Designing a medical ethics curriculum in ophthalmology

Ethical principles form a bedrock to medical practice in any specialty,guiding physicians to appropriate attitudes and behaviors.A formal ethics curriculum can be difficult to generate de novo in an ophthalmology training program.A number of barriers exist in most ophthalmology departments:trainees may think ethics is of secondary importance compared to core basic and clinical science topics;most ophthalmology faculty have no formal degree in medical ethics;there is limited didactic time with competing academic,clinical,and surgical priorities;work-hours regulations may limit the time available to deliver“para-professional”lectures;and there is a belief that the medical ethics lectures during medical school is a sufficient amount of coursework to last through a physician’s career with no need for continuing professional development.The four pillars of medical ethics are beneficence,non-maleficence,autonomy,and justice.In addition,morals,ethics,and professionalism are important aspects of sound medical practice.A curriculum specific to medical ethics in ophthalmology can be developed in any of our sub-specialties and include lectures,curated readings,case rounds,and clinic wrap-up sessions.Ethical considerations are part of everyday clinical practice,and a structured ethics curriculum can be incorporated into ophthalmology training programs.The concept of backward design can be used to structure the curriculum,starting with the expected outcome,then designing authentic assessments,and finally putting together a learning plan that has students actively involved in ethical discussions.This paper will provide a guide to developing an ethics curriculum for an ophthalmology training program utilizing the concept of backwards design and guide the reader through the process of developing expected learning outcomes,authentic assessments,and a unified learning plan.

Relations among sensitivity,specificity and predictive values of medical tests based on biomarkers

Diagnostic tests are usually based on some quantitative biomarkers.Two key parameters used to characterise the quality of a test are test sensitivity and specificity.Predictive values of the disease status based on test results are also of interest in medical research and public health management.In this paper,we study the relations among sensitivity,specificity and predictive values of the test.The core concept is risk function,which is assumed to be an increasing function of the biomarker.Our results show that test sensitivity and specificity change in opposite directions.The positive predictive value and the sensitivity also change in opposite directions.Likewise,the negative predictive value and the specificity change in opposite directions.

The roles of bone remodeling in normal hematopoiesis and age-related hematological malignancies

Prior research establishing that bone interacts in coordination with the bone marrow microenvironment(BMME)to regulate hematopoietic homeostasis was largely based on analyses of individual bone-associated cell populations.Recent advances in intravital imaging has suggested that the expansion of hematopoietic stem cells(HSCs)and acute myeloid leukemia cells is restricted to bone marrow microdomains during a distinct stage of bone remodeling.These findings indicate that dynamic bone remodeling likely imposes additional heterogeneity within the BMME to yield differential clonal responses.A holistic understanding of the role of bone remodeling in regulating the stem cell niche and how these interactions are altered in age-related hematological malignancies will be critical to the development of novel interventions.To advance this understanding,herein,we provide a synopsis of the cellular and molecular constituents that participate in bone turnover and their known connections to the hematopoietic compartment.Specifically,we elaborate on the coupling between bone remodeling and the BMME in homeostasis and age-related hematological malignancies and after treatment with bone-targeting approaches.We then discuss unresolved questions and ambiguities that remain in the field.

Evidence of bisphosphonate-conjugated sitafloxacin eradication of established methicillin-resistant S.aureus infection with osseointegration in murine models of implant-associated osteomyelitis

Eradication of MRSA osteomyelitis requires elimination of distinct biofilms.To overcome this,we developed bisphosphonateconjugated sitafloxacin(BCS,BV600072)and hydroxybisphosphonate-conjugate sitafloxacin(HBCS,BV63072),which achieve“target-and-release”drug delivery proximal to the bone infection and have prophylactic efficacy against MRSA static biofilm in vitro and in vivo.Here we evaluated their therapeutic efficacy in a murine 1-stage exchange femoral plate model with bioluminescent MRSA(USA300LAC::lux).Osteomyelitis was confirmed by CFU on the explants and longitudinal bioluminescent imaging(BLI)after debridement and implant exchange surgery on day 7,and mice were randomized into seven groups:1)Baseline(harvested at day7,no treatment);2)HPBP(bisphosphonate control for BCS)+vancomycin;3)HPHBP(hydroxybisphosphonate control for HBCS)+vancomycin;4)vancomycin;5)sitafloxacin;6)BCS+vancomycin;and 7)HBCS+vancomycin.BLI confirmed infection persisted in all groups except for mice treated with BCS or HBCS+vancomycin.Radiology revealed catastrophic femur fractures in all groups except mice treated with BCS or HBCS+vancomycin,which also displayed decreases in peri-implant bone loss,osteoclast numbers,and biofilm.To confirm this,we assessed the efficacy of vancomycin,sitafloxacin,and HBCS monotherapy in a transtibial implant model.The results showed complete lack of vancomycin efficacy while all mice treated with HBCS had evidence of infection control,and some had evidence of osseous integrated septic implants,suggestive of biofilm eradication.Taken together these studies demonstrate that HBCS adjuvant with standard of care debridement and vancomycin therapy has the potential to eradicate MRSA osteomyelitis.

Astrocyte chloride,excitatory-inhibitory balance and epilepsy

Excitation and inhibition are at the core of brain function and malfunction.To sustain the activity of neuronal networks over time and space,glutamatergic excitation is balanced by GABAergic inhibition.The equipoise of excitation and inhibition,known as the excitation/inhibition(E/I)balance,is crucial for proper brain function.The E/I balance is highly dynamic and shifts across different brain states:wakefulness primarily augments excitatory activity,while sleep promotes a decrease in excitation and an increase in inhibition(Bridi et al.,2020).Neuronal activity during various brain states is primarily regulated by neurotransmitters(Schiemann et al.,2015),alongside non-synaptic mechanisms that operate on a slower timescale.The non-synaptic mechanisms are many,with the ionic composition of the extracellular space playing a significant role;altering extracellular ion concentrations affects sleep,arousal,electroencephalogram patterns,and behavioral states(Ding et al.,2016).

RANKL inhibition reduces lesional cellularity and Gαs variant expression and enables osteogenic maturation in fibrous dysplasia

Fibrous dysplasia(FD)is a rare,disabling skeletal disease for which there are no established treatments.Growing evidence supports inhibiting the osteoclastogenic factor receptor activator of nuclear kappa-B ligand(RANKL)as a potential treatment strategy.In this study,we investigated the mechanisms underlying RANKL inhibition in FD tissue and its likely indirect effects on osteoprogenitors by evaluating human FD tissue pre-and post-treatment in a phase 2 clinical trial of denosumab(NCT03571191)and in murine in vivo and ex vivo preclinical models.Histological analysis of human and mouse tissue demonstrated increased osteogenic maturation,reduced cellularity,and reduced expression of the pathogenic Gαs variant in FD lesions after RANKL inhibition.RNA sequencing of human and mouse tissue supported these findings.The interaction between osteoclasts and mutant osteoprogenitors was further assessed in an ex vivo lesion model,which indicated that the proliferation of abnormal FD osteoprogenitors was dependent on osteoclasts.The results from this study demonstrated that,in addition to its expected antiosteoclastic effect,denosumab reduces FD lesion activity by decreasing FD cell proliferation and increasing osteogenic maturation,leading to increased bone formation within lesions.These findings highlight the unappreciated role of cellular crosstalk between osteoclasts and preosteoblasts/osteoblasts as a driver of FD pathology and demonstrate a novel mechanism of action of denosumab in the treatment of bone disease.

Spontaneous Tumor Lysis Syndrome Secondary to Iatrogenic Acute Kidney Injury: A Case Report

Spontaneous Tumor Lysis Syndrome (STLS) is a rare oncologic condition caused by the breakdown of neoplastic tissue in the absence of traditional anti-tumor therapy. It is postulated that cancers with rapidly dividing cells lead to increased cell turnover which exceeds the kidneys’ ability to adequately filtrate by-products of cellular breakdown (i.e., phosphate, potassium, anduric acid), leading to end organ damage. It has been reported in the past that kidney failure is a sequelae of Tumor Lysis Syndrome (TLS), but there have been no reports that demonstrate acute kidney injury (AKI) preceding TLS. The case presented here demonstrates TLS in a patient with no formal cancer diagnosis, who had received no chemotherapy or radiation that was precipitated by an iatrogenic AKI with chlorthalidone and ibuprofen. This unusual pattern of AKI preceding STLS may provide insight into the pathophysiology of the condition and could possibly lead to greater understanding of this phenomenon.

Evolving concepts in bone infection: redefining “biofilm”,“acute vs. chronic osteomyelitis”, “the immune proteome” and “local antibiotic therapy”

Osteomyelitis is a devastating disease caused by microbial infection of bone. While the frequency of infection following elective orthopedic surgery is low, rates of reinfection are disturbingly high. Staphylococcus aureus is responsible for the majority of chronic osteomyelitis cases and is often considered to be incurable due to bacterial persistence deep within bone. Unfortunately, there is no consensus on clinical classifications of osteomyelitis and the ensuing treatment algorithm. Given the high patient morbidity,mortality, and economic burden caused by osteomyelitis, it is important to elucidate mechanisms of bone infection to inform novel strategies for prevention and curative treatment. Recent discoveries in this field have identified three distinct reservoirs of bacterial biofilm including: Staphylococcal abscess communities in the local soft tissue and bone marrow, glycocalyx formation on implant hardware and necrotic tissue, and colonization of the osteocyte-lacuno canalicular network(OLCN) of cortical bone. In contrast, S.aureus intracellular persistence in bone cells has not been substantiated in vivo, which challenges this mode of chronic osteomyelitis. There have also been major advances in our understanding of the immune proteome against S. aureus, from clinical studies of serum antibodies and media enriched for newly synthesized antibodies(MENSA), which may provide new opportunities for osteomyelitis diagnosis, prognosis, and vaccine development. Finally, novel therapies such as antimicrobial implant coatings and antibiotic impregnated 3D-printed scaffolds represent promising strategies for preventing and managing this devastating disease. Here, we review these recent advances and highlight translational opportunities towards a cure.

Influences of trans-trans farnesol,a membrane-targeting sesquiterpenoid,on Streptococcus mutans physiology and survival within mixed-species oral biofilms

Trans-trans farnesol （tt-farnesol） is a bioactive sesquiterpene alcohol commonly found in propolis （a beehive product） and citrus fruits, which disrupts the ability of Streptococcus mutans （S. mutans） to form virulent biofilms. In this study, we investigated whether tt-farnesol affects cell-membrane function, acid production and/or acid tolerance by planktonic cells and biofilms of S. mutans UA159. Furthermore, the influence of the agent on S. mutans gene expression and ability to form biofilms in the presence of other oral bacteria （Streptococcus oralis （S. oralis） 35037 and Actinomyces naeslundii （.4. naeslundil） 12104） was also examined. In general, tt-farnesol （1 mmol-L-1） significantly increased the membrane proton permeability and reduced glycolytie activity of S. mutans in the planktonic state and in biofilms （P〈0.05）. Moreover, topical applications of 1 mmol-L＂l tt-farnesol twice daily （1 min exposure/treatment） reduced biomass accumulation and prevented ecological shifts towards S. mutans dominance within mixed-species biofilms after introduction of 1% sucrose. S. oralis （a non-cariogenie organism） became the major species after treatments with tt-farnesol, whereas vehicle-treated biofilms contained mostly S. mutans （〉90% of total bacterial population）. However, the agent did not affect significantly the expression of S. mutans genes involved in acidogenicity, acid tolerance or polysaccharide synthesis in the treated biofilms. Our data indicate that tt-farnesoi may affect the competi- tiveness of S. mutans in a mixed-species environment by primarily disrupting the membrane function and physiology of this bacterium. This naturally occurring terpenoid could be a potentially useful adjunctive agent to the current anti-biofilm/anti-caries chemotherapeutic strategies.

Notch signaling controls chondrocyte hypertrophy via indirect regulation of Sox9

RBPjk-dependent Notch signaling regulates both the onset of chondrocyte hypertrophy and the progression to terminal chondrocyte maturation during endochondral ossification. It has been suggested that Notch signaling can regulate Sox9 transcription, although how this occurs at the molecular level in chondrocytes and whether this transcriptional regulation mediates Notch control of chondrocyte hypertrophy and cartilage development is unknown or controversial. Here we have provided conclusive genetic evidence linking RBPjk-dependent Notch signaling to the regulation of Sox9 expression and chondrocyte hypertrophy by examining tissuespecific Rbpjk mutant（Prx1Cre;Rbpjkf/f）, Rbpjk mutant/Sox9 haploinsufficient（Prx1Cre;Rbpjkf/f;Sox9f/1）,and control embryos for alterations in SOX9 expression and chondrocyte hypertrophy during cartilage development. These studies demonstrate that Notch signaling regulates the onset of chondrocyte maturation in a SOX9-dependent manner, while Notch-mediated regulation of terminal chondrocyte maturation likely functions independently of SOX9. Furthermore, our in vitro molecular analyses of the Sox9 promoter and Notch-mediated regulation of Sox9 gene expression in chondrogenic cells identified the ability of Notch to induce Sox9 expression directly in the acute setting, but suppresses Sox9 transcription with prolonged Notch signaling that requires protein synthesis of secondary effectors.

Clinical efficacy of the over-the-scope clip device: A systematic review

BACKGROUND The over-the-scope clip(OTSC)system has been increasingly utilized as a nonsurgical option to endoscopically manage refractory gastrointestinal(GI)hemorrhage,perforations/luminal defects and fistulas.Limited data exist evaluating the efficacy and safety of OTSC.AIM To determine the clinical success and adverse event(AE)rates of OTSC across all GI indications.METHODS A PubMed search was conducted for eligible articles describing the application of the OTSC system for any indication in the GI tract.Any article or case series reporting data for less than 5 total patients was excluded.The primary outcome was the rate of clinical success.Secondary outcomes included:Technical success rate,OTSC-related AE rate and requirement for surgical intervention despite-OTSC placement.Pooled rates(per-indication and overall)were calculated as the number of patients with the event of interest divided by the total number of patients.RESULTS A total of 85 articles met our inclusion criteria(n=3025 patients).OTSC was successfully deployed in 94.4%of patients(n=2856/3025).The overall rate of clinical success(all indications)was 78.4%(n=2371/3025).Per-indication clinical success rates were as follows:(1)86.0%(1120/1303)for GI hemorrhage;(2)85.3%(399/468)for perforation;(3)55.8%(347/622)for fistulae;(4)72.6%(284/391)for anastomotic leaks;(5)92.8%(205/221)for defect closure following endoscopic resection(e.g.,following endoscopic mucosal resection or endoscopic submucosal dissection);and(6)80.0%(16/20)for stent fixation.AE’s related to the deployment of OTSC were only reported in 64 of 85 studies(n=1942 patients),with an overall AE rate of 2.1%(n=40/1942).Salvage surgical intervention was required in 4.7%of patients(n=143/3025).CONCLUSION This systematic review demonstrates that the OTSC system is a safe and effective endoscopic therapy to manage GI hemorrhage,perforations,anastomotic leaks,defects created by endoscopic resections and for stent fixation.Clinical success in fistula management appears limited.Further studies,including randomized controlled trials comparing OTSC with conventional and/or surgical therapies,are needed to determine which indication(s)are the most effective for its use.

dentification of testosterone-/androgen receptor-regulated genes in mouse Sertoli cells

Androgen and androgen receptor （AR） play important roles in male spermatogenesis and fertility, yet detailed androgen/AR signals in Sertoli cells remain unclear. To identify AR target genes in Sertoli cells, we analyzed the gene expression profiles of testis between mice lacking AR in Sertoli cells （S-AR-/y） and their littermate wild-type （WT） mice. Digital gene expression analysis identified 2276 genes downregulated and 2865 genes upregulated in the S-AR-/y mice testis compared to WT ones. To further nail down the difference within Sertoli cells, we first constructed Sertoli cell line TM4 with stably transfected AR （named as TM4/AR） and found androgens failed to transactivate AR in Sertoli TM4 and TM4/AR cells. Interestingly, additional transient transfection of AR-cDNA resulted in significant androgen responsiveness with TM4/AR cells showing 10 times more androgen sensitivity than TM4 cells. In the condition where maximal androgen response was demonstrated, we then analyzed gene expression and found the expression levels of 2313 genes were changed more than twofold by transient transfection of AR-cDNA in the presence of testosterone. Among these genes, 603 androgen-/ AR-regulated genes, including 164 upregulated and 439 downregulated, were found in both S-AR-/y mice testis and TM4/AR cells. Using informatics analysis, the gene ontology was applied to analyze these androgen-/AR-regulated genes to predict the potential roles of androgen/AR in the process of spermatogenesis. Together, using gene analysis in both S-AR-/y mice testis and TM4/AR cells may help us to better understand the androeen/AR signals in Sertoli cells and their influences in spermatogenesis.

Utilization of longitudinal ultrasound to quantify joint soft-tissue changes in a mouse model of posttraumatic osteoarthritis

To assess the utility of longitudinal ultrasound （US） to quantify volumetric changes in joint soft tissues during the progression of posttraumatic osteoarthritis （PTOA） in mice, and validate the US results with histological findings. A longitudinal cohort of 3-month-old wild-type C57BL/6 male mice received the Hulth-Telhag surgical procedure on right knee to induce ~OA, and sham surgery on their left knee as control. US scans were performed on both knees before, 2, 4, 6, and 8 weeks post-surgery. Joint space volume and Power-Doppler （PD） volume were obtained from US images via Amira software. A paraUel cross-sectional cohort of mice was killed at each US time point, and knee joints were subjected to histological analysis to obtain synovial soft-tissue area and OARSI scores. The correlation between US joint space volume and histological synovial soft-tissue area or OARSI score was assessed via linear regression analysis. US images indicated increased joint space volume in PTOA joints over time, which was associated with synovial inflammation and cartilage damage by histology. These changes started from 2 weeks post-surgery and gradually became more severe. No change was detected in sham joints. Increased joint space volume was significantly correlated with increased synovial soft-tissue area and the OARSI score （P 〈 0.001）. PD signal was detected in the joint space of PTOA joints at 6 weeks post-surgery, which was consistent with the location of blood vessels that stained positively for CD31 and alpha-smooth muscle actin in the synovium. This study indicates that US is a cost-effective longitudinal outcome measure of volumetric and vascular changes in joint soft tissues during PTOA progression in mice, which positively correlates with synovial inflammation and cartilage damage.

Expression of human AR cDNA driven by its own promoter results in mild promotion, but not suppression, of growth in human prostate cancer PC-3 cells

Aim： To examine the physiological role of the androgen receptor （AR） in the PC-3 cell line by transfecting full-length functional AR cDNA driven by its natural human AR promoter. Methods： We generated an AR-expressing PC-3（AR）9 stable clone that expresses AR under the control of the natural human AR promoter and compared its proliferation to that of the PC-3（AR）2 （stable clone that expresses AR under the control of the cytomegalovirus （CMV） promoter, established by Heisler et al.） after androgen treatment. Results： We found that dihydrotestosterone （DHT） from 0.001 nmol/L to 10 nmol/L induces cell cycle arrest or inhibits proliferation of PC-3（AR）2 compared with its vector control, PC-3（plRES）. In contrast, PC-3（AR）9 cell growth slightly increased or did not change when treated with physiological concentrations of 1 nmol/L DHT. Conclusion： These data suggest that intracellular control of AR expression levels through the natural AR promoter might be needed for determining AR function in androgen-independent prostate cancer （AIPC） PC-3 cells. Unlike previous publications that showed DHT mediated suppression of PC-3 growth after transfection of viral promoter-driven AR overexpression, we report here that DHT-mediated PC-3 proliferation is slightly induced or does not change compared with its baseline after reintroducing AR expression driven by its own natural promoter, as shown in PC-3（AR）9 prostate cancer cells.

Ribavirin induced hemolysis:A novel mechanism of action against chronic hepatitis C virus infection

Hepatitis C virus(HCV)is not usually cleared by our immune system,leading to the development of chronic hepatitis C infection.Chronic HCV induces the production of various cytokines,predominantly by Kupffer cells(KCs),and creates a pro-inflammatory state in the liver.The chronic dysregulated production of interferon(IFN)and other cytokines by KCs also promotes innate immune tolerance.Ribavirin(RBV)monotherapy has been shown to decrease inflammation in liver of patients with chronic hepatitis C.Sustained virological response(SVR)is significantly higher when IFN is combined with RBV in chronic HCV(c HCV)infection.However,the mechanism of their synergy remains unclear.Previous theories have attempted to explain the anti-HCV effect based on direct action of RBV alone on the virus or on the immune system;however,these theories have serious shortcomings.We propose that hemolysis,which universally occurs with RBV therapy and which is considered a limiting side effect,is precisely the mechanism by which the anti-HCV effect is exerted.Passive hemolysis results in anti-inflammatory/antiviral actions within the liver that disrupt the innate immune tolerance,leading to the synergy ofRBV with IFN-α.Ribavirin-induced hemolysis floods the hepatocytes and KCs with heme,which is metabolized and detoxified by heme oxygenase-1(HMOX1)to carbon monoxide(CO),biliverdin and free iron(which induces ferritin).These metabolites of heme possess anti-inflammatory and antioxidant properties.Thus,HMOX1 plays an extremely important anti-oxidant,anti-inflammatory and cytoprotective role,particularly in KCs and hepatocytes.HMOX1 has been noted to have anti-viral effects in hepatitis C infected cell lines.Additionally,it has been shown to enhance the response to IFN-αby restoring interferon-stimulated genes(ISGs).This mechanism can be clinically corroborated by the following observations that have been found in patients undergoing RBV/IFN combination therapy for c HCV:(1)SVR rates are higher in patients who develop anemia;(2)once anemia(due to hemolysis)occurs,the SVR rate does not depend on the treatment utilized to manage anemia;and(3)ribavirin analogs,such as taribavirin and levovirin,which increase intrahepatic ribavirin levels and which produce lesser hemolysis,are inferior to ribavirin for treating c HCV.This mechanism can also explain the observed RBV synergy with direct antiviral agents.This hypothesis is testable and may lead to newer and safer medications for treating c HCV infection.

Transdermal delivery of 4-aminopyridine accelerates motor functional recovery and improves nerve morphology following sciatic nerve crush injury in mice

Oral 4-aminopyridine(4-AP)is clinically used for symptomatic relief in multiple sclerosis and we recently demonstrated that systemic 4-AP had previously unknown clinically-relevant effects after traumatic peripheral nerve injury including the promotion of re-myelination,improvement of nerve conductivity,and acceleration of functional recovery.We hypothesized that,instead of oral or injection administration,transdermal 4-AP(TD-4-AP)could also improve functional recovery after traumatic peripheral nerve injury.Mice with surgical traumatic peripheral nerve injury received TD-4AP or vehicle alone and were examined for skin permeability,pharmacokinetics,functional,electrophysiological,and nerve morphological properties.4-AP showed linear pharmacokinetics and the maximum plasma 4-AP concentrations were proportional to TD-4-AP dose.While a single dose of TD-4-AP administration demonstrated rapid transient improvement in motor function,chronic TD-4-AP treatment significantly improved motor function and nerve conduction and these effects were associated with fewer degenerating axons and thicker myelin sheaths than those from vehicle controls.These findings provide direct evidence for the potential transdermal applicability of 4-AP and demonstrate that 4-AP delivered through the skin can enhance in-vivo functional recovery and nerve conduction while decreasing axonal degeneration.The animal experiments were approved by the University Committee on Animal Research(UCAR)at the University of Rochester(UCAR-2009-019)on March 31,2017.

Biofilm three-dimensional architecture influences in situ pH distribution pattern on the human enamel surface

To investigate how the biofilm three-dimensional(3D) architecture influences in situ pH distribution patterns on the enamel surface. Biofilms were formed on human tooth enamel in the presence of 1% sucrose or 0.5% glucose plus 0.5% fructose. At specific time points, biofilms were exposed to a neutral pH buffer to mimic the buffering of saliva and subsequently pulsed with 1% glucose to induce re-acidification. Simultaneous 3D pH mapping and architecture of intact biofilms was performed using two-photon confocal microscopy. The enamel surface and mineral content characteristics were examined successively via optical profilometry and microradiography analyses. Sucrose-mediated biofilm formation created spatial heterogeneities manifested by complex networks of bacterial clusters(microcolonies). Acidic regions(pH<5.5) were found only in the interior of microcolonies,which impedes rapid neutralization(taking more than 120 min for neutralization). Glucose exposure rapidly re-created the acidic niches, indicating formation of diffusion barriers associated with microcolonies structure. Enamel demineralization(white spots),rougher surface, deeper lesion and more mineral loss appeared to be associated with the localization of these bacterial clusters at the biofilm-enamel interface. Similar 3D architecture was observed in plaque-biofilms formed in vivo in the presence of sucrose. The formation of complex 3D architectures creates spatially heterogeneous acidic microenvironments in close proximity of enamel surface, which might correlate with the localized pattern of the onset of carious lesions(white spot like) on teeth.

Role of copper transporters in platinum resistance

Platinum(Pt)-based antitumor agents are effective in the treatment of many solid malignancies. However, their efficacy is limited by toxicity and drug resistance. Reduced intracellular Pt accumulation has been consistently shown to correlate with resistance in tumors. Proteins involved in copper homeostasis have been identified as Pt transporters. In particular, copper transporter receptor 1(CTR1), the major copper influx transporter, has been shown to play a significant role in Pt resistance. Clinical studies demonstrated that expression of CTR1 correlated with intratumoral Pt concentration and outcomes following Pt-based therapy. Other CTRs such as CTR2, ATP7 A and ATP7 B, may also play a role in Pt resistance. Recent clinical studies attempting to modulate CTR1 to overcome Pt resistance may provide novel strategies. This review discusses the role of CTR1 as a potential predictive biomarker of Pt sensitivity and a therapeutic target for overcoming Pt resistance.

Chemotherapy plus percutaneous radiofrequency ablation in patients with inoperable colorectal liver metastases

AIM:To access the efficacy of chemotherapy plus radiofrequency ablation(RFA)as one line of treatment in inoperable colorectal liver metastases.METHODS:Eligible patients were included in three PhaseⅡstudies.In the first study percutaneous RFA was used first followed by 6 cycles of 5-fluorouracil,leucovorin and irinotecan combination(FOLFIRI)(adjunctive chemotherapy trial).In the other two,chemotherapy(FOLFIRI or 5-fluorouracil,leucovorin and oxaliplatin combination)up to 12 cycles was used first with percutaneous RFA offered to responding patients (primary chemotherapy trials).RESULTS:Thirteen patients were included in the adjunctive chemotherapy trial and 17 in the other two.At inclusion they had 1-4 liver metastases(up to 6.5 cm in size).Two patients died during chemotherapy.All patients in the adjunctive chemotherapy trial and 44%in the primary chemotherapy studies had their metastases ablated.Median PFS and overall survival in the adjunctive study were 13 and 24 mo respectively while in the primary chemotherapy studies they were 10 and 21 mo respectively.Eighty one percent of the patients had tumour relapse in at least one previously ablated lesion.CONCLUSION:Chemotherapy plus RFA in patients with low volume inoperable colorectal liver metastases seems safe and relatively effective.The high local recurrence rate is of concern.

A case of steroid-dependent myeloid granulocytic sarcoma masquerading as Crohn's disease

Small bowel tumors and Crohn's disease are common causes of small bowel obstruction.Early stage neoplasms can easily be mistaken for Crohn's disease.Therefore,thorough work-ups including imaging studies and endoscopic evaluation with biopsies are critical for accurate diagnosis.Here we report a case of an otherwise healthy female with progressive onset of multiple,recurrent obstructive symptoms secondary to terminal ileal narrowing who was referred for management of steroid-dependent Crohn's disease.After thorough evaluation,the diagnosis was revised to myeloid granulocytic sarcoma involving the terminal ileum.In this case,a delay in diagnosis can be detrimental for prognosis,as myeloid granulocytic sarcoma is highly predictive of underlying acute myeloid leukemia and needs urgent referral for chemotherapy and/or resection.