The increasing threat to European forests from the invasive foliar pine pathogen, Lecanosticta acicola.

European forests are threatened by increasing numbers of invasive pests and pathogens. Over the past century, Lecanosticta acicola, a foliar pathogen predominantly of Pinus spp., has expanded its range globally, and is increasing in impact. Lecanosticta acicola causes brown spot needle blight, resulting in premature defoliation, reduced growth, and mortality in some hosts. Originating from southern regions of North American, it devastated forests in the USA's southern states in the early twentieth century, and in 1942 was discovered in Spain. Derived from Euphresco project 'Brownspotrisk,' this study aimed to establish the current distribution of Lecanosticta species, and assess the risks of L. acicola to European forests. Pathogen reports from the literature, and new/ unpublished survey data were combined into an open-access geo-database (http://www.portalofforestpathology.com), and used to visualise the pathogen's range, infer its climatic tolerance, and update its host range. Lecanosticta species have now been recorded in 44 countries, mostly in the northern hemisphere. The type species, L. acicola, has increased its range in recent years, and is present in 24 out of the 26 European countries where data were available. Other species of Lecanosticta are largely restricted to Mexico and Central America, and recently Colombia. The geo-database records demonstrate that L. acicola tolerates a wide range of climates across the northern hemisphere, and indicate its potential to colonise Pinus spp. forests across large swathes of the Europe. Preliminary analyses suggest L. acicola could affect 62% of global Pinus species area by the end of this century, under climate change predictions. Although its host range appears slightly narrower than the similar Dothistroma species, Lecanosticta species were recorded on 70 host taxa, mostly Pinus spp., but including, Cedrus and Picea spp. Twenty-three, including species of critical ecological, environmental and economic significance in Europe, are highly susceptible to L. acicola, suffering heavy defoliation and sometimes mortality. Variation in apparent susceptibility between reports could reflect variation between regions in the hosts' genetic make-up, but could also reflect the significant variation in L. acicola populations and lineages found across Europe. This study served to highlight significant gaps in our understanding of the pathogen's behaviour. Lecanosticta acicola has recently been downgraded from an A1 quarantine pest to a regulated non quarantine pathogen, and is now widely distributed across Europe. With a need to consider disease management, this study also explored global BSNB strategies, and used Case Studies to summarise the tactics employed to date in Europe.

Nationwide investigation of Shiga toxin-producing Escherichia coli among cattle in Japan revealed the risk factors and potentially virulent subgroups.

A nationwide study of Shiga toxin-producing Escherichia coli (STEC) was performed to determine the prevalence, characteristics and risk factors for fecal shedding of STEC among cattle in Japan. Information on rearing practices was also collected to identify risk factors for fecal shedding of STEC. STEC was isolated from 24·1% of samples (133/551) collected from 59·1% of farms (65/110). Bayesian clustering using the virulence marker profiles of the isolates subdivided the isolates into four genetically distinct groups, two of which corresponded to eae- or saa-positive STEC, which can cause severe disease in human. Both STEC groups exhibited characteristic phylogeny and virulence marker profiles. It is noteworthy that the tellurite resistance gene was not detected in all saa-positive STEC isolates, suggesting that the standard isolation method using tellurite might lead to an underestimation of the prevalence of saa-positive STEC. A multivariate logistic regression model using epidemiological information revealed a significantly (P < 0·01) high odds ratio on STEC fecal shedding in tie-stall housing and a low odds ratio in flat feed box and mechanical ventilation. Information on isolate characteristics of the two major pathotypes and risk factors in rearing practices will facilitate the development of preventative measures for STEC fecal shedding from cattle.

Distribution of extended-spectrum cephalosporin resistance determinants in Salmonella enterica and Escherichia coli isolated from broilers in southern Japan.

This study was conducted to investigate the distribution and diversity of extended-spectrum cephalosporin (ESC) resistance determinants in Salmonella enterica and Escherichia coli obtained from the same cecal samples and to provide evidence of transmission of the resistance determinants among these bacteria in broiler farms in southern Japan. Salmonella enterica and E. coli were characterized by serotyping and multilocus sequence typing, respectively. An antimicrobial susceptibility test, plasmid analysis, and identification and localization of resistance genes were performed to determine the relatedness of ESC resistance determinants among the isolates. Of 48 flocks examined, 14 had S. enterica. In total, 57 S. enterica isolates were obtained, 45 of which showed ESC resistance. Extended-spectrum cephalosporin-resistant E. coli were also obtained from all of these ESC-resistant Salmonella-positive samples. ß-Lactamase genes, blaTEM-52 (38 isolates), blaCTX-M-14 (1 isolate), and blaCMY-2 (6 isolates), were carried by conjugative untypable or IncP plasmids detected in the S. enterica serovars Infantis and Manhattan. The ß-lactamase genes blaCTX-M-14 (3 isolates), blaCTX-M-15 (3 isolates), blaSHV-2 (1 isolate), blaSHV-12 (2 isolates), and blaCMY-2 (32 isolates) associated with IncI1-Iγ, IncFIB, IncFIC, IncK, IncB/O, and IncY plasmids were detected in E. coli co-isolates. Restriction mapping revealed similar plasmids in Salmonella Infantis and Salmonella Manhattan and in different sequence types of E. coli. Intraspecies transmission of plasmids was suggested within S. enterica and E. coli populations, whereas interspecies transmission was not observed. This study highlights the importance of plasmids as carriers of ESC resistance determinants.

Colonization of chicken flocks by Campylobacter jejuni in multiple farms in Japan.

Campylobacter jejuni was monitored in 4 chicken farms during the period 2003 to 2006 to elucidate the mechanisms of transmission. Three farms (1 to 3), located at least 14 km from each other, belonged to an integrated poultry company, which also provided the farms with day-old chicks from several hatcheries as well as chicken feed. Another farm (4), which belonged to a different company, was located 270 m from farm 1. A total of 206 C. jejuni isolates obtained from the 4 farms were classified into 10 flaA-based RFLP types. Identical RFLP types were found in isolates obtained from chickens originating from multiple hatcheries and reared in different chicken houses on individual farms. Flocks were colonized by strains with 1 or 2 RFLP types in each production cycle, sometimes differing between cycles. Identical RFLP types were found in isolates obtained from the environment around the chicken houses. Using multilocus sequence typing, strains with different RFLP types could be distinguished from each other. Identical RFLP and multilocus sequence typing profiles were found in isolates obtained from farms 1 and 4, and from farms 1 and 2. These results suggest that C. jejuni in these farms comes from common sources external to the farms, even if the farms belong to different companies and obtain chicks from different suppliers.

Photon number resolving SiPM detector with 1 GHz count rate.

We demonstrate 1 GHz count rate photon detection with photon number resolution by using a multi-pixel photon counter (MPPC) and performing baseline correction. A bare MPPC chip mounted on a high-frequency circuit board is employed to increase response speed. The photon number resolving capability is investigated at high repetition rates. This capability remains at a repetition rate of 1 GHz and at rates as high as an average of 2.6 photons detected per optical pulse. The photon detection efficiencies are 16% at λ = 450 nm and 4.5% at λ = 775 nm with a dark count rate of 270 kcps and an afterpulse probability of 0.007.

Source of N-nitrosodimethylamine in river waters of the upper Tone River basin in Japan.

The presence of N-nitrosodimethylamine (NDMA) in the Hirose River and its tributaries, located in the upper Tone River basin, in the Kanto region of Japan, was investigated. NDMA was detected at high levels in the Arato River, one of the tributaries of the Hirose River, at high concentrations (up to 2,100 ng/L). Due to the confluence of the Arato River, NDMA concentration in the Hirose River increased (up to 61 ng/L). The NDMA in the Arato River was due to industrial discharge from a livestock processing plant located near the river. There were three discharges at the plant, with NDMA concentrations of 78, 11, and 33,000 ng/L. The industrial discharges from the livestock processing plant did not contain significant amounts of NDMA precursors on chloramination. On the other hand, sewage effluent was shown to contain NDMA precursors. The amounts of NDMA precursors in the sewage effluent that were rapidly transformed into NDMA were considered to be lower than those slowly transformed into NDMA.

Evaluation of Papillomacular Nerve Fiber Bundle Thickness in Glaucoma Patients with Visual Acuity Disturbance.

PURPOSE: Assessing the papillomacular nerve fiber bundle (PMB) can identify glaucoma patients with decreased visual acuity. In this study, we explore efficient methods for evaluating PMB thickness in glaucoma patients, based on swept source-optical coherence tomography (SS-OCT). METHODS: This study included 347 eyes of 205 open-angle glaucoma (OAG) patients. Patients were excluded if they had best-corrected decimal visual acuity < 0.3, axial length >28 mm, non-glaucoma ocular disease, or systemic disease affecting the visual field. We obtained vertical 12.0 × 9.0 mm 3D volume scans covering both the macular and optic disc regions with SS-OCT (DRI OCT Triton, Topcon), and measured the thickness of the PMB, as well as average macular retinal nerve fiber layer thickness (mRNFLT) and macular ganglion cell complex thickness (mGCCT) in the macular map and temporal-quadrant circumpapillary RNFL thickness (tcpRNFLT). We also measured central-strip RNFLT (csRNFLT) and GCC (csGCCT) in a 1.5 × 6.6 mm area of the scan centered between the fovea and optic nerve head. CsRNFLT and csGCCT were divided lengthwise into three 1.5 × 2.2 mm sections. We then calculated Spearman's rank correlation coefficient between these OCT measurements and visual acuity. Logistic regression analysis was used to find the cutoff value for the OCT measurements to predict logMAR < 0. RESULTS: The correlation coefficients with logMAR were 0.38 for mRNFLT, 0.44 for mGCCT, 0.37 for middle csRNFLT, 0.50 for middle csGCCT, and 0.33 for tcpRNFLT (all P < .0001). For middle csGCCT, the area under the curve indicating decreased visual acuity was 0.80, with a cutoff value of 88.6 µm (P < .001). CONCLUSIONS: We found strong associations between OCT parameters in the PMB, especially middle csGCCT, and visual acuity in patients with OAG. The thickness of the PMB may therefore be valuable information for glaucoma care and may help prevent visual acuity disturbance.

Multipixel silicon avalanche photodiode with ultralow dark count rate at liquid nitrogen temperature.

Multipixel silicon avalanche photodiodes (Si APDs) are novel photodetectors used as silicon photomultipliers (SiPMs), or multipixel photon counter (MPPC), because they have fast response, photon-number resolution, and a high count rate; one drawback, however, is the high dark count rate. We developed a system for cooling an MPPC to liquid nitrogen temperature and thus reduce the dark count rate. Our system achieved dark count rates of <0.2 cps. Here we present the afterpulse probability, counting capability, timing jitter, and photon-number resolution of our system at 78.5 K and 295 K.

Development and evaluation of a reverse transcription-loop-mediated isothermal amplification assay for rapid and high-sensitive detection of Cryptosporidium in water samples.

We describe a novel assay for simple, rapid and high-sensitive detection of Cryptosporidium oocysts in water samples using a reverse transcription-loop-mediated isothermal amplification (RT-LAMP). The assay is based on the detection of 18S rRNA specific for Cryptosporidium oocysts. The detection limit of the developed RT-LAMP assay was as low as 6 x 10(-3) oocysts/test tube, which theoretically enables us to detect a Cryptosporidium oocyst and perform duplicated tests even if water samples contain only one oocyst. The developed RT-LAMP assay could more sensitively detect Cryptosporidium oocysts in real water samples than the conventional assay based on microscopic observation.

Sustained-Release Tacrolimus Stabilizes Decline of Forced Expiratory Volume in 1 Second Through Decreasing Fluctuation of Its Trough Blood Level.

BACKGROUND: Calcineurin inhibitors are a commonly used immunosuppressive drug and over 80% of lung transplant (LTx) recipients use tacrolimus. Sustained-release tacrolimus (SRT) was developed as a once-daily formulation, resulting in slower release and reduction in peak concentration compared with twice-daily immediate-release tacrolimus (IRT). Previous reports indicate that SRT may carry fewer side effects than IRT; however, the impact of SRT in bronchiolitis obliterans syndrome (BOS) after LTx is unclear. OBJECTIVE: Our study objective was to evaluate the effect of SRT in BOS after LTx. MATERIALS AND METHODS: We investigated the effect of SRT for BOS among 75 LTx recipients who were alive in 2017 in our LTx program. All analyses were carried out using student t test or F test. RESULTS: Thirty-five recipients took IRT, 32 recipients used SRT, 7 recipients used cyclosporine, and 1 patient who received bone marrow and a lung graft from the same donor did not use a calcineurin inhibitor. The most frequent reason for conversion of IRT to SRT was kidney dysfunction, followed by other IRT complications. Five recipients underwent conversion of IRT to SRT because of decline of forced expiratory volume in 1 second (FEV1) with fluctuation of the tacrolimus trough level. After induction of SRT, the fluctuation of the tacrolimus trough level was significantly reduced in 4 of 5 patients (P < .05). Before drug form conversion, the FEV1 in these 5 patients was significantly decreased; however, this exacerbation of FEV1 was attenuated after SRT induction (P < .05). CONCLUSION: SRT appeared to stabilize decline of FEV1 in patients with BOS possibly due to reducing the fluctuation of tacrolimus trough blood concentration.

Gonadotropin stimulates ovarian renin-angiotensin system in the rabbit.

The present study was undertaken to assess the role of ovarian renin-angiotensin system (RAS) in the preovulatory cascade induced by gonadotropin exposure. In the in vitro perfused rabbit ovaries, exposure to human chorionic gonadotropin (hCG) enhanced the secretion rate of angiotensin II (Ang II) within 1 h. The secretion rate reached maximal levels at 6 h and then declined thereafter. The intrafollicular Ang II content and renin-like activity were also significantly increased at 2 and 4 h after exposure to hCG, compared with control ovaries perfused with medium alone. The level of intrafollicular Ang II after hCG exposure significantly exceeded the concentration of Ang II in an equivalent volume of plasma. The addition of 1 microM captopril to the perfusate significantly inhibited the secretion rate of Ang II stimulated by hCG; however, captopril affected neither the ovulatory efficiency nor prostaglandin production in ovaries treated with hCG. Captopril significantly inhibited the resumption of meiosis in the ovulated ova and follicular oocytes stimulated by hCG. The administration of 100 micrograms Ang II at 2-h intervals to the perfusate reversed the inhibitory effects of captopril on hCG-induced oocyte maturation. In conclusion, these data indicate that gonadotropin stimulates renin-like activity and Ang II production in the rabbit ovary. Ovarian renin-angiotensin system may play an important role in the process of oocyte maturation after exposure to gonadotropin.

Low-noise and high-speed photodetection system using optical feedback with a current amplification function.

A photodetection system with an optical-feedback circuit accompanied by current amplification was fabricated to minimize the drawbacks associated with a transimpedance amplifier (TIA) with a very high resistance feedback resistor. Current amplification was implemented by extracting an output light from the same light source that emitted the feedback light. The current gain corresponds to the ratio of the photocurrent created by the output light to that created by the feedback light because the feedback current value is identical to the input photocurrent value generated by an input light to be measured. The current gain has no theoretical limit. The output light was detected by a photodiode with a TIA having a small feedback resistance. The expression for the input-referred noise current of the optical-feedback photodetection system was derived, and the trade-off between sensitivity and response, which is a characteristic of TIA, was found to considerably improve. An optical-feedback photodetection system with an InGaAs pin photodiode was fabricated. The measured noise equivalent power of the system was 1.7 fW/Hz(1/2) at 10 Hz and 1.3 µm, which is consistent with the derived expression. The time response of the system was found to deteriorate with decreasing photocurrent. The 50% rise time for a light pulse input increased from 3.1 µs at a photocurrent of 10 nA to 15 µs at photocurrents below 10 pA. The bandwidth of the input-referred noise current was 7 kHz, which is consistent with rise times below 10 pA.

Locally produced angiotensin II induces ovulation by stimulating prostaglandin production in in vitro perfused rabbit ovaries.

The present study was undertaken to investigate the role of exogenous and endogenous angiotensin II (Ang II) in ovarian steroidogenesis and production of prostaglandin (PG) in in vitro perfused rabbit ovaries. The addition of 100 or 10 micrograms Ang II at 2-h intervals to the perfusate did not stimulate progesterone production, but significantly stimulated estradiol (E2) production by perfused rabbit ovaries. When the specific antagonist of Ang II, saralasin at 2 x 10(-6) M, was added to the perfusate 30 min before the onset of Ang II administration, Ang II-stimulated production of E2 was significantly blocked. Ang II also significantly stimulated both PGE2 and PGF2 alpha production, while the addition of saralasin to the perfusate significantly inhibited the Ang II-stimulated production of PG. The levels of PGs in ovaries perfused with saralasin plus 100 micrograms Ang II did not differ significantly from those in control ovaries perfused with medium alone. Exposure to human CG (hCG) significantly stimulated production of progesterone and E2 by perfused rabbit ovaries, while the concomitant administration of 2 x 10(-6) M saralasin significantly reduced only E2 production. Addition of saralasin to the perfusate inhibited hCG-stimulated PG production in a dose-dependent manner. The ovulatory efficiency in ovaries treated with hCG alone or hCG plus saralasin was significantly correlated with PG production by perfused rabbit ovaries at 12 h after exposure to hCG. The production of PG stimulated by Ang II was completely reduced by indomethacin treatment during the entire perfusion period. Indomethacin completely blocked Ang II-induced ovulation, but not Ang II-stimulated oocyte maturation. Concurrent administration of staurosporine, a protein kinase C inhibitor, at 10(-6) M significantly inhibited Ang II-stimulated meiotic maturation of ovulated ova and follicular oocytes. In conclusion, these results indicate that Ang II has a direct role in ovarian production of E2 and PG. An intrinsic renin-angiotensin system in the rabbit ovary may act as an intermediary of gonadotropin-stimulated PG production. Locally produced Ang II may induce ovulation in the rabbit ovary, at least in part, by stimulating PG production.

Growth hormone stimulates follicular development by stimulating ovarian production of insulin-like growth factor-I.

The present study was undertaken to investigate the effects of GH on follicular growth, oocyte maturation, ovulation, and production of insulin-like growth factor-I (IGF-I) in the in vitro perfused rabbit ovaries. Ovulation did not occur in any ovaries perfused with GH at a concentration of 1, 10, 100, or 200 ng/ml, but the addition of GH to the perfusate increased the follicle diameter in a dose-dependent manner. The production of IGF-I by ovaries perfused with medium alone was very low throughout the perfusion period. The addition of 100 ng/ml GH to the perfusate significantly increased ovarian production of IGF-I at 4, 6, 8, and 12 h compared with the contralateral control ovaries. Changes in the tissue concentrations of IGF-I in ovaries perfused with 100 ng/ml GH paralleled those triggered by exposure to 50 IU human CG (hCG). When the effect of GH on the tissue concentration of IGF-I was determined at 4 h, GH stimulated the tissue concentration of IGF-I in perfused rabbit ovaries in a dose-dependent manner. The percent increase in follicle diameter in ovaries treated with GH was significantly correlated with the intraovarian IGF-I content. The mean number of ovulations per ovary and the ovulatory efficiency were significantly reduced in ovaries perfused with 5 IU hCG, compared with those in ovaries perfused with 50 IU hCG. The addition of 100 ng/ml GH to the perfusate significantly increased the ovulatory efficiency and follicle diameter in the 5 IU hCG-treated ovaries. Exposure to GH significantly stimulated the resumption of meiosis in the follicular oocytes compared with that in ovaries perfused with medium alone. Furthermore, GH significantly stimulated the resumption of meiosis in ovulated ova and follicular oocytes in ovaries treated with 5 IU hCG. Thus, exposure to GH-stimulated follicular growth, oocyte maturation, and production of IGF-I in the in vitro perfused rabbit ovaries, which indicates that the ovary is in fact a site of GH reception and action. Additionally, GH enhanced the effects of gonadotropins, acting synergistically to promote the ovulatory process. These observations suggest that GH may amplify gonadotropin actions in the process of follicular development and ovulation, at least in part, by stimulating ovarian IGF-I production.

Evidence for the in vivo formation of ascorbic acid 2-O-alpha-glucoside in guinea pigs and rats.

In vivo formation of ascorbic acid 2-O-alpha-glucoside (AA-2G) in guinea pigs and rats given ascorbic acid (AA) orally in combination with maltose was examined. A metabolite of AA which has the same HPLC retention characteristics as authentic AA-2G was detected in the blood, urine and liver of guinea pigs 1-2 hr after their administration. The metabolite was isolated from the urine by chromatographic procedures and identified as AA-2G by its UV spectrum, non-reducibility, susceptibility to alpha-glucosidase hydrolysis, HPLC profile and elementary analysis. The same glucoside was also synthesized by rats and found in the urine, although it could not be determined qualitatively in the blood. AA-2G-forming activities of tissue homogenates from both animals were apparently correlated with their alpha-glucosidase activities and, moreover, both activities were completely inhibited by a specific neutral alpha-glucosidase inhibitor. Thus, we conclude that AA-2G is a possible metabolite produced by enzymatic alpha-glucosidation after a combined administration of AA and maltose to guinea pigs and rats.

Clonal turnover of enterohemorrhagic Escherichia coli O157:H7 in experimentally infected cattle.

A total of 401 enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates from two experimentally infected calves were analyzed using molecular biological methods. Genetic differences detected by pulsed-field gel electrophoresis were observed between the inoculated and recovered strains as early as 1 day post inoculation. The loss of the inoculated clone was observed in one calf. Replication and dissemination of the EHEC O157:H7 strains that mutated in cattle may result in the diversification of this organism among cattle populations.

Comparative study of hormonal dynamics in pregnant and nonpregnant cycles during pulsatile subcutaneous administration of human menopausal gonadotropin in anovulatory infertile women.

OBJECTIVE: To assess the clinical relevance of daily hormonal changes for achieving a successful pregnancy in anovulatory infertile women. DESIGN: A comparative study of hormonal dynamics in pregnant and nonpregnant cycles during the pulsatile subcutaneous administration of hMG. Subjects received subcutaneous injection of either 9.375 IU or 14.0625 IU of hMG diluted in 50-microL physiological saline (total daily dose, 150 or 225 IU) at 90-minute intervals by means of a portable peristaltic pump. SETTING: Kyorin University Hospital and Ichikawa General Hospital. PATIENTS: We analyzed 18 pregnant and 42 nonpregnant cycles in 17 patients with secondary hypothalamic/pituitary amenorrhea who conceived after receiving pulsatile hMG treatment. Another 14 women with normal spontaneous ovulation, including 14 pregnant and 15 nonpregnant cycles, served as controls. MEASUREMENTS: Serum concentrations of LH, FSH, E2, and P were measured, and the P:E2 ratio was determined. RESULTS: Serum concentrations of LH and FSH did not differ significantly between the pregnant and nonpregnant cycles. Serum levels of P and E2 were significantly higher during the hMG treatments than those of the spontaneous ovulatory cycles throughout the follicular and luteal phases. Up to the midluteal phase, the P and E2 values in the nonpregnant cycles during the hMG treatments did not differ significantly from those in the pregnant cycles. The P:E2 ratios were comparable between the pulsatile stimulatory cycles and the normal spontaneous ovulatory cycles. However, the P:E2 ratio in the early and midluteal phases was significantly greater in the pregnant cycles than in the nonpregnant cycles. CONCLUSION: The P:E2 ratio in the early and midluteal phases is a more important indicator of hormonal function for implantation than the absolute levels of either P or E2.

Effects of synthetic and naturally occurring flavonoids on Na+,K+-ATPase: aspects of the structure-activity relationship and action mechanism.

A comparative study was made of the effects of 15 synthetic and naturally occurring flavonoids on the hydrolytic activity of Na+, K+-adenosine triphosphatase (ATPase). Twelve of the flavonoids examined were mono-hydroxy or mono-methoxy derivatives. All inhibited Na+, K+-ATPase from dog kidney cortex when present at concentrations from 40-1000 microM. Flavones possessing cyclohexyl instead of the phenyl group (i.e., 2-cyclohexyl-benzopyran-4-one derivatives), were the most potent with IC50 at 257-320 microM. Structure-activity relationships were observed among the following mono-substituted flavones as: i) 2-cyclohexyl-benzopyran-4-one much greater than 2-phenyl-benzopyran-4-one; ii) 2-cyclohexyl-7-hydroxybenzopyran-4-one greater than 2-cyclohexyl-6-hydroxybenzopyran-4-one greater than 2-cyclohexyl-5-hydroxybenzopyran-4-one. Some flavonoids showing potent inhibitory activity were also examined for ouabain-displacement activity on human erythrocytes. Hardly any of the flavonoids were able to block [3H]ouabain binding to erythrocytes. These results suggest that the mechanism by which flavonoid block Na+, K+-ATPase is not related to the cardiac glycoside-specific binding site(s) of this enzyme.

Effects of synthetic and naturally occurring flavonoids on mitogen-induced proliferation of human peripheral-blood lymphocytes.

Examination was made of the effects of 17 synthetic and naturally occurring flavonoids on human lymphocyte proliferation in the presence of concanavalin A as a mitogen. Twelve of the flavonoids examined were mono-hydroxy or methoxy derivatives. The mitogen-induced response of lymphocytes was evaluated from the extent of the incorporation of [3H]thymidine into cells in vitro. All the compounds showed inhibitory effects; 4.5-77.7% of [3H]thymidine incorporation was blocked by an 1.0 micrograms/ml concentration. The viability of lymphocytes before and after treatment, as assessed by a dye exclusion test, indicated no change, and thus the flavonoids may inhibit DNA synthesis. The flavonoids possessing 5-hydroxyl, 5-methoxyl and 6-methoxyl groups, and those with cyclohexyl instead of phenyl substituent (i.e. 2-cyclohexyl-benzopyran-4-one), showed the greatest inhibition. The inhibitory effect of any one of them was less than one half that of prednisolone, but essentially the same or somewhat exceeding that of bredinine or azathioprine. It would thus appear that the well-known anti-inflammatory effects of flavonoids may possibly arise in part from the inhibition of the proliferative response of lymphocytes.

High-speed recovery of germanium in a convection-aided mode using functional porous hollow-fiber membranes.

A porous hollow-fiber membrane capable of recovery of germanium from a liquid stream was prepared by radiation-induced graft polymerization of an epoxy-group-containing vinyl monomer, glycidyl methacrylate, and subsequent functionalization with 2,2'-iminodiethanol, di-2-propanolamine, N-methylglucamine, and 3-amino-1,2-propanediol. The functional group density was as high as 1.4 mol per kg of the resultant hollow fiber. The polymer chains containing functional groups surrounding the pores enabled a high-speed recovery of germanium during permeation of a germanium oxide (GeO2) solution through the pores of the hollow fiber. Because of a negligible diffusional mass-transfer resistance, germanium concentration changes with the effluent volume, i.e., breakthrough curves, overlapped irrespective of the residence time of the solution, which ranged from 0.37 to 3.7 s across the hollow fiber. After repeated use of adsorption and elution, the adsorption capacity did not deteriorate.