Endothelial cell senescence in human atherosclerosis: role of telomere in endothelial dysfunction

BACKGROUND

The functional changes associated with cellular senescence may be involved in human aging and age-related vascular disorders. We have shown the important role of telomere and telomerase in vascular cell senescence in vitro. Progressive telomere shortening in vivo has been observed in the regions susceptible to atherosclerosis, implying contributions to atherogenesis. However, whether senescent vascular cells are present in the vasculature and contribute to the pathogenesis of atherosclerosis remains unclear.

METHODS AND RESULTS

Senescence-associated beta-galactosidase (beta-gal) activity was examined in the coronary arteries and the internal mammary arteries retrieved from autopsied individuals who had had ischemic heart diseases. Strong beta-gal stainings were observed in atherosclerotic lesions of the coronary arteries but not in the internal mammary arteries. An immunohistochemical analysis using anti-factor VIII antibody demonstrated that beta-gal stained cells are vascular endothelial cells. To determine whether endothelial cell senescence causes endothelial dysfunction, we induced senescence in human aortic endothelial cells (HAECs) by inhibiting telomere function and examined the expression of intercellular adhesion molecule (ICAM)-1 and endothelial nitric oxide synthase (eNOS) activity. Senescent HAECs exhibited increased ICAM-1 expression and decreased eNOS activity, both of which are alterations implicated in atherogenesis. In contrast, introduction of telomerase catalytic component significantly extended the life span and inhibited the functional alterations associated with senescence in HAECs.

CONCLUSIONS

Vascular endothelial cells with senescence-associated phenotypes are present in human atherosclerotic lesions, and endothelial cell senescence induced by telomere shortening may contribute to atherogenesis.

Exceptionally potent inhibitors of fatty acid amide hydrolase: the enzyme responsible for degradation of endogenous oleamide and anandamide

The development of exceptionally potent inhibitors of fatty acid amide hydrolase (FAAH), the enzyme responsible for the degradation of oleamide (an endogenous sleep-inducing lipid), and anandamide (an endogenous ligand for cannabinoid receptors) is detailed. The inhibitors may serve as useful tools to clarify the role of endogenous oleamide and anandamide and may prove to be useful therapeutic agents for the treatment of sleep disorders or pain. The combination of several features-an optimal C12-C8 chain length, pi-unsaturation introduction at the corresponding arachidonoyl Delta(8,9)/Delta(11,12) and oleoyl Delta(9,10) location, and an alpha-keto N4 oxazolopyridine with incorporation of a second weakly basic nitrogen provided FAAH inhibitors with K(i)s that drop below 200 pM and are 10(2)-10(3) times more potent than the corresponding trifluoromethyl ketones.

End-to-side portocaval shunting for a small-for-size graft in living donor liver transplantation

In the development of adult-to-adult living donor liver transplantation (LDLT), the small-for-size graft has been associated with poor clinical outcome. Persistent portal hypertension or portal venous overperfusion are considered to be causative factors, and partial diversion of portal flow to systemic circulation may be effective for avoiding injuries that occur in the small-for-size (SFS) graft. Recently, we constructed an end-to-side portocaval shunting using 1 of the portal branches and anastomosed the other branch with the portal vein of the graft in 2 cases of LDLT recipients transplanted with a SFS graft. With the suppression of portal hypertension, as well as sufficient portal flow to the graft, the recipients recovered successfully with favorable graft function. This new and simple technique may be able to be used as a feasible and effective method to attenuate the SFS syndrome.

Fatty acid amide hydrolase substrate specificity

Fatty acid amide hydrolase (FAAH), also referred to as oleamide hydrolase and anandamide amidohydrolase, is a serine hydrolase responsible for the degradation of endogenous oleamide and anandamide, fatty acid amides that function as chemical messengers. FAAH hydrolyzes a range of fatty acid amides, and the present study examines the relative rates of hydrolysis of a variety of natural and unnatural fatty acid primary amide substrates using pure recombinant rat FAAH.

Bovine lactoferrin stimulates the phagocytic activity of human neutrophils: identification of its active domain

Bovine LF (bLF) at concentrations in the range of 50-250 micrograms/ml enhanced the phagocytic activity of human neutrophils as determined by measuring the incorporation of FITC-labeled latex beads by flow cytometry. The stimulatory effect of bLF was not abrogated by hydrolysis with pepsin. Bovine lactoferricin (bLFcin), which is a bactericidal fragment purified from a pepsin hydrolysate of bLF (bLFH), also enhanced the phagocytic activity, whereas, in contrast, the fraction of bLFH depleted of bLFcin showed no stimulatory effect. The phagocytosis-enhancing activity of bLF still remained after washing the neutrophils, following exposure to bLF. Also, bLF pretreatment of the latex beads stimulated their uptake. These results demonstrate that bLF is effective in promoting the phagocytic activity of human neutrophils. This activity appears to be due to its bLFcin domain and may involve dual mechanisms of direct binding to neutrophils and opsonin-like activity.

alpha-Keto heterocycle inhibitors of fatty acid amide hydrolase: carbonyl group modification and alpha-substitution

Two sets of novel analogues of the recently disclosed alpha-keto heterocycle inhibitors of fatty acid amide hydrolase (FAAH), the enzyme responsible for regulation of endogenous oleamide and anandamide, were synthesized and evaluated in order to clarify a role of the electrophilic carbonyl group and structural features important for their activity. Both the electrophilic carbonyl and the degree of alpha-substitution markedly affect inhibitor potency.

Phototoxicity and photoallergenicity of quinolones in guinea pigs

Clinical reports indicate that the fluoroquinolone group of antibiotics can induce cutaneous photosensitivity reactions. In the present study, phototoxicity and photoallergenicity of quinolones including nalidixic acid (NA) norfloxacin (NFLX), ofloxacin (OFLX), enoxacin (ENX), ciprofloxacin (CPFX), lomefloxacin (LFLX), and tosufloxacin (TFLX) were experimentally examined in an in vivo system using the guinea pig. Phototoxicity of all quinolones tested was demonstrated after a single, oral administration of the drugs and subsequent exposure to long-wave ultraviolet (UVA) at a dose of 30 J/cm2. The phototoxic potencies were: ENX, LFLX > OFLX > NA, TFLX > NFLX, CPFX. Photoallergic reaction was also induced to LFLX and NA by pretreatment with cyclophosphamide, an immunoadjuvant. No cross-reactions in photoallergy were observed among quinolones. The photo-ingestion test was positive in photoallergically sensitized animals, while the photopatch test was negative. This is the first report which demonstrated experimentally the photoallergenicity of quinolones. Clinical features of the photosensitivity due to quinolones can be explained by the results of the present experiments.

Endoscopic Diagnostic Support System for cT1b Colorectal Cancer Using Deep Learning

OBJECTIVE

This study aimed to use convolutional neural network (CNN), a deep learning software, to assist in cT1b diagnosis.

METHODS

This retrospective study used 190 colon lesion images from 41 cases of colon endoscopies performed between February 2015 and October 2016. Unenhanced colon endoscopy images (520 × 520 pixels) with white light were used. Images included 14 cTis cases with endoscopic resection and 14 cT1a and 13 cT1b cases with surgical resection. Protruding, flat, and recessed lesions were analyzed. AlexNet and Caffe were used for machine learning. Fine tuning of data to increase image numbers was performed. Oversampling for the training images was conducted to avoid impartiality in image numbers, and learning was carried out. The 3-fold cross-validation method was used. Sensitivity, specificity, accuracy, and area under the curve (AUC) values in the receiver operating characteristic curve were calculated for each group.

RESULTS

The results were the average of obtained values. With CNN learning, cT1b sensitivity, specificity, and accuracy were 67.5, 89.0, and 81.2%, respectively, and AUC was 0.871.

CONCLUSION

Quantitative diagnosis is possible using an endoscopic diagnostic support system with machine learning, without relying on the skill and experience of endoscopists. Moreover, this system could be used to objectively evaluate endoscopic diagnoses.

N , N -Dimethylformamide: significance of dermal absorption and adjustment method for urinary N -methylformamide concentration as a biological exposure item

OBJECTIVES

To clarify the potential for dermal absorption of N,N-dimethylformamide (DMF) (CAS No. 68-12-2) vapor, and the appropriate adjustment method and the half-lives of urinary concentrations of N-methylformamide (NMF) as the biological exposure item of DMF.

METHODS

Thirteen healthy male volunteers (mean age: 22.7 years, range: 20-27) were exposed to DMF vapor twice, via both the skin and the lung, for 4 h at concentrations below 10 ppm, the recommended occupational exposure limit set by the Japan Society for Occupational Health, the American Conference of Governmental and Industrial Hygienists, and Deutsche Forschungsgemeinschaft, under conditions of 27 degrees C and 44% humidity. Each volunteer was exposed to DMF via the skin in a whole-body type exposure chamber and outside the chamber, via the lung by a respirator connected to the chamber. Exposure levels were 6.2 +/- 1.0 ppm in dermal exposure and 7.1 +/- 1.0 ppm in inhalation exposure. Urine samples were collected at every opportunity until 72 h after exposure; and NMF, as well as volume, creatinine, and specific gravity were measured. Dermal and inhalation intakes were compared after adjusting concentrations.

RESULTS AND CONCLUSIONS

DMF vapor absorptions via the skin and the lung were estimated to be 40.4 and 59.6%, respectively. Workers need to be aware of the risk of dermal absorption of DMF vapor as well as of the liquid. Though NMF concentrations adjusted by creatinine, specific gravity, and urinary volume showed good correlation with total NMF excretion and the absolute amount of NMF at each sampling time, creatinine-adjusted NMF concentration correlated better than the others. The biological half-life of urinary NMF after dermal exposure, 4.75 +/- 1.63 h, was longer than that after respiratory exposure, 2.42 +/- 0.63 h.

Immunomodulatory effect of bovine lactoferrin pepsin hydrolysate on murine splenocytes and Peyer's patch cells

The effects were examined of a pepsin hydrolysate of bovine lactoferrin on the proliferation of murine splenocytes. The hydrolysate enhanced [3H]thymidine uptake by splenocytes, but undigested bovine lactoferrin exerted an inhibitory effect. The hydrolysate had the ability to inhibit the blastogenesis that was induced by mitogens such as concanavalin A, phytohemagglutinin, and lipopolysaccharide; inhibition was similar to that with undigested lactoferrin. These results suggested that the hydrolysate contained both immunostimulatory and immunoinhibitory peptides. The stimulatory effect of the hydrolysate in the absence of mitogens was then explored in more detail using nonadherent splenocytes. The proliferative response of splenocytes to the hydrolysate was much greater in the fraction that was enriched with B cells than in the fraction that was enriched with T cells. The hydrolysate did not affect thymocyte proliferation. These data indicated that the adherent cells resembling macrophages and found among the splenocytes were not the target cells of the hydrolysate. The stimulatory effect of the hydrolysate was due to the activation of B cells by the hydrolysate and enhanced immunoglobulin production by splenocytes. Because the hydrolysate also enhanced the proliferation and immunoglobulin A production of Peyer's Patch cells, the immunostimulatory effect of the hydrolysate in vivo was examined using mice that had been orally immunized with cholera toxin. The concentrations of immunoglobulin A conjugated against cholera toxin in bile and in the intestinal contents of mice fed liquid diets containing 1% (wt/vol) lactoferrin hydrolysate were greater than those of mice fed control diets. This result suggested that the use of the lactoferrin hydrolysate is beneficial to enhance mucosal immunity.

Orally administered bovine lactoferrin inhibits bacterial translocation in mice fed bovine milk

Feeding of bovine milk to mice induced a high incidence of bacterial translocation from the intestines to the mesenteric lymph nodes, and the bacteria involved were mainly members of the family Enterobacteriaceae. Supplementation of the milk diet with bovine lactoferrin or a pepsin-generated hydrolysate of bovine lactoferrin resulted in significant suppression of bacterial translocation. Our findings suggest that this ability of lactoferrin to inhibit bacterial translocation may be due to its suppression of bacterial overgrowth in the guts of milk-fed mice.

Fibrocytes are involved in inflammation as well as fibrosis in the pathogenesis of Crohn's disease

BACKGROUND

We previously showed that fibrocytes, a hematopoietic stem cell source of fibroblasts/myofibroblasts, infiltrated the colonic mucosa of a murine colitis model.

AIM

We investigated whether fibrocytes were involved in the pathogenesis of Crohn's disease.

METHODS

Human surgical intestinal specimens were stained with anti-leukocyte-specific protein 1 and anti-collagen type-I (ColI) antibodies. Circulating fibrocytes in the human peripheral blood were quantified by fluorescence-activated cell sorting with anti-CD45 and anti-ColI antibodies. Cultured human fibrocytes were prepared by culturing peripheral CD14(+) monocytes.

RESULTS

In the specimens of patients with Crohn's disease, the fibrocyte/total leukocyte percentage was significantly increased in inflammatory lesions (22.2 %, p < 0.01) compared with that in non-affected areas of the intestine (2.5 %). Interestingly, the percentage in fibrotic lesions was similar (2.2 %, p = 0.87) to that in non-affected areas. The percentages of circulating fibrocytes/total leukocytes were significantly higher in patients with Crohn's disease than in healthy controls. Both CXC-chemokine receptor 4(+) and intercellular adhesion molecule 1(+) fibrocyte numbers were significantly increased in Crohn's disease, suggesting that circulating fibrocytes have a higher ability to infiltrate injured sites and traffic leukocytes. In cultured fibrocytes, lipopolysaccharide treatment remarkably upregulated tumor necrosis factor (TNF)-α mRNA (17.0 ± 5.7-fold) and ColI mRNA expression (12.8 ± 5.7-fold), indicating that fibrocytes stimulated by bacterial components directly augmented inflammation as well as fibrosis.

CONCLUSIONS

Fibrocytes are recruited early in the inflammatory phase and likely differentiate into fibroblasts/myofibroblasts until the fibrosis phase. They may enhance inflammation by producing TNF-α and can directly augment fibrosis by producing ColI.

Epigenetic silencing of microRNA-373 plays an important role in regulating cell proliferation in colon cancer

microRNAs (miRNA) are non-coding RNAs that negatively control gene expression by cleaving or inhibiting the translation of target gene mRNAs. We used a microarray-based transcriptomic analysis to identify miRNA expression levels that changed in response to epigenetic factors. Specifically, we searched for increased expression of miRNAs prepared from colon cancer cell line DLD-1 after a 96-h treatment with 5 µM of 5-aza-2'-deoxycytidine (DAC). Among those identified, transient transfection of miRNA hsa-miR-373 resulted in cytostasis. In addition, bisulfate sequence analysis of the promoter regions of these miRNAs showed aberrant methylation in the cancer cells. In clinical colon samples, hsa-miR-373 was down-regulated in colon cancers (29/40, 72.5%) relative to control samples, whereas the purported oncogene RAB22A (a target gene of hsa-miR-373) was up-regulated (24/40, 60%). Using methylation-specific PCR, we also observed aberrant methylation of hsa-miR-373 in colon cancers (35/40, 87.5%) relative to controls (8/40, 20%). Based on these results, we conclude that expression of hsa-miR-373 is down-regulated by aberrant methylation in colon cancer and that this miRNA may function by regulating expression of the oncogene RAB22A.

Cockayne syndrome in two adult siblings

Although survival beyond the second decade is unusual in patients who have Cockayne syndrome, we describe two brothers with the syndrome who are 42 and 55 years of age. Their cultured skin fibroblasts showed extreme UV sensitivity but had almost normal UV-induced unscheduled DNA synthesis. The patients were classified as genetic complementation group B after study of the recovery of RNA synthesis after UV irradiation of fused cells. Clinical phototesting revealed a reduced threshold for UVB erythema.

High expression of Krüppel-like factor 5 is associated with poor prognosis in patients with colorectal cancer

Krüppel‐like factor 5 (KLF5) plays an oncogenic role and has diverse functions in cancer cells. However, correlation between KLF5 and clinical outcome has not been determined in patients with colorectal cancer and colorectal liver metastasis. Herein, we analyzed 65 patients with colorectal cancer who developed colorectal liver metastasis. Clinical effects were assessed through immunohistochemical analysis of primary colorectal cancer lesions and metastatic liver lesions. High expression of KLF5 in these tissues correlated with the presence of vascular invasion, elevated serum carbohydrate antigen 19‐9 levels, large diameters of metastatic liver tumors, and poor prognosis following surgery. Multivariate analyses revealed that high expression of KLF5 was an independent prognostic factor. Increased expression of KLF5 in both colorectal cancer primaries and colorectal liver metastasis was significantly associated with shorter overall survival time and time to surgical failure. Krüppel‐like factor 5 expression positively correlated with Ki‐67 and c‐Myc expression in colorectal cancer tissues. In vitro experiments with colon cancer cell lines showed that siRNA knockdown of KLF5 inhibited cell proliferation. Western blot analyses revealed that knockdown of KLF5 expression reduced cyclin D1 and c‐Myc expression. It also impaired the stem cell‐like properties of cancer cells in tumorsphere formation assays. Furthermore, anoikis assay indicated that KLF5 contributed to anoikis resistance. High KLF5 expression is associated with poor prognosis in patients with colorectal cancer and liver metastasis by promoting cell proliferation and cancer stem cell‐like properties.

The HLA-A*0201-restricted minor histocompatibility antigen HA-1H peptide can also be presented by another HLA-A2 subtype, A*0206

HA-1(H) is one of the most attractive minor histocompatibility antigens (mHA) as a target for immunotherapy of hematopoietic malignancies, but HLA-A*0201 and HLA-B60 molecules capable of presenting HA-1(H)-derived peptides are less common in eastern Asian populations when compared with Caucasian populations. Therefore, an attempt was made to search for novel epitopes presented by HLA alleles other than those previously reported by generating CTL lines from patients undergoing HLA-identical, HA-1 disparate hematopoietic stem cell transplantation (hematopoietic SCT) by stimulation with a 29-mer HA-1(H) peptide spanning a central polymorphic histidine (His). Two CTL clones established were found to be restricted by HLA-A*0206, which is the second or third most common HLA-A2 subtype worldwide. Epitope mapping revealed that the clones recognized the same nonameric peptide as A*0201-restricted HA-1(H), VLHDDLLEA. This epitope was unexpected, since it does not contain any preferred anchor motifs for HLA-A*0206. However, an HLA peptide binding assay revealed stronger binding of this peptide to A*0206 than to A*0201. Interestingly, HLA-A*0206-restricted CTL clones could lyse both HLA-A*0206(+) and HLA-A*0201(+) targets (including leukemic blasts) that express HA-1(H) peptide endogenously, whereas an HLA-A*0201-restricted, HA-1(H)-specific CTL clone failed to lyse HLA-A*0206(+) targets. This finding will expand the patient population who can benefit from HA-1(H)-based immunotherapy.

The effect of ultraviolet (UVB and PUVA) radiation on the expression of epidermal keratins

Using a panel of monoclonal antibodies directed against keratins (PKK2, CK8.12 and KL1), the effects of ultraviolet B (UVB) and psoralen plus ultraviolet A (PUVA) irradiation on keratin expression in guinea-pig skin were examined immunohistochemically. Following irradiation, whether by UVB or PUVA, rapid alterations in the distribution pattern of keratins were observed in the epidermis. The alterations included the induction of basal cell-type keratins (PKK2 and CK8.12 staining) in the suprabasal layers, with concomitant reduction of the suprabasal-type keratins (KL1 staining). These alterations in keratin expression were observed during the period when DNA synthesis appears to be accelerated by ultraviolet light exposure (5 h-5 days after UVB, and 2-10 days after PUVA irradiation). Therefore, these changes are probably reflections of a proliferative or regenerative state of keratinocytes. This explanation was supported by the result of an experiment involving tape stripping of the epidermal horny layers, which also accelerates DNA synthesis by keratinocytes. Immunohistochemistry appears to be a useful and sensitive method of detecting the effect of ultraviolet light on keratinization.

Ultraviolet B-induced local immunosuppression of contact hypersensitivity is modulated by ultraviolet irradiation and hapten application

The induction of contact hypersensitivity is suppressed when hapten is applied topically to an area irradiated by ultraviolet B (UVB). There is no standardized procedure to induce this local immunosuppression by UVB. We investigated the effects of the following factors on induction of dinitrofluorobenzene contact hypersensitivity in mice. UVB dose, divided UVB exposure, timing of sensitization after irradiation, hapten concentration, hapten volume (application area), sex, age, and simultaneous sensitization on UV-exposed and nonexposed skin. The suppression was enhanced by increasing the UVB dose. When 100 mJ/cm2 of UVB was irradiated, divided daily exposure (25 mJ x 4 d) was more suppressive than single exposure (100 mJ x 1 d). Sensitization 2 d after irradiation (100 mJ/cm2) induced suppression most effectively. When 25 microliters of dinitrofluorobenzene solution was applied to exposed skin, higher concentrations induced lower suppression. When the total dose of hapten was kept constant (92 micrograms), the application of lower concentrations to large areas (0.25%, 25 microliters) caused stronger suppression than higher concentrations (1%, 6.25 microliters) to small areas. Simultaneous sensitization on UV-exposed and nonexposed skin revealed less suppression than sensitization only on exposed skin. The suppression of contact hypersensitivity was significantly greater in young than in old mice. These results provide details that may be useful in designing studies involving immunosuppression by UVB radiation.

Causal relationship between a case of severe hepatic dysfunction and low exposure concentrations of N,N-dimethylformamide in the synthetics industry

A 19-year-old man suffered hepatic dysfunction after 5 months of exposure to N,N-dimethylformamide (DMF) at his job in the synthetic resins industry. Laboratory data revealed elevated levels of AST (578 IU/l), ALT (1193 IU/l), and gamma-GTP (107 IU/l), no viral infection with HAV, HBV, or HCV, and no history or evidence of hepatic injury, although he did have a slight abdominal abnormality and swelling which was detected by palpation. His urinary N-methylformamide level, as a biological exposure index of DMF, was 42.8 mg/l, indicating 10-30 ppm of DMF exposure. After 2 months he was reinstated in two workplaces, the former where he worked in the morning and the other in the afternoon where environmental DMF concentrations were less than those in the former workplace. On the 18th day after his reinstatement, his liver function became exasperated again. After the second period of medication and one month of rest from work, he had fully recovered and was reinstated, but to a workshop without DMF exposure.

Detection of action, inhibition and augmentation spectra in solar urticaria

BACKGROUND

The action spectrum of solar urticaria varies among cases. In addition, light spectra outside the activating wavelengths can influence the wheal formation in selected patients.

OBJECTIVE

To know the mechanisms of light energy, we examined the effect of wavelengths on the skin and the serum factor.

METHODS

The patient's skin and serum were exposed to artificial light sources, in vivo and in vitro, respectively.

RESULTS

The action spectrum ranged from UVA to visible light (approximately 480 nm). The exposure to longer wavelengths immediately after the exposure inhibited the development of urticaria. Conversely, the irradiation of longer wavelengths before exposure increased the wheal formation. Furthermore, UVB irradiation prior to the exposure of urticaria-eliciting light also increased the urticarial reaction, while postirradiation of UVB had no effect. The patient developed an urticarial wheal at the site of injection of her own serum, which had been previously exposed to the action spectrum in vitro. Preirradiation increased the production of the photosensitizer, while postirradiation revealed no effect. Ultrafiltration techniques showed that the molecular weight of the photosensitizer is more than 300 kD.

CONCLUSION

We detected action, inhibition and augmentation spectra in a patient with a severe solar urticaria. Various wavelengths influence the wheal-forming factor in complex interactions.

An internally and externally validated nomogram for predicting the risk of irinotecan-induced severe neutropenia in advanced colorectal cancer patients

Background:

In Asians, the risk of irinotecan-induced severe toxicities is related in part to UGT1A1*6 (UGT, UDP glucuronosyltransferase) and UGT1A1*28, variant alleles that reduce the elimination of SN-38, the active metabolite of irinotecan. We prospectively studied the relation between the UGT1A1 genotype and the safety of irinotecan-based regimens in Japanese patients with advanced colorectal cancer, and then constructed a nomogram for predicting the risk of severe neutropenia in the first treatment cycle.

Methods:

Safety data were obtained from 1312 patients monitored during the first 3 cycles of irinotecan-based regimen in a prospective observational study. In development of the nomogram, multivariable logistic regression analysis was used to test the associations of candidate factors to severe neutropenia in the first cycle. The final nomogram based on the results of multivariable analysis was constructed and validated internally using a bootstrapping technique and externally in an independent data set (n=350).

Results:

The UGT1A1 genotype was confirmed to be associated with increased risks of irinotecan-induced grade 3 or 4 neutropenia and diarrhoea. The final nomogram included type of regimen, administered dose of irinotecan, gender, age, UGT1A1 genotype, Eastern Cooperative Oncology Group performance status, pre-treatment absolute neutrophil count, and total bilirubin level. The model was validated both internally (bootstrap-adjusted concordance index, 0.69) and externally (concordance index, 0.70).

Conclusions:

Our nomogram can be used before treatment to accurately predict the probability of irinotecan-induced severe neutropenia in the first cycle of therapy. Additional studies should evaluate the effect of nomogram-guided dosing on efficacy in patients receiving irinotecan.