Pan-cancer analysis of SLC2A family genes as prognostic biomarkers and therapeutic targets

Background

The major facilitator superfamily glucose transporters (GLUTs), encoded by solute carrier 2A (SLC2A) genes, mediate the transmembrane movement and uptake of glucose. To satisfy the improved energy demands, glycolysis flux is increased in cancers compared with healthy tissues. Multiple diseases, including cancer, have been associated with GLUTs. Nevertheless, not much research has been done on the functions of SLC2As in pan-cancer prognosis or their clinical treatment potential.

Methods

The SLC2A family genes' level of expression and prognostic values were analyzed in relation to pan-cancer. We then examined the association among SLC2As expression and TME, Stemness score, clinical characteristics, immune subtypes, and drug sensitivity. We merged bioinformatics analysis techniques with up-to-date public databases. Additionally, SLC2As from the KOBAS database were subjected to enrichment analysis.

Results

We discovered that SLC2As' gene expression differed significantly between normal tissues and many malignancies. A number of tumors from various databases demonstrate a relationship between prognosis and SLC2A family gene expression. For instance, SLC2A2 and SLC2A5 were associated with the overall survival (OS) of hepatocellular carcinoma. SLC2A1 was associated with the OS of lung adenocarcinoma and pancreatic adenocarcinoma. Moreover, the SLC2A family gene expression is significantly correlated with the pan-cancer stromal and immune scores, and the RNA and DNA stemness scores. Furthermore, we found that the majority of SLC2As had a strong correlation with the tumor stages in KIRC. The immunological subtypes and all members of the SLC2A gene family exhibited a substantial correlation. Moreover, pathways containing insulin resistance and adipocytokine signaling pathway may influence the progression of some cancers. Finally, there is a significant positive or negative connection between drug sensitivity and SLC2A1 expression.

Conclusion

Our research highlights the significant promise of SLC2As as prognostic indicators and offers insightful approaches for upcoming exploration of SLC2As as putative therapeutic targets in malignancies.

Toxicity profiles of immune checkpoint inhibitors for recurrent or metastatic head and neck squamous cell carcinoma: A systematic review and meta-analysis

BACKGROUND

Immune checkpoint inhibitors (ICIs) are widely used in recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC); however, the toxicity profiles are inconclusive.

METHODS

Clinical trials evaluating ICIs for R/M HNSCC were searched from online databases. The characteristics of the studies and the results of incidences of any grade treatment-related adverse events (trAEs), grade three or more trAEs, treatment-related deaths, trAEs leading to discontinuation of treatment, and specific trAEs were extracted.

RESULTS

Twenty studies with 3756 patients were included. The pooled incidences of any grade trAEs, grade three or more trAEs, treatment-related deaths, trAEs leading to discontinuation of treatment for overall population were 62.07% (95% CI, 59.07%-65.02%), 13.82% (95% CI, 11.23%-16.62%), 0.39% (95% CI, 0.15%-0.71%), 3.99% (95% CI, 2.36%-5.95%), respectively. Programmed cell death protein 1 (PD-1) inhibitors monotherapy and ICIs combination therapy had significantly higher incidences of any grade trAEs (odds ratio [OR], 1.25, 95% CI, 1.05-1.49 and 1.36, 95% CI, 1.15-1.60, respectively), grade three or more trAEs (OR, 1.41, 95% CI, 1.08-1.84 and 1.79, 95% CI, 1.39-2.30, respectively), trAEs leading to discontinuation of treatment (OR, 3.98, 95% CI, 2.06-7.70 and 10.14, 95% CI, 5.49-18.70, respectively) compared with programmed death-ligand 1 (PD-L1) inhibitors monotherapy. ICIs combination therapy had a significantly higher incidence of grade three or more trAEs compared with PD-1 inhibitors monotherapy (OR, 1.27, 95% CI, 1.03-1.55); however, the incidences of any grade trAEs and trAEs leading to discontinuation of treatment were not significant different.

CONCLUSIONS

Our study suggests that the incidences of grade three or more trAEs, treatment-related deaths, and trAEs leading to discontinuation of treatment are low in R/M HNSCC patients treated with ICIs. PD-L1 inhibitors monotherapy may be safer compared with PD-1 inhibitors monotherapy and ICIs combination therapy.

The value of T2-weighted MRI contrast ratio combined with DWI in evaluating the pathological grade of solid lung adenocarcinoma

AIM

To assess the predictive value of T2-weighted (T2W) magnetic resonance imaging (MRI) in combination with diffusion-weighted imaging (DWI) for determining the pathological grading of solid lung adenocarcinoma.

MATERIALS AND METHODS

The clinical and imaging data from 153 cases of solid lung adenocarcinoma (82 men, 71 women, mean age 63.2 years) confirmed at histopathology in The First Affiliated Hospital of Xi'an Jiaotong University from January 2017 to May 2022 were analysed retrospectively. Adenocarcinomas were classified into low-grade (G1 and G2) and high-grade (G3) groups following the 2020 pathological grading system proposed by the International Association for the Study of Lung Cancer. The T2-weighted contrast ratio (T2CR), calculated as the T2 signal intensity of the lung mass/nodule divided by the T2 signal intensity of the right rhomboid muscle was utilised. Two experienced radiologists reviewed the MRI images independently, measured the T2CR, and obtained apparent diffusion coefficient (ADC) values. The Mann-Whitney U-test was used to compare general characteristics (sex, age, maximum diameter), T2CR, and ADC values between the low-grade and high-grade groups. The non-parametric Kruskal-Wallis test determined differences in T2CR and ADC values among the five adenocarcinoma subtypes. Receiver characteristic curve (ROC) analysis, along with area under the curve (AUC) calculation, assessed the effectiveness of each parameter in distinguishing the pathological grade of lung adenocarcinoma. A Z-test was used to compare the AUC values.

RESULTS

Among the 153 patients with adenocarcinoma, 103 had low-grade adenocarcinoma, and 50 had high-grade adenocarcinoma. The agreement between T2CR and ADC observers was good (0.948 and 0.929, respectively). None of the parameters followed a normal distribution (p<0.05). The ADC value was lower in the high-grade adenocarcinoma group compared to the low-grade adenocarcinoma group (p=0.004), while the T2CR value was higher in the high-grade group (p=0.011). Statistically significant differences were observed in maximum diameter and gender between the two groups (p<0.001 and p=0.005, respectively), while no significant differences were noted in age (p=0.980). Among the five adenocarcinoma subtypes, only the lepidic and micropapillary subtypes displayed statistical differences in ADC values (p=0.047), with the remaining subtypes showing no statistical differences (p>0.05). The AUC values for distinguishing high-grade adenocarcinoma from low-grade adenocarcinoma were 0.645 for ADC and 0.627 for T2CR. Combining T2CR, ADC, sex, and maximum diameter resulted in an AUC of 0.778, sensitivity of 70%, and specificity of 75%. This combination significantly improved diagnostic efficiency compared to T2CR and ADC alone (p=0.008, z = 2.624; p=0.007, z = 2.679).

CONCLUSION

The MRI quantitative parameters are useful for distinguishing the pathological grades of solid lung adenocarcinoma, offering valuable insights for precise lung cancer treatment.

The syndrome of inappropriate antidiuretic hormone associated with nasal and paranasal malignant tumors

PURPOSE

To investigate the clinical characteristics of the syndrome of inappropriate antidiuretic hormone (SIADH) associated with nasal and paranasal malignant tumors.

METHODS

Patients with locally advanced or recurrence/metastatic malignant tumors of the nasal and paranasal sinuses were included. The SIADH was diagnosed according to the diagnostic criteria. The clinical characteristics of SIADH patients were retrospectively analyzed.

RESULTS

Six patients (6/188, 3.2%) met the diagnostic criteria of SIADH, including four olfactory neuroblastoma (4/26, 15.4%), one neuroendocrine carcinoma (1/9, 11.1%), and one squamous cell carcinoma (1/63, 1.6%). Five patients (83.3%) had severe hyponatremia; however, the hyponatremia could be improved by fluid restriction or tolvaptan. Three patients' SIADH were recovered during the chemotherapy and the other three were recovered after the surgery.

CONCLUSION

The incidence of SIADH associated with nasal and paranasal malignant tumors is relatively more common in olfactory neuroblastoma and neuroendocrine carcinoma. The hyponatremia caused by SIADH may be corrected by fluid restriction or tolvaptan, and the SIADH may be recovered through anti-tumor therapy.

Pan-cancer analysis of SERPINE family genes as biomarkers of cancer prognosis and response to therapy

Background: Serine protease inhibitor E (SERPINE) family genes participate in the tumor growth, cancer cell survival and metastasis. However, the SERPINE family members role in the prognosis and their clinical therapeutic potentials in various human cancer types have not been elaborately explored. Methods: We preliminarily analyzed expression levels and prognostic values of SERPINE family genes, and investigated the correlation between SERPINEs expression and tumor microenvironment (TME), Stemness score, clinical characteristic, immune infiltration, tumor mutational burden (TMB), immune subtype, and drug sensitivity in pan-cancer, which based on updated public databases and integrated some bioinformatics analysis methods. In addition, we conducted the enrichment analysis of SERPINEs from DAVID and KOBAS databases. Results: SERPINE1, SERPINE2, and SERPINE3 expression were upregulated in nine cancers, twelve cancers, and six cancers, respectively. The expression of SERPINE family genes was associated with the prognosis in several cancers from The Cancer Genome Atlas (TCGA). Furthermore, SERPINE family genes expression also had a significant relation to stromal and immune scores, and RNA stemness score and DNA stemness score in pan-cancer. SERPINE1 and SERPINE2 expression significantly increased in tumor advanced stage in colon adenocarcinoma (COAD). Results showed that SERPINE1 and SERPINE2 expression were negatively related with B cells and Monocytes, respectively. SERPINE2 expression had a significantly positive relation with B cells and Macrophages. In terms of TMB, SERPINE1, SERPINE2, and SERPINE3 were found to associated with TMB in seven cancers, fourteen cancers, and four cancers, respectively. Moreover, all SERPINE gene family members were significantly correlated with immune subtypes. SERPINE1 expression had a significantly positive or negative correlation with drug sensitivity. Conclusion: The study indicated the great potential of SERPINE family genes as biomarkers for prognosis and provided valuable strategies for further investigation of SERPINE family genes as potential targets in cancer.

Pan-cancer analysis reveals the characteristics and roles of tooth agenesis mutant genes

Tooth development is regulated by numerous genes and signaling pathways. Some studies suggest that mutations in these genes may be associated with several cancer types. However, the tooth agenesis mutated genes role in the prognosis and their clinical therapeutic potentials in pan-cancer have not been elaborately explored. Moreover, the intrinsic correlation between tooth agenesis and cancers also needs to be further verified. We preliminarily analyzed expression levels and prognostic values of causative genes of tooth agenesis, and explored the correlation between the expression of tooth agenesis mutated genes and TME, Stemness score, clinical characteristic, immune subtype, and drug sensitivity in pan-cancer, which based on updated public databases and integrated some bioinformatics analysis methods. In addition, we conducted the enrichment analysis of tooth agenesis mutant genes from KOBAS database. We observed that TA mutant genes had significant gene expression differences in multiple cancer types compared with normal tissues. The expression of causative genes of TA is associated with the prognosis in several cancers from different databases. For example, AXIN2 and MSX1 were correlated to the overall survival (OS) of uterine corpus endometrial carcinoma. PAX9 and TP63 were related to OS of lung squamous cell carcinoma. And TP63 was associated with OS in breast invasive carcinoma and pancreatic adenocarcinoma. Furthermore, the expression of TA mutant genes also has a significant correlation with stromal and immune scores, and RNA stemness score and DNA stemness score in pan-cancer. Besides, we observed that all causative genes of TA were significantly correlated with immune subtypes. Moreover, KEGG pathway analysis showed that causative genes of TA were associated with the development and progression of breast cancer, basal cell carcinoma, gastric cancer, and hepatocellular carcinoma. Finally, AXIN2 expression has a significantly positive or negative correlation with drug sensitivity. Our study indicates the great potential of TA mutant genes as biomarkers for prognosis and provides valuable strategies for further investigation of TA mutant genes as potential therapeutic targets in cancers. Our study can further verify that there may be an intrinsic correlation between tooth agenesis and the occurrence of multiple cancers.

Efficacy and safety of immune checkpoint inhibitors in recurrent or metastatic head and neck squamous cell carcinoma: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Immune checkpoint inhibitors (ICIs) showed antitumor activity for recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC). However, the results from different studies were controversial.

METHODS

Online databases were searched for randomized clinical trials (RCTs) evaluating ICIs for R/M HNSCC. The characteristics of the studies and the results of overall survival (OS), progression-free survival (PFS), objective response rate (ORR), treatment-related adverse events (TRAEs) were extracted.

RESULTS

A total of 4936 patients from eight studies were included. Anti-PD1/PDL1 monotherapy significantly improved OS in total population (hazard ratio, HR, 0.87, 95% CI, 0.79-0.95, p = 0.003) and PD-L1 high expression patients (HR, 0.71, 95% CI, 0.55-0.90, p = 0.006) with significant lower incidence of any grade TRAEs (odds ratio, OR, 0.16, 95% CI, 0.07-0.37, p < 0.00001) and Grades 3-5 TRAEs (OR, 0.18, 95% CI, 0.10-0.33, p < 0.0001) compared with standard of care (SOC); however, the pooled results of PFS and ORR were not significant different. PD1/PDL1 inhibitors plus CTLA4 inhibitors did not improve OS, PFS, ORR compared with SOC or ICIs monotherapy; however, the incidence of Grades 3-5 TRAEs was significant higher compared with ICIs monotherapy (OR, 1.80, 95% CI, 1.34-2.41, p = 0.0001).

CONCLUSIONS

Anti-PD1/PDL1 monotherapy could improve OS for R/M HNSCC with significant lower incidence of TRAEs compared with SOC. PD1/PDL1 inhibitors plus CTLA4 inhibitors showed no more benefit compared with both SOC and ICIs monotherapy, but the incidence of Grades 3-5 TRAEs was significant higher compared with ICIs monotherapy.

MRI-based radiomics analysis in differentiating solid non-small-cell from small-cell lung carcinoma: a pilot study

AIM

To investigate the ability of a T2-weighted (W) magnetic resonance imaging (MRI)-based radiomics signature to differentiate solid non-small-cell lung carcinoma (NSCLC) from small-cell lung carcinoma (SCLC).

MATERIALS AND METHODS

The present retrospective study enrolled 152 eligible patients (NSCLC = 125, SCLC = 27). All patients underwent MRI using a 3 T scanner and radiomics features were extracted from T2W MRI. The least absolute shrinkage and selection operator (LASSO) logistic regression model was used to identify the optimal radiomics features for the construction of a radiomics model to differentiate solid NSCLC from SCLC. Threefold cross validation repeated 10 times was used for model training and evaluation. The conventional MRI morphology features of the lesions were also evaluated. The performance of the conventional MRI morphological features, and the radiomics signature model and nomogram model (combining radiomics signature with conventional MRI morphological features) was evaluated using receiver operating characteristic (ROC) curve analysis.

RESULTS

Five optimal features were chosen to build a radiomics signature. There was no significant difference in age, gender, and the largest diameter. The radiomics signature and conventional MRI morphological features (only pleural indentation and lymph node enlargement) were independent predictive factors for differentiating solid NSCLC from SCLC. The area under the ROC curves (AUCs) for MRI morphological features, and the radiomics model, and nomogram model was 0.69, 0.85, and 0.90 (ROC), respectively.

CONCLUSIONS

The T2W MRI-based radiomics signature is a potential non-invasive approach for distinguishing solid NSCLC from SCLC.

Adamts18 Deficiency Causes Spontaneous SMG Fibrogenesis in Adult Mice

Chronic sclerosing sialadenitis of the submandibular gland (also known as Küttner tumor) is characterized by concomitant swelling of the submandibular glands secondary to strong lymphocytic infiltration and fibrosis. The pathogenesis of this disease has been unclear, but it is associated with immune disorders. ADAMTS18 is a member of the ADAMTS superfamily of extracellular proteinases. In this study, we showed that Adamts18 is highly expressed in submandibular salivary gland (SMG) during embryonic development and decreases but is retained in adult SMG tissue in mice. Adamts18 deficiency led to reduced cleft formation and epithelial branching in embryonic SMG before embryonic day 15.5 in mice. No significant histologic changes in the later stages of branching or the morphology of SMG were detected in Adamts18^-/- mice. However, Adamts18 deficiency causes spontaneous SMG fibrogenesis and fibrosis in adult mice. At 8 wk of age, Adamts18^-/- mice began to manifest the first signs of pathologic changes of mild fibrosis and CD11b⁺ cell infiltration in SMG tissues. At ≥8 mo, all male and female Adamts18^-/- mice developed unilateral or bilateral SMG scleroma that is similar to patients with chronic sclerosing sialadenitis of the submandibular gland. Adamts18^-/- mice also showed secretory dysfunction and severe dental caries. Histologically, SMG scleroma is characterized by progressive periductal fibrosis, acinar atrophy, irregular duct ectasis, and dense infiltration of IgG-positive plasma cells. A significant infiltration of CD4⁺ T lymphocytes and CD11b⁺ monocytes and macrophages was also detected in the SMG scleroma of Adamts18^-/- mice. The levels of TGF-β1, IL-6, and IL-33 were significantly increased in Adamts18^-/- SMGs, which induces chronic inflammation and myofibroblast activation, ultimately leading to fibrosis. This study indicates that Adamts18 regulates the early branching morphogenesis of embryonic SMG and plays a role in protecting from spontaneous SMG fibrogenesis via modulating local inflammation, autoimmune reaction, and myofibroblast activation in adult mice.

Effect of radiomics from different virtual monochromatic images in dual-energy spectral CT on the WHO/ISUP classification of clear cell renal cell carcinoma

AIM

To investigate the effect of radiomics obtained from different virtual monochromatic images (VMIs) in dual-energy spectral computed tomography (CT) on the World Health Organization/International Association for Urological Pathology (WHO/ISUP) classification of clear cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

A retrospective study of 99 ccRCC patients who underwent contrast-enhanced dual-energy CT was undertaken. ccRCC was confirmed at surgery or biopsy and graded according to the WHO/ISUP pathological grading criteria as low grade (n=68, grade I and II) or high grade (n=31, grade III and IV). Radiomics risk scores (RRSs) for differentiating high and low grades of ccRCC were constructed from 11 sets of VMI in (40-140 keV, 10 keV interval) the cortical phase. Receiver operating characteristic (ROC) curves were drawn and the area under the curves (AUCs) was calculated to evaluate the discriminatory power of RRS for each VMI. The Hosmer-Lemeshow test was used to evaluate the goodness-of-fit of each model and the decision curve was used to analyse its net benefit to patients.

RESULTS

The AUC values for distinguishing low-from high-grade ccRCC with RRS of 40-140 keV VMIs were all >0.920. The Hosmer-Lemeshow test showed that the p-values of RRS of VMIs were >0.05, suggesting good fits. In the decision curve analysis, RRS from the 40-140 keV VMIs had similar decision curves and provided better net benefits than considering all patients either as high-grade or low-grade.

CONCLUSIONS

The RRS obtained from multiple VMIs in dual-energy spectral CT have high diagnostic efficiencies for distinguishing between low- and high-grade ccRCC with no significant differences between different VMIs.

Synthesis of silver nanoparticles using Lactobacillus bulgaricus and assessment of their antibacterial potential

Many pathogenic strains have acquired multidrug-resistant patterns in recent a year, which poses a major public health concern. The growing need for effective antimicrobial agents as novel therapies against multidrug-resistant pathogens has drawn scientist attention toward nanotechnology. Silver nanoparticles are considered capable of killing multidrug-resistant isolates due to their oligo-dynamic effect on microorganisms. In this research study NPs were synthesized using the gram-positive bacteria Lactobacillus bulgaricus and its activity against selected pathogenic strains. Lactobacillus bulgaricus pure cultures were isolated from raw milk and grown in "De Man, Rogasa, and Sharp" broth for synthesis of nanoparticles. Lactobacillus bulgaricus culture was centrifuged and Cell- free supernatant of it was employed with aqueous silvery ions and evaluated their antibacterial activities against bacterial strains i.e. Staphylococcus aureus, Staphylococcus epidermidis and Salmonella typhi using agar well diffusion assay. Antibiotic profiling against selected pathogenic strains were also conducted using disc diffusion method. The synthesis and characterization of silver nanoparticles were monitored primarily by the conversion of the pale-yellow color of the mixture into a dark-brown color and via ultraviolet-visible absorption spectroscopy and Scanning electron microscopy respectively. The result showed that that AgNPs with size (30.65-100 nm) obtained from Lactobacillus bulgaricus were found to exhibit antibacterial activities against selected bacterial strains. Taken together, these findings suggest that Lactobacillus bulgaricus has great potential for the production of AgNPs with antibacterial activities and highly effective in comparison to tested antibiotics.

Replacing true unenhanced imaging in renal carcinoma with virtual unenhanced images in dual-energy spectral CT: a feasibility study

AIM

To investigate the clinical value of virtual unenhanced (VNC) spectral computed tomography (CT) images to replace the conventional true unenhanced spectral CT images (TNC) in diagnosing renal carcinoma.

MATERIALS AND METHODS

Fifty-six cases of renal carcinoma confirmed by histopathology underwent conventional plain CT and contrast-enhanced spectral CT at arterial phase (AP) and venous phase (VP). VNC images were generated on an AW4.6 workstation. The CT attenuation, image noise, contrast-to-noise ratio (CNR), and signal-noise-ratio (SNR) of the renal lesions and normal kidneys, long and short axis diameters of the lesion were measured from the three image sets and analysed using one-way analysis of variance (ANOVA). Two radiologists evaluated image quality subjectively using a five-point score, and lesion signature using a three-point score. Image quality scores were compared statistically and tested for consistency.

RESULTS

The two reviewers had good agreement for subjective evaluation (Kappa>0.70) and there was no difference in the quality of the scores among the three image groups. The lesion signature scores were all above the acceptable level. The CNR and SNR values in VNC were significantly higher than in TNC (p<0.05). VNC images had lower renal noise than in TNC (p<0.05). There was no difference in the long and short axis diameters of the lesion among the three image groups. VNC had higher CT attenuation values for the lesion and kidney than TNC (p<0.05), but the differences were <5 HU.

CONCLUSION

VNC images in spectral CT may be used to replace the conventional plain CT to reduce imaging duration and radiation dose in diagnosing renal carcinoma.

Piezoelectric modulation of broadband photoresponse of flexible tellurium nanomesh photodetectors

Flexible photodetector shows great potential applications in intelligent wearable devices, health monitoring, and biological sensing. In this work, single crystal β-tellurium nanowires were grown on flexible muscovite by molecular beam epitaxy, constructing high-density ordered nanomesh structure. The prepared photodetectors based on tellurium nanomesh exhibit excellent mechanical flexibility, fast response in a broad range from ultraviolet to near-infrared, and good photosensitivity. We found that the flexible photodetectors with Shottky contact drastically suppressed dark current, while the response speed was lowered in comparison to the devices with ohmic contact, as holes would take a long time to tunnel through the Shottky barrier between metal and p-type Te. Moreover, the photoresponse of flexible Shottky photodetectors can be modulated by piezoelectricity of tellurium, and pronounced photocurrent increase after bending many times. Under external stress, polarization charges could tune Shottky barrier height of the metal/tellurium, resulting in variation of photocurrent. This research not only explores the broadband photoresponse and piezoelectric effect of tellurium nanomesh, but also promotes the integration and development of broadband flexible optoelectronic devices.

Systematic review with meta-analysis: effectiveness and tolerability of interferon-free direct-acting antiviral regimens for chronic hepatitis C genotype 1 in routine clinical practice in Asia

BACKGROUND

Direct-acting antiviral (DAA) regimens have shown high efficacy and tolerability for patients with HCV genotype 1/1b (GT1/1b) in clinical trials. However, robust real-world evidence of interferon (IFN)-free DAA treatment for HCV GT1-infected patients in Asia is still lacking.

AIM

To systematically review and meta-analyse the effectiveness and tolerability of IFN-free DAA therapy for HCV GT1 infection in Asia.

METHODS

We included studies that enrolled adult patients with HCV GT1 infection in routine clinical practice in Asia, using IFN-free DAA regimens, and reported sustained virological response (SVR) after 12/24 weeks end-of-treatment by 31 May 2017. The pooled SVR rates were computed with a random-effects model. Subgroup analysis and meta-regression as previously registered in PROSPERO were performed to determine how pre-planned variables might have affected the pooled estimates.

RESULTS

We included 41 studies from eight countries and regions, comprising of 8574 individuals. The pooled SVR rates for GT1 were 89.9% (95% CI 88.6-91.1, I²  = 55.1%) with daclatasvir/asunaprevir (DCV/ASV) and 98.1% (95% CI 97.0-99.0, I²  = 41.0%) with ledipasvir/sofosbuvir ± ribavirin (LDV/SOF ± RBV). Baseline cirrhosis but not prior treatment history and age, attenuated the effectiveness of both regimens. Baseline resistance associated substitutions (RASs) severely attenuated SVR of DCV/ASV (65.4% vs 94.3%, P < 0.001) and only minimally with LDV/SOF ± RBV (94.5% vs 99.2%, P = 0.003). Patients with renal dysfunction treated with DCV/ASV showed a higher SVR rate (93.9% vs 89.8%, P = 0.046). Patients with hepatocellular carcinoma (HCC) LDV/SOF ± RBV achieved a lower SVR than those without HCC (94.1% vs 98.7%, P = 0.001).

CONCLUSION

All oral DAA treatment of HCV GT1 resulted in high cure rates in Asian patients in routine clinical practice setting including elderly patients and those with end-stage renal disease.

Influence of VEGF, COX-2, and MMP-9 expression on the molybdenum-targeted X-ray in breast cancer

AIM

To investigate the correlation of the expression of vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), and matrix metalloprotease-9 (MMP-9) in breast cancer tissues with molybdenum-targeted X-ray images.

MATERIALS AND METHODS

Sixtynine patients with invasive ductal carcinoma of the breast confirmed by molybdenum-targeted mammography, surgical, and pathologic examinations were enrolled. The expression of VEGF, COX-2, and MMP-9 were detected by immunohistochemical staining (IHS) and the correlation of VEGF, COX-2, and MMP-9 expression and classification of breast cancer on molybdenum-targeted X-ray was statistically analyzed.

RESULTS

The expression of VEGF, COX-2, and MMIP-9 were significantly higher (p < 0.05) in spiculation group (n = 50), vascular abnormalities group (n = 21), and lymph node metastasis group (n = 29),than the other three groups, respectively. However, the expression of VEGF, COX-2, and MMP-9 had no significant differences (p > 0.05) between the group with (n = 30) and without (n = 39) calcification.

CONCLUSION

Expression of VEGF, COX-2, and MMP-9 is highly correlated to the mammaographic appearance of spiculation, vascular abnormalities, and lymph node metastasis. However, the present results suggest that expression of VEGF, COX-2, and MMP-9 is either not or weakly correlated to mammographic appereance of calcification.

Escherichia coli biofilm: development and therapeutic strategies

Escherichia coli biofilm consists of a bacterial colony embedded in a matrix of extracellular polymeric substances (EPS) which protects the microbes from adverse environmental conditions and results in infection. Besides being the major causative agent for recurrent urinary tract infections, E. coli biofilm is also responsible for indwelling medical device-related infectivity. The cell-to-cell communication within the biofilm occurs due to quorum sensors that can modulate the key biochemical players enabling the bacteria to proliferate and intensify the resultant infections. The diversity in structural components of biofilm gets compounded due to the development of antibiotic resistance, hampering its eradication. Conventionally used antimicrobial agents have a restricted range of cellular targets and limited efficacy on biofilms. This emphasizes the need to explore the alternate therapeuticals like anti-adhesion compounds, phytochemicals, nanomaterials for effective drug delivery to restrict the growth of biofilm. The current review focuses on various aspects of E. coli biofilm development and the possible therapeutic approaches for prevention and treatment of biofilm-related infections.

Evaluation of the Antimicrobial Functions of N-halamine Dental Unit Waterline Tubing for One Year

OBJECTIVES

The objective of this study was to test the biofilm-controlling properties of N-halamine antimicrobial dental unit waterline (DUWL) tubing (T) tubing, without recharging over one year, compared to a control line (C).

METHODS

A simulated clinical model was used to pump ultrapure water through T and C lines at a rate of 1.4 mL/min, five minutes on, 15 minutes off, eight hours/day, five days a week. Samples of source water, effluent from T and C, and from the stagnant water in the carboy (liquid container) after bench work was completed (S2), were collected aseptically, serially diluted, and cultured on R2A agar for seven days every six weeks. SEM images of the inside surfaces of detached tubing sections were also taken. The carboy was rinsed with a 1:10 dilution of sodium hypochlorite after six months. Means of log transformed CFU values obtained in triplicate were paired by T and C lines across months for comparison by paired Student's t-tests.

RESULTS

An increase in effluent and carboy bacterial counts were noted after six months, but decreased after bleach rinse of the carboy. No significant difference (p > 0.25) between T and C lines were observed; similarly, T and carboy were not significantly different (p > 0.30). SEM images showed biofilm attachment on the inside surface of C after two months, but not on T. Organisms identified in the effluent reflected those in the source carboy.

CONCLUSIONS

No biofilm attachment was detected on the N-halamine test line after 12 months, indicating its antimicrobial properties were retained. Further evaluation is recommended to determine the optimal recharge interval for N-halamine DUWL tubing when ultrapure source water is used.

Nutritional outcomes with implementation of probiotics in preterm infants

OBJECTIVE

To assess nutritional outcomes in preterm infants after the implementation of probiotics.

STUDY DESIGN

Retrospective chart review of infants with birth weight⩽1250 grams and/or⩽28 weeks of gestational age admitted to the KCH-Neonatal Intensive Care Unit was done. Data were collected over two periods, period 1 (before probiotics) and period 2 (after probiotics) and included demographic data, daily weight gain, feeding strategies (type, amount, caloric content and frequency of feeds) and comorbidities affecting feedings (Patent ductus arteriosus, Sepsis). Primary outcomes-extra uterine growth restriction (EUGR) status and incidence of necrotizing enterocolitis (NEC) as well as secondary outcomes-time to reach full feeds, feeding intolerance episodes and weight gain were compared between the two groups.

RESULTS

A total of 113 infants (period 1) were compared with 108 infants (period 2). The odds of EUGR was significantly lower with probiotics (odds ratio: 0.3, 95% confidence interval 0.138 to 0.611). Time to reach full feeds was significantly reduced and weight gain was significantly better in period 2. Significant reduction was also noted in number of total parental nutrition days, central line days, nil per os days and number of feeding intolerance episodes in period 2. There was no significant difference in the incidence of NEC.

CONCLUSION

Probiotics improve feeding tolerance leading to better overall growth and decreases the incidence of EUGR in preterm infants.

Inhibition of 12/15-lipoxygenase by baicalein induces microglia PPARβ/δ: a potential therapeutic role for CNS autoimmune disease

12/15-Lipoxygenase (12/15-LO) is an enzyme that converts polyunsaturated fatty acids into bioactive lipid derivatives. In this study, we showed that inhibition of 12/15-LO by baicalein (BA) significantly attenuated clinical severity of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Inhibited migration of autoimmune T cells into the central nervous system (CNS) by BA treatment could be attributed to reduced activation of microglia, which was indicated by suppressed phagocytosis, and decreased production of proinflammatory cytokines and chemokines in the CNS. We further observed that inhibition of 12/15-LO with BA led to increased expression of peroxisome proliferator-activated receptor (PPAR)β/δ in microglia of EAE mice. This was confirmed in vitro in primary microglia and a microglia cell line, BV2. In addition, we demonstrated that BA did not affect 12/15-LO or 5-lipoxygenase (5-LO) expression in microglia, but significantly decreased 12/15-LO products without influencing the levels of 5-LO metabolites. Moreover, among these compounds only 12/15-LO metabolite 12-hydroxyeicosatetraenoic acid was able to reverse BA-mediated upregulation of PPARβ/δ in BV2 cells. We also showed that inhibition of microglia activation by PPARβ/δ was associated with repressed NF-κB and MAPK activities. Our findings indicate that inhibition of 12/15-LO induces PPARβ/δ, demonstrating important regulatory properties of 12/15-LO in CNS inflammation. This reveals potential therapeutic applications for MS.

MR imaging assessment of lumbar intervertebral disk degeneration and age-related changes: apparent diffusion coefficient versus T2 quantitation

BACKGROUND AND PURPOSE

T2 and ADC mappings are 2 quantitative MR imaging tools for assessing IVDD. This study aimed to compare these 2 measures in detecting IVDD and its age-related changes.

MATERIALS AND METHODS

Thirty-seven asymptomatic volunteers and 28 patients with back pain or sciatica were examined, and their lumbar disk T2 and ADC maps were quantified via sagittal imaging protocols at 1.5T. For all participants, the Pfirrmann system was used by 2 radiologists for grading disks. T2 and ADC values in the inner portion of disks were measured, and their variances in different grades were analyzed by 1-way ANOVA testing. The ability of T2 and ADC measures to differentiate IVDD grades was compared on the basis of their ROC curves. For asymptomatic subjects, the correlations between age and the 2 MR imaging measures were assessed by the Pearson correlation test.

RESULTS

Both T2 and ADC values were found to decrease with the increasing Pfirrmann grades except T2 in grade V. Significant T2 differences were seen among grades I-IV, but not between grades IV and V. There were no significant ADC differences among grades I-III. Moreover, the areas under the ROC curves differed significantly (0.95 and 0.67 for T2 and ADC, respectively). Linear regression analysis revealed that T2 yielded more significant correlation with age (r = -0.77) than ADC did (r = -0.37).

CONCLUSIONS

T2 quantitation provides a more sensitive and robust approach for detecting and characterizing the early stage of IVDD and age-related disk changes.

[Plasticity of the motor system in multiple sclerosis]

Multiple Sclerosis (MS) is associated with a chronic demyelinating and axonal injury to the central nervous system. Functional activation studies in MS patients have demonstrated that performance of simple motor tasks may activate non-canonical brain regions. Using virtual lesion induction by transcranial magnetic stimulation, it is possible to show that this activation is functionally relevant. Rapid-onset neuronal plasticity in patients with mild-to-moderate MS is uncompromised despite many plasticity-impeding factors. Long-term adaptive mechanisms, relying on the formation on new neuronal connections, most likely are the principal mechanism underlying compensation of brain injury in MS.

HIV vulnerabilities and conflict dynamics. Understanding HIV vulnerabilities in the context of Nepal's conflict

The purpose of this research is to understand how Nepal's conflict is affecting vulnerabilities to HIV and exposure to the virus among females and males. Data was primarily collected during a three-week exploratory field study of Surkhet district in 2005. Twenty key informants and 35 stakeholders were interviewed, with the results triangulated by six focus groups. Documentary sources complement this data. A sociological model is designed depicting how the impact of the conflict and the responses of those affected have given rise to three different vulnerabilities to HIV: imposed contextual, conditional contextual and internalised. The paper concludes that the majority of those affected by Nepal's conflict are more vulnerable to the disease and that exposure to the virus may be increasing with forced displacement and migration.

Rosai Dorfman syndrome with sinonasal mucosa and intraocular involvement

A 15 year-old-male presented with concurrent sinonasal polyposis and anterior uveitis with cervical lymph node enlargement. Cervical lymph node biopsy confirmed Rosai-Dorfman disease. Though patient's eye symptoms did not respond well to topical corticosteroid treatment but he showed a remarkable regression in the size of nasal polyps and cervical lymph nodes after systemic corticosteroids. Intraocular involvement in such a case is rare.

High altitude and early childhood growth retardation: new evidence from Tibet

OBJECTIVE

To assess possible effect of high altitude on early childhood growth in Tibet.

METHOD

A cross-sectional survey on child health and nutrition was conducted in Tibet with stratified multistage cluster random sampling technique. Height and weight status of Tibetan children <36 months of age was measured. A questionnaire was administered to mothers of children for information on family background, child feeding practice and health care and maternal care. A total of 1458 children with complete information were used for analysis. A logistic regression model was used to control for selected potential confounding factors and then observed altitude effect on growth of Tibetan children.

RESULTS

Positive association of stunting with altitude was observed for each age group, even after controlling for selected potential affecting factors. Children above 3500 m had two to six times risk of getting stunting compared with those at 3000 m when socioeconomic and other factors were controlled. Effect of altitude on underweight was observed only among children <24 months old and significant increase in odds ratio appeared only above 4000 m after controlling for those confounding factors. Indicator of wasting was not related to altitude.

CONCLUSIONS

Altitude might result in a delay in height of younger Tibetan children, independent of socioeconomic and other factors operating through nutrition and disease, and took adverse effect persistently through birth to 3 years old. Its adverse effect on weight could be limited. For comparison and assessment of nutritional status of Tibetan children, the effect of altitude on growth should be taken into account.

Human muscle fatigue and elastic compressive stockings

The present study was performed to test if elastic compressive stockings (ECSs) increase muscle fatigability during sustained muscle contraction or if it improves the recovery after fatigue. Surface electromyograms (EMGs) were recorded on 4 leg and thigh muscles, and static ankle dorsal flexion force levels were measured in the right limb of 15 healthy subjects. The subjects maintained a 50% maximum ankle dorsal flexion force (MVF) for as long as possible without and, after a 30 min rest, with a European class I ECS. Finally, after another 30 mn rest, the pressure exerted by the ECS on the skin was measured at standard points on the limb, using a Salzmann apparatus. During the first 10 min of both rest periods, the subjects performed brief static maximum ankle dorsal flexions every 30 s. ECS exerted a 14.3 mm Hg mean pressure at tibial level C. Linear relationships, whose slopes were not influenced by ECS, existed between the maintenance time and both the mean power frequency and the logarithm of the total power of the tibialis anterior and gastrocnemius lateralis EMGs. The endurance times, the force recovery times after fatigue and the linear relationships between the logarithm of the time elapsing after exhaustion and the MVF reached during the recovery period were also independent of ECS. The results show that class I ECSs are not responsible for greater muscle fatigability; but they do not improve force recovery during rest following static fatiguing voluntary contractions.

Feeding practice among younger Tibetan children living at high altitudes

OBJECTIVE

Few published data are available on the feeding practice of younger children in Tibet. Our study investigated feeding pattern of younger Tibetan children.

DESIGN AND SUBJECTS

The study was a cross-sectional survey conducted in Tibet. A sample of 1655 children younger than 36 months old and their mothers was obtained by stratified multistage cluster random sampling method. Mothers were interviewed to collect information on feeding practice by a designed family questionnaire including initial time and duration of breastfeeding and time, frequency and types of complementary foods introduced.

RESULTS

Most of the children was ever or being breastfed at the time of interview. The median duration of breastfeeding was 26 months. The prevalence of almost exclusive breastfeeding for 4 months was 20.1%. Mothers' age and education, child's residence, and introduction of egg, fresh milk and milk powder were strongly associated with the duration of breastfeeding. The partial feeding was a main pattern in the first 6 months of life. Zanban and porridge were offered at about 1 month after birth. By 6th month, less than 25% of children were fed protein foods such as egg and meats and only near 20% of children were fed fresh vegetables. Bean products, fish and chicken were seldom offered to children.

CONCLUSIONS

We conclude that although they were breastfed for long time, complementary feeding practice of Tibetan children was disadvantaged, especially of rural children. Improvement of monotonous complementary foods and timely introduction should be stressed in local programmatic nutritional interventions.

Poor nutritional status of younger Tibetan children living at high altitudes

BACKGROUND

The growth, development and nutrition of children in Tibet with high-altitude and unique traditional culture have recently gained attention. However, few researches are available on the nutritional status of younger children of Tibet.

OBJECTIVE

The objective of the study was to evaluate the nutritional status of children below 36 months old in Tibet by means of anthropometry.

DESIGN

The cross-sectional survey was conducted between August and September in 1999 and a sample of 1655 children below 36 months old was obtained using a stratified multistage cluster random sampling method from a total of seven districts of Tibet. Height, weight and hemoglobin concentration were measured and at the same time related sociodemographic and environmental information were collected. NCHS/CDC/WHO reference data were used to evaluate the nutritional status of the entire study children population and estimate the prevalence of stunting, underweight and wasting.

RESULTS

Compared with the reference of NCHS/CDC/WHO, the distributions of HAZ and WAZ shifted to the left significantly and the means of HAZ and WAZ were -1.53 and -1.05, respectively, which were significantly lower than the reference value. The distribution of WHZ, however, was close to that of the reference. The reduction of Z-scores for height and weight occurred very early in life and was greatest in the second year after birth. The prevalence of malnutrition of children was 39.0% for stunting, 23.7% for underweight and 5.6% for wasting, respectively. Rural children had prevalence of stunting of 41.4% and underweight of 24.7%, as compared with prevalence of stunting of 25.3% and underweight of 18.1% for urban children. Stunting and underweight were associated with altitudes. The mean of hemoglobin (Hb) of children was 120.4 g/l and rural children had a significantly lower Hb concentration (119.9 g/l) than urban children (123.3 g/l). The prevalence of anemia seemed higher when using different altitude corrections for Hb to estimate the prevalence, but the consequences were uneven.

CONCLUSIONS

For Tibetan young children, the nutritional status of the entire population is poor and the prevalence of malnutrition is higher, especially for stunting. Malnutrition is related to high altitudes. Although the Hb concentration is higher induced by high altitude, there must be quite a lot of anemic children at high altitudes. The relationship between altitude and Hb for children on the Tibetan plateau requires further study in order to determine correctly the magnitude of anemia of children.

The influence of water on the nanomechanical behavior of the plant biopolyester cutin as studied by AFM and solid-state NMR

Atomic force microscopy and solid-state nuclear magnetic resonance have been used to investigate the effect of water absorption on the nanoscale elastic properties of the biopolyester, cutin, isolated from tomato fruit cuticle. Changes in the humidity and temperature at which fruits are grown or stored can affect the plant surface (cuticle) and modify its susceptibility to pathogenic attack by altering the cuticle's rheological properties. In this work, atomic force microscopy measurements of the surface mechanical properties of isolated plant cutin have been made as a first step to probing the impact of water uptake from the environment on surface flexibility. A dramatic decrease in surface elastic modulus (from approximately 32 to approximately 6 MPa) accompanies increases in water content as small as 2 wt %. Complementary solid-state nuclear magnetic resonance measurements reveal enhanced local mobility of the acyl chain segments with increasing water content, even at molecular sites remote from the covalent cross-links that are likely to play a crucial role in cutin's elastic properties.

Calpain-mediated regulation of NMDA receptor structure and function

Calpains have been previously shown to regulate AMPA receptor properties by producing partial truncation of the C-terminal domains of several receptor subunits. We now report that NMDA receptor subunits, in particular NR2 subunits, are also subjected to calpain-mediated truncation. Treatment of synaptic membranes with calpain I resulted in truncation of both NR1 and NR2 subunits, with the appearance of NR2 species with lower mol.wt. than native subunits, but still recognized by antibodies directed at the C-terminal domain. This treatment did not modify the binding of several ligands of the NMDA receptors, such as glutamate, glycine or TCP. Incubation of thin frozen-thawed brain sections with calcium resulted in calpain-mediated selective degradation of NR2 subunits, as truncation into smaller fragments was totally blocked by calpain inhibitors. Under the same conditions, TCP binding to sections was decreased by about 50%, an effect also blocked by calpain inhibitors. Treatment of hippocampal slices in culture with the excitotoxin, kainic acid, also produced calpain-mediated truncation of the C-terminal domain of NR2 but not NR1 subunits of the NMDA receptors. The results indicate that calpain activation produces several modifications of NMDA receptors, including the truncation of the C-terminal domain of NR2 subunits, and changes in channel binding properties. They suggest that calpain-mediated regulation of NMDA receptors might represent a feed-back regulation of the receptors which could be used to limit receptor activation.

Characterization of calpain-mediated proteolysis of GluR1 subunits of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors in rat brain

Previous results have indicated that GluR1 subunits of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors are targets of calpain. In the present study, we determined the effects of calpain treatment of synaptic membranes on GluR1 subunits using western blots with antibodies directed against the C-terminal (C-Ab) and the N-terminal (N-Ab) domains of the proteins, and compared them with the effects of calcium treatment of frozen-thawed brain sections. Calpain treatment of synaptic membranes resulted in a large decrease in the GluR1 band (105 kDa) labeled with C-Ab and in the formation of a doublet band labeled with N-Ab due to the appearance of a new species of GluR1 (98 kDa). These effects were blocked almost completely by calpain inhibitors. Calpain-induced changes in GluR1 immunological properties were not associated with modifications of [3H]AMPA or 6-cyano-7-[3H]nitroquinoxaline-2,3-dione ([3H]CNOX) binding. Treatment of frozen-thawed brain sections with concentrations of calcium as low as 0.2 mM resulted in a large decrease in the 105-kDa GluR1 band and in the concurrent appearance of the 98-kDa band. This treatment was associated with increased [3H]-AMPA and [3H]CNOX binding. These results suggest that there exist several types/states of GluR1 subunits exhibiting different sensitivities to calpain. Our data also indicate the existence of additional calcium-dependent processes regulating the characteristics of receptors in intact tissues.

Corneal endothelial hyaluronidase: a role in anterior chamber hyaluronic acid catabolism

The possible role of the human corneal endothelium in the turnover of anterior chamber hyaluronic acid (HA) was investigated. Hyaluronidase, an endoglycosidase that degrades HA and other glycosaminoglycans, is thought to play a role in HA homeostasis. The presence of hyaluronidase in the corneal endothelium was demonstrated immunohistochemically in sections from normal adult human cornea. Additionally, by using a modified enzyme-linked immunosorbent assay-like assay, active hyaluronidase was detected in the supernatant from primary culture human corneal endothelial cells. The optimal activity for the corneal endothelial hyaluronidase was in the acid range (pH 4.0), similar to previously isolated lysosomal hyaluronidase. Further immunohistochemistry showed that the corneal endothelial cells also express CD44, the receptor for HA, which would allow endocytosis of HA. Human corneal endothelial hyaluronidase may play a role in normal anterior segment HA metabolism and in the degradation of highly concentrated HA used as a visco-elastic.

Activation of MAP kinases in airway smooth muscle

To test the hypothesis that mitogen-activated protein (MAP) kinases are activated by contractile agonists in intact nonproliferating airway smooth muscle, kinase activities were compared in resting and stimulated canine tracheal smooth muscle. Kinase activities in sodium dodecyl sulfate extracts were assayed by a gel renaturation method. Myelin basic protein kinase activities corresponding to ERK1 and ERK2 immunoreactive proteins were activated twofold above the basal level within 5 min by 1 microM carbachol. MAP kinase activity assayed in crude homogenates using a synthetic peptide substrate (APRTPGGRR) also increased twofold above basal in muscles stimulated with 1 microM carbachol. Two protein kinases separated by Mono-Q chromatography were identified on Western blots as ERK1 and ERK2 MAP kinases. Carbachol stimulation increased caldesmon phosphorylation in intact muscle, and purified caldesmon was a substrate for activated murine ERK2 MAP kinase. Activated ERK2 MAP kinase added to Triton X-100-permeabilized fibers potentiated Ca2+-induced contraction. The results show that ERK MAP kinases are activated after stimulation of muscarinic receptors in airway smooth muscle, which is consistent with coupling of MAP kinases to phosphorylation of caldesmon in vivo.

Activation of MAP kinases and phosphorylation of caldesmon in canine colonic smooth muscle

1. Phosphorylation of caldesmon was assayed in canine colonic circular smooth muscle strips labelled with 32P and stimulated with 10 microM acetylcholine. Caldesmon was isolated by two-dimensional non-equilibrium pH gel electrophoresis. Stimulation with acetylcholine increased caldesmon phosphorylation significantly from a basal level of 0.6 +/- 0.07 to 1.1 +/- 0.15 mol P1 (mol caldesmon)-1 after 2 min. 2. MAP kinase activities were measured in SDS extracts of muscle by a gel reconstitution method using myelin basic protein. Myelin basic protein kinase activities were observed at 38, 44, 50 and 57 kDa by the gel reconstitution method. Endogenous caldesmon kinase activities were also identified by the gel reconstitution method at 38, 44 and 50 kDa. The 38 and 44 kDa kinases comigrated with proteins labelled by anti-ERK1 MAP kinase antibodies on Western blots. Both 38 and 44 kDa MBP kinase activities increased significantly during contractions induced by 10 microM acetylcholine, 0.1 microM neurokinin A and 70 mM potassium. 3. Phorbol dibutyrate (0.1 microM) potentiated activation of MAP kinases and contraction of depolarized muscles while producing a decrease in fura-2 fluorescence ratio. This suggests that protein kinase C activation is coupled to MAP kinase activity in colonic smooth muscle. 4. MAP kinases isolated form muscle homogenates by Mono Q chromatography were assayed using the specific MAP kinase substrate peptide APRTPGGRR. Stimulation of muscles for 2 min with 10 microM acetylcholine activated both ERK1 and ERK2 MAP kinase activities 2-fold. 5. To determine the effects of caldesmon phosphorylation by MAP kinase on the cross-bridge cycle, actin sliding velocity was measured with an in vitro motility assay. Unphosphorylated turkey gizzard caldesmon (3 microM) significantly reduced mean sliding velocity. Phosphorylation of caldesmon with sea star ERK1 MAP kinase reversed the inhibitory effect of caldesmon on sliding velocity. The results are consistent with a protein kinase cascade being activated by contractile agonists in gastrointestinal smooth muscle which activates ERK MAP kinases leading to phosphorylation of caldesmon. Phosphorylation of caldesmon in vivo may reverse inhibitory influences of caldesmon on cross-bridge cycling.

Immunocytochemical localization of desferrioxamine in the kidney, liver and brain of the developing and adult mouse: implications for drug processing and therapeutic mechanisms

The iron chelator, desferrioxamine, has been shown to interfere with hydroxyl radical formation, which mediates tissue damage in several disease states. In this study, young and adult mice were given intraperitoneal injections of desferrioxamine and sacrificed after 1, 24 or 72 hr, and adult rats were given intraventricular injections and sacrificed after 24 or 72 hr. Immunohistochemical experiments, that utilized an anti-desferrioxamine antiserum, were performed to localize the cellular distribution of the drug in the kidney, liver and brain. In the kidney, the findings were as follows: 1) at 0 days, there was heterogeneous distribution of desferrioxamine, which suggests that there are functional differences between nephrons in the immature kidney; 2) with increasing age, the degree of staining decreased, which suggests that the efficiency of renal clearance of desferrioxamine increases with maturity; 3) punctate staining was superimposed onto diffuse staining, which suggests that the drug can get taken up in pinocytotic vesicles during tubular reabsorption; and 4) staining was present at 72 hr, which suggests a prolonged clearance period. In the liver, there was an absence of staining at 24 and 72 hr and only diffuse staining at 1 hr, which suggests a rapid processing of the drug by the liver. In the normal mouse brain, the drug was found localized to the choroid plexus and ependymal cells at all ages, and the staining decreased with increasing time following injection. These results indicate that there are differences in the way that desferrioxamine is processed by cells in different tissues and indicate possible therapeutic mechanisms.