenvironment. However, its role in acute myeloid leukaemia (AML) is still unclear. MATERIALS AND METHODS: In this study, we established a HL-60 cell line with CCL2 knockdown to explore its effect on leukemogenesis. Lentivirus with CCL2-knockdown was successfully constructed after screening effective CCL2 short hairpin RNA (shRNA) sequences and was transfected into HL-60 cells, which was further validated at the mRNA and protein levels by real-time polymerase chain reaction (PCR) and Western blotting, respectively. RESULTS: Low expression of CCL2 significantly decreased HL-60 cell growth by increasing the cell arrest at G1 phase by 12% more than controls. We applied RNA sequencing technology to discriminate the gene expression profiles between the cells with CCL2 knockdown and the controls, and Cyclin D1 was selected for further experiments as its expression level was significantly downregulated, which was validated at the mRNA and protein levels. Cyclin D1 knockdown experiments showed that the cell proliferation rate was evidently decelerated, and cell cycle analysis also indicated a similar pattern for CCL2. CONCLUSIONS: Our study revealed that Cyclin D1 is an effector that mediates CCL2's function in cell proliferation by blocking cells at G1 phase.

Convection and diffusion in charged hydrated soft tissues: a mixture theory approach.

The extracellular matrix of cartilage is a charged porous fibrous material. Transport phenomena in such a medium are very complex. In this study, solute diffusive flux and convective flux in porous fibrous media were investigated using a continuum mixture theory approach. The intrinsic diffusion coefficient of solute in the mixture was defined and its relation to drag coefficients was presented. The effect of mechanical loading on solute diffusion in cartilage under unconfined compression with a frictionless boundary condition was analyzed numerically using the model developed. Both strain-dependent hydraulic permeability and diffusivity were considered. Analyses and results show that (1) In porous media, the convective velocity for each solute phase is different. (2) The solute convection in tissue is governed by the relative convective velocity (i.e., relative to solid velocity). (3) Under the assumption that all the frictional interactions among solutes are negligible, the relative convective velocity for alpha-solute phase is equal to the relative solvent velocity multiplied by its convective coefficient (H (alpha)) which is also known as the hindrance factor in the literature. The relationship between the convective coefficient and the relative diffusivity of solute is presented. (4) Solute concentration profile within the cartilage sample depends on the phase of dynamic compression.

New insight into deformation-dependent hydraulic permeability of gels and cartilage, and dynamic behavior of agarose gels in confined compression.

Equilibrium, creep, and dynamic behaviors of agarose gels (2.0-14.8%) in confined compression were investigated in this study. The hydraulic permeabilities of gels were determined by curve-fitting creep data to the biphasic model (J. Biomech. Eng. 102 (1980) 73) and found to be similar in value to those published in the literature (AIChE J. 42 (1996) 1220). A new relationship between intrinsic permeability and volume fraction of water was found for agarose gel, capable of predicting deformation-dependent permeabilities of bovine articular cartilage and 2% agarose gel published in literature. This relationship is accurate for gels and cartilage over a wide range of permeabilities (four orders of magnitude variation). The dynamic stiffness of the gels increases with gel concentration and loading frequency (0.01-1.0Hz). The increase in dynamic stiffness with loading frequency is less pronounced for gels with higher concentrations. The results of this study provide a new insight into deformation-dependent permeability behavior of agarose gel and cartilage, and are important for understanding biological responses of cells to interstitial fluid flow in gel or in cartilage under dynamic mechanical loading.

A triphasic analysis of negative osmotic flows through charged hydrated soft tissues.

Osmotic flow and ion transport in a one-dimensional steady diffusion process through charged hydrated soft tissues such as articular cartilage were analysed using the triphasic theory (Lai et al., 1991, J. biomech. Engng 113, 245-258). It was found that solvent would flow from the high NaCl concentration side to the low concentration side (i.e. negative osmosis) when the fixed charge density within the tissue (or membrane) separating the two electrolyte (NaCl) solutions was lower than a critical value. The condition for negative osmosis was derived based on a linear version of the triphasic theory. Distributions of ion concentration and strain field within the tissue were calculated numerically. Quantitative results of osmotic flow rates (ordinary and negative osmosis), ion flux and electric potential across the tissue during this diffusion process suggest that the negative osmosis phenomenon is due to the friction between ions and water since they could flow through the tissues at different rates and different directions.

On the conditional equivalence of chemical loading and mechanical loading on articular cartilage.

Osmotic pressure loading of articular cartilage has been customarily invoked to be equivalent to mechanical loading. In the literature, this equivalence is defined by the amount of water squeezed from the tissue, i.e. if the amount of water content lost by these two modes of loading are the same, it has been generally regarded that the two loadings are equivalent. This assumption has never been proven. Using the water content lost concept, in this paper, we derived the exact conditions under which an osmotic pressure loading of cartilage can be considered to be equivalent to a mechanical loading. However, the mechanical loading condition satisfying this equivalency criterion, i.e. an isotropic loading delivered via a porous permeable rigid platen uniformly applied all around the specimen, is not practically achievable. Moreover, even if this were achieved experimentally, the interstitial fluid pressure caused by the two loading conditions are not the same. This result has important ramifications for interpretation of experimental data from mechanical stimulations of cartilage explant studies.

Transport of fluid and ions through a porous-permeable charged-hydrated tissue, and streaming potential data on normal bovine articular cartilage.

Using the triphasic mechano-electrochemical theory [Lai et al., J. biomech. Engng 113, 245-258 (1991)], we analyzed the transport of water and ions through a finite-thickness layer of charged, hydrated soft tissue (e.g. articular cartilage) in a one-dimensional steady permeation experiment. For this problem, we obtained numerically the concentrations of the ions, the strain field and the fluid and ion velocities inside when the specimen is subject to an applied mechanical pressure and/or osmotic pressure across the layer. The relationships giving the dependence of streaming potential and permeability on the negative fixed charge density (FCD) of the tissue were derived analytically for the linear case, and calculated for the nonlinear case. Among the results obtained were: (1) at a fluid pressure difference of 0.1 MPa across the specimen layer, there is a 10% flow-induced compaction at the downstream boundary; (2) the flow-induced compaction causes the FCD to increase and the neutral salt concentration to decrease in the downstream direction; (3) while both ions move downstream, relative to the solvent (water), the anions (Cl-) move with the flow whereas cations (Na+) move against the flow. The difference in ion velocities depends on the FCD, and this difference attained a maximum at a physiological FCD of around 0.2 meq ml-1; (4) the apparent permeability decreases nonlinearly with FCD, and the apparent stiffness of the tissue increases with FCD; and (5) the streaming potential is not a monotonic function of the FCD but rather it has a maximum value within the physiological range of FCD for articular cartilage. Finally, experimental data on streaming potential were obtained from bovine femoral cartilage. These data support the triphasic theoretical prediction of non-monotonicity of streaming potential as a function of the FCD.

Streaming potential of human lumbar anulus fibrosus is anisotropic and affected by disc degeneration.

The streaming potential responses of non-degenerate and degenerate human anulus fibrosus were measured in a one-dimensional permeation configuration under static and dynamic loading conditions. The goal of this study was to investigate the influence of the changes in tissue structure and composition on the electrokinetic behavior of intervertebral disc tissues. It was found that the static streaming potential of the anulus fibrosus depended on the degenerative grade of the discs (p = 0.0001) and on the specimen orientation in which the fluid flows (p = 0.0001). For a statically applied pressure of 0.07 MPa, the ratio of streaming potential to applied pressure ranged from 5.3 to 6.9 mV/MPa and was largest for Grade I tissue with axial orientation and lowest for Grade III tissue with circumferential orientation. The dynamic streaming potential responses of anulus fibrosus were sensitive to the degeneration of the disc: the total harmonic distortion factor increased by 108%, from 3.92 +/- 0.66% (mean +/- SD) for Grade I specimens to 8.15 +/- 3.05% for Grades II and III specimens. The alteration of streaming potential reflects the changes in tissue composition and structure with degeneration. To our knowledge, this is the first reported data for the streaming potential of human intervertebral disc tissues. Knowledge of the streaming potential response of the intervertebral disc provides an understanding of potentially important signal transduction mechanisms in the disc and of the etiology of intervertebral disc degeneration.