Pharmacokinetic and dose-finding study of osimertinib in patients with impaired renal function and low body weight.

The safety of osimertinib is limited in patients with severe or moderate renal impairment, or low body weight. This study aimed to investigate the safety, pharmacokinetics (PK) and recommended dose (RD) of osimertinib in patients with epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) with impaired renal function and low body weight. Thirty-one eligible patients were enrolled and allocated into four cohorts: A, normal renal function (estimated glomerular filtration rate [eGFR] ≥ 50 mL/min/1.73 m2 ) and normal body weight (≥45 kg); B, moderate renal impairment (eGFR = 30-50 mL/min/1.73 m2 ); C, low body weight (<45 kg); and D, severe renal impairment (eGFR <30 mL/min/1.73 m2 or undergoing dialysis). PK parameters and safety were evaluated with a starting dose of 80 mg osimertinib administered orally once daily in cohorts A, B, and C and 40 mg once daily in cohort D. The PK parameters in cohorts A, B, and C were found to be similar. No dose-limiting toxicity was observed, and the RD was determined to be 80 mg once daily in patients with moderate renal function and low body weight. Four serious adverse events, acneiform rash, diarrhea, QTc prolongation, and interstitial lung disease, were noted. Although the PK parameters of osimertinib were similar across all cohorts, toxicity occurred more frequently in patients with impaired renal function and low body weight. Clinicians should prescribe osimertinib with caution in NSCLC patients with impaired renal function and low body weight.

PTEN-induced kinase 1 gene single-nucleotide variants as biomarkers in adjuvant chemotherapy for colorectal cancer: a retrospective study.

BACKGROUND: Fluoropyrimidine-based postoperative adjuvant chemotherapy is globally recommended for high-risk stage II and stage III colon cancer. However, adjuvant chemotherapy is often associated with severe adverse events and is not highly effective in preventing recurrence. Therefore, discovery of novel molecular biomarkers of postoperative adjuvant chemotherapy to identify patients at increased risk of recurrent colorectal cancer is warranted. Autophagy (including mitophagy) is activated under chemotherapy-induced stress and contributes to chemotherapy resistance. Expression of autophagy-related genes and their single-nucleotide polymorphisms are reported to be effective predictors of chemotherapy response in some cancers. Our goal was to evaluate the relationship between single-nucleotide variants of autophagy-related genes and recurrence rates in order to identify novel biomarkers that predict the effect of adjuvant chemotherapy in colorectal cancer. METHODS: We analyzed surgical or biopsy specimens from 84 patients who underwent radical surgery followed by fluoropyrimidine-based adjuvant chemotherapy at Saitama Medical University International Medical Center between January and December 2016. Using targeted enrichment sequencing, we identified single-nucleotide variants and insertions/deletions in 50 genes, including autophagy-related genes, and examined their association with colorectal cancer recurrence rates. RESULTS: We detected 560 single-nucleotide variants and insertions/deletions in the target region. The results of Fisher's exact test indicated that the recurrence rate of colorectal cancer after adjuvant chemotherapy was significantly lower in patients with the single-nucleotide variants (c.1018G > A [p < 0.005] or c.1562A > C [p < 0.01]) of the mitophagy-related gene PTEN-induced kinase 1. CONCLUSIONS: The two single-nucleotide variants of PINK1 gene may be biomarkers of non-recurrence in colorectal cancer patients who received postoperative adjuvant chemotherapy.

Evaluation of hepatic CYP3A enzyme activity using endogenous markers in lung cancer patients treated with cisplatin, dexamethasone, and aprepitant.

PURPOSE: Aprepitant is used with dexamethasone and 5-HT3 receptor antagonists as an antiemetic treatment for chemotherapy, including cisplatin. Aprepitant is a substrate of cytochrome P450 (CYP) 3A4 and is known to cause its inhibition and induction. In addition, dexamethasone is a CYP3A4 substrate that induces CYP3A4 and CYP3A5 expression. In this study, we aimed to quantitatively evaluate the profile of CYP3A activity using its endogenous markers in non-small cell lung cancer patients receiving a standard cisplatin regimen with antiemetics, including aprepitant. METHODS: Urinary 11ß-hydroxytestosterone (11ß-OHT)/testosterone concentration ratio and plasma 4ß-hydroxycholesterol (4ß-OHC) concentrations were measured before and after cisplatin treatment (days 1, 4, and 8). CYP3A5 was genotyped, and plasma aprepitant concentrations were measured on day 4 to examine its influence on CYP3A endogenous markers. RESULTS: The urinary 11ß-OHT/testosterone concentration ratio in the 35 patients included in this study increased by 2.65-fold and 1.21-fold on days 4 and 8 compared with day 1, respectively. Their plasma 4ß-OHC concentration increased by 1.46-fold and 1.66-fold, respectively. The mean plasma aprepitant concentration on day 4 was 1,451 ng/mL, which is far lower than its inhibitory constant. The allele frequencies of CYP3A5*1 and CYP3A5*3 were 0.229 and 0.771, respectively. In patients with the CYP3A5*1 allele, the plasma 4ß-OHC concentration was significantly lower at baseline but more potently increased with chemotherapy. CONCLUSION: CYP3A activity was significantly induced from day 4 to day 8 in patients receiving cisplatin and three antiemetic drugs.

Exacerbation of atrioventricular block associated with concomitant use of amlodipine and aprepitant in a lung cancer patient: A case report.

OBJECTIVE: To report a case of second-degree atrioventricular block associated with concomitant use of aprepitant and amlodipine. CASE: A 73-year-old man with lung cancer was treated with aprepitant for prophylactic use for the prevention of nausea and vomiting, concomitantly with cisplatin, gemcitabine, and an investigational drug (anti-epidermal growth factor receptor monoclonal antibody). He was diagnosed with first-degree atrioventricular block and was taking amlodipine for hypertension. During the first cycle of chemotherapy, 5 days after the start of aprepitant, he experienced Wenckebach second-degree atrioventricular block (Mobitz type I), and amlodipine was discontinued. After day 6, the atrioventricular block was not shown. According to the Naranjo adverse drug reaction scale, a score of 7 was obtained (causality: probable). In addition, using the Drug Interaction Probability Scale, a score of 6 was obtained (causality: probable). CONCLUSION: The drug-drug interaction between aprepitant and amlodipine was considered to have deteriorated his atrioventricular block, conceivably due to the inhibition of cytochrome P450 (CYP) 3A-mediated metabolism of amlodipine by aprepitant.

Impact of peripheral neuropathy induced by platinum in first-line chemotherapy on second-line chemotherapy with paclitaxel for advanced gastric cancer.

BACKGROUND: Fluoropyrimidine plus platinum, followed by paclitaxel (PTX) plus ramucirumab is a recommended treatment strategy for advanced gastric cancer (AGC). We investigated how peripheral neuropathy (PN), induced by platinum in first-line chemotherapy, affected the tolerability of second-line chemotherapy with PTX (2nd-PTX). METHODS: The subjects were AGC patients who received second-line chemotherapy with PTX (2nd-PTX) after the failure of platinum-based chemotherapy between March 2015 and June 2018. We retrospectively reviewed PN severity, and dose reduction and/or discontinuation due to PN during 2nd-PTX, and compared the cumulative incidence of grade 2 PN between the two groups according to first-line chemotherapy containing oxaliplatin (L-OHP) or cisplatin (CDDP). RESULTS: The L-OHP and CDDP groups consisted of 50 patients each. PN severity before 2nd-PTX was grade 1/2 in 46/12% of patients in the L-OHP group, and 100/0% in the CDDP group. The worst grades of chemotherapy-induced PN during 2nd-PTX were grades 1/2/3 in 40/34/14% of patients in the L-OHP group, and 36/18/0% in the CDDP group. Median time to grade 2 PN after starting second-PTX was 2.5 months in the L-OHP group and 8.6 months in the CDDP group (hazard ratio 3.34, p = 0.002). The frequencies of a PN-related dose reduction and/or discontinuation of PTX were 18% in the L-OHP group and 8% in the CDDP group (p = 0.234). CONCLUSIONS: The severity of PN and tolerability of 2nd-PTX may be affected by first-line chemotherapy with L-OHP or CDDP for AGC.

Individual optimal dose of amrubicin to prevent severe neutropenia in Japanese patients with lung cancer.

This study determined individual optimal amrubicin doses for Japanese patients with lung cancer after platinum-based treatment. We carried out population pharmacokinetic and pharmacodynamic modeling incorporating gene polymorphisms of metabolizing enzymes and transporters. Fifty patients with lung cancer, who were given 35-40 mg/m2 amrubicin on days 1-3 every 3-4 weeks, were enrolled. Mechanism-based modeling described relationships between the pharmacokinetics of amrubicin and absolute neutrophil counts. A population pharmacokinetic and pharmacodynamic model was developed for amrubicin and amrubicinol (active metabolite), connected by a delay compartment. The final model incorporated body surface area as a covariate of amrubicin and amrubicinol clearance and distribution volume. SLC28A3 single nucleotide polymorphism (rs7853758) was also incorporated as a constant covariate of the delay compartment of amrubicinol. Performance status was considered a covariate of pharmacokinetic (amrubicinol clearance) and pharmacodynamic (mean maturation time) parameters. Twenty-nine patients with grade 4 neutropenia showed higher amrubicinol area under the plasma concentration-time curve from 0 to 72 hours (AUC0-72 , P = .01) and shorter overall survival periods than other patients did (P = .01). Using the final population pharmacokinetic and pharmacodynamic model, median optimal dose to prevent grade 4 neutropenia aggravation was estimated at 22 (range, 8-40) mg/m2 for these 29 patients. We clarified correlations between area under the plasma concentration-time curve from 0 to 72 hours of amrubicinol and severity of neutropenia and survival of patients given amrubicin after platinum chemotherapy. This analysis revealed important amrubicin pharmacokinetic-pharmacodynamic covariates and provided useful information to predict patients who would require prophylactic granulocyte colony stimulating factor.

Evaluation of aprepitant and fosaprepitant in pediatric patients.

BACKGROUND: Single-dose i.v. fosaprepitant has been approved as an alternative to 3 day oral aprepitant, a neurokinin-1 receptor antagonist, and improves prevention of chemotherapy-induced nausea and vomiting (CINV). Because fosaprepitant has shown similar efficacy to aprepitant in adult patients only, this study compared the efficacy and safety of aprepitant and fosaprepitant in pediatric patients. METHODS: Children younger than 18 years who received aprepitant or fosaprepitant to manage CINV between January 2015 and March 2018 at the National Cancer Center Hospital (Tokyo) were recruited to this study. The primary endpoint was complete response (CR; no vomiting/rescue medication) between 0 and 120 h after the start of chemotherapy. Secondary endpoints were safety based on the frequency of severe adverse events, and evaluation of patient characteristics as risk factors (effect of age and sex). RESULTS: A total of 125 chemotherapy cycles were evaluated. In the aprepitant group, CR was observed in 36 of 80 treatment cycles (45.0%), whereas in the fosaprepitant group, it was observed in 19 of 45 cycles (42.2%; P = 0.852). No treatment-related severe adverse events were observed in either group. The number of non-CR was greater than that of CR in patients aged 6-14 years. The difference in CR rate between male and female patients was not statistically significant (47.1% vs 40.0%, respectively; P = 0.471). CONCLUSIONS: Aprepitant and fosaprepitant were safely used and may be equally useful for pediatric patients receiving highly emetogenic chemotherapy. CR rate may be associated with patient age.

Feasibility of olanzapine, multi acting receptor targeted antipsychotic agent, for the prevention of emesis caused by continuous cisplatin- or ifosfamide-based chemotherapy.

Background To determine the feasibility and efficacy of olanzapine, which is approved by the Pharmaceuticals and Medical Devices Agency as multi acting receptor targeted antipsychotic agent of the thienobenzodiazepine class, for prevention of chemotherapy-induced nausea and vomiting (CINV) in patients undergoing continuous five-day chemotherapy. Patients and methods This study was a prospective dose escalation study at a single center (UMIN ID: UMIN000015386). Patients received a combination of adriamycin and ifosfamide (AI) or a combination of bleomycin, etoposide, and cisplatin (BEP). On days 1-5, all patients received intravenous granisetron (1 mg) and intravenous dexamethasone sodium phosphate (24 mg). Olanzapine was administrated on day-1 to day5 at bedtime. The dose of olanzapine followed a dose-escalation scheme, with monitoring of safety and tolerability at each dose. A 3 + 3 cohort design was used, with three to six patients per cohort. Results Nine patients were enrolled (three for each cohort). No patients experienced dose-limiting toxicity (DLT). The most frequent adverse events were dry mouth and constipation. In each cohort, the maximum severity of nausea was Grade 2, and no patients experienced a vomiting episode. Conclusion A 2.5 mg/day dosage of olanzapine is sufficient to prevent from CINV in Japanese patients receiving continuous five-day chemotherapy. A dose of 10 mg/day, which is recommended by international CINV guidelines, is also tolerated. If CINV is not controlled by an initial dose of 2.5 mg/day of olanzapine, dosage escalation is encouraged. Future studies should compare olanzapine with aprepitant.

Neonatal testis growth recreated in vitro by two-dimensional organ spreading.

Organ culture experiments can be hampered by central degeneration or necrosis due to the inadequate permeation of oxygen and nutrients, which deteriorates the function and growth of cultured tissues. In the current study, we aimed to overcome this limitation of organ culture through spreading the tissue two dimensionally on an agarose gel stand and molding into a disc shape by placing a ceiling of polydimethylsiloxane (PDMS) chip, which is highly oxygen permeable. By this, every part of the tissue can receive a sufficient supply of oxygen through PDMS as well as nutrients through the agarose gel below. This method not only prevented central necrosis of tissues, but also supported the tissue growth over time. In addition, such growth, as volume enlargement, could be easily measured. Under these conditions, we examined the effect of several factors on the growth of neonatal mouse testis, and found that follicle stimulating hormone (FSH) and insulin significantly promoted the growth. These results are in good agreement with previous in vivo reports. Notably, the growth achieved over 7 days in our in vitro system is almost comparable to, about 80% of, that observed in vivo. Thus, we successfully monitored the promotion of tissue growth beyond the limits of the conventional organ culture method. This extremely simple method could offer a unique platform to evaluate the growth as well as functional properties of organs, not only the testis but also others as well.

Symptom management: the utility of regional cooling for hand-foot syndrome induced by pegylated liposomal doxorubicin in ovarian cancer.

PURPOSE: Hand-foot syndrome (HFS) is a major side effect of pegylated liposomal doxorubicin (PLD). Regional cooling during PLD infusion was shown to improve severe HFS. We investigated the utility of frozen gloves and socks (FGS) as a simpler cooling method. METHODS: To evaluate the utility and safety of regional cooling with FGS for PLD-induced HFS, we retrospectively analyzed patients with advanced ovarian cancer who used FGS during PLD-containing regimens. RESULTS: Ninety-six patients were analyzed. The incidence of HFS was 51% (≥ grade 2, 32%) in the PLD group and 38% (≥ grade 2, 6%) in the PLD + CBDCA group. The respective percentages of patients who underwent PLD dose modification/discontinuation were 41%/75% in the PLD group and 9%/30% in the PLD + CBDCA group. The reasons for discontinuation of PLD and PLD + CBDCA therapy were progressive disease, HFS, allergy, oral mucositis, and others. HFS was the only reason for PLD dose modification in both the PLD and PLD + CBDCA groups. The completion rate of FGS was 96%, with discontinuation in three cases due to pain from cooling. CONCLUSIONS: Our study indicates that FGS is a safe, simple method with good tolerability. A prospective study is needed for further assessment.

A retrospective study of treatment and prophylaxis of ifosfamide-induced hemorrhagic cystitis in pediatric and adolescent and young adult (AYA) patients with solid tumors.

OBJECTIVE: Ifosfamide (IFO) is considered an essential drug for the treatment of pediatric, adolescent and young adult patients with solid tumors. Hemorrhagic cystitis (HC) is one of the dose-limiting toxicity of IFO. However, there are insufficient evidence for risk factor and supportive care of IFO-induced HC. METHODS: In this retrospective study, patients (<30-year-old) with malignant solid tumors who had been treated with IFO-based chemotherapy, were categorized according to the presence or absence of HC, and were analyzed possible risk factors for IFO-induced HC. In our institution, continuous hydration to increase urine output and intravenous 2-mercaptethane sulfonate (mesna) are used for prophylaxis of IFO-induced HC. Increased hydration and dosage of mesna are administered to patients who develop IFO-induced HC; they also receive 24-h continuous infusion of mesna in subsequent treatment cycles. RESULTS: Nine treatment regimens were used in the 70 study patients. The range of daily IFO dosage was 1.2-3.0 g/m(2). HC occurred in 14/425 IFO-based chemotherapy cycles (3.3%). The daily IFO dosages (mean ± SD) in patients with or without HC were 2.23 ± 0.58 g/m(2) and 1.85 ± 0.50 g/m(2), respectively (P = 0.006). Only one of the nine patients who developed IFO-induced HC had experienced this complication in a subsequent cycle of treatment. CONCLUSION: The incidence of IFO-induced HC may be associated with the dosage of IFO. When administering IFO higher than 2.0 g/m(2)/day, the volume of hydration, dosage of mesna and duration of mesna infusion should be increased to prevent HC.

Viroporin activity of the JC polyomavirus is regulated by interactions with the adaptor protein complex 3.

Viroporins, which are encoded by a wide range of animal viruses, oligomerize in host cell membranes and form hydrophilic pores that can disrupt a number of physiological properties of the cell. Little is known about the relationship between host cell proteins and viroporin activity. The human JC polyomavirus (JCV) is the causative agent of progressive multifocal leukoencephalopathy. The JCV-encoded agnoprotein, which is essential for viral replication, has been shown to act as a viroporin. Here we demonstrate that the JCV agnoprotein specifically interacts with adaptor protein complex 3 through its δ subunit. This interaction interrupts adaptor protein complex 3-mediated vesicular trafficking with suppression of the targeting of the protein to the lysosomal degradation pathway and instead permits the transport of agnoprotein to the cell surface with resulting membrane permeabilization. The findings demonstrate a previously undescribed paradigm in virus-host interactions allowing the host to regulate viroporin activity and suggest that the viroporins of other viruses may also be highly regulated by specific interactions with host cell proteins.

[The Importance of Medication History Management by Hospital and Community Pharmacists for Oral Anticancer Drug S-1(Tegafur/Gimeracil/Oteracil Potassium)--A Retrospective Study].

S-1 (tegafur/gimeracil/oteracil potassium) is an effective oral anticancer drug for treatment of a wide spectrum of cancers. However, it may incur serious adverse effects through factors such as interactions with other drugs, renal dysfunction, or an insufficient washout period. In view of this, pharmacists should play an increasingly significant role in managing the medication history of patients treated with S-1. As there seems to be no standardized management tool for patients receiving S-1, we conducted a retrospective study to evaluate medication history management methods, which are commonly available in community pharmacies as well as hospitals. We identified 128 outpatients who were prescribed S-1 for the first time at the National Cancer Center Hospital from July to December of 2011. These patients were divided into in-hospital (n=48) and out-of-hospital (n=80) groups. The percentage of patients, who dropped out during the first course of S-1 treatment, was 16.7% for the in-hospital group, and 10% for the out-of-hospital group. Examining renal dysfunction, non-elderly patients with low creatinine clearance (Ccr) were found. These results suggest that there is the possibility of side effect occurrence in both the in-hospital and out-of-hospital prescription groups. Community pharmacists should check prescriptions with particular attention to the Ccr. It is necessary to develop mechanisms for cooperation between hospital and community pharmacists, with clear role sharing between them, allowing the community pharmacists to exercise medication history management for patients prescribed S-1 to the same degree as hospital pharmacists based on available information including laboratory test values.

[A Case of Severe Hematological Toxicity in Response to Pazopanib].

The patient(woman, approximately 46 years old)began pazopanib (PAZ) treatment (800 mg/day)f ollowing the recurrence of retroperitoneal leiomyosarcoma. Prior to treatment, the patient's platelet count was 18.6×10(4)/µl and her neutrophil count was 1.61×10(3)/µl . The platelet count decreased to 9.2×10(4)/µl on day 7 and to 5.4×10(4)/µl on day 21 after commencement of treatment. The neutrophil count was 0.97×10(3)/µl on day 28 and 0.68×10(3)/µl on day 35 after commencement of treatment. Thus, PAZ treatment was stopped on day 35. The blood sampling results on day 42 after commencement of treatment showed that the platelet count was 13.0×10(4)/µl and that the neutrophil count had recovered to 1.28×10(3)/µl . At that time, PAZ treatment was resumed at a reduced dose of 600 mg/day. By day 84 after commencement of treatment, the platelet count had increased from 12.7 to 13.8×10(4)/µl and the neutrophil count had increased from 1.02 to 1.34×10(3)/µl ; treatment was subsequently continued. The main adverse effects that have been reported for PAZ are hypertension and frequent liver dysfunction; these reports also indicate that the incidence of severe cytopenia(thrombocytopenia, neutropenia)is quite low. However, our patient exhibited cytopenia after commencement of PAZ treatment and her blood cell counts recovered once treatment was ceased, independent of other possible medications. Our findings suggest that cytopenia should be considered as an adverse effect of PAZ.

Tyr724 phosphorylation of ELMO1 by Src is involved in cell spreading and migration via Rac1 activation.

BACKGROUND: The complex of Dock180/ELMO1 that functions as a bipartite guanine nucleotide exchange factor for Rac is essential for diverse physiological and pathological processes of cells such as cell migration, phagocytosis, and invasion of cancer cells. Among the Src-family tyrosine kinases (SFKs), it has been reported that Hck directly phosphorylates ELMO1, regulating phagocytosis by promoting activation of Rac1; however, the involvement of other SFKs in ELMO1 phosphorylation has remained unknown. Here, we identified novel tyrosine (Y) residues of ELMO1 phosphorylated by SFKs, and examined the effects on Rac1 activity, cell adhesion, spreading, and cell motility on extracellular matrix (ECM). RESULTS: In this study, we unveiled that Src and Fyn can induce tyrosine phosphorylation of ELMO1 in in vivo and in vitro phosphorylation assays. Mutational analyses identified both Y720 and Y724 residues of ELMO1 as Src-mediated phosphorylation sites, preferentially on Y724. Single substitution of Y724 to Phe abrogated Rac1 activation triggered by Src. To elucidate the biological function of pY724, we established NIH3T3 cells stably expressing wild-type ELMO1 or its Y724F mutant together with Dock180. Among them, Y724-deficient cells exhibited a depletion of Rac1 activity with diminished phosphorylation of ELMO1 even upon the ECM-stimulation. It is noteworthy that NIH3T3 cells with ELMO1 Y724F were strikingly defective to promote cell spreading on fibronectin-coated dish, concomitantly exhibiting immature assemblies of actin stress fibers and focal adhesions. Eventually, ELMO1 Y724F significantly impaired cell migration. CONCLUSION: These results define that Src-mediated Y724 phosphorylation in ELMO1 plays a critical role for cell spreading via activation of Rac1, leading to promotion of cell migration. As the overexpression and/or hyperactivation of Src have been shown in a wide variety of human cancers, Src-mediated phosphorylation of Y724 in ELMO1 may regulate cancer cell adhesion to the ECM, invasion into surrounding tissues, and subsequent distant metastasis.

New screw technique for posterior column and ischial fixation from the anterior approach for acetabular fractures.

Management of the ischial fragment in acetabular fractures is a considerable problem. In this report, we presented how to drill or screw around the posterior column and ischium from the anterior approach using a novel 'sleeve guide technique' and the difficulty of plating. A sleeve, drill, depth gauge and driver from DepuySynthes were prepared. The portal was about 2-3 cm inside the anterior superior iliac spine opposite to the side of the fracture. The sleeve was inserted to the screw point around quadrilateral area through the retroperitoneal space. Drilling, measuring screw length by a depth gauge and the screwing were performed through the sleeve. Case 1 used a one-third plate and case 2 used a reconstruction plate. With this technique, the approach angles to the posterior column and ischium were inclined, and plating and screw insertion could be performed with a low risk of organ injury.

In vitro spermatogenesis in isolated seminiferous tubules of immature mice.

Mouse spermatogenesis, from spermatogonial stem cell proliferation to sperm formation, can be reproduced in vitro by culturing testis tissue masses of neonatal mice. However, it remains to be determined whether this method is also applicable when testis tissues are further divided into tiny fragments, such as segments of the seminiferous tubule (ST), a minimal anatomical unit for spermatogenesis. In this study, we investigated this issue using the testis of an Acrosin-GFP/Histone H3.3-mCherry (Acr/H3) double-transgenic mouse and monitored the expression of GFP and mCherry as indicators of spermatogenic progression. Initially, we noticed that the cut and isolated stretches of ST shrunk rapidly and conglomerated. We therefore maintained the isolation of STs in two ways: segmental isolation without truncation or embedding in soft agarose. In both cases, GFP expression was observed by fluorescence microscopy. By whole-mount immunochemical staining, meiotic spermatocytes and round and elongating spermatids were identified as Sycp3-, crescent-form GFP-, and mCherry-positive cells, respectively. Although the efficiency was significantly lower than that with tissue mass culture, we clearly showed that spermatogenesis can be induced up to the elongating spermatid stage even when the STs were cut into short segments and cultured in isolation. In addition, we demonstrated that lowered oxygen tension was favorable for spermatogenesis both for meiotic progression and for producing elongating spermatids in isolated STs. Culturing isolated STs rather than tissue masses is advantageous for explicitly assessing the various environmental parameters that influence the progression of spermatogenesis.

Equine major histocompatibility complex class I molecules act as entry receptors that bind to equine herpesvirus-1 glycoprotein D.

The endotheliotropism of equine herpesvirus-1 (EHV-1) leads to encephalomyelitis secondary to vasculitis and thrombosis in the infected horse central nervous system (CNS). To identify the host factors involved in EHV-1 infection of CNS endothelial cells, we performed functional cloning using an equine brain microvascular endothelial cell cDNA library. Exogenous expression of equine major histocompatibility complex (MHC) class I heavy chain genes conferred susceptibility to EHV-1 infection in mouse NIH3T3 cells, which are not naturally susceptible to EHV-1 infection. Equine MHC class I molecules bound to EHV-1 glycoprotein D (gD), and both anti-gD antibodies and a soluble form of gD blocked viral entry into NIH3T3 cells stably expressing the equine MHC class I heavy chain gene (3T3-A68 cells). Treatment with an anti-equine MHC class I monoclonal antibody blocked EHV-1 entry into 3T3-A68 cells, equine dermis (E. Derm) cells and equine brain microvascular endothelial cells. In addition, inhibition of cell surface expression of MHC class I molecules in E. Derm cells drastically reduced their susceptibility to EHV-1 infection. These results suggest that equine MHC class I is a functional gD receptor that plays a pivotal role in EHV-1 entry into equine cells.