NACP, a protein implicated in Alzheimer's disease and learning, is natively unfolded

The "non-A beta component of Alzheimer's disease amyloid plaque" (NAC) is a minor peptide component of the insoluble fibrillar core of the Alzheimer's disease (AD) neuritic plaque. NAC amyloid fibrils seed the polymerization of A beta 1-40, the major AD amyloid protein. NAC is derived from a 14 kDa precursor protein, designated NACP, a member of a highly conserved family of heat-stable brain-specific acidic proteins which have been suggested to be involved in synapse formation and/or stabilization. NACP has also been suggested to play a role in AD. We present herein a conformational analysis of human NACP. NACP has a much larger Stokes radius (34 A) but sedimented more slowly (s20,w = 1.7S) than globular proteins of similar molecular weight, indicating that the native protein is elongated. Circular dichroism (CD) and Fourier-transform infrared spectroscopy (FTIR) indicate the absence of significant amounts of secondary structure in NACP, while CD and ultraviolet spectroscopy suggest the lack of a hydrophobic core. The conformational properties of NACP were unchanged by boiling and were independent of concentration, pH, salt, and chemical denaturants. These features indicate that NACP exists as a mixture of rapidly equilibrating extended conformers and is representative of a class of "natively unfolded" proteins, many of which potentiate protein-protein interactions.

Long-term effects in children treated with radiotherapy for head and neck rhabdomyosarcoma

PURPOSE

To examine the long-term effects of treatment in children receiving radiotherapy for head and neck rhabdomyosarcoma.

METHODS

From 1967 to 1994, a total of 30 children with head and neck rhabdomyosarcoma received megavoltage radiotherapy at one institution. Seventeen patients (57%) have survived and have at least a 5-year follow-up. There were 11 males and 6 females, with a median age of 5.7 years (range 2.2-11.6) at the time of radiotherapy. Tumor location was orbit in 6 patients, infratemporal fossa in 4, paranasal sinuses in 2, and supraglottic larynx in 2; the nasopharynx, pterygopalatine fossa, and parotid gland were sites for the remaining children. All but 2 patients had tumors of embryonal histology. The Intergroup Rhabdomyosarcoma Study (IRS) Group was I in 2, II in 3, and III in 11 children; 1 patient had a recurrent tumor after surgery alone. Radiotherapy volume was the primary tumor or tumor bed in 13, tumor and whole brain in 3, and tumor and craniospinal axis in 1. Median radiotherapy dose to the primary site was 5,040 cGy (range 4,140-6,500) and to the whole brain was 3,000 cGy. All but 1 were treated with 150-200-cGy fractions; 1 patient received 250-cGy fractions for a tumor in the larynx. Chemotherapy was vincristine (V), actinomycin-D (A), and cyclophosphamide (C) in 10 patients, VAC + adriamycin in 2, VA in 1, VA + ifosfamide in 1, VC + adriamycin in 1, and none in 2. One patient had salvage chemotherapy consisting of cisplatin and etoposide. Median follow-up time was 20 years (range 7.5-33).

RESULTS

Late effects of treatment were seen in all patients and included facial growth retardation in 11, neuroendocrine dysfunction in 9, visual/orbital problems in 9, dental abnormalities in 7, hearing loss in 6, and hypothyroidism in 3. Intellectual and academic delays were documented in 3 patients who had received whole brain radiotherapy. While neuroendocrine, thyroid, dental, and cognitive sequelae were primarily attributed to radiotherapy, hearing loss was thought to be a direct result of tumor destruction and, in 1 case, cisplatin chemotherapy. Late effects at or beyond 10 years from radiotherapy were few, but severe, and included chondronecrosis, esophageal stenosis, second malignancy, and brain hemorrhage.

CONCLUSION

Late effects of treatment in children receiving radiotherapy for head and neck rhabdomyosarcoma are frequent. Although radiotherapy is a significant contributor of neuroendocrine, dental, thyroid, and cognitive toxicity, it is not usually implicated with hearing loss. Late toxicity of treatment beyond 10 years is not as frequent as those occurring within 10 years of therapy.

The effect of icariin on bone metabolism and its potential clinical application

Osteoporosis is a bone disease characterized by reduced bone mass, which leads to increased risk of bone fractures, and poses a significant risk to public health, especially in the elderly population. The traditional Chinese medicinal herb Epimedii has been utilized for centuries to treat bone fracture and bone loss. Icariin is a prenylated flavonol glycoside isolated from Epimedium herb, and has been shown to be the main bioactive component. This review provides a comprehensive survey of previous studies on icariin, including its structure and function, effect on bone metabolism, and potential for clinical application. These studies show that icariin promotes bone formation by stimulating osteogenic differentiation of BMSCs (bone marrow-derived mesenchymal stem cells), while inhibiting osteoclastogenic differentiation and the bone resorption activity of osteoclasts. Furthermore, icariin has been shown to be more potent than other flavonoid compounds in promoting osteogenic differentiation and maturation of osteoblasts. A 24-month randomized double-blind placebo-controlled clinical trial reported that icariin was effective in preventing postmenopausal osteoporosis with relatively low side effects. In conclusion, icariin may represent a class of flavonoids with bone-promoting activity, which could be used as potential treatment of postmenopausal osteoporosis.

The effect of pore size on tissue ingrowth and neovascularization in porous bioceramics of controlled architecture in vivo

The purpose of this study was to investigate the role of pore size on tissue ingrowth and neovascularization in porous bioceramics under the accurate control of the pore parameters. For that purpose, β-tricalcium phosphate (β-TCP) cylinders with four different macropore sizes (300-400, 400-500, 500-600 and 600-700 µm) but the same interconnection size (120 µm) and unchangeable porosity were implanted into fascia lumbodorsalis in rabbits. The fibrous tissues and blood vessels formed in scaffolds were observed histologically and histomorphometrically. The vascularization of the porous bioceramics was analyzed by single-photon emission computed tomography (SPECT). It is found that pore size as an important parameter of a porous structure plays an important role in tissue infiltration into porous biomaterial scaffolds. The amount of fibrous tissue ingrowth increases with the decrease of the pore size. In four kinds of scaffolds with different macropore sizes (300-400, 400-500, 500-600 and 600-700 µm) and a constant interconnection size of 120 µm, the areas of fibrous tissue (%) were 60.5%, 52.2%, 41.3% and 37.3%, respectively, representing a significant decrease at 4 weeks (P < 0.01). The pore size of a scaffold is closely related to neovascularization of macroporous biomaterials implanted in vivo. A large pore size is beneficial for the growth of blood vessels, and the diameter of a pore smaller than 400 µm limits the growth of blood vessels and results in a smaller blood vessel diameter.

National survey of head and neck verrucous carcinoma: patterns of presentation, care, and outcome

BACKGROUND

Verrucous carcinoma is distinguished by controversy regarding appropriate diagnosis and treatment. This study provides a contemporary survey of demographics, patterns of care, and outcome for this disease in the United States.

METHODS

The National Cancer Data Base had 2350 cases of verrucous carcinoma of the head and neck diagnosed between 1985 and 1996. Statistical procedures included chi-square analyses, Student t tests, and relative survival.

RESULTS

Tumors originated most frequently in the oral cavity (55.9%) and larynx (35.2%). Although most patients were male (60.0%), oral cavity tumors were more common among older females. The most prevalent treatment was surgery alone (69.7%), followed by surgery combined with irradiation (11.0%) and irradiation alone (10.3%). For oral cavity tumors, surgery alone was more common among early (85.8%) than advanced cases (56.9%); a larger proportion of advanced disease received radiation alone or surgery and irradiation combined. Most laryngeal tumors were treated with surgery (60.3% for early and 55.6% for advanced disease), but a higher proportion received radiation alone or surgery combined with radiation compared with oral cavity cases. Five-year relative survival was 77.9%. For localized disease, survival after surgery was 88.9% compared with 57.6% after irradiation.

CONCLUSIONS

Demographic differences implicate different mechanisms of carcinogenesis for verrucous carcinoma arising in the oral cavity and the larynx. Although selection bias may account for the differences observed, patients receiving initial treatment with surgery had better survival than those treated with irradiation, especially for cases originating in the oral cavity.

Pixel analysis of MR perfusion imaging in predicting radiation therapy outcome in cervical cancer

The purpose of this study was to assess heterogeneity of tumor microcirculation determined by dynamic contrast-enhanced magnetic resonance (MR) imaging and its prognostic value for tumor radiosensitivity and long-term tumor control using pixel-by-pixel analysis of the dynamic contrast enhancement. Sixteen patients with advanced cervical cancer were examined with dynamic contrast-enhanced MR imaging at the time of radiation therapy. Pixel-by-pixel statistical analysis of the ratio of post- to precontrast relative signal intensity (RSI) values in the tumor region was performed to generate pixel RSI distributions of dynamic enhancement patterns. Histogram parameters were correlated with subsequent tumor control based on long-term cancer follow-up (median follow-up 4.6 years; range 3.8-5.2 years). The RSI distribution histograms showed a wide spectrum of heterogeneity in the dynamic enhancement pattern within the tumor. The quantity of low-enhancement regions (10th percentile RSI < 2.5) significantly predicted subsequent tumor recurrence (88% vs. 0%, P = 0.0004). Discriminant analysis based on both 10th percentile RSI and pixel number (reflective of tumor size) further improved the prediction rate (100% correct prediction of subsequent tumor control vs. recurrence). These preliminary results suggest that quantification of the extent of poor vascularity regions within the tumor may be useful in predicting long-term tumor control and treatment outcome in cervical cancer. J. Magn. Reson. Imaging 2000;12:1027-1033.

Coronavirus disease 2019 in pregnancy

OBJECTIVES

This study aimed to compare clinical courses and outcomes between pregnant and reproductive-aged non-pregnant women with COVID-19, and to assess the vertical transmission potential of COVID-19 in pregnancy.

METHODS

Medical records of pregnant and reproductive-aged non-pregnant women hospitalized with COVID-19 from January 15 to March 15, 2020 were retrospectively reviewed. The severity of disease, virus clearance time, and length of hospital stay were measured as the primary objective, while the vertical transmission potential of COVID-19 was also assessed.

RESULTS

Eighty-two patients (28 pregnant women, 54 reproductive-aged non-pregnant women) with laboratory-confirmed COVID-19 were enrolled in this study. Univariate regression indicated no association between pregnancy and severity of disease (OR 0.73, 95% CI 0.08-5.15; p=0.76), virus clearance time (HR 1.16, 95% CI 0.65-2.01; p=0.62), and length of hospital stay (HR 1.10, 95% CI 0.66-1.84; p=0.71). Of the pregnant women, 22 delivered 23 live births, either by cesarean section (17, 60.7%) or vaginal delivery (5, 17.9%), and no neonate was infected with SARS-CoV-2.

CONCLUSIONS

Pregnant women have comparable clinical courses and outcomes with reproductive-aged non-pregnant women when infected with SARS-CoV-2. No evidence supported vertical transmission of COVID-19 in the late stage of pregnancy, including vaginal delivery.

National cancer database report on chondrosarcoma of the head and neck

BACKGROUND

Management of chondrosarcoma of the head and neck is largely based on single-institution reports with small numbers accrued over several decades.

METHODS

The American College of Surgeons' National Cancer Data Base included 400 cases of chondrosarcoma of the head and neck diagnosed between 1985 and 1995. Chi square analyses of selected contingency tables and Wilcoxon regression analyses of selected survival stratifications were performed.

RESULTS

Histologic types included conventional (80.8%), myxoid (10.5%), and mesenchymal (8.8%). The mesenchymal and myxoid subtypes were rare among white patients (17.1%) and more common among African-American (31.8%) and Hispanic patients (44.9%). Treatment was most commonly surgery alone (59.5%) and surgery with irradiation (21.0%). Disease-specific survival was 87.2% at 5 years and 70.6% at 10 years. Worse 5-year survival was associated with higher grade (67.3%), regional or distant spread (71.0%), and the myxoid (45.0%) or mesenchymal (53.2%) subtypes.

CONCLUSIONS

Chondrosarcoma of the head and neck encompasses a variety of lesions that differ substantially by demographic and tumor characteristics. Individual tumors can be classified further according to site of origin, histologic subtype, and tumor grade, which can be used to predict biologic behavior and prognosis.

Epidemiology and outcomes of hospital-acquired bloodstream infections in intensive care unit patients: the EUROBACT-2 international cohort study

PURPOSE

In the critically ill, hospital-acquired bloodstream infections (HA-BSI) are associated with significant mortality. Granular data are required for optimizing management, and developing guidelines and clinical trials.

METHODS

We carried out a prospective international cohort study of adult patients (≥ 18 years of age) with HA-BSI treated in intensive care units (ICUs) between June 2019 and February 2021.

RESULTS

2600 patients from 333 ICUs in 52 countries were included. 78% HA-BSI were ICU-acquired. Median Sequential Organ Failure Assessment (SOFA) score was 8 [IQR 5; 11] at HA-BSI diagnosis. Most frequent sources of infection included pneumonia (26.7%) and intravascular catheters (26.4%). Most frequent pathogens were Gram-negative bacteria (59.0%), predominantly Klebsiella spp. (27.9%), Acinetobacter spp. (20.3%), Escherichia coli (15.8%), and Pseudomonas spp. (14.3%). Carbapenem resistance was present in 37.8%, 84.6%, 7.4%, and 33.2%, respectively. Difficult-to-treat resistance (DTR) was present in 23.5% and pan-drug resistance in 1.5%. Antimicrobial therapy was deemed adequate within 24 h for 51.5%. Antimicrobial resistance was associated with longer delays to adequate antimicrobial therapy. Source control was needed in 52.5% but not achieved in 18.2%. Mortality was 37.1%, and only 16.1% had been discharged alive from hospital by day-28.

CONCLUSIONS

HA-BSI was frequently caused by Gram-negative, carbapenem-resistant and DTR pathogens. Antimicrobial resistance led to delays in adequate antimicrobial therapy. Mortality was high, and at day-28 only a minority of the patients were discharged alive from the hospital. Prevention of antimicrobial resistance and focusing on adequate antimicrobial therapy and source control are important to optimize patient management and outcomes.

Giant-cell tumour of bone. The long-term results of treatment by curettage and bone graft

Giant-cell tumour of bone (GCT) is a locally benign aggressive tumour. The use of adjuvant agents, such as phenol or liquid nitrogen has been recommended to destroy the remaining tumour cells after curettage, and filling of the defect with methylmethacrylate cement has been advocated. Between 1957 and 1992 we treated 92 patients with a GCT with 50% aqueous zinc chloride solution and bone grafting. Their mean age at the time of surgery was 31 years (15 to 59) and the mean follow-up was 11 years (5 to 31). Twelve (13%) had a local recurrence and one had a wound infection. Two developed degenerative changes around the knee. Eighty-six (93%) achieved good or excellent function. Three had moderate function, and three needed amputation. Our findings indicate that treatment with an aqueous solution of zinc chloride and reconstructive bone grafting after curettage gives good results.

Multi-organ point-of-care ultrasound for COVID-19 (PoCUS4COVID): international expert consensus

COVID-19 has caused great devastation in the past year. Multi-organ point-of-care ultrasound (PoCUS) including lung ultrasound (LUS) and focused cardiac ultrasound (FoCUS) as a clinical adjunct has played a significant role in triaging, diagnosis and medical management of COVID-19 patients. The expert panel from 27 countries and 6 continents with considerable experience of direct application of PoCUS on COVID-19 patients presents evidence-based consensus using GRADE methodology for the quality of evidence and an expedited, modified-Delphi process for the strength of expert consensus. The use of ultrasound is suggested in many clinical situations related to respiratory, cardiovascular and thromboembolic aspects of COVID-19, comparing well with other imaging modalities. The limitations due to insufficient data are highlighted as opportunities for future research.

Esthesioneuroblastoma: the University of Iowa experience 1978-1998

OBJECTIVE

Esthesioneuroblastoma is rare and the best treatment has yet to be defined. The purpose of this study is to analyze the natural history, treatment, and patterns of failure of esthesioneuroblastoma treated at one institution.

METHODS

Between 1978 and 1998, 13 patients with esthesioneuroblastoma were identified using the University of Iowa Tumor Registry. All patients were staged according to Kadish criteria. Mean follow-up was 6.3 years. Six patients had 5 or more years of follow-up and four had follow-up exceeding 9.5 years. One patient was lost to follow-up at 36 months.

RESULTS

No patients had Kadish stage A disease, five were stage B, and eight stage C. Overall actuarial 5- and 10-year survival rate was 61% and 24%, respectively. Disease-free survival rate at 5 and 10 years was 56% and 42%, respectively. Seven patients have died, three of intercurrent disease and three of disease progression, one with an unknown disease status. Six patients remain alive, three without evidence of disease and three have experienced a local or regional recurrence. Five patients who were initially controlled developed recurrence, three local only, one locoregional, and one regional and distant. Median time to failure was 96 months. All patients with follow-up exceeding 12 years have experienced either a local or regional recurrence. Survival after salvage therapy in these patients ranged from 3 to 12 years.

CONCLUSION

Esthesioneuroblastoma has a long natural history characterized by frequent local or regional recurrence after conventional treatment. Successful retreatment can lead to prolonged survival.

Synthesis and amyloid binding properties of rhenium complexes: preliminary progress toward a reagent for SPECT imaging of Alzheimer's disease brain

The definitive diagnosis of Alzheimer's disease (AD) requires the detection of amyloid plaques in postmortem brain. Although the amount of fibrillar amyloid roughly correlates with the severity of symptoms at the time of death, the temporal relationship between amyloid deposition, neuronal loss, and cognitive decline is unclear. To elucidate this relationship, a noninvasive, practical method for the quantitation of brain amyloid deposition is required. We describe herein the initial stages of a strategy to accomplish this goal by single photon computed tomographic imaging. The amyloid-binding dye Congo Red was modified to allow its conjugation to the monoamine-monoamide bis(thiol) ligand. This ligand complexes technetium(V) in its neutral oxo form. A biphenyl-containing building block was conjugated to the protected ligand, and the product was coupled to the relevant aromatic compounds. Rhenium oxo complexes, which are isosteric, but nonradioactive, analogues of the potential imaging agent technetium oxo complexes, were synthesized. These complexes bound to Abeta amyloid fibrils produced in vitro and stained amyloid plaques and vascular amyloid in AD brain sections.

The Drosophila homolog of the human tumor suppressor gene BHD interacts with the JAK-STAT and Dpp signaling pathways in regulating male germline stem cell maintenance

Birt-Hogg-Dubé syndrome (BHD) is a rare, inherited genodermatosis characterized by hair follicle hamartomas, kidney tumors and spontaneous pneumothorax. The BHD locus was mapped to chromosome 17p11.2 by linkage analysis, and germline mutations in a novel gene (BHD) were identified in a panel of BHD families. Using RNA interference to decrease expression of the Drosophila BHD homolog (DBHD), we have demonstrated that DBHD is required for male germline stem cell (GSC) maintenance in the fly testis. Reduction of DBHD gene activity suppresses the GSC overproliferation phenotype associated with overexpression of either unpaired (upd) or decapentaplegic (dpp). Further genetic interaction experiments suggest that DBHD regulates GSC maintenance downstream or in parallel of the JAK/STAT and Dpp signal-transduction pathways. These findings suggest that the BHD protein may regulate tumorigenesis through modulating stem cells in human.

The relative radiosensitivity of TK6 and WI-L2-NS lymphoblastoid cells derived from a common source is primarily determined by their p53 mutational status

The lymphoblastoid cell lines WI-L2-NS and TK6 were derived from a non-clonal pool of cells taken from a human spleen. Despite their common background they exhibit marked differences in radiosensitivities; D0 values of 93 and 67 cGy have been reported for WI-L2-NS and TK6 cells respectively. We show here that this differential radiosensitivity is due to a decreased ability of the WI-L2-NS cell line to undergo radiation-induced apoptosis. Further, the WI-L2-NS cell line overexpresses the p53 gene product as a result of a mutation in codon 237 of the p53 gene. These data indicate that WI-L2-NS cells through disruption of normal p53 function are unable to engage the radiation-induced apoptosis program and so are relatively radioresistant.

Increased gene-specific repair of cisplatin interstrand cross-links in cisplatin-resistant human ovarian cancer cell lines

We have studied several aspects of DNA damage formation and repair in human ovarian cancer cell lines which have become resistant to cisplatin through continued exposure to the anticancer drug. The resistant cell lines A2780/cp70 and 2008/c13*5.25 were compared with their respective parental cell lines, A2780 and 2008. Cells in culture were treated with cisplatin, and the two main DNA lesions formed, intrastrand adducts and interstrand cross-links, were quantitated before and after repair incubation. This quantitation was done for total genomic lesions and at the level of individual genes. In the overall genome, the initial frequency of both cisplatin lesions assayed was higher in the parental than in the derivative resistant cell lines. Nonetheless, the total genomic repair of each of these lesions was not increased in the resistant cells. These differences in initial lesion frequency between parental and resistant cell lines were not observed at the gene level. Resistant and parental cells had similar initial frequencies of intrastrand adducts and interstrand cross-links in the dihydrofolate reductase (DHFR) gene and in several other genes after cisplatin treatment of the cells. There was no increase in the repair efficiency of intrastrand adducts in the DHFR gene in resistant cell lines compared with the parental partners. However, a marked and consistent repair difference between parental and resistant cells was observed for the gene-specific repair of cisplatin interstrand cross-links. DNA interstrand cross-links were removed from three genes, the DHFR, multidrug resistance (MDR1), and delta-globin genes, much more efficiently in the resistant cell lines than in the parental cell lines. Our findings suggest that acquired cellular resistance to cisplatin may be associated with increased gene-specific DNA repair efficiency of a specific lesion, the interstrand cross-link.

Deficient gene specific repair of cisplatin-induced lesions in Xeroderma pigmentosum and Fanconi's anemia cell lines

Cisplatin is a chemotherapeutic agent known to cause DNA damage. The cytotoxicity of this drug is believed to result from the formation of DNA intrastrand adducts (IA) and DNA interstrand crosslinks (ICL). While there are many studies on DNA repair of cisplatin damage at the overall level of the genome in various human cell lines, there is little information on the gene-specific repair. In this report, we have measured the formation and repair of cisplatin induced DNA adducts in the dihydrofolate reductase (DHFR) and ribosomal RNA (rRNA) genes in three cell lines: normal human fibroblasts, Fanconi's anemia complementation group A (FAA) and Xeroderma pigmentosum complementation group A (XPA). It is generally thought that XPA cells lack nucleotide excision repair and that FAA cells are deficient in the repair of DNA ICL. We find that normal human fibroblast cells repair 84% of the ICL in the DHFR gene after 24 h, whereas XPA and FAA cell lines only repaired 32 and 50% of the ICL respectively. Furthermore, 69% of the cisplatin IA in the DHFR gene were repaired in 24 h in normal human fibroblasts compared to 22% for XPA and 24% for FAA cells. The repair of the rRNA gene was less efficient than in the DHFR gene, but the relative pattern between the different cell lines was similar to that of the DHFR gene. We thus find that FAA cells are deficient not only in the gene specific repair of cisplatin ICL, but also in the gene specific repair of the more common cisplatin IA. XPA cells are normally thought to be without any nucleotide excision repair capacity, but our data could support a slight ICL unhooking activity.

Clinical pharmacokinetic study of tiazofurin administered as a 1-hour infusion

Tiazofurin, 2-beta-D-ribofuranosylthiazole-4-carboxamide, is cytotoxic to murine and human tumor cells. In earlier Phase-I/-II trials performed in other centers in patients with solid tumors, the drug was given mainly as a 10-min bolus or as a continuous i.v. infusion for 5 days. These protocols were associated with serious side effects, including neurotoxicity, pleuropericarditis, and occasional myelosuppression. In our study, 26 patients with end-stage leukemia were treated with tiazofurin with 1-hr daily i.v. infusions, resulting in lower incidence and less severity of side effects. In this group, 7 attained complete remission and 7 showed hematologic responses. Out of 12 evaluable patients with myeloid blast crisis of chronic granulocytic leukemia, 10 (83%) responded to therapy, with 6 attaining complete response. We present pharmacokinetic parameters of our clinical study and examine some of the reasons for the lower toxicity found in our trials. In leukemic patients during and after infusion at doses of 1,100, 2,200 and 3,300 mg/m2 tiazofurin peak plasma concentrations were 245, 441 and 736 microM, respectively, values one-half of those calculated from other reports with a 10-min bolus administration. In our 1-hr infusion method, biphasic pharmacokinetics were noted with alpha t1/2 and beta t1/2 of 0.5 and 6.2 hr, and tiazofurin was eliminated at a faster rate than in previous trials with continuous infusion. The area under the curve with our 1-hr infusion was 52% of that reported for the same dose given by continuous infusion. Our 1-hr infusion method and prompt and effective treatment of side effects enabled us to administer higher doses and larger total amounts of tiazofurin in longer treatment cycles than in any previous trials elsewhere. Tiazofurin therapy using 1-hr infusion may be feasible for other carefully selected types of malignancies.

DNA strand-specific repair of (+-)-3 alpha,4 beta-dihydroxy-1 alpha,2 alpha-epoxy-1,2,3,4-tetrahydrobenzo[c]phenanthrene adducts in the hamster dihydrofolate reductase gene

We evaluated the formation and removal of (+-)-3 alpha,4 beta-dihydroxy-1 alpha,2 alpha-epoxy-1,2,3,4- tetrahydrobenzo[c]phenanthrene (BcPHDE)-DNA adducts in two Chinese hamster ovary (CHO) cell lines. One line of repair-proficient cells (MK42) carries a stable 150-fold amplification of the dihydrofolate reductase (DHFR) locus. The other line of repair-deficient cells (UV-5) is diploid for this gene and is defective in excision of bulky DNA lesions. Two methods were used to quantitate adduct levels in treated cells: Escherichia coli UvrABC excision nuclease cleavage and 32P-postlabeling. DNA repair was examined in the actively transcribed DHFR gene, in an inactive region located 25 kilobases downstream, and in the overall genome. Between 8 and 24 hr after BcPHDE exposure, preferential repair of the DHFR gene compared to the noncoding region was apparent in MK42 cells. This gene-specific repair was associated with adduct removal from the DHFR transcribed strand. However, UV-5 cells showed no lesion reduction from this strand of the gene. By both quantitation methods, regions accessible to repair in MK42 cells showed a 2-fold reduction in DNA adduct levels by 24 hr. That the decline in adducts reflects genomic repair was demonstrated by the constant damage level remaining in UV-5 cells. Since BcPHDE-induced mutations in DHFR apparently arise from adducted purines on the nontranscribed strand, results from the present study support the idea that a consequence of strand-specific repair is strand-biased mutations.

Apatinib has anti-tumor effects and induces autophagy in colon cancer cells

OBJECTIVES

Apatinib recently has been used to treat patients with gastric cancer, but the function of apatinib in colon cancer remains unclear. This study was conducted to investigate the impacts of apatinib on the biological function and its potential mechanism of colon cancer cells in vitro.

MATERIALS AND METHODS

The effect of apatinib in colon cancer cells were detected by assessing cell viability, migration and invasion capabilities. Apoptosis cells and the cell cycle distribution of colon cancer cells were analyzed by flow cytometry. The potential mechanism was investigated via autophagy related proteins and pathways in vitro.

RESULTS

The proliferation, migration and invasion of colon cancer cells were inhibited when they were treated with different concentration of apatinib (20, 40 μM). When HCT116 and SW480 cells were treated with apatinib at the concentration of 20 μM, the apoptosis percentage were 3.7% and 5.8% respectively. As the drug concentration increased to 40μΜ, the the apoptosis percentage increased to 11.9% and 13.5%. Meanwhile, cell cycle was also altered. Furthermore, apatinib inhibited the expression of AKT-mTOR signaling pathway and increased the expression of LC3-II.

CONCLUSION

Apatinib can significantly inhibit the malignant phenotype of colon cancer cells, and it was involved in regulation of autophagy.

Reduction-responsive PEtOz-SS-PCL micelle with tailored size to overcome blood-brain barrier and enhance doxorubicin antiglioma effect

A series of novel reduction-responsive micelles with tailored size were designed and prepared to release doxorubicin (DOX) for treating glioma, which were developed based on amphiphilic block copolymer poly (2-ethyl-2-oxazoline)-b-poly (ε-caprolactone) (PEtOz-SS-PCL) and the micelle size could be regulated by designing the polymer structure. The DOX-loaded PEtOz-SS-PCL micelles had small size and rapid drug release in reductive intracellular environments. Biodistribution and in vivo imaging studies in C6 glioma mice tumor model showed that DOX loaded PEtOz-SS-PCL43 micelles with the smallest size had superior accumulation and fast drug release in tumor sites. In vivo antitumor activity demonstrated that DOX-loaded PEtOz-SS-PCL43 micelles improved antitumor efficacy in contrast to PEtOz-SS-PCL micelles with larger size toward the orthotopic C6-Luci cells-bearing mice. This study shows great potential in tailoring the micelle size and introducing the responsive bonds or compartment for intracellular drug delivery and release in glioma treatment by designing the architecture of the polymer.

Commissioning and quality assurance for MLC-based IMRT

The commissioning and quality assurance (QA) associated with the implementation of linear accelerator multileaf collimator (MLC)-based intensity-modulated radiation therapy (IMRT) at the University of Nebraska Medical Center are described. Our MLC-based IMRT is implemented using the PRIMUS linear accelerator interface through the IMPAC record and verification system to the CORVUS treatment planning system. The "step-and-shoot" technique is used for this MLC-based IMRT. Commissioning process requires the verification of predefined parameters available on the CORVUS and the collection of some machine data. The machine data required are output factor in air and output factor in phantom, and percent depth dose for a number of field sizes. In addition, inplane and crossplane dose profiles of 4 x 4 cm and 20 x 20 cm field sizes and diagonal dose profiles of a large field size have to be measured. Validation of connectivity and dose model includes the use of uniform intensity bar strips, triangular-shaped nonuniform intensity bar strip, and N-shaped target. QA procedure follows the recommendation of the AAPM Task Group No. 40 report. In addition, the leaf position accuracy and reproducibility of the MLC should be checked at regular intervals. The dose validation is implemented through the hybrid plan where the patient beam parameters are applied to a flat phantom. Independent dose calculation method is used to confirm the dose delivery plan and data input to the CORVUS.

Anti- trachea inflammatory effects of diosgenin from Dioscorea nipponica through interactions with glucocorticoid receptor α

Asthma is a heterogeneous disease characterized by symptoms of chronic inflammation and airway structural and functional changes. It affects about 300 million people worldwide and causes 250 000 deaths annually, but its symptoms can be greatly relieved by regular use of inhaled glucocorticoids (GCs). GCs exert their function through interacting with glucocorticoid receptors (GRs). Diosgenin is a naturally occurring steroidal saponin abundantly present in many medicinal plants, including Dioscorea nipponica, which shares a similar steroidal structure with GC. In this study, ovalbumin (OVA)-induced asthmatic mice and primary tracheal epithelial cells (TECs) were used as research models. ELISAs were applied to measure the secretion of TNF-α, IL-1β, and IL-6, while quantitative PCR and western blotting were applied to evaluate expression of GRs SLPI, TTP, GILZ, MKP-1, and NF-κB. Our data demonstrated that diosgenin suppressed the secretion of TNF-α, IL-1β, and IL-6 by enhancing the expression of GRs, SLPI, GILZ, and MKP-1, and inhibiting the expression of HSP70. These data provide some evidence on the molecular mechanism of diosgenin, which might facilitate its clinical applications.