Demonstration of nuclear gamma-ray polarimetry based on a multi-layer CdTe Compton camera.

To detect and track structural changes in atomic nuclei, the systematic study of nuclear levels with firm spin-parity assignments is important. While linear polarization measurements have been applied to determine the electromagnetic character of gamma-ray transitions, the applicable range is strongly limited due to the low efficiency of the detection system. The multi-layer Cadmium-Telluride (CdTe) Compton camera can be a state-of-the-art gamma-ray polarimeter for nuclear spectroscopy with the high position sensitivity and the detection efficiency. We demonstrated the capability to operate this detector as a reliable gamma-ray polarimeter by using polarized 847-keV gamma rays produced by the [Formula: see text]([Formula: see text]) reaction. By combining the experimental data and simulated calculations, the modulation curve for the gamma ray was successfully obtained. A remarkably high polarization sensitivity was achieved, compatible with a reasonable detection efficiency. Based on the obtained results, a possible future gamma-ray polarimetery is discussed.

In-process monitoring of a tissue-engineered oral mucosa fabricated on a micropatterned collagen scaffold: use of optical coherence tomography for quality control.

Background: We previously reported a novel technique for fabricating dermo-epidermal junction (DEJ)-like micropatterned collagen scaffolds to manufacture an ex vivo produced oral mucosa equivalent (EVPOME) for clinical translation; however, more biomimetic micropatterns are required to promote oral keratinocyte-based tissue engineering/regenerative medicine. In addition, in-process monitoring for quality control of tissue-engineered products is key to successful clinical outcomes. However, evaluating three-dimensional tissue-engineered constructs such as EVPOME is challenging. This study aimed to update our technique to fabricate a more biomimetic DEJ structure of oral mucosa and to investigate the efficacy of optical coherence tomography (OCT) in combination with deep learning for non-invasive EVPOME monitoring. Methods: A picosecond laser-textured microstructure mimicking DEJ on stainless steel was used as a negative mould to fabricate the micropatterned collagen scaffold. During EVPOME manufacturing, OCT was applied twice to monitor the EVPOME and evaluate its epithelial thickness. Findings: Our moulding system resulted in successful micropattern replication on the curved collagen scaffold. OCT imaging visualised the epithelial layer and the underlying micropatterned scaffold in EVPOME, enabling to non-invasively detect specific defects not found before the histological examination. Additionally, a gradual increase in epithelial thickness was observed over time. Conclusion: These findings demonstrate the feasibility of using a stainless-steel negative mould to create a more biomimetic micropattern on collagen scaffolds and the potential of OCT imaging for quality control in oral keratinocyte-based tissue engineering/regenerative medicine.

Semisupervised Deep State-Space Model for Plant Growth Modeling.

The optimal control of sugar content and its associated technology is important for producing high-quality crops more stably and efficiently. Model-based reinforcement learning (RL) indicates a desirable action depending on the type of situation based on trial-and-error calculations conducted by an environmental model. In this paper, we address plant growth modeling as an environmental model for the optimal control of sugar content. In the growth process, fruiting plants generate sugar depending on their state and evolve via various external stimuli; however, sugar content data are sparse because appropriate remote sensing technology is yet to be developed, and thus, sugar content is measured manually. We propose a semisupervised deep state-space model (SDSSM) where semisupervised learning is introduced into a sequential deep generative model. SDSSM achieves a high generalization performance by optimizing the parameters while inferring unobserved data and using training data efficiently, even if some categories of training data are sparse. We designed an appropriate model combined with model-based RL for the optimal control of sugar content using SDSSM for plant growth modeling. We evaluated the performance of SDSSM using tomato greenhouse cultivation data and applied cross-validation to the comparative evaluation method. The SDSSM was trained using approximately 500 sugar content data of appropriately inferred plant states and reduced the mean absolute error by approximately 38% compared with other supervised learning algorithms. The results demonstrate that SDSSM has good potential to estimate time-series sugar content variation and validate uncertainty for the optimal control of high-quality fruit cultivation using model-based RL.

Prediction of surgical difficulty in minimally invasive surgery for rectal cancer by use of MRI pelvimetry.

BACKGROUND: Technical difficulties in rectal surgery are often related to dissection in a limited surgical field. This study investigated the clinical value of MRI pelvimetry in the prediction of surgical difficulty associated with minimally invasive rectal surgery. METHODS: Patients with rectal cancer who underwent laparoscopic or robotic total mesorectal excision between 2005 and 2017 were reviewed retrospectively and categorized according to surgical difficulty on the basis of duration of surgery, conversion to an open procedure, use of the transanal approach, postoperative hospital stay, blood loss and postoperative complications. Preoperative clinical and MRI-related parameters were examined to develop a prediction model to estimate the extent of surgical difficulty, and to compare anastomotic leakage rates in the low- and high-grade surgical difficulty groups. Prognosis was investigated by calculating overall and relapse-free survival, and cumulative local and distant recurrence rates. RESULTS: Of 121 patients analysed, 104 (86·0 per cent) were categorized into the low-grade group and 17 (14·0 per cent) into the high-grade group. Multivariable analysis indicated that high-grade surgical difficulty was associated with a BMI above 25 kg/m2 (odds ratio (OR) 4·45, P = 0·033), tumour size 45 mm or more (OR 5·42, P = 0·042), anorectal angle 123° or more (OR 5·98, P = 0·028) and pelvic outlet less than 82·7 mm (OR 6·62, P = 0·048). All of these features were used to devise a four-variable scoring model to predict surgical difficulty. In patients categorized as high grade for surgical difficulty, the anastomotic leakage rate was 53 per cent (9 of 17 patients), compared with 9·6 per cent (10 of 104) in the low-grade group (P < 0·001). The high-grade group had a significantly higher local recurrence rate than the low-grade group (P = 0·002). CONCLUSION: This study highlights the impact of clinical variables and MRI pelvimetry in the prediction of surgical difficulty in minimally invasive rectal surgery.

ANTECEDENTES: Las dificultades técnicas en la cirugía del recto a menudo están relacionadas con la disección en un campo quirúrgico limitado. Este estudio se propuso investigar la utilidad clínica de la pelvimetría con MRI para predecir la dificultad quirúrgica asociada con la cirugía mínimamente invasiva del recto. MÉTODOS: Pacientes con cáncer de recto sometidos a resección total del mesorrecto laparoscópica o robótica entre 2005 y 2017 fueron revisados retrospectivamente y categorizados de acuerdo con la dificultad técnica en base al tiempo operatorio, conversión, uso de abordaje transanal, estancia hospitalaria postoperatoria, pérdida sanguínea y complicaciones postoperatorias. Se examinaron parámetros clínicos preoperatorios y relacionados con la MRI para desarrollar un modelo de predicción que estimara el grado de dificultad técnica y pudiera comparar la tasa de dehiscencias anastomóticas en los grupos de bajo y alto riesgo. También se evaluó el pronóstico con el cálculo de la supervivencia global, supervivencia libre de recidiva y tasas acumuladas de recidiva local y a distancia. RESULTADOS: De un total de 121 pacientes analizados, 104 pacientes (85,9%) fueron categorizados en el grupo con bajo grado de dificultad técnica, mientras que 17 pacientes (14,1%) lo fueron en el grupo de alto grado. En el análisis multivariable, un alto grado de dificultad técnica se asociaba con un índice de masa corporal (body mass index, BMI) > 25 kg/m2 (razón de oportunidades, odds ratio (OR), 4,5; P = 0,033), tamaño tumoral ≥ 45 mm (OR, 5,4; P = 0,042), ángulo anorrectal ≥ 123 grados (OR, 6,0; P = 0,028), estrecho pélvico < 82,7 mm (OR, 6,6; P = 0,048); en consecuencia, todas estas características fueron utilizadas para establecer un modelo de puntuación con 4 variables que pudiera predecir la dificultad técnica. En los pacientes categorizados como de alto grado de dificultad técnica, la tasa de dehiscencia anastomótica fue del 52,9%, mientras que en el grupo de bajo grado fue del 9,6% (P < 0,001). Finalmente, el grupo con alto grado mostró una tasa significativamente más elevada de recidiva local en comparación con el grupo de bajo grado (P = 0,002). CONCLUSIÓN: Este estudio pone de relieve el impacto de variables clínicas y de la pelvimetría con MRI para predecir la dificultad técnica en la cirugía mínimamente invasiva del recto.

Relationship between frontal craniofacial morphology and horizontal balance of lip-closing forces during lip pursing.

The objectives of this study were to quantitatively evaluate the relationship between frontal craniofacial morphology and the horizontal balance of the lip-closing forces (LCF) generated during maximum voluntary pursing-like movements in patients with mandibular deviation. Thirty-one subjects (median age 25·4 ± 8·9 years) without a history of orthodontic treatment were randomly selected from among the orthodontic patients who visited our hospital. Lip-closing forces was recorded in eight directions during maximum voluntary pursing-like lip-closing movements. The subjects were divided into the deviation (two males and 11 females) and non-deviation groups (four males and 14 females). There was no significant difference in the total LCF between the deviation and non-deviation groups. In the deviation group, the mean LCF value on the deviation side of the upper lip was significantly lower than that detected on the non-deviation side of the upper lip, while the mean LCF value for the deviation side of the lower lip was significantly higher than that for the non-deviation side of the lower lip. In contrast, no significant difference in upper or lower lip LCF was detected between the deviation and non-deviation sides in the non-deviation group. The difference in the LCF generated in the lower lip between the deviation and non-deviation sides was significantly positively correlated with mandibular menton deviation and significantly negatively correlated with the difference in maxillary height between the deviation and non-deviation sides. These results suggest that the horizontal balance of the upper and lower lip LCF produced during pursing-like lip-closing movements in patients with mandibular deviation is related to frontal craniofacial morphology.

An abscess mimicking a left incarcerated groin hernia.

We present the case of a 79-year-old man with an irreducible and painful left groin mass. Obtaining a detailed history of present illness and assessment of radiological findings revealed an abscess in a groin hernia sac, which was formed secondary to perforation of the descending colon. Various examinations, however, failed to reveal the cause of the bowel perforation. Percutaneous drainage improved his symptoms. He was discharged home 24 days after admission with no further sequelae. An abscess in a groin hernia sac is very rare. Although neither bowel perforation nor hernia is rare, surgeons do not sufficiently consider the possibility of an abscess in a groin hernia sac. Thus, surgeons often encounter unexpected abscesses in the groin hernia sac during operations. Our case points to the necessity of obtaining a detailed history of present illness as well as assessment of radiological findings, and presents a therapeutic option for an abscess in a groin hernia sac.

Depressed recovery of subendocardial perfusion in persistent heart failure after complete revascularisation in diabetic patients with hibernating myocardium.

OBJECTIVES: To investigate the relation between myocardial perfusion and heart failure (HF) status after revascularisation in patients with HF due to hibernating myocardium (HM) in diabetic and non-diabetic subjects. METHODS: 31 diabetic and 33 non-diabetic subjects with HF due to HM, who were already scheduled for complete revascularisation, were studied. Before and after revascularisation, left ventricular function and regional perfusion in subendocardial and subepicardial portions of the left ventricular wall were evaluated. RESULTS: Before revascularisation, left ventricular function and regional perfusion were similar in diabetic and non-diabetic subjects. At 6 months after revascularisation, subepicardial perfusion was markedly improved both in diabetic and non-diabetic subjects. However, subendocardial perfusion was markedly improved only in non-diabetic subjects and was little changed in diabetic patients. Thus, subendocardial perfusion was much lower in diabetic than non-diabetic subjects. Left ventricular function was improved more in non-diabetic than in diabetic subjects. Persistent HF was found much more often in diabetic than non-diabetic subjects. At multivariate analysis, subendocardial perfusion at 6 months independently contributed to persistent HF. CONCLUSIONS: This study describes the intramural heterogeneity of recovery of myocardial perfusion with depressed improvement in the subendocardial portion and its relation with persistent HF after complete revascularisation in diabetic patients with HF due to HM.

PCB contamination assessment of yusho patients by using preserved human umbilical cord.

PCB concentrations in umbilical cord preserved from the time when Yusho patients and healthy subjects gave birth were examined. The total concentration of the 12 DL-PCB isomers ranged from 130 to 12,000 pg/g in the umbilical samples, was about 700 pg/g around 1950 but began to increase in the mid 1960s, reached about 12,000 pg/g between 1968 and 1970 immediately after the Yusho incident. However, the DL-PCB concentration was high between 1968 and 1970 in not only the designated Yusho patients but also healthy subjects, and the maximum DL-PCB concentration was close between the two groups.

Properties of milk protein gels formed by phosphates.

We investigated the properties of gels that were formed by adding emulsifying salts, such as tetrasodium pyrophosphate (TSPP), to reconstituted milk protein concentrate solution. The pH of a 51 g/L milk protein concentrate solution was adjusted to 5.8 after adding TSPP. Milk protein concentrate solutions were placed in glass jars and allowed to stand at 25 degrees C for 24 h. Gels with the highest breaking force were formed when TSPP was added at a concentration of 6.7 mM, whereas no gel was formed when TSPP was added at concentrations of < or =2.9 or > or =10.5 mM. Several other phosphate-based emulsifying salts were tested but for these emulsifying salts, gelation only occurred after several days or at greater gelation temperatures. No gelation was observed for trisodium citrate. Gelation induced by TSPP was dependent on pH, and the breaking force of gel was greatest at pH 6.0. Furthermore, when the concentration of milk protein concentrate in solution was increased to 103 g/L, the breaking force of the gel increased, and a clearly defined network between caseins could be observed by using confocal scanning laser microscopy. These results suggest that TSPP-induced gelation occurs when the added TSPP acts with calcium as a cross-linking agent between dispersed caseins and when the balance between (a reduced) electrostatic repulsion and (enhanced) attractive (hydrophobic) interactions becomes suitable for aggregation and eventual gelation of casein molecules.

Effects of two types of emulsifying salts on the functionality of nonfat pasta filata cheese.

Effects of 2 types of emulsifying salts (ES) on the functionality of nonfat pasta filata cheese were examined. Nonfat pasta filata cheese was made from skim milk by direct acidification. Trisodium citrate (TSC) and tetrasodium pyrophosphate (TSPP) were added to curds (at 1, 3, and 5%, wt/wt) at the dry-salting step, together with glucono-delta-lactone to maintain a constant pH. When TSC was added, there were no significant compositional differences, although insoluble Ca and P contents significantly decreased with the addition of TSC. When TSPP was added, fat content was not significantly different, but protein content decreased with increasing concentrations of TSPP. Both insoluble Ca and P contents increased with the addition of 1% TSPP. The addition of ES affected textural and functional properties. With increasing concentrations of TSC, meltability increased, whereas increasing the TSPP content decreased meltability. Cheese made with 1% TSC had better stretchability compared with control cheese. However, the addition of more than 3% TSC decreased stretchability. Addition of TSPP caused a considerable decrease in stretchabilty. Scanning electron microscopy revealed that the size and number of serum pockets decreased and protein appeared more hydrated with the addition of both ES. These results suggested that TSC and TSPP influenced the functionality of nonfat pasta filata cheese differently; that is, the effects of TSC were probably caused by a decrease in the number of colloidal calcium phosphate cross-links and an increase in electrostatic repulsion, whereas the effects of TSPP may have been related to the formation of new TSPP-induced casein-casein interactions.

Effects of emulsifying salts on the turbidity and calcium-phosphate-protein interactions in casein micelles.

Influence of emulsifying salts (ES) on some physical properties of casein micelles was investigated. A reconstituted milk protein concentrate (MPC) solution (5% wt/wt) was used as the protein source and the effects of ES [0 to 2.0% (wt/wt)] were estimated by measuring turbidity, acid-base titration curves and amount of casein-bound Ca and inorganic P (P(i)). Various ES, trisodium citrate (TSC), or sodium phosphates (ortho-, pyro-, or hexameta-) were added to MPC solution, and all samples were adjusted to pH 5.8. Acid-base buffering curves were used to observe changes in the amount and type of insoluble Ca phosphates. An increase in the concentration of TSC added to MPC solution decreased turbidity, buffering at pH approximately 5 (contributed by colloidal Ca phosphate), and amount of casein-bound Ca and P(i). Addition of up to 0.7% disodium orthophosphate (DSP) did not significantly influence turbidity, buffering curves, or amount of casein-bound Ca and P(i). When higher concentrations (i.e., > or =1.0%) of DSP were added, there was a slow decrease in turbidity. With increasing concentration of added tetrasodium pyrophosphate (TSPP), turbidity and buffering at pH approximately 5 decreased, and amount of casein-bound Ca and P(i) increased. When small concentrations (i.e., 0.1%) of sodium hexameta-phosphate were added, effects were similar to those when TSPP were added but when higher concentrations (i.e., > or =0.5%) were added, the buffering peak shifted to a higher pH value, and amount of casein-bound Ca and P(i) decreased. These results suggested that each type of ES influenced casein micelles by different mechanisms.

Akt activation in renal cell carcinoma: contribution of a decreased PTEN expression and the induction of apoptosis by an Akt inhibitor.

BACKGROUND: Akt has been implicated in the oncogenesis of human malignant tumors, because Akt regulates many key effector molecules involved in cell survival. PTEN (phosphatase and tensin homolog deleted on chromosome 10) negatively regulates Akt activation. MATERIALS AND METHODS: The expression of phosphorylated Akt (p-Akt), total Akt and PTEN was analyzed by Western blotting in 45 renal cell carcinoma (RCC) patients. The Bad and phosphorylated Bad (p-Bad) statuses were analyzed in 20 RCC patients. A phosphatidylinositol ether analog was used as an Akt inhibitor to treat four RCC cell lines, namely Caki-1, KU19-20, SW839 and Caki-2. RESULTS: The PTEN expression in RCC was observed to decrease and p-Akt expression to increase significantly in comparison with that in the corresponding normal kidney tissue. The PTEN expression inversely correlated with the p-Akt expression. These alterations were specific for clear cell type RCC, but not for papillary or chromophobe type RCC. Alterations in Bad phosphorylation were also specifically observed in clear cell type. The Akt inhibitor induced apoptosis in KU19-20 and Caki-2 cells with a high Akt activity. CONCLUSIONS: A decreased expression of PTEN may be an underlying mechanism for Akt activation. An Akt inhibitor may be a therapeutic option for a subset of RCC with an elevated Akt activity.

Inhibition of Wnt signaling downregulates Akt activity and induces chemosensitivity in PTEN-mutated prostate cancer cells.

BACKGROUND: The cross-talk between Wnt signaling and the Akt pathway in prostate cancer (Pca) is still unclear. In the present study, we found that WIF-1 downregulates the Akt pathway and also enhances chemosensitivity in PTEN-null Pca cells. METHODS: Wnt inhibitory factor-1 (WIF-1), an inhibitor of Wnt proteins, was transfected into PC-3 and DU145 Pca cells. RESULTS: Akt was phosphorylated in PTEN-null PC-3 cells but underphosphorylated in PTEN-expressed DU145 cells. The levels of phosphorylated Akt in WIF-1 overexpressing PC-3 cells were lower than those in native or control vector-transfected PC-3 cells. However, WIF-1 showed no additional inhibition of already reduced Akt activity in DU145 cells. Overexpression of WIF-1 resulted in sensitizing PC-3 cells for paclitaxel to induce apoptosis. DU145 cells were more sensitive to paclitaxel but were not affected by WIF-1 transfection. The PI3K inhibitor LY294002 seemed to restore the chemosensitivity of native PC-3 cells like WIF-1 did. CONCLUSIONS: Our results show that Wnt signaling is involved in Akt activation in Pca cells. Our data also indicate the possibility that Wnt and its signaling pathway can be therapeutic targets for PTEN-mutated advanced Pca.

Use of an otolith-deficient mutant in studies of fish behavior in microgravity.

The mutant strain (ha) of medaka (Oryzias latipes) lack utricular otoliths as fry, and some never form otoliths for life. The cross (F1 generation) between the strain having good eyesight and another strain having ordinary eyesight augmented visual acuity of the F1 generation. Crossing the good eyesight strain and ha mutant produced fish having good eyesight and less sensitivity to gravity in the F2 population. Their tolerance to microgravity was tested by parabolic flight using an airplane. The fish exhibited less looping and no differences in degree of looping between light and dark conditions, suggesting that loss of eyesight (in darkness) is not a direct cause for looping behavior in microgravity. The ha embryos could not form utricular otoliths. They did form saccular otoliths, but with a delay. Fry of the mutant fish lacking the utricular otoliths are highly dependent on light upon hatching and exhibit a perfect dorsal-light response (DLR). As they grow, they eventually shift from being light-dependent to being gravity-dependent. Continuous treatment of the fry with altered light direction suppressed this shift to gravity dependence. Being less dependent on gravity, these fish can serve as models in studying the differences expected for the vestibular system of fish reared in microgravity. When these fish were exposed to microgravity (parabolic flights) of an airplane, they spent far less time looping than fish reared in an ordinary light regimen.

Otolith formation in a mutant Medaka with a deficiency in gravity-sensing.

Mutant Medaka ha exhibit spontaneous mutation that is characterized by frequent inhibition or perturbation in the formation of utricular otoliths and/or semicircular canals. Three major features of otolith morphogenesis were observed in ha strain: 1) The initial appearance of otoliths was delayed, mispositioned, and malformed compared to normal embryos. 2) No utricular otoliths appeared on macula of any ha fry just after hatching. A symmetric state of otoliths was seen only when saccular otoliths were situated on macula in both inner ears. 3) In some fry, formation of utricular otoliths was observed in their later development. However, no new utricular otoliths appeared after fish were seventy or more days old after hatching. These observations show that otolith morphogenesis in ha is very different from that of wild-type. In this study, we classified adult ha into four different phenotypes using the existence or absence of utricular otoliths as our criteria. We concluded that dysfunction of utricular otoliths and semicircular canals cause a defect that affects the gravity-sensing abilities of medaka ha.

Aquatic animal research in space station and its issues--focus on support technology on nitrate toxicity.

We studied the effects of accumulated nitrate in water on the spawning, hatching and development of medaka using a simple nitrifying filter and a combined filter having both nitrifying and denitrifying capabilities. A nitrate concentration of 100 mg NO3(-)-N/L was clearly of lethal toxicity to fish when they were exposed to nitrate in both adult and the growing phases. A nitrate concentration of 75 mg NO3(-)-N/L reduced the fertilization rate, delayed the hatching time and reduced the hatching rate of the eggs laid by adults and decreased the growth rate of juveniles. In addition, nitrate accumulations as low as 50 mg NO3(-)-N/L remarkably retarded spawning and lowered the number of eggs laid by fish exposed in the juvenile phase. The effects on the reproduction system may be initiated by a low concentration, approximately 30 mg NO3(-)-N/L.

Myocardial ultrasonic tissue characterization for estimating histological abnormalities in hypertrophic cardiomyopathy: comparison with endomyocardial biopsy findings.

AIMS: In this study, we investigated the clinical usefulness of ultrasonic tissue characterization with integrated backscatter for the evaluation of myocardial histological abnormalities in comparison with endomyocardial biopsy findings in patients with hypertrophic cardiomyopathy. METHODS: Twenty patients with hypertrophic cardiomyopathy and 20 normal subjects were enrolled in this study. We measured two parameters for the ultrasonic tissue characterization with integrated backscatter: the magnitude of the cardiac-cycle-dependent variation in integrated backscatter signals (cdv-IB) and the mean value of integrated backscatter signals calibrated by the pericardium (cal-IB). These parameters were measured at both the interventricular septum and the left ventricular posterior wall. Histological findings of right ventricular endomyocardial biopsy specimens were analyzed by computer image analyzer. RESULTS: cdv-IB was significantly lower and cal-IB significantly higher in both the interventricular septum and the left ventricular posterior wall in patients with hypertrophic cardiomyopathy compared with normal subjects. In patients with hypertrophic cardiomyopathy, the degree of myocardial disarray, interstitial fibrosis, and nonhomogeneity of myocyte size showed positive correlations with cal-IB and negative correlations with cdv-IB. CONCLUSIONS: Ultrasonic tissue characterization with IB enables the noninvasive evaluation of myocardial histological abnormalities in patients with hypertrophic cardiomyopathy.

B16-BL6 melanoma cells release inhibitory factor(s) of active pump activity in isolated lymph vessels.

We investigated whether supernatant cultured with melanoma cell lines B16-BL6 and K1735 or the Lewis lung carcinoma cell line (LLC) can regulate lymphatic pump activity with bioassay preparations isolated from murine iliac lymph vessels. B16-BL6 and LLC supernatants caused significant dilation of lymph microvessels with cessation of pump activity. B16-BL6 supernatant produced dose-related cessation of lymphatic pump activity. There was no significant tachyphylaxis in the supernatant-mediated inhibitory response of lymphatic pump activity. Pretreatment with 3 x 10(-5) M N(omega)-nitro-L-arginine methyl ester (L-NAME) or 10(-7) M or 10(-6) M glibenclamide and 5 x 10(-4) M 5-hydroxydecanoic acid caused significant reduction of supernatant-mediated inhibitory responses. Simultaneous treatment with 10(-3) M L-arginine and 3 x 10(-5) M L-NAME significantly lessened L-NAME-induced inhibition of the supernatant-mediated response, suggesting that endogenous nitric oxide (NO) plays important roles in supernatant-mediated inhibitory responses. Chemical treatment dialyzed substances of <1,000 molecular weight (MW), producing complete reduction of the supernatant-mediated response. In contrast, pretreatment with heating or digestion with protease had no significant effect on supernatant-mediated response. These findings suggest that B16-BL6 cells may release nonpeptide substance(s) of <1,000 MW, resulting in significant cessation of lymphatic pump activity via production and release of endogenous NO and activation of mitochondrial ATP-sensitive K(+) channels.

Electron transport inhibitor in Cyperus javanicus.

The natural quinone, hydroxydietrichequinone (3-heptadec-8-enyl-2-hydroxy-5-methoxy-[1,4]benzoquinone) is a secondary metabolite of Cyperus javanicus. We found that this quinone inhibited both mitochondrial respiration and photosynthesis in their electron transportation systems. The quinone was found to have a mode of action against the ubiquinone reductase site from the results of different electron donor experiments on intact mitochondria from rat liver. The electron transport system, photosystem-II (PS-II), in chroloplast from spinach leaves was inhibited by the quinone in a similar way to that of the triazin sires herbicide, atrazin, with its mode of action against PS II. This natural quinone has a long aliphatic chain (C17) including an unsaturated bond at its midpoint. We recognized 8-9 unsaturated bonds in the aliphatic chain from an MS analysis of the methylthio-addact, and spectral data presumed a configuration of cis. form.