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Objective: To investigate the expression of B7 homolog 4 (B7-H4) and its clinical significance in endometrial cancer. Methods: A total of 833 patients with endometrial cancer admitted to Peking Union Medical College Hospital, Chinese Academy of Medical Sciences from 2009 to 2019, were enrolled. The expression of B7-H4, mismatch repair (MMR), p53, programmed cell death ligand 1 (PD-L1) protein, and CD8+ T lymphocyte density in endometrial cancer tissues were detected by the EnVision two-step method of immunohistochemical staining. First-generation sequencing (Sanger method) was used to determine molecular subtyping of endometrial cancer. The χ2 test was used to compare the differences in positive expression rate of B7-H4 protein in endometrial cancer tissues with different clinicopathological features and molecular subtyping, PD-L1 protein expression, and CD8+ T lymphocyte density. Survival analyses [including recurrence-free survival (RFS) and disease-specific survival (DSS)] were performed for 664 patients with follow-up time≥3 months, with a median follow-up time of 31 months (range: 4-121 months), and the Cox proportional hazards regression model was used to analyze the relevant factors affecting the prognosis of patients with endometrial cancer. Results: (1) The median age of 833 patients was 58 years (range: 25-88 years); pathological type: 595 with endometrioid carcinoma, 238 with non-endometrioid carcinoma; surgical-pathological staging: 542 cases at stage â , 38 cases at stage â ¡, 173 cases at stage â ¢, and 45 cases at stage â £. Molecular subtyping was performed in 590 patients, including 50 with POLE mutation, 163 with mismatch repair defect (MMR-d) type, 246 with nospecific molecular change (NSMP) type, and 131 with p53 mutation subtype. (2) B7-H4 protein was expressed with brownish-yellow stainind in the cell membrane and cytoplasm of endometrial carcinoma, and the positivity rate of B7-H4 protein was 71.5% (596/833). The positivity rates of B7-H4 protein among patients with different age, surgical-pathological stage, tumor grade, pathological type, depth of muscular invasion, presence or absence of lymphovascular space invasion, and molecular subtype were significantly different (all P<0.05). The positivity rates of B7-H4 protein among patients with different PD-L1 protein expression and CD8+ T lymphocyte density were not significantly different (P>0.05). The 5-year RFS (83.9%) and DSS (87.3%) of B7-H4 protein-positive patients had an increasing trend compared with the 5-year RFS (77.2%) and DSS (78.1%) of B7-H4 protein-negative patients, but there were not statistically significant differences (P=0.053, P=0.083). (3) Univariate analysis showed that the 5-year RFS and DSS of patients with different age, tumor grade, surgical-pathological stage, pathological type, depth of muscular invasion, lymphovascular space invasion, and molecular subtype were significantly different (all P<0.01). There were no significant differences in 5-year RFS (P=0.184, P=0.113) and DSS (P=0.549, P=0.247) among patients with different CD8+ T lymphocyte density and PD-L1 protein expression. Further analysis according to molecular subtype, the results of CD8+ T lymphocyte density and PD-L1 protein expression showed that the 5-year RFS and DSS of B7-H4 protein-positive patients were higher than those of B7-H4 protein-negative patients with NSMP subtype, low density of CD8+ T lymphocyte and PD-L1 protein-negative endometrial carcinoma (all P<0.05), however, there was no significant difference in 5-year DSS between B7-H4 protein-positive patients and B7-H4 protein-negative patients with PD-L1 protein-negative endometrial cancer (P=0.060). Multivariate analysis showed that positive expression of B7-H4 protein was an independent factor for 5-year RFS (HR=0.27, 95%CI: 0.09-0.78, P=0.016) and DSS (HR=0.16, 95%CI: 0.05-0.58, P=0.005) in patients with NSMP subtype endometrial carcinoma. In patients with low-density CD8+ T lymphocytes endometrial cancer, positive expression of B7-H4 protein was an independent factor for 5-year RFS (HR=0.45, 95%CI: 0.26-0.80, P=0.006), but it was not an independent factor for 5-year DSS. In patients with PD-L1 protein-negative endometrial cancer, B7-H4 protein was not an independent factor for 5-year RFS. Conclusion: B7-H4 protein expressed highly in endometrial carcinoma tissues, and its high expression is closely related to clinicopathological features, molecular subtype of p53 mutant and NSMP, and the favorable prognosis of patients with low density of CD8+ T lymphocyte immunophenotype endometrial carcinoma.
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Carcinoma Endometrioide , Neoplasias Endometriales , Inhibidor 1 de la Activación de Células T con Dominio V-Set , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Persona de Mediana Edad , Biomarcadores de Tumor/metabolismo , Carcinoma Endometrioide/metabolismo , Carcinoma Endometrioide/patología , Neoplasias Endometriales/metabolismo , Neoplasias Endometriales/patología , Pronóstico , Proteína p53 Supresora de Tumor/metabolismo , Inhibidor 1 de la Activación de Células T con Dominio V-Set/metabolismoAsunto(s)
Neoplasias Endometriales , Neoplasias Endometriales/genética , Endometrio , Femenino , HumanosRESUMEN
Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "MicroRNA-1269a promotes the occurrence and progression of osteosarcoma by inhibiting TGF-ß1 expression, by S.-N. Yu, Y.-Y. Miao, B.T. Zhang, Y.-M. Dai, L. Liu, Z.-L. Gao, G.-F. Liu, published in Eur Rev Med Pharmacol Sci 2019; 23 (3): 972-981-DOI: 10.26355/eurrev_201902_16984-PMID: 30779063" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/16984.
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Objective: To evaluate clinical value of suspicious calcification in the diagnosis and surgical treatment of breast lesions using contrast-enhanced spectral mammography. Methods: Ninty-four patients who underwent CESM with suspicious calcification on the low-energy(LE) images in Third Affiliated Hospital of Soochow University from April 2017 to April 2019 were collected.All patients were female, with an average age of 51 years (26 to 89 years).All patients underwent biopsy or surgery to obtain pathological results. Two experienced radiologists provide BI-RADS classification for LE images and CESM. To assess pairwise agreement between BI-RADS classification on CESM and LE images among readers, kappa test were calculated. Using pathology results as the gold standard,the diagnostic efficacy of LE images and CESM were analyzed by receiver operating characteristic (ROC)curve, and Z test was used to compare the areas under the ROC curves (AUC) among them, calculated the sensitivity, specificity. The intraclass correlation coefficient (ICC) was used to analyze the consistency of the maximum image diameter and pathological diameter of malignant lesions. Two experienced radiologists provided the preferred surgical treatment (breast conservation therapy versus mastectomy) for all malignant cases according the imaging findings. McNemars test was used to compare the difference between surgical decision making and final surgical procedure. Results: One hundred and three lesions were found in 94 patients, in which 49 were benign and 54 were malignant.Overall agreement on BI-RADS classification between LE imaging and CESM among readers was substantial (0.74 vs 0.86), CESM was higher than LE images. The sensitivity of LE images and CESM were 80.4%, 96.2%, specificity was 75.0%, 94.0%, AUC were 0.810, 0.960 respectively. There was significant difference of the AUC between LE images and CESM (Z=3.66, P<0.01). The ICC of malignant lesions measured on LE images and CESM and histopathological results were 0.86 and 0.96, respectively. Based on LE images, 44.4%(24/54) of patients recommended BCT, 55.6%(30/54) of patients recommended mastectomy, the difference was statistically significant (P=0.008). Based on CESM, 27.8%(15/54) of patients recommended breast conservation therapy, 72.2%(39/54) of patients recommended mastectomy,there was no significant statistically difference with the final surgical procedure (P=0.125). Conclusion: CESM has a high diagnostic accuracy for suspicious calcification of breast. And its accuracy in assessing malignant lesion size is higher, which can provide a basis for preoperative surgical decision making.
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Neoplasias de la Mama , Calcinosis , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/cirugía , Medios de Contraste , Femenino , Humanos , Mamografía , Mastectomía , Persona de Mediana EdadRESUMEN
Objective: To investigate the feasibility of blood oxygen level-dependent magnetic resonance imaging (MRI) in evaluating the response of metastatic lymph nodes of rabbit VX2 tumor to radiotherapy. Methods: Twenty-eight healthy New Zealand white rabbits which were provided by the Laboratory Animal Center of Soochow University, male or female, 2 to 3 months, weighing 2 to 3 kg, were used to establish the animal model of VX2 tumor popliteal fossa metastatic lymph node, and then were divided into either the radiotherapy group (n=16) or the control group (n=12). The radiotherapy group received a 20 Gy radiotherapy per rabbit, the control group received sham radiotherapy. All rabbits underwent MRI scan on four time points, including before (0 day), 3rd, 7th and 14th days after radiotherapy. The two parameters of size and R(2*) value (s(-1)) of lymph node were measured. At each time point,two rabbits in each group were sacrificed randomly to resect lymph nodes for pathological examination, and two parameters of microvessel density (MVD, strip/HP) and apoptosis index (AI, %) were analyzed. The parameters among the four time points in each group or between the two groups were compared. The correlation of lymph node size and R(2*) value with MVD or AI was analyzed, respectively. Results: A significant size difference was neither between the two groups or among the each time points in each group (P>0.05). The R(2*) of lymph node in the radiotherapy group was (29.6±1.7),(36.8±2.6),(44.8±5.8) and (57.7±6.2) s(-1) at the time points of 0, 3, 7 and 14 days, respectively, showing a gradual increase trend; MVD was (52.3±2.5),(41.0±3.6),(34.0±3.6) and (22.7±2.5) strip/HP respectively, showing a decreasing trend; AI was 12.8%±0.5%,14.9%±0.6%,20.6%±0.5% and 27.5%±0.7% respectively, showing a gradual increase trend (all P<0.05). In the control group, both R(2*) value and AI among the four time points did not change statistically (all P>0.05), but MVD showed a gradual increase trend,(50.0±3.0),(53.0±1.7),(60.3±2.5) and (70.0±2.0) strip/HP, respectively, P<0.05. There were significant differences in R(2*) and MVD at 3, 7 and 14 days, in AI at 7 and 14 days between the two groups (all P<0.05). There was a linear correlation of R(2*) value, but not of size, with MVD and AI (r=-0.87 and 0.94, respectively). Conclusion: Blood oxygen level-dependent MRI can indirectly reflect the hypoxic status of metastatic lymph nodes after radiotherapy, and has potential value in evaluating the response of metastatic lymph nodes to radiotherapy.
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Imagen por Resonancia Magnética , Neoplasias , Animales , Estudios de Factibilidad , Femenino , Ganglios Linfáticos , Masculino , Neoplasias/diagnóstico por imagen , Neoplasias/radioterapia , Oxígeno , ConejosRESUMEN
OBJECTIVE: MicroRNAs are endogenous, non-coding small RNAs that are capable of regulating biological and pathological processes. Previous studies have shown that microRNA-1269a serves as an oncogene. However, the role of microRNA-1269a in the pathogenesis of osteosarcoma (OS) has not been reported. The aim of this work was to investigate the expression characteristics of microRNA-1269a in OS and to further study its regulatory effects on the malignant progression of OS. PATIENTS AND METHODS: The expression of microRNA-1269a in 61 pairs of OS tissues and para-cancerous tissues was detected by quantitative Real Time-polymerase Chain Reaction (qRT-PCR). Chi-square test was used to analyze the relationship between microRNA-1269a expression and the characteristics of OS patients, including age, sex, clinical stage and distant metastasis. Subsequently, microRNA-1269a expression in OS cell lines was detected as well. After knockdown of microRNA-1269a by constructing relevant small interference RNA, biological performances of MG63 and U2OS cells were accessed by cell counting kit-8 (CCK-8), colony formation and transwell assay. Meanwhile, the protein expressions of key genes in the EMT/Smad pathway were detected by Western blot. Finally, si-TGF-ß1 (transforming growth factor-ß1) was transfected into OS cells, and cell migration and invasion were detected by transwell assay. RESULTS: MicroRNA-1269a was highly expressed in OS tissues compared with para-cancerous tissues. High expression of microRNA-1269a was positively correlated with young OS patients and high rate of distant metastasis, whereas was not correlated with age, sex and Enneking stage. Kaplan-Meier survival curves showed that high expression of microRNA-1269a was significantly associated with poor prognosis of OS. The knockdown of microRNA-1269a in MG63 and U2OS cells significantly inhibited cell proliferation, migration and invasion. Meanwhile, microRNA-1269a knockdown in OS cells markedly downregulated the expressions of TGF-ß1, p-Smad2, p-Smad3, N-cad, Vimentin and MMP9. Furthermore, TGF-ß1 knockdown remarkably decreased migratory and invasive abilities of OS cells. CONCLUSIONS: MicroRNA-1269a is highly expressed in OS, which is remarkably correlated with tumor stage, distant metastasis and poor prognosis of OS. In addition, microRNA-1269a promotes the malignant progression of OS by regulating TGF-ß1 expression.
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MicroARNs/fisiología , Osteosarcoma/fisiopatología , Factor de Crecimiento Transformador beta1/biosíntesis , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/fisiología , Humanos , MicroARNs/biosíntesis , Invasividad Neoplásica/fisiopatología , Osteosarcoma/diagnóstico , Osteosarcoma/metabolismo , Pronóstico , ARN Interferente Pequeño/farmacología , Transfección , Factor de Crecimiento Transformador beta1/genética , Ensayo de Tumor de Célula MadreRESUMEN
We report the case of a breast cancer patient in whom a two-phase 18F-sodium-fluoride (18F-NaF) bone PET/CT was useful for detecting hidden bone metastases and assessing treatment response. The patient underwent a two-phase bone PET/CT to evaluate a newly developed lesion found on bone scintigraphy following surgery. In the perfusion and bone phase PET/CT images, focally increased perfusion and bony uptake were found in the sacrum and L5 vertebra, suggesting bone metastases of breast cancer. Therefore, the patient subsequently underwent palliative treatment. In another twoPET/CT studies (each including two-phase bone images) performed after 3and 6months of follow-up, the perfusion phase images showed an improvement of the lesion uptake more clearly than in the bone phase images in the visual and semi-quantitative analyses, and thus the perfusion phase images were more useful for clarifying the treatment response earlier than the bone phase images. This is the first case showing the clinical usefulness of 18F-NaF bone PET/CT with the perfusion imaging technique for evaluating bone metastases and the therapeutic response of metastatic bone lesions.
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Neoplasias Óseas/secundario , Neoplasias de la Mama/patología , Carcinoma Ductal de Mama/secundario , Vértebras Lumbares/diagnóstico por imagen , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Sacro/diagnóstico por imagen , Neoplasias Óseas/diagnóstico por imagen , Neoplasias Óseas/tratamiento farmacológico , Neoplasias Óseas/radioterapia , Remodelación Ósea , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/radioterapia , Neoplasias de la Mama/cirugía , Carcinoma Ductal de Mama/diagnóstico por imagen , Carcinoma Ductal de Mama/terapia , Quimioterapia Adyuvante , Terapia Combinada , Femenino , Radioisótopos de Flúor , Humanos , Mastectomía Segmentaria , Persona de Mediana Edad , Osteoblastos/metabolismo , Cuidados Paliativos , Radiofármacos , Radioterapia Adyuvante , Fluoruro de SodioRESUMEN
Objective: To evaluate the effect of snow sports to the knee cartilage maturation of children and adolescent with quantitative analysis of 3.0 T MRI. Methods: Twenty children and adolescent who underwent snow sports training more than 6 months (11 males and 9 females) were recruited and named with sports group, and twenty children and adolescent who live regularly without any exercise (10 males and 10 females) were recruited as control group from June 2014 to June 2015.Each group was divided into subgroups according to their gender.Both groups were scanned by 3.0 T MR.According to the loading features of knee articular cartilage in snow sports, medial femoral condyle, lateral femoral condyle, medial tibial condyle and lateral tibial condyle were divided into subareas.T2 values and cartilage thickness were measured in all areas. Results: The median ages of the sports group and control group were 14.2 and 13.6 years old, which showed no statistical difference between two groups.The BMI of the sports group and control group were 18.3 and 17.9 kg/m2, which showed no statistical difference between two groups.Both in sports group and control group, the thickness and T2 values of all areas showed significant differences between man and women in each group (all P<0.05). The cartilage thickness of sports group was higher than control group (P<0.05). The T2 values showed no statistical difference in anterior central, posterior central of femoral condyles and anterior, central areas of tibial condyles between sports group and control group(P≥0.05). The T2 values of anterior part of posterior femur and posterior areas of tibial condyle in sports group was higher than control group (P≥0.05). Conclusion: Gender difference may be an important effect factor of cartilage thickness. Scientific snow sports training maybe has positive influence for cartilage maturation of children and adolescent.
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Cartílago Articular , Articulación de la Rodilla , Deportes de Nieve , Adolescente , Epífisis , Fémur , Humanos , Imagen por Resonancia Magnética , TibiaRESUMEN
OBJECTIVE: To explore the correlation between susceptibility weighted imaging (SWI) manifestation and serum cystatin C level for delayed graft function (DGF). METHODS: The conventional MRI, SWI and serum cystatin C of 27 cases with DGF in nephrotransplantation center in Third Affiliated Hospital of Suzhou University from September 2014 and August 2015 were retrospectively analyzed.By contrasting conventional MRI images of transplanted kidney in DGF, the imaging manifestations of benign tumors such as cysts and angiomyolipomas were excluded on SWI images, and then making the renal cortex as the reference, if the abnormal signal lesions were found in the transplanted kidney, the location and signal intensity would be analyzed. The differences in serum cystatin C level between DGF groups without and with abnormal signal lesions were compared by using independent-sample t-test.The correlation between SWI manifestation and serum cystatin C level for DGF was assessed with Spearman rank correlation analysis. RESULTS: A total of 15 cases were found without abnormal signal lesions and the average value of their serum cystatin C level was (2.92±0.44) mg/L.A total of 12 cases were found with abnormal low signal lesions located at junctional zone between cortex and medulla, and the average value of their serum cystatin C level was (6.91±0.96) mg/L. The differences in serum cystatin C level between the two DGF groups were statistically significant (t=-4.040, P=0.000). There was a positive correlation between the abnormal low signal lesions on SWI and serum cystatin C level (r=0.660, P=0.000). CONCLUSION: The status of renal function impairment could be reflected by being with or without abnormal signal lesions on SWI. A relatively big renal function impairment may be predicted by the appearance of abnormal low signal lesions at junctional zone between cortex and medulla on SWI.
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Cistatina C/sangre , Funcionamiento Retardado del Injerto/sangre , Trasplante de Riñón/efectos adversos , Riñón/cirugía , Imagen por Resonancia Magnética/métodos , Humanos , Riñón/fisiopatología , Trasplante de Riñón/métodos , Valor Predictivo de las Pruebas , Insuficiencia Renal , Estudios RetrospectivosRESUMEN
SETTINGS: A tertiary referral centre in South Korea. OBJECTIVE: To investigate the incidence, clinical characteristics and outcomes of late paradoxical response (>4 months after the initiation of anti-tuberculosis treatment) during and after anti-tuberculosis treatment in non-human immunodeficiency virus (HIV) infected patients with lymph node tuberculosis (TB). DESIGN: We retrospectively reviewed the medical records of non-HIV-infected patients with lymph node TB between 1997 and 2007, and prospectively enrolled patients with newly diagnosed lymph node TB between 2008 and 2013. RESULTS: Of 467 patients with confirmed and probable lymph node TB, 83 (18%) displayed a paradoxical response: 57 of these (69%) were classified as early and 26 (31%) as late paradoxical response. Patients with late paradoxical response (median 12 months) received more prolonged anti-tuberculosis treatment than those with early (median 9 months, P < 0.001) or no paradoxical response (median 9 months, P < 0.001). The frequency of post-treatment lymph node enlargement increased progressively from those without any paradoxical response (6%), through those with an early response (12%) to those with a late response (23%). CONCLUSIONS: Paradoxical response presents late in about one third of non-HIV-infected patients with lymph node TB who experience a response. Although anti-tuberculosis treatment is commonly prolonged in patients with late paradoxical response, post-treatment lymph node enlargement is more frequent in these patients.
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Antituberculosos/uso terapéutico , Seronegatividad para VIH , Ganglios Linfáticos/patología , Tuberculosis Ganglionar/tratamiento farmacológico , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , República de Corea , Estudios Retrospectivos , Centros de Atención Terciaria , Insuficiencia del TratamientoRESUMEN
OBJECTIVES: During mass antibiotic distributions for trachoma, certain individuals are difficult to locate and go untreated. These untreated individuals may serve as a source of community reinfection. The importance of this difficult-to-locate, untreated population is unclear. We sought to determine whether individuals who are difficult to locate were more likely to be infected with ocular chlamydia than those who were easier to locate. METHODS: We monitored 12 Ethiopian communities 1 year after a third annual mass azithromycin treatment for trachoma. Conjunctival swabbing for chlamydial RNA was performed in a random sample of children from each community. If insufficient numbers of children were enrolled on the first monitoring day, we returned on subsequent days. RESULTS: Of the 12 communities, 10 required more than one monitoring day. On average, 16.1% (95% CI 7.9-30.0) of children were enrolled after the initial day. Evidence of chlamydia was found in 7.1% (95% CI 2.7-17.4) of 0- to 9-year-old children. No ocular swabs collected after the initial day were positive for chlamydial RNA. Children examined after the initial monitoring day were significantly less likely to have ocular chlamydial infection than children seen on the initial day; Mantel-Haenszel common OR = 0 (95% CI 0-0.77). CONCLUSIONS: In a setting of repeated annual mass azithromycin treatments, after approximately 80% of individuals have been located in a community, extra efforts to find absent individuals may not yield significantly more cases of ocular chlamydia.
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Azitromicina/uso terapéutico , Chlamydia trachomatis/genética , Conjuntiva/microbiología , Atención a la Salud , Accesibilidad a los Servicios de Salud , Vigilancia de la Población , Tracoma/diagnóstico , Humanos , Oportunidad Relativa , Características de la Residencia , Tracoma/tratamiento farmacológico , Tracoma/epidemiología , Tracoma/microbiologíaRESUMEN
The main purpose of this study is to investigate the effects of chronic electrical stimulation of acupuncture points on rat diabetic neuropathy. Diabetes mellitus was induced by a single dose of intravenous streptozotocin. The efficacies of several different protocols of electrical stimulation were compared. The evaluation measures included nerve conduction velocity, tactile threshold and blood perfusion on eye and footpad. Electrical stimulation was administered 30 min/day for 4 weeks. On the 4th weekend of stimulation, when compared with the control group, the stimulated groups showed differential benefits on different evaluation measures. The results indicated that chronic electrical stimulation could reduce the functional deficits of diabetic neuropathy.
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The effects of random potential on the transport of two systems, which are the motion of motor proteins along a biopolymer and the thermally assisted vortex diffusion in layered high-Tc superconductors, are investigated, respectively. It is found that the effects of the random potential on the transport process as the amplitude of random potential increased are much more remarkable than those as the correlation length of random potential increased. The amplitude and the correlation length of random potential play opposing roles in the transport of the systems.
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Transporte de Proteínas , Proteínas/química , Fenómenos Biofísicos , Biofisica , Biopolímeros/química , Modelos TeóricosRESUMEN
The muscle I2 is a smooth muscle from the buccal mass of the marine mollusc Aplysia californica whose neural control, in vivo kinematics, and behavioral role have been extensively analyzed. In this study, we measured the activation and contractile dynamics of the muscle in order to construct a Hill-type kinetic model of the muscle. This is the first study to our knowledge, of Aplysia muscle contractile dynamics. The isometric force-frequency relationship of I2 had a frequency threshold of about 6-8 Hz, and its force output saturated at 20-25 Hz, properties that match the high frequency (20 Hz) bursts generated by the B31/B32 neurons that innervate it. Peak isometric force was generated at about 118% of the in situ relaxed length. These results and I2's estimated in vivo kinematics suggest that it generates maximum force at the onset of protraction. The muscle tension during iso-velocity lengthening and shortening was an asymmetric function of velocity. Short range stiffness and yielding responses were observed in lengthening, whereas muscle tension decreased smoothly in shortening. These visco-elastic properties suggest that the I2 muscle can serve to brake forceful retraction movements. A Hill-type model, parameterized from the measurements, captured many of the mechanical properties of I2. Our results provide a quantitative understanding of the biomechanical significance of the muscle's neural control and provide a basis for simulation studies of the control of feeding behavior.
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Aplysia/fisiología , Cibernética , Modelos Biológicos , Músculo Liso/fisiología , Animales , Conducta Animal/fisiología , Fenómenos Biomecánicos , Mejilla , Elasticidad , Estimulación Eléctrica , Técnicas In Vitro , Contracción Isométrica/fisiología , Cinética , Músculo Liso/inervación , ViscosidadRESUMEN
The suppression subtractive hybridization (SSH) method was used to isolate differentially expressed genes during carnation flower maturation. Five cDNA clones, designated as carnation flower maturation-induced (CFMI), were verified as flower maturation-induced cDNAs. Sequence analysis of five CFMI (CFMI-5, CFMI-6, CFMI-7, CFMI-9, and CFMI-10) clones revealed that one of the clones, CFMI-5, showed high sequence similarity to the cysteine proteinase inhibitor gene, predicted to be involved in flower maturation. The full length cDNA clone CFMI-5 was 531 nucleotides (nts) long and consisted of an open reading frame of 294 nucleotides, encoding a 98 amino acid protein, 12 nucleotides of 5'-untranslated region and 3'-untranslated region (225 nts) with a poly(A)+ tail. The predicted CFMI-5 amino acid sequence had a conserved sequence Gln-Val-Val-Ala-Gly, which corresponds to the active site of proteinase inhibition. Northern blot analysis revealed tissue-specific expression of CFMI-5 transcripts, as the transcripts were expressed preferentially in petals and styles. A PCR-based cDNA subtraction method, termed suppression subtractive hybridization, was identified as a rapid method to screen differentially expressed genes in a short time.