Myocardial metastasis from ZEB1- and TWIST-positive spindle cell carcinoma of the esophagus: A case report

BACKGROUND

Metastatic cardiac tumors are known to occur more frequently than primary cardiac tumors, however, they often remain asymptomatic and are commonly discovered on autopsy. Malignant tumors with a relatively high frequency of cardiac metastasis include mesothelioma, melanoma, lung cancer, and breast cancer, whereas reports of esophageal cancer with cardiac metastasis are rare.

CASE SUMMARY

The case of a 60-year-old man who complained of dysphagia is presented. Upper gastrointestinal endoscopy showed a submucosal tumor-like elevated lesion in the esophagus causing stenosis. Contrast-enhanced computed tomography showed left atrial compression due to the esophageal tumor, multiple liver and lung metastases, and a left pleural effusion. Pathological examination of a biopsy specimen from the esophageal tumor showed spindle-shaped cells, raising suspicion of esophageal sarcoma. The disease progressed rapidly, and systemic chemotherapy was deemed necessary, however, due to his poor general condition, administration of cytotoxic agents was considered difficult. Given his high Combined Positive Score, nivolumab was administered, however, the patient soon died from the disease. The autopsy confirmed spindle cell carcinoma (SCC) of the esophagus and cardiac metastasis with similar histological features. Cancer stem cell markers, ZEB1 and TWIST, were positive in both the primary tumor and the cardiac metastasis.

CONCLUSION

To the best of our knowledge, there have been no prior reports of cardiac metastasis of esophageal SCC. This case highlights our experience with a patient with esophageal SCC who progressed rapidly and died from the disease, with the autopsy examination showing cardiac metastasis.

Liquid biopsy for breast cancer and other solid tumors: a review of recent advances

Liquid biopsy using circulating tumor DNA (ctDNA) has been reported to be less invasive and effective for comprehensive genetic analysis of heterogeneous solid tumors, including decision-making for therapeutic strategies, predicting recurrence, and detecting genetic factors related to treatment resistance in various types of cancers. Breast cancer, colorectal cancer, and lung cancer are among the most prevalent malignancies worldwide, and clinical studies of liquid biopsy for these cancers are ongoing. Liquid biopsy has been used as a companion diagnostic tool in clinical settings, and research findings have accumulated, especially in cases of colorectal cancer after curative resection and non-small cell lung cancer (NSCLC) after curative chemoradiotherapy, in which ctDNA detection helps predict eligibility for adjuvant chemotherapy. Liquid biopsy using ctDNA shows promise across a wide range of cancer types, including breast cancer, and its clinical applications are expected to expand further through ongoing research. In this article, studies on liquid biopsy in breast cancer, colorectal cancer, and NSCLC are compared focusing on ctDNA.

Case report: A rare case of triple negative breast cancer with development of acute pancreatitis due to dexamethasone during adjuvant chemotherapy

Here, we present the case of a 42-year-old female who developed acute pancreatitis due to dexamethasone during adjuvant chemotherapy for early triple negative breast cancer (TNBC). The patient received partial mastectomy and sentinel lymph node biopsy for early TNBC (cT1N0M0, cStage I) of the left breast. Dose-dense doxorubicin plus cyclophosphamide (ddAC) was administered as the adjuvant-chemotherapy; however, epigastralgia appeared on the fifth day of the first administration. A blood test showed a remarkable increase of serum pancreatic enzyme levels and computed tomography (CT) showed the swelling of pancreas and surrounding effusion, and she was diagnosed with moderate acute pancreatitis. As she had no history of excessive alcohol consumption or complication of cholelithiasis, dyslipidemia, or pancreatic neoplasm, drug-induced pancreatitis was suspected. Dexamethasone, which was administered as an antiemetic, was the suspected drug based on the drug administration history and previous report, and dexamethasone was discontinued from the second administration of ddAC. There was subsequently no recurrence of pancreatitis with no increase in serum pancreatic enzyme levels, and it was possible to complete adjuvant-chemotherapy. Alcohol, gallstones, dyslipidemia, and drugs have been reported as causes of pancreatitis; however, steroid-induced acute pancreatitis is extremely rare. We present the first case of acute pancreatitis induced by dexamethasone as the antiemetic.

Preferential B cell differentiation by combined immune checkpoint blockade for renal cell carcinoma is associated with clinical response and autoimmune reactions

Combined immune checkpoint blockade (ICB) is effective therapy for renal cell carcinoma (RCC). However, the dynamic changes in circulating B cells induced by combined ICB have not been clarified. The present study prospectively examined 22 patients scheduled to receive ICB for unresectable or metastatic RCC between March 2018 and August 2021. Eleven patients received combined therapy with anti-PD-1 (nivolumab) and anti-CTLA-4 (ipilimumab), and the other 11 patients received nivolumab monotherapy. Comprehensive phenotypes of circulating immune cells obtained prior to and after ICB therapy were analyzed by flow cytometry. Although the proportion of naïve B cells among total B cells was significantly decreased, that of switched memory B cells was significantly increased after combined therapy. In responders, the proportion of B cells among peripheral blood mononuclear cells was significantly higher prior to ICB therapy, and the proportion of switched memory B cells among total B cells tended to increase after ICB therapy. Of note, the proportion of plasmablasts among total B cells was significantly increased after ICB therapy in patients who developed severe immune-related adverse events (irAEs), and the proportion of B cells among peripheral blood decreased significantly. Furthermore, in four of five patients who developed immune-related hypophysitis following combined therapy, anti-pituitary antibody was detected in the serum. These results suggested that immune-related hypophysitis was closely related to the increase in circulating plasmablasts. Collectively, this study suggests that combined ICB promotes the differentiation of B cell populations, which is associated with efficient tumor suppression and development of irAEs.

Survival outcomes including salvage therapy of adult head and neck para-meningeal rhabdomyosarcoma: a multicenter retrospective study from Japan

BACKGROUND

Rhabdomyosarcoma is the most common soft tissue sarcoma in children, but rare in adults. Para-meningeal rhabdomyosarcoma in head and neck (PM-HNRMS) is less applicable for surgery due to the anatomic reason. PM-HNRMS has a poor prognosis in children. However, its clinical outcomes remain unclear in adults due to the rarity. Further, there is almost no detailed data about salvage therapy.

METHODS

We retrospectively examined the adult patients with PM-HNRMS treated at institutions belonging to the Kyushu Medical Oncology Group from 2009 to 2022. We evaluated the overall survival (OS) and progression-free survival (PFS) of the patients who received a first-line therapy. We also reviewed the clinical outcomes of patients who progressed against a first-line therapy and received salvage therapy.

RESULTS

Total 11 patients of PM-HNRMS received a first-line therapy. The characteristics were as follows: median age: 38 years (range 25 - 63 years), histology (alveolar/spindle): 10/1, and risk group (intermediate/high): 7/4. As a first-line therapy, VAC and ARST0431-based regimen was performed in 10 and 1 patients, respectively. During a first-line therapy, definitive radiation for all lesions were performed in seven patients. The median PFS was 14.2 months (95%CI: 6.0 - 25.8 months): 17.1 months (95%CI: 6.0 - not reached (NR)) for patients with stage I-III and 8.5 months (95%CI: 5.2 - 25.8 months) for patients with stage IV. The 1-year and 3-year PFS rates were 54.5% and 11.3% for all patients. Median OS in all patients was 40.8 months (95%CI: 12.1 months-NR): 40.8 months (95%CI: 12.1 - NR) for patients with stage I-III and NR for patients with stage IV. The 5-year OS rate was 48.5% for all patients. Among seven patients who received salvage therapy, three are still alive, two of whom remain disease-free for over 4 years after completion of the last therapy. Those two patients received multi-modal therapy including local therapy for all detected lesions.

CONCLUSION

The cure rate of adult PM-HNRMS is low in spite of a first-line therapy in this study. Salvage therapy might prolong the survival in patients who received the multi-modal therapy including local therapy for all detected lesions.

Case Report: Resolution of remitting seronegative symmetrical synovitis with pitting edema during nivolumab therapy for gastric cancer

The anti-programmed cell death-1 (PD-1) antibody nivolumab has been shown to significantly prolong the survival of patients with unresectable advanced or recurrent gastric cancer (AGC). However, immune-related adverse events (irAEs), which show different profiles from those of cytotoxic agents or conventional molecular-targeted drugs including tyrosine kinase inhibitors, have been reported. Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) is a rare autoimmune disorder with acute-onset, rheumatoid factor-negative, symmetric synovitis associated with limb edema observed in elderly persons. A case of RS3PE syndrome that developed after administration of nivolumab for advanced gastric cancer is reported. This is the first report of a case of RS3PE syndrome as an irAE caused by nivolumab in a patient with gastric cancer.

Effect of high ambient temperature on physiological responses during incremental exercise in Thoroughbred horses

Several reports have suggested that the risk of exertional heat illness (EHI) in Thoroughbred racehorses increases in high ambient temperatures. Heat dissipation in horses during exercise becomes less efficient when the body temperature and ambient temperature are close. Therefore, we hypothesised that exercise at 40 °C may increase body temperature, oxygen consumption, and cardiac output during incremental exercise tests compared to 20 and 30 °C. Six trained Thoroughbred horses were studied in a randomised, crossover design at three ambient temperatures with a 6-day washout period. Using a 3% inclined treadmill, horses performed incremental exercise tests at 1.7, 3.5, 6, 8, and 10 m/s for 90 s at ambient temperatures of 20, 30, and 40 °C. The effects of ambient temperature at 10 m/s on physiological variables were analysed using mixed models (P<0.05). Pulmonary arterial temperature and rectal temperature at 40 °C were higher than those at 20 °C (P<0.001) and 30 °C (P<0.001). Similarly, oxygen consumption (vs 20 °C, P=0.009; vs 30 °C, P=0.006) and cardiac output (vs 20 °C, P=0.001; vs 30 °C, P=0.001) at 40 °C were higher than those at 20 and 30 °C. Arterial O2 partial pressure, O2 saturation, and pH at 40 °C were lower than those at 20 and 30 °C. Arterial CO2 partial pressure at 40 °C was higher than that at 20 and 30 °C. No differences were observed in arterial-mixed venous O2 concentration difference (P=0.391) and plasma lactate concentration (P=0.134) at different ambient temperatures. These results indicate that exercise at 40 °C causes excessive high body temperature, decreased running economy, and increased cardiac output compared to exercise at 20 and 30 °C. We strongly suggest that trainers and veterinarians should anticipate the occurrence of increased thermal stresses when ambient temperature is extremely high even in dry conditions and prepare to mitigate the risk of EHI from the perspective of equine welfare.

Dynamic Changes in Peripheral Systemic Immunity Markers During Chemotherapy in HER2-negative Advanced Breast Cancer

BACKGROUND/AIM

The immune system has a pivotal role in modulating the response to chemotherapy in breast cancer (BC). However, the immune status during chemotherapy remains unclear. We evaluated the sequential changes in peripheral systemic immunity markers in BC patients treated with various chemotherapeutic agents.

MATERIALS AND METHODS

We examined the correlation between the peripheral systemic immunity markers, neutrophil-to-lymphocyte ratio (NLR), absolute lymphocyte count (ALC) and the local cytolytic activity (CYT) score obtained by quantitative reverse-transcription polymerase chain reaction of 84 preoperative BC patients. Next, we observed the sequential changes in the peripheral systemic immunity markers during treatment with four anticancer drugs: oral 5-fluorouracil derivative; S-1, epirubicin plus cyclophosphamide; paclitaxel plus the anti-vascular endothelial growth factor antibody bevacizumab, and eribulin in 172 HER2-negative advanced BC patients. Finally, we examined the correlation between the changes in the peripheral systemic immunity markers, time to treatment failure (TTF) and progression-free survival (PFS).

RESULTS

A negative correlation was found between ALC and NLR. ALC-low and NLR-high cases were positively associated with CYT score-low cases. The ratio of ALC-increase and NLR-decrease varies depending on the anticancer drugs used. The responder group (TTF ≥3 months) had a higher NLR-decrease ratio than the nonresponder group (TTF <3 months). Patients with a high NLR-decrease ratio showed higher PFS.

CONCLUSION

The change in ALC or NLR varies according to the anticancer drugs, suggesting differential immunomodulatory effects of the drugs. Furthermore, the change in NLR reflects the therapeutic efficacy of chemotherapy in advanced BC.

Trousseau's Syndrome with Advanced Neuroendocrine Carcinoma of Colon: A Case Report

Here, we present a 69-year-old female with advanced neuroendocrine carcinoma (NEC) of colon with multiple liver, bone, and kidney metastases who developed Trousseau's syndrome. The patient received etoposide plus cisplatin (EP) as the first-line therapy; however, after single administration of EP, she developed the severe lower-limb edema and EP was considered to be intolerable. Etoposide plus carboplatin was administered as the second-line therapy and after 3 cycles of administration, the progressive disease (PD) was confirmed and 5-fluorouracil + leucovorin + irinotecan (FOLFIRI) plus ramucirumab was administered as the third-line therapy. However, PD was confirmed after 3 cycles of the therapy, and she was to receive the best supportive care and was hospitalized in our hospital. Four weeks after hospitalization, mild impaired consciousness and dysarthria were observed. Blood tests showed coagulation abnormalities including elevation of plasma fibrin/fibrinogen degradation products (FDPs) and D-dimer levels, and the diffusion-weighted image of magnetic resonance imaging (MRI) of the head showed multiple cerebral infarcts. She was diagnosed with Trousseau's syndrome due to the progression of NEC and intravenous unfractionated heparin was administered as anticoagulant therapy. After the administration of heparin, plasma FDP and D-dimer levels decreased; however, due to the progression of NEC, the patient died 6 weeks after hospitalization. This is the first report of NEC of the colon that developed Trousseau's syndrome.

IMPROVE bleeding score predicts major bleeding in advanced gastrointestinal cancer patients with venous thromboembolism

BACKGROUND

The incidence of venous thromboembolism has been reported as 20% in cancer patients. Anticoagulation therapy is the standard treatment for venous thromboembolism. On the other hand, bleeding should be carefully managed, because advanced cancer, particularly gastrointestinal cancer, carries a high risk of bleeding. However, the optimal management for cancer-associated thromboembolism remains to be clarified.

METHODS

We retrospectively examined patients with advanced gastrointestinal cancer, including gastric cancer and colorectal cancer, who were treated with chemotherapy between 2014 and 2018 for the incidence and characteristics of venous thromboembolism and bleeding.

RESULTS

In total, 194 patients (120 men, 74 women) were enrolled in this study. The underlying pathology was gastric cancer in 74 cases and colorectal cancer in 120 cases. Of the 194 patients, 40 patients (20.6%) were diagnosed with venous thromboembolism and 10 patients (5.2%) were diagnosed with concomitant pulmonary thromboembolism. Conversely, bleeding was observed in 29 patients (15%). The location of bleeding was the primary tumor in 17 cases, metastatic tumor in 9 and hemorrhagic gastric ulcer in 3. Within the venous thromboembolism group (n = 40), bleeding was observed in 10 patients (25%). Multivariate analysis showed that International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) bleeding score ≥7 correlated significantly with major bleeding (P = 0.01). In patients with a low risk of bleeding, major bleeding was observed in only three patients.

CONCLUSIONS

IMPROVE bleeding score may predict the risk for bleeding in gastrointestinal cancer patients with venous thromboembolism. Selecting patients with a low risk of bleeding using with IMPROVE bleeding score is expected to contribute to the safer management of anticoagulation therapy for cancer-associated thromboembolism.

Effect of post-exercise muscle cooling on PGC-1α and VEGF mRNA expression in Thoroughbreds

Besides preventing exertional heat illness, muscle cooling can be a potential strategy to enhance exercise-training induced adaptations. This study aimed to examine the effects of post-exercise cooling on the mRNA expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and vascular endothelial growth factor (VEGF) in Thoroughbred skeletal muscle. Five Thoroughbred horses performed treadmill running until their pulmonary artery temperature reached 42 °C, followed by walking on the treadmill with no additional cooling (CONT) or muscle cooling with a shower using the tap water (26 °C, 0.4 l/s; COOL), for 30 min. Muscle biopsies were obtained before (PRE) and 3 h after exercise (3 Hr-REC) from the gluteus medius muscle. PGC-1α mRNA expression was elevated 3 h after exercise in both the CONT (PRE vs 3 Hr-REC: 1.0±0.1 vs 5.0±0.8, P<0.01) and COOL (PRE vs 3 Hr-REC: 1.1±0.3 vs 6.6±0.9, P<0.01) conditions; however, there was no difference between the two conditions at 3 h after exercise (P=0.17). VEGF mRNA expression was elevated 3 h after exercise in COOL (PRE vs 3 Hr-REC: 1.0±0.2 vs 2.2±0.2, P<0.05) but not in CONT (PRE vs 3 Hr-REC: 1.0±0.1 vs 1.8±0.3, P=0.08). VEGF mRNA expression at 3 h after exercise was significantly negatively correlated with rectal temperature at the end of the 30-min cooling period (r = -0.65, P<0.05). Our results suggest that the decline in body temperature after exercise may lead to greater expression of the key angiogenic gene in Thoroughbred horses.

Improvement in recurring nivolumab-induced pneumonitis with repetitive administration of infliximab in a patient with head and neck cancer: A case report

Severe pneumonitis induced by nivolumab, an anti-programmed cell death-1 monoclonal antibody, is a rare but potentially fatal immune-related adverse event. In cases of steroid-refractory pneumonitis, an appropriate therapeutic strategy using anti-tumor necrosis factor-α (TNF-α) antibody has not been established. A 59-year-old female was diagnosed with hypopharyngeal squamous cell carcinoma. Previous therapies including chemoradiotherapy and throat laryngectomy were performed, but metastatic recurrence appeared in the intrapulmonary and mediastinal lymph nodes. The patient was administered nivolumab. On the 14th day of nivolumab administration, the patient experienced dyspnea and computed tomography of the chest showed multiple consolidations in the right lung. She was diagnosed with nivolumab-induced pneumonitis. Because the pneumonitis was refractory to steroid therapy, she was administered infliximab, and the pneumonitis improved. On the 72nd and 101st days of nivolumab administration, nivolumab-induced pneumonitis re-appeared with an elevated serum TNF-α concentration. In each occurrence of pneumonitis, repetitive administration of infliximab improved the pneumonitis. Repetitive administration of infliximab may be effective for treating recurrent nivolumab-induced pneumonitis that is associated with an increased serum TNF-α concentration.

Prominent PD-L1-positive M2 macrophage infiltration in gastric cancer with hyper-progression after anti-PD-1 therapy: A case report

RATIONALE

Anti-PD-1 antibody is the standard therapy for treatment-resistant gastric cancer, but only a limited number of patients respond. Additionally, cases of hyper-progressive disease (HPD) in which tumor growth accelerates after anti-PD-1 antibody administration have been reported; however, the biological mechanism has not been elucidated.

PATIENT CONCERNS

In the present case, metastatic gastric cancer was treated with the anti-PD-1 antibody, nivolumab, as third-line treatment.

DIAGNOSIS

After the initiation of nivolumab therapy, a rapidly enlarging para-aortic lymph nodes were observed leading to the diagnosis of HPD.

INTERVENTIONS

Multiplex immunohistochemistry was used to examine immune cells infiltrating in the primary tumor and in liver metastasis which were obtained before nivolumab treatment, and in lymph node metastasis which presented with HPD after nivolumab therapy.

OUTCOMES

In the primary tumor, helper T (Th) cells, cytotoxic T lymphocytes (CTLs), regulatory T (Treg) cells, and PD-L1-negative macrophages were observed. On the other hand, in metastatic lymph nodes presenting with HPD, PD-L1-positive macrophages prominently increased, while Treg cells, CTLs, and Th cells decreased. PD-L1 expression was not observed in gastric cancer cells among the three specimens.

LESSONS

The findings suggest the possibility that PD-L1-positive M2 macrophage might contribute to acceleration of tumor growth with anti-PD-1 therapy in the present case.

Changes in muscle activity with exercise-induced fatigue in Thoroughbred horses

Understanding the effects of fatigue can provide guidance for training regimens and injury prevention. We have previously reported that the integrated-electromyogram (iEMG) values of the M. gluteus medius and brachiocephalicus decreased with exercise-induced fatigue, whereas those of the M. longissimus dorsi and infraspinatus were not affected. We hypothesised that exercise-induced fatigue would decrease the activities of the muscles associated with propulsive force but not associated with joint stabilisation. Surface EMG recordings of the forelimb muscles (M. triceps brachii, common digital extensor, ulnaris lateralis), and hindlimb muscles (M. semitendinosus, extensor digitorum longus, extensor digitorum lateralis and flexor digitorum lateralis) were conducted on eight Thoroughbreds. Horses galloped on a treadmill (grade, 3%) at a constant speed (12.6-14.8 m/s) until they could not maintain their position with minimal human encouragement (~5 min). The stride frequency, iEMG for a stride and median frequency during muscle discharge were calculated every 30 s. These parameters were compared between the start and end of the test phase for the leading and trailing limbs. The stride frequency (P<0.01) and iEMG values of the M. semitendinosus in both the leading (P<0.01) and trailing limbs (P<0.05) and those of the M. extensor digitorum longus in the trailing limbs (P<0.05) significantly decreased at the end of the test. No median frequency changes were observed in the assessed muscles. Although muscular fatigue itself was not detected, observed fatigue caused by high-intensity exercise resulted in inability to maintain speed, which was associated with decreased iEMG values in the hip extensor muscles that generate propulsive force. In contrast, almost all muscles that stabilise joints were unaffected by fatigue. One exception was the decreased muscle activity observed in the M. extensor digitorum longus of the trailing limb, which may suggest unstable ground contact. Muscle activity changes with fatigue might be associated with muscle functions.

Eribulin as a first-line treatment for soft tissue sarcoma patients with contraindications for doxorubicin

Doxorubicin is a first-line therapy for patients with unresectable advanced soft tissue sarcoma (STS). However, because of cardiotoxicities, it is not used for patients with cardiac problems. Eribulin has exhibited efficacy for advanced STS in second- or later-line treatments. In the present study, we retrospectively analyzed the efficacy and safety of first-line eribulin therapy for patients with advanced STS unable to receive doxorubicin. Six of 28 patients who received eribulin as any line treatment received eribulin as a first-line treatment. The reasons for avoiding doxorubicin were as follows: cardiac problems for four patients and advanced age for two. Median progression-free survival (PFS) of the patients who received eribulin as first-line and, second or later-line therapy were 9.7 months (95% CI: 1.0-not reached) and 3.9 months (95% CI: 2.7–5.9), which were not significantly different. The reasons for discontinuation of eribulin were disease progression and adverse events (2 fatigue and 1 neuropathy) for three patients each. No treatment-related cardiotoxicity was observed. The findings of this study indicated that eribulin exhibits meaningful efficacy for the patients with contraindications for doxorubicin as a first-line treatment without cardiac adverse events. However, appropriate safety management is necessary because older patients are typically among those intolerable of doxorubicin.

RNA N6-methyladenosine demethylase FTO regulates PD-L1 expression in colon cancer cells

Fat mass and obesity-associated protein (FTO) is an enzyme that demethylates N6-methyladenosine (m⁶A), the most abundant RNA modifications in a cell. The upregulated expression of FTO promotes the progression of various types of cancer by modulating cell-intrinsic genes which relate to malignant potential. However, the impact of FTO on the expression of immune-checkpoint molecules in the tumor cells, which are important for immune escape, has not been well understood. We examined the relevance of FTO to programmed cell death-ligand 1 (PD-L1) expression in colon cancer cells. HCT-116 cells showed high expression of both FTO and PD-L1 proteins. The knockdown of FTO by small interfering RNA decreased mRNA and protein levels of PD-L1 in HCT-116 cells. To elucidate the underlying mechanism by which FTO regulates the expression of PD-L1, we depleted FTO in HCT-116 in the presence of IFN-γ, which is a major stimulus to upregulate PD-L1 expression. Depletion of FTO reduced PD-L1 expression in an IFN-γ signaling-independent manner. RNA immunoprecipitation assay revealed the m⁶A modification of the PD-L1 mRNA and the binding of FTO to the PD-L1 mRNA in HCT-116. Taken together, our results indicated that FTO could regulate PD-L1 expression in colon cancer cells and provides new insights into the regulation of PD-L1 expression by RNA modification.

Effect of lactate administration on exercise-induced PGC-1α mRNA expression in Thoroughbreds

The aim of this study was to examine the effects of lactate administration on the mRNA response of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) to acute exercise in Thoroughbred skeletal muscle. Five Thoroughbred horses performed treadmill running at 90% of maximal oxygen consumption for 2 min on two separate occasions, either after the administration of two litres of a sodium lactate solution (LAC; 500 mmol/l sodium lactate in 0.9% NaCl) or a saline solution as a control (CON; 0.9% NaCl). Lactate administration significantly elevated the peak plasma lactate concentration during exercise (16.0±2.8 mmol/l in LAC vs 10.8±2.2 mmol/l in CON). The increase in PGC-1α mRNA expression after 4 h of recovery from exercise was similar between treatments. However, there was positive correlation between exercise-induced PGC-1α mRNA response at 4 h after exercise and peak plasma lactate concentration during exercise. These results suggest that the exercise intensity-dependent adaptation of PGC-1α may be attributed, at least in part, to an increased lactate concentration.

OX40 and LAG3 are associated with better prognosis in advanced gastric cancer patients treated with anti-programmed death-1 antibody

Background

Anti-PD-1 monoclonal antibody, nivolumab, has shown efficacy for advanced gastric cancer (AGC). However, the specific immune cell subsets predominantly activated during the period of anti-PD-1 therapy for AGC have not been clarified.

Methods

Peripheral blood of 30 AGC patients treated with nivolumab was prospectively obtained before the initial and second administrations and at the time of progressive disease (PD). The proportions of immune cell subsets and the serum concentrations of cytokines were systematically analysed by flow cytometry. Associations of subsets and serum cytokines with therapeutic effects were evaluated.

Results

After the initial administration, significant increases in activated central/effector memory, activated effector T cells, and activated T-helper 1 subsets were observed. At the time of PD, activated regulatory T cells, LAG3-positive CD4+/CD8+ T cells, and TIM3-positive CD4+/CD8+ T cells increased significantly. Significant positive correlations were shown between progression-free survival and proportions of LAG3-positive CD4+/CD8+ T cells and of OX40-positive CD4+/CD8+ T cells (log-rank p = 0.0008, 0.0003, 0.0035 and 0.0040).

Conclusions

Nivolumab therapy enhances activation of central/effector memory and effector subsets of CD4+/CD8+ T cells. The expression levels of LAG-3 and OX40 on T cells correlated with the efficacy of nivolumab therapy and could be reasonable biomarkers for anti-PD-1 therapy.

Helper T cell-dominant tertiary lymphoid structures are associated with disease relapse of advanced colorectal cancer

Tertiary lymphoid structures (TLSs), clusters of immune cells found around tumor tissue, have been shown to be associated with anti-tumor immunity, but the cellular composition within each TLS and whether the cellular composition of a TLS affects a patient’s prognosis are poorly understood. In the present study, each TLS was categorized according to its cellular composition determined by a system of multiplex immunohistochemical staining and quantitative analysis, and the correlation between the category and prognosis was examined. Sixty-seven patients with curatively resected stage II/III colorectal cancer (CRC) were enrolled. A TLS, consisting of germinal center B cells, follicular dendritic cells, T helper (Th) cells, B cells, cytotoxic T cells, and macrophages, was confirmed in the tumor tissue of 58 patients (87%). The densities of Th cells and macrophages were significantly higher in relapsed patients than in not-relapsed patients (p = .043 and p = .0076). A higher ratio of Th cells was the most significant independent risk factor for disease relapse on multivariate analysis. The subset increasing in Th cells was GATA3⁺ Th2. A total of 353 TLSs was divided into five clusters according to immune cell composition. Among them, the Th-rich type TLS was significantly increased (p = .0009) in relapsed patients. These data suggest the possibility that Th cell-dominant composition might disturb the anti-tumor immune response, and the function of each TLS might differ depending on its composition.

Activation of memory/effector T cells and association between prognosis and OX40-positive T cells in advanced head and neck cancer patients treated with anti-programmed death-1 antibody

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Background: Anti-programmed death-1 (PD-1) monoclonal antibody, nivolumab, enhances anti-tumor activity by inhibiting the interaction of PD-1 and programmed death-1 ligand 1 and has shown efficacy for platinum-refractory recurrent or advanced head and neck cancer (HNC). However, subsets of immune cells predominantly activated during the period of anti-PD-1 therapy for HNC and specifically associated with the prognosis have not been clarified. Methods: Peripheral blood mononuclear cells of 15 HNC patients treated with nivolumab were prospectively obtained before the initial and second administrations of nivolumab, and at the time of progressive disease (PD). We performed comprehensive analysis of the proportion of immune cell subsets by flow cytometry, including the expression of coinhibitory and costimulatory molecules such as T-cell immunoglobulin and mucin domain 3 (TIM-3), lymphocyte-activation gene 3 (LAG-3), T-cell immunoreceptor with Ig and ITIM domains (TIGIT), B and T lymphocyte attenuator (BTLA), CD28, OX40, inducible T cell costimulator (ICOS). Association between changes in the proportion of the subsets and therapeutic effect were also analyzed. Results: Median progression free survival (PFS) of the whole patients was 96 days (95% CI 70–308). After a single course of nivolumab, patients showed a significant increase in activated central memory and effector subsets of CD4+/CD8+ T cells and activated helper T1 cells (p = 0.0039, 0.0078, 0.0273, 0.0391, 0.0391). A trend of increase of activated effector memory CD4+/CD8+ T cell was observed (p = 0.4961, 0.3594). At the time of PD, effector regulatory T cells, LAG3 positive CD4+/CD8+ T cells, TIM-3 positive CD4+/CD8 T cells and BTLA positive CD4+/CD8+ T cells significantly increased. Significant positive correlations were found between PFS and the proportion of OX40 positive CD4+/CD8+ T cells before nivolumab therapy (p = 0.0239, 0.0134). Conclusions: Nivolumab therapy enhances activation of central memory and effector subsets of CD4+/CD8+ T cells. The expression level of OX40 on T cells was correlated with efficacy of nivolumab therapy in HNC patients.

Thrombocytopenia Caused by Dexamethasone in a Patient with Colorectal Cancer

Drug-induced immune thrombocytopenia (DITP) is an important cause of thrombocytopenia. A 73-year-old man with relapsed rectal carcinoma received S-1, oxaliplatin and bevacizumab combination therapy (SOX+Bev). Dexamethasone was administered as an antiemetic prophylaxis. On day 2 of the first cycle, thrombocytopenia (8,000/μL) was observed. We sequentially omitted any drugs suspected to possibly induce thrombocytopenia and confirmed dexamethasone as the cause of thrombocytopenia. DITP induced by synthetic corticosteroids is very rare and this is the first case report of DITP induced by dexamethasone. Although rare, DITP due to synthetic corticosteroids including dexamethasone should be a differential diagnosis among patients receiving synthetic corticosteroids with thrombocytopenia.

Methylation of drug resistance-related genes in chemotherapy-sensitive Epstein-Barr virus-associated gastric cancer

Epstein–Barr virus (EBV)‐associated gastric cancer (GC) is associated with a high degree of DNA methylation. However, the association between chemotherapy susceptibility and tumor DNA methylation in advanced diseases remains unclear. The comprehensive DNA methylation status of GC cells obtained from an advanced EBV‐associated GC (EBVGC) case, in which complete response to S‐1 plus cisplatin chemotherapy was achieved, was analyzed using a DNA methylation microarray. We compared DNA methylation of GC cells with public data and identified genes with higher methylation in EBVGC cell lines than in normal gastric cells, and genes in which methylation was increased by EBV. Of these genes, ABCG2, AHNAK2, BCL2, FZD1, and TP73 are associated with published evidence for resistance to 5‐fluorouracil and cisplatin. Silencing of these genes may be associated with hypersensitivity to chemotherapy.

Activation of central/effector memory T cells in advanced gastric cancer patients treated with antiprogrammed death-1 antibody

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Background: Anti-programmed death-1 (PD-1) monoclonal antibody, nivolumab, enhances antitumor activity by inhibiting the interaction of PD-1 and programmed death-1 ligand 1 (PD-L1) and has shown efficacy for advanced gastric cancer (AGC) in the salvage line. However, specific subsets of immune cells predominantly activated during the period of anti-PD-1 therapy for AGC have not been clarified. Methods: Peripheral blood mononuclear cells of 20 AGC patients treated with nivolumab were prospectively obtained before the initial and second administrations of nivolumab, and at the time of progressive disease (PD). The proportion of immune cell subsets were systematically analyzed by flow cytometry, including the expression of costimulatory and coinhibitory molecules such as T-cell immunoglobulin and mucin domain 3 (TIM-3), Lymphocyte-activation gene 3 (LAG-3), T-cell immunoreceptor with Ig and ITIM domains (TIGIT), cytotoxic T cell antigen-4 (CTLA-4), CD28, OX40, and inducible T cell costimulator (ICOS). Association between changes in the proportion of the subsets and therapeutic effect were analyzed. Results: Median progression free survival (PFS) of the whole patients was 51 days (95% CI 35–83). After a single course of nivolumab, patients showed a significant increase in activated effector memory and activated effector subsets of CD4+/CD8+ T cells (p = 0.018, 0.018, 0.032, 0.024). At the time of PD, proportions of myeloid dendritic cell, IgM memory B cell and Tfh-Th1/17 cell subsets decreased (p = 0.024, 0.013, 0.0039). On the other hand, LAG3 positive CD4+/CD8+ T cells, TIM-3 positive CD4+/CD8 T cells increased at the time of PD (p = 0.013, 0.032, 0.042, 0.042). Significant positive correlations were found between PFS and the proportion of LAG3 positive CD4+/CD8+ T cells (p = 0.0056, 0.0054), OX 40 positive CD4+/CD8+ T cells (p = 0.0034, 0.0006) prior to the initial nivolumab therapy. Conclusions: Nivolumab therapy enhances activation of effector memory and effector subsets of CD4+/CD8+ T cells. The expression level of LAG3 and OX40 on T cells might be correlated with efficacy of nivolumab therapy.

PD-1+ TIM-3+ T cells in malignant ascites predict prognosis of gastrointestinal cancer

The liquid biopsy of ascites fluid could be an excellent source of tumor and microenvironment for the study of prognostic biomarkers because of its accessibility. Tumor-infiltrating lymphocytes (TILs) can predict prognosis in multiple malignancies, including the response to immune checkpoint inhibitors, a breakthrough cancer therapy. However, TILs' profiles from malignant ascites have not been extensively studied. Using flow cytometric analysis, we quantified the proportion of exhausted T cells and memory/naive/effector T-cell subsets, among the CD4+ and CD8+ T-cell populations of paired TILs and peripheral blood T cell samples (n = 22). The correlation between CD4+ and CD8+ subset profiles suggested that the combined analysis of CD4+ and CD8+ cells in malignant ascites was clinically significant. We found that cells positive for the exhaustion markers programmed cell death-1 (PD-1), and T-cell immunoglobulin and mucin domain 3 (TIM-3), and cells coexpressing PD-1 and TIM-3 abundantly exist among malignant ascites TILs. Furthermore, patients with high frequency of PD-1+ TIM-3+ cells among the CD4+ and CD8+ T-cell population showed worse clinical outcome in multivariate analysis (n = 27). We propose that exhausted ascites TILs represent a clinically significant prognostic biomarker in advanced gastrointestinal cancer and represent an important target for immune checkpoint inhibitors.

Activation of central/effector memory T cells and T-helper 1 polarization in malignant melanoma patients treated with anti-programmed death-1 antibody

Human anti-programmed death-1 (PD-1) antibody possesses the capability to revitalize host T cells and has been an effective therapy for metastatic malignant melanoma (MM). The precise subsets of T cells predominantly activated by anti-PD-1, however, have not yet been clarified. In this study, peripheral blood mononuclear cells obtained from MM patients scheduled to receive anti-PD-1 (nivolumab) therapy, and healthy subjects (HS), were systematically examined on flow cytometry to identify changes in the proportion of immune cell subsets. Compared with HS, MM patients prior to therapy had an increased proportion of activated CD8+ T cells with effector memory phenotypes (Tem), and PD-1 positive subsets of CD4+ central memory T cells (Tcm) and T-helper (Th)17 cells. After a single course of anti-PD-1 therapy, MM patients had an increase in activated Tem and Tcm subsets of CD4+ and CD8+ T cells, and activated Th1 plus T-helper follicular 1 cells. There was no consistent change in the proportion of Tfh cells, B cells, natural killer cells, or dendritic cells. The observed activated phenotypes were attenuated during the course of therapy, but regulatory T cells belonging to the CD3+CD4+CD45RO+CD25high fraction increased at disease progression. Taken together, anti-PD-1 therapy modulates systemic immune reactions and exerts anti-tumor effects, not only by revitalizing Tem and Tcm of CD4+ and CD8+ T cells, but also via a shift to a Th1 phenotype.

Predictive value of the modified Glasgow Prognostic Score for the therapeutic effects of molecular-targeted drugs on advanced renal cell carcinoma

Inflammation is considered to be a prognostic factor for renal cell carcinoma (RCC). An inflammation-based prognostic score (modified Glasgow Prognostic Score; mGPS) is widely used for preoperative patients; however, little information is available regarding its prognostic value in patients with RCC treated with molecular-targeted drugs. A total of 32 advanced and recurrent RCC patients initially treated with molecular-targeted drugs from October, 2009 to August, 2015 were retrospectively investigated. Information on patient characteristics prior to treatment initiation and the clinical course were retrieved from clinical records. The correlation between survival and patient variables was analyzed. Survival was compared among patient groups according to the mGPS score. The median patient age was 66 years. The percentage of patients with an Eastern Cooperative Oncology Group performance status of 0 or 1 was 87.5, and 65.6% of the RCCs were clear cell carcinomas. A Memorial Sloan-Kettering Cancer Center index of good or intermediate was determined for 75% of the patients. Sunitinib, pazopanib or sorafenib was administered to 56, 22 and 13% of the cases, respectively. An mGPS score of 0, 1 and 2 was calculated for 66, 9 and 25% of the cases, respectively. Patients in the mGPS low group (score 0) exhibited significantly better progression-free survival (PFS) and overall survival (OS) compared with patients in the mGPS high group (score 1 or 2) (median PFS, 307 vs. 70 days and median OS, 1,081 vs. 140 days, respectively). In conclusion, inflammatory status as assessed by the mGPS score was closely associated with the prognosis of RCC patients treated with molecular-targeted therapy.

Gossypol inhibits aromatase activity in cultured porcine granulosa cells

The present study investigated whether gossypol inhibited aromatase activity in cultured porcine granulosa cells. Aromatase activity was assayed by measuring (3)H-H(2)O released from [1beta-(3)H]-androstenedione. First, immature porcine granulosa cells were cultured with various doses of follicle stimulating hormone (FSH, 1 to 1000 ng/ml) for 1 to 5 d to determine optimal culture conditions for aromatase activity assay. Second, porcine granulosa cells were cultured with or without FSH in the presence or absence of gossypol. Gossypol, at 4 muM, significantly inhibited FSH-induced aromatase activity while showing no effect on basal aromatase activity. Gossypol did not inhibit cell proliferation during cell culture. These results suggest that gossypol inhibits aromatase activity by interfering with FSH induction of aromatase in cultured porcine granulosa cells.

Comparison of net anaerobic energy utilisation estimated by plasma lactate accumulation rate and accumulated oxygen deficit in Thoroughbred horses

REASONS FOR PERFORMING STUDY

Accumulated O(2) deficit (AOD) and plasma lactate accumulation rate (PLAR) are alternative methods for estimating net anaerobic energy utilisation (NAEU) in exercising horses. How they compare or their accuracy is unknown.

OBJECTIVES

We hypothesised net anaerobic energy utilisation calculated by PLAR (NAUE(PLAR)) is equivalent to NAUE estimated by AOD (NAUE(AOD)).

METHODS

Six Thoroughbred horses ran at identical supramaximal speeds (118% aerobic capacity) until exhaustion for 2 runs while breathing normoxic (NO, 21% O(2)) or hyperoxic (HO, 26% O(2)) gas. Jugular blood was sampled at 15 s intervals to measure plasma lactate concentration. Horses also ran at incremental submaximal speeds from 1.7-11.0 m/s to determine the linear relationship between speed and O(2) consumption to estimate O(2) demand for AOD calculations.

RESULTS

Maximum O(2) consumption of horses increased 11.6 ± 2.3% in HO and NAEU(PLAR) and NAUE(AOD) decreased 38.5 ± 8.0% and 46.2 ± 17.7%, respectively. The NAEU(PLAR) in NO was 114.5 ± 27.4 mlO(2) (STPD) equivalent/kg bwt contributing 23.5 ± 3.7% to total energy turnover and in HO was 70.9 ± 19.8 mlO(2) (STPD) equivalent/kg bwt contributing 14.6 ± 3.8% to total energy turnover. The NAUE(AOD) in NO was 88.6 ± 24.3 mlO(2) (STPD) equivalent/kg bwt contributing 19.9 ± 2.1% to total energy turnover and in HO was 56.2 ± 19.1 mlO(2) (STPD) equivalent/kg bwt contributing 10.9 ± 4.3% to total energy turnover. Overall, NAEU(AOD) was systematically biased -23.5 ± 16.8 mlO(2) (STPD) equivalent/kg bwt below NAEU(PLAR). Total energy demand estimated by PLAR was 11.1 ± 5.4% greater than that estimated by AOD and was higher in every horse.

CONCLUSIONS

The NAUE(PLAR) estimates average 40.0 ± 29.6% higher than NAUE(AOD) and are highly correlated (r(2) = 0.734), indicating both indices are sensitive to similar changes in NAEU. Accuracy of the estimates remains to be determined. Multiple considerations suggest NAUE(AOD) may underestimate total energy cost during high-speed galloping, thus biasing low the AOD estimate of NAEU.

Effects of three warm-up regimens of equal distance on VO2 kinetics during supramaximal exercise in Thoroughbred horses

REASONS FOR PERFORMING STUDY

Several studies have indicated that even low-intensity warm-up increases O(2) transport kinetics and that high-intensity warm-up may not be needed in horses. However, conventional warm-up exercise for Thoroughbred races is more intense than those utilised in previous studies of equine warm-up responses.

OBJECTIVES

To test the hypothesis that warm-up exercise at different intensities alters the kinetics and total contribution of aerobic power to total metabolic power in subsequent supramaximal (sprint) exercise in Thoroughbred horses.

METHODS

Nine well-trained Thoroughbreds ran until fatigue at 115% of maximal oxygen consumption (VO2max) 10 min after warming-up under each of 3 protocols of equal running distance: 400 s at 30% VO2max (LoWU), 200 s at 60% VO2max (MoWU) and 120 s at 100% VO2max (HiWU). Variables measured during exercise were rates of O(2) and CO(2) consumption/production (VO2,VO2), respiratory exchange ratio (RER), heart rate, blood lactate concentration and accumulation rate and blood gas variables.

RESULTS

VO2 was significantly higher in HiWU than in LoWU at the onset of the sprint exercise and HR was significantly higher in HiWU than in LoWU throughout the sprint. Accumulation of blood lactate, RER, P(a)CO(2) and PvCO2 in the first 60 s were significantly lower in HiWU than in LoWU and MoWU. There were no significant differences in stroke volume, run time or arterial-mixed venous O(2) concentration.

CONCLUSIONS

These results suggest HiWU accelerates kinetics and reduces reliance on net anaerobic power compared with LoWU at the onset of the subsequent sprint.

Utilisation of the time constant calculated from heart rate recovery after exercise for evaluation of autonomic activity in horses

REASONS FOR PERFORMING STUDY

Heart rate (HR) recovery immediately after exercise is controlled by autonomic functions and the time constant (T) calculated from HR recovery is thought to be an index of parasympathetic activity in man.

OBJECTIVES

To investigate whether it is possible to evaluate autonomic function using the time constant in horses.

METHODS

Five Thoroughbred horses were subjected to a standard exercise test. Following pre-medication with saline, atropine and/or propranolol, the horses ran for 2.5 min at a speed of 8 m/sec at a 10% incline and T was calculated from HR after the exercise. Secondly, 7 Thoroughbred horses were then trained for 11 weeks and T and maximal oxygen uptake (VO2max) measured at intervals of 1 or 2 weeks. In 6 horses, T with atropine pre-medication was also measured before and after the whole training period. Furthermore, the HR variability at rest was evaluated by power spectral analysis at intervals of 3 or 4 weeks.

RESULTS

Time constant was increased by atropine and/or propranolol pre-medication, decreased with the progress of training and inversely correlated with VO2max during training (r = 0.43, P<0.005). Parasympathetic blockade significantly decreased T only after and not before, the training; however, T was lower in post training than in pretraining, irrespective of parasympathetic blockade. On the other hand, parasympathetic activity at rest was attenuated and sympathetic activity became predominant following the training.

CONCLUSION

Heart rate recovery is affected by sympathetic withdrawal and parasympathetic reactivation in horses and suggests that physical training hastened HR recovery by improving the parasympathetic function after exercise with aerobic capacity. However, the effects of other factors need to be considered because the training effect appeared on T even under parasympathetic blockade. The parasympathetic activity at rest is in contrast to that after exercise, suggesting that T does not reflect parasympathetic activity at rest.

POTENTIAL RELEVANCE

If demonstrated how HR recovery is controlled after exercise, its analysis will be important in the evaluation of physical fitness in horses.

Effect of amino acid and glucose administration following exercise on the turnover of muscle protein in the hindlimb femoral region of Thoroughbreds

REASONS FOR PERFORMING STUDY

In man, muscle protein synthesis is accelerated by administering amino acids (AA) and glucose (Glu), because increased availability of amino acids and increased insulin secretion, is known to have a protein anabolic effect. However, in the horse, the effect on muscle hypertrophy of such nutrition management following exercise is unknown.

OBJECTIVES

To determine the effect of AA and Glu administration following exercise on muscle protein turnover in horses. We hypothesise that administration of AA and Glu after exercise effects muscle hypertrophy in horses, as already shown in man and other animals.

METHODS

Measurements of the rate of synthesis (Rs) and rate of degradation (Rd) of muscle protein in the hindlimb femoral region of thoroughbred horses were conducted using the isotope dilution method to assess the differences between the artery and iliac vein. Six adult Thoroughbreds received a continuous infusion of L-[ring-2H5]- phenylalanine during the study, the stable period for plasma isotope concentrations (60 min), resting periods (60 min), treadmill exercise (15 min) and recovery period (240 min). All horses were given 4 solutions (saline [Cont], 10% AA [10-AA], 10% Glu [10-Glu] and a mixture with 10% AA and 10% Glu [10-Mix]) over 120 min after exercise, and the Rs and Rd of muscle protein in the hindlimb measured.

RESULTS

The average Rs during the 75-120 min following administration of 10-Mix was significantly greater than for the other solutions (P<0.05). The second most effective solution was 10-AA, and there was no change in Rs after 10-Glu.

CONCLUSIONS

Administration of AA following exercise accelerated Rs in the hindlimb femoral region, and this effect was enhanced when combined with glucose, because of increasing insulin secretion or a decreased requirement for AA for energy.

POTENTIAL RELEVANCE

Further studies are required regarding the effect on muscle hypertrophy of supplementing amino acids and glucose in the feed of exercising horses.

Effect of detraining on cardiorespiratory variables in young thoroughbred horses

REASONS FOR PERFORMING STUDY

Thoroughbred racehorses often experience interruptions to their training. Identifying the effects of these changes and how they alter athletic performance might provide an insight on to how to prevent these changes from occurring.

HYPOTHESIS

Training and detraining young Thoroughbreds alters their aerobic capacities with correlated changes in circulatory capacities; if horses remained spontaneously active in a pasture during their detraining period, their decreases in aerobic capacity during detraining would be reduced.

METHODS

We trained 6 Thoroughbred yearlings for 6 months using a conventional yearling race training programme. They were then detrained for 10 weeks with free range on pasture for 8 h/day and stall rest at night. Treadmill measurements of O2 transport variables were made before training (PRE), after training (TR) and after detraining (DT). A step-test protocol identified each horse's aerobic capacity (VO2max) and speed to attain it, and a steady-state run at VO2max was used to quantify 02 transport variables at each time period.

RESULTS

The mass-specific and whole-body VO2max, cardiac output (Q) and stroke volume (Vs) increased from PRE to TR. All mass-specific values decreased significantly from TR to DT; however, because body mass increased by 8.3% from TR to DT, none of the variables changed significantly from TR to DT on a whole-body basis.

CONCLUSIONS

Changes in aerobic capacity are highly correlated with changes in Vs and circulatory capacity during training and detraining. Exercise activity of trained young horses free at pasture for 8 h/day is sufficient to maintain VO2max, (Q and Vs during 10 weeks of DT.

POTENTIAL RELEVANCE

Aerobic and cardiovascular fitness may be maintained in young Thoroughbred horses during at least 10 weeks of detraining by maintaining modest spontaneous exercise activity.

Energetic cost of locomotion on different equine treadmills

REASON FOR PERFORMING STUDY

Human athletes run faster and experience fewer injuries when running on surfaces with a stiffness 'tuned' to their bodies. We questioned if the same might be true for horses, and if so, would running on surfaces of different stiffness cause a measurable change in the amount of energy required to move at a given speed?

HYPOTHESIS

Different brands of commercial treadmills have pans of unequal stiffness, and this difference would result in different metabolic power requirements to locomote at a given speed.

METHODS

We tested for differences in stiffness between a Mustang 2200 and a Säto I commercial treadmill by incrementally loading each treadmill near the centre of the pan with fixed weights and measuring the displacement of the pan as weights were added or removed from the pan. We trained six 3-year-old Thoroughbreds to run on the 2 treadmills. After 4 months the horses ran with reproducible specific maximum rates of O2 consumption (VO2max/kg bwt, 2.62 +/- 0.23 (s.d.) mlO2 STPD/sec/kg) at 14.2 +/- 0.7 (s.d.) m/sec. They were alternately run on the 2 treadmills at identical grade (0.40 +/- 0.02%) and speeds (1.83 (walk), 4.0 (trot) and 8.0 (canter) m/sec, all +/- 0.03 m/sec) while wearing an open-flow mask for measurement of VO2.

RESULTS

The Mustang treadmill was over 6 times stiffer than the Säto. The VO2/kg bwt increased by approximately 4-fold over the range of speeds studied on both treadmills. Oxygen consumption was significantly lower at all speeds for the Mustang treadmill compared to the Säto. The fractional difference in energy cost decreased by a factor of 6 with increasing speed, although absolute difference in cost was relatively constant.

CONCLUSIONS

We suggest it costs less energy for horses to walk, trot or canter on a stiffer treadmill than on a more compliant treadmill, at least within the ranges of stiffness evaluated.

POTENTIAL RELEVANCE

It may be possible to define a substrate stiffness 'tuned' to a horse's body enabling maximal energetic economy when running. The differences between treadmills allows more accurate comparisons between physiological studies conducted on treadmills of different stiffness, and might help to identify an ideal track stiffness to reduce locomotor injuries in equine athletes.

Method for quantifying net anaerobic power in exercising horses

REASON FOR PERFORMING STUDY

There is no good method for measuring net anaerobic power in exercising horses to allow accurate estimates of total metabolic power.

HYPOTHESIS

The increase in VO2max when breathing hyperoxic (HO) gas should be accompanied by a stoichiometrically equal (in terms of ATP turnover, i.e. energy equivalents) decrease in plasma lactate accumulation rate (Mlactate).

METHODS

Six 3-year-old Thoroughbreds were trained on an equine treadmill wearing a semi-open flow mask for measurement of VO2. After 4 months the horses ran with reproducible specific VO2max (VO2max/kg bwt). The mask design allowed mixing of O2 or N2 with the inward bias flow of gas so that inspired O2 concentration of the horse could be controlled. While the horse breathed either HO (25.1% O2), normoxic (NO, 21% O2) or hypoxic (LO, 19.5% O2) gas, it ran at a speed sufficient to elicit VO2max in NO while jugular venous blood was drawn at 15 sec intervals over a period of 2 min to determine Mlactate.

RESULTS

VO2max/kg bwt was not significantly different between LO and NO conditions, and LO data could not be used in the comparison. The VO2max/kg bwt increased from 2.59 +/- 0.24 (s.d.) to 2.86 +/- 0.24 mlO2 (STPD)/sec/kg in NO and HO, respectively, while Mlactate decreased from 11.5 +/- 4.2 to 9.0 +/- 3.9 mmol/min as VO2 increased.

CONCLUSIONS

The ratio of delta Mlactate to delta VO2max/kg bwt suggests that Mlactate of approx 11.1 +/- 6.7 mmol/min is associated with net anaerobic power approximately equivalent to 1.0 mlO2 (STPD)/sec/kg of aerobic power (20.1 W/kg(-1)). The high variability in VO2max/kg bwt observed in data from some runs, particularly in LO, suggests that caution must be used when comparing data from the same horse during different runs.

POTENTIAL RELEVANCE

This study provides a tool for estimating net anaerobic power and, more accurately, evaluating total metabolic power of horses exercising at or above their aerobic capacities.

Studies on Oxidopyrylium [5 + 2] Cycloadditions: Toward a General Synthetic Route to the C12-Hydroxy Daphnetoxins

[Structure: see text] 12-hydroxydaphnetoxins, members of the structurally fascinating daphnane diterpene family, exhibit a wide range of significant biological activities. A general route to the BC-ring system of 12-hydroxy daphnetoxins is reported based on D-ribose. Depending on the choice of protecting groups and solvent, the oxidopyrylium-alkene [5+2] cycloaddition originating from A provides cycloadduct diastereomer B or C with good to excellent selectivity.

(2,5)-Ene cyclization catalyzed by mesoporous solid acids: isotope labeling study and ab initio calculation for continuum from concerted to stepwise ene mechanism

(2,5)-Ene reactions catalyzed by mesoporous solid acids are reported from the mechanistic point of view. The continuum (2,5)-ene mechanism from the concerted to the cationic cyclization followed by 1,2-hydride shift is evaluated. The solid-acid-catalyzed cyclization of the oxonium ion intermediate 4 derived from cyclic allylic lactol ether 3 bearing allylic hydroxy group affords the (2,5)-ene product as the enol form, eventually tautomerizing to the corresponding aldehyde 6. The continuum from the concerted to stepwise mechanism is experimentally and theoretically verified in the present ene cyclization of the oxonium ion intermediate such as 4. The stepwise cyclization leading to aldehyde 6 is thus shown to associate with the concerted version as a result of the stabilization of the beta-hydroxycarbenium ion intermediate.

One-pot synthesis of tropinone by tandem (domino) ene-type reactions of acetone silyl enol ethers

A synthetic approach for tropane alkaloids on the basis of tandem (domino) ene-type reactions of acetone silyl enol ethers with iminium ions is shown to be triggered by intermolecular ene-type reactions followed by 6-(2,5) silatropic ene-type cyclizations.

Palladium-catalyzed isobenzofuran generation under neutral conditions via oxidative addition to lactol methyl ether

A novel method for generation of isobenzofuran is developed from lactol methyl ether using palladium catalysts. This reaction can be carried out under neutral conditions and hence improves on the precedent methods under acidic or basic conditions and at high temperatures. Furthermore, this Pd-catalyzed isobenzofuran generation suggests the involvement of oxidative addition of Pd catalyst into benzylic or allylic methyl ethers. [reaction: see text]

Physiological responses of young Thoroughbreds during their first year of race training

Yearling horses are typically trained for more than a year before they begin racing; therefore, we questioned how relevant analyses of the initial responses to training are compared to physiological responses that occur over a year of training, and whether young horses with no history of training would respond the same as older horses that had been trained previously. We hypothesised that changes in O2 transport over the last months of a year of training would be different than at the beginning. We trained 5 yearling Thoroughbreds and evaluated metabolism, O2 transport and echocardiograms. Measurements were made before breaking (T1), after 6 months of training (T2) and following an additional 4 months of training (T3). We compared 5 trained horses (TR) with 5 untrained (UT) sex-, size- and age-matched yearlings kept at pasture and in boxes. Satellite telemetry indicated UT moved less total daily distance than TR during winter and more during summer, but UT walked for 80% of their distance, TR only 25%. The UT increased body mass (Mb) after T1 by 13% and were significantly heavier and fatter than TR. Specific aerobic capacity (VO2max/Mb) increased by 16% in both groups at T2, but by T3 was not different from T1 in UT, but was higher in TR (19%>T1, 15%>UT). In TR, specific cardiac output (Q/Mb) increased by 13% at T2, and specific stroke volume (V(S)/Mb) were larger at T2 and T3 than T1 and UT at the same times both by physiological (15-16%) and echocardiographical (22-23%) estimates. Increased Vs was a primary correlate of the sustained increase in VO2max/Mb in TR. The large increases in V(S) and VO2max had occurred by T2 and changed only slightly by T3.

Effects of repeated atropine injection on heart rate variability in Thoroughbred horses

To investigate the effects of repeated atropine injection on heart rate (HR) variability in resting Thoroughbred horses, two microg/ kg of atropine as parasympathetic nervous blockade was injected intravenously every 6 min to a total of 8 microg/kg after intravenous administration of 0.2 mg/kg of propranolol as sympathetic nervous blockade. We recorded electrocardiograms and obtained the HR, then evaluated variation in HR from the power spectrum in terms of low frequency (LF, 0.01-0.07 Hz) power and high frequency (HF, 0.07-0.6 Hz) power. Administration of atropine decreased parasympathetic nervous activity in a dose-dependent manner, affecting first the LF power, then the HF power and finally HR. These responses may provide valuable information for evaluating autonomic nervous activity in Thoroughbred horses.

Asymmetric catalytic ene-cyclization approach to 2-fluoro-19-nor-1,25-dihydroxyvitamin D(3) A-ring analog with significant transactivation activity

1alpha,25-Dihydroxyvitamin D(3) (1alpha,25(OH)2D3) has been shown to modulate not only proliferation and differentiation, but also apoptosis in malignant cells, indicating that it could be useful for the treatment of cancer and psoriasis. However, little information has been available on the binding conformation of the 1alpha,25(OH)2D3 molecule and its analogs with the vitamin D receptor (VDR). Therefore, we synthesized 2alpha-fluorinated A-ring analogs of 19-nor-1alpha,25(OH)2D3 in order to investigate the VDR-binding conformation of the A-rings on the basis of the (19)F NMR analysis. The 2alpha-fluoro-19-nor-1alpha,25-dihydroxyvitamin D3 A-ring analog thus synthesized via a asymmetric catalytic carbonyl-ene cyclization, shows significant activity in transactivation.